AUTHOR OF THIS BLOG

DR ANTHONY MELVIN CRASTO, WORLDDRUGTRACKER

Deltamethrin an agrochemical can help control Malaria

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Oct 272014
 

Deltamethrin

 

Deltamethrin

Deltamethrin is a pyrethroid ester insecticide.

: AC1O570W; NRDC-161; 52918-63-5; FMC-45498; ZINC01532093; RU 23938; UNII-26515THS0L component OWZREIFADZCYQD-BJLQDIEVSA-N

CAS : 52918-63-5
CAS Name: (1R,3R)-3-(2,2-Dibromoethenyl)-2,2-dimethylcyclopropanecarboxylic acid (S)-cyano(3-phenoxyphenyl)methyl ester
Additional Names: (S)-a-cyano-3-phenoxybenzyl-(1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylate; decamethrin; esbecythrin
Manufacturers’ Codes: FMC-45498; NRDC-161; RU-22974
Trademarks: Butox (Intervet); Decis (Bayer CropSci.); K-Othrine (Bayer CropSci.); Scalibor (Intervet)
Molecular Formula: C22H19Br2NO3
Molecular Weight: 505.20
Percent Composition: C 52.30%, H 3.79%, Br 31.63%, N 2.77%, O 9.50%
Properties: Crystals, mp 98-101°. Sol in ethanol, acetone, dioxane. Insol in water. LD50 in female rats (mg/kg): 31 orally; 4 i.v. (Kavlock).
Melting point: mp 98-101°
Toxicity data: LD50 in female rats (mg/kg): 31 orally; 4 i.v. (Kavlock)
Use: Insecticide.
Therap-Cat-Vet: Ectoparasiticide.
Malaria causes more than 300 million clinical cases and 665,000 deaths each year, and the majority of the mortality and morbidity occurs in sub-Saharan Africa. Due to the lack of effective vaccines and wide-spread resistance to antimalarial drugs, mosquito control is the primary method of malaria prevention and control. Currently, malaria vector control relies on the use of insecticides, primarily pyrethroids. The extensive use of insecticides has imposed strong selection pressures for resistance in the mosquito populations. Consequently, resistance to pyrethroids in Anopheles gambiae, the main malaria vector in sub-Saharan Africa, has become a major obstacle for malaria control. A key element of resistance management is the identification of resistance mechanisms and subsequent development of reliable resistance monitoring tools. Field-derived An. gambiae from Western Kenya were phenotyped as deltamethrin-resistant or -susceptible by the standard WHO tube test, and their expression profile compared by RNA-seq. Based on the current annotation of the An. gambiae genome, a total of 1,093 transcripts were detected as significantly differentially accumulated between deltamethrin-resistant and -susceptible mosquitoes. These transcripts are distributed over the entire genome, with a large number mapping in QTLs previously linked to pyrethorid resistance, and correspond to heat-shock proteins, metabolic and transport functions, signal transduction activities, cytoskeleton and others. The detected differences in transcript accumulation levels between resistant and susceptible mosquitoes reflect transcripts directly or indirectly correlated with pyrethroid resistance. RNA-seq data also were used to perform a de-novo Cufflinks assembly of the An. gambiae genome.

Purified deltamethrin is an off-white powder that has none to slight musty odour. Technical deltamethrin (purity 98.9-99.3%w/w) melts at 98.1-99.4 °C and decomposes before boiling (245-320 °C). The density is 1.5 g/cm3
at 20°C and the solubility in water is < 5µg/l at pH 6.2and 20 °C (based on the LOQ of the HPLC-method used for quantification). Deltamethrin is notconsidered to be able to dissociate within the environmentally relevant pH range due to the lack
of functional groups with acidic or alkaline properties. The vapour pressure is 1.24 x 10-8 Pa at
25 °C and the Henry’s law constant of 1.252 x 10-3 Pa.m3.mol-1 indicates that volatilisation is
not expected to significantly contribute to the dissipation of deltamethrin in the environment.
The Log Pow is 4.6 in distilled water (pH not stated) which indicates that deltamethrin may bioaccumulate. The following solvent solubilities were determined for deltamethrin (g/l): 300-600 (acetone), 60-75 (acetonitrile), >600 (1,2-dichloroethane), 200-300 (DMSO and ethyl actetate), 2.47 (n-heptane), 8.15 (methanol) and 150-200 (p-xylene). Deltamethrin is not highly
flammable, auto-flammable, exploosive or oxidizing and does not react with the packaging material (black plastic pouches).

Molecular formula:  C22H19Br2NO3

Chemical Structure

Chemical Structure

    Deltamethrin is the first pyrethroid composed of a single 
isomer of 8 stereoisomers selectively prepared by the 
esterification of [1R, 3R or  cis]-2,2-dimethyl-3-(2,2-dibromovinyl) 
cyclopropanecarboxylic acid with (alphaS)- or (+)-alpha-cyano-3-
phenoxybenzyl alcohol or by selective recrystallization of the 
racemic esters obtained by esterification of the (1R, 3R or  cis)-
acid with the racemic or [alphaR, alphaS, or alphaRS or ±]-alcohol 
(Elliott et al., 1974).  Thus, its stereospecific structure (4) is 
the ester of [1R, 3R or  cis]-acid with (alphaS)-alcohol. 

    The acid is a characteristic dibromo analogue of chrysanthemic 
acid.

 

 

Deltamethrin (S-α-cyano-3-phenoxybenzyl-(1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylic acid ester) is an insecticide from the class of the pyrethroids and has been used extensively and for a long time for controlling pests (C. D. S. Tomlin, The Pesticide Manual, 11th Edition, British Crop Protection Council, Farnham 1997).

Deltamethrin is a pyrethroid insecticide that kills insects on contact and through digestion. It is used to control apple and pear suckers, plum fruit moth, caterpillars on brassicas, pea moth, aphids (apples, plums, hops), winter moth (apples and plums), codling and tortrix moths (apples). Control of aphids, mealy bugs, scale insects, and whitefly on glasshouse cucumbers, tomatoes, peppers, potted plants, and ornamentals. It also controls numerous insect pests of field crops. Formulations include emulsifiable concentrates, wettable powders, ULV and flowable formulations and granules. There are no known incompatibilities with other common insecticides and fungicides

The pyrethroids with which the present invention is concerned are crystallizable esters having at least one asymmetric carbon atom to which an epimerizable proton is attached. The more pesticidally active pyrethroids additionally contain at least one and usually two or more other asymmetric carbon atoms and therefore comprise isomeric mixtures wherein one or more of the isomers are more pesticidally active than the others. Representative of such pyrethroids are the alpha-cyanobenzyl esters of the formula (A) :

 

Figure imgf000003_0001

wherein R1 is halogen, haloalkyl, alkenyl or halo- alkenyl; each R2 independently is halogen, alkyl, halo- alkyl, alkoxy, phenyl, phenoxy, phenylalkyl, substituted phenyl and substituted phenylalkyl wherein the substituents include one or more of alkyl, halogen, haloalkyl, nitro, hydroxy and cyano; and n is 0-5, preferably 1-3. In the above formula the asymmetric carbon atoms are marked 1, 3 and alpha. All of the substituents on a host group may be the same, or the substituents may be different. Alkyl and alkoxy may contain 1-8 carbon atoms, preferably 1-4 carbon atoms. Alkenyl may comprise 2-8 carbon atoms, preferably 2-4 carbon atoms. Halogen includes fluorine, chlorine and bromine. A typical phenylalkyl group is benzyl. Substituted phenyl includes tolyl, xylyl, trichlorophenyl and trifluoro- methylphenyl. Substituted phenylalkyl includes methyl- benzyl, trichlorobenzyl and trifluoromethylbenzyl.

The foregoing and other pyrethroids are well known as disclosed, for example, in Kirk-Othmer, Encyclopedia of Chemical Technology, Second Edition, Vol. 13, pages 456-458, in the following U.S. Patents: 4,024,163 – Elliot et al (NRDC)

4,133,826 – Warnant et al (Roussel Uclaf)

4,136,195 – Warnant et al (Roussel Uclaf)

4,213,916 – Davies et al (Shell)

4,287,208 – Fuchs et al (Bayer) 4,308,279 – Smeltz (FMC)

4,427,598 – Mason et al (Shell)

4,512,931 – Robson (ICI)

4,544,508 – Fuchs et al (Bayer)

4,544,510 – Van Berkel et al (Shell) 4,560,515 – Stoutamire et al (Shell)

4,582,646 – Stoutamire et al (Shell)

4,670,464 – Doyle et al (ICI)

4,681,969 – Williams et al (ICI) and in the following PCT patent publications:

WO 86/04215 – Hidasi et al (Chinoin)

WO 86/04216 – Hidasi et al (Chinoin)

Preferred pyrethroids convertible to more active isomers in accordance with the present invention are those of formula A wherein R1 is dihalovinyl or tetrahalopropenyl, R2 is phenoxy, and n is l. The more preferred pyrethroids are those wherein n is 1, R1 is dihalovinyl or tetrahalopropenyl and R2 is phenoxy; and those wherein n is 2, R1 is dihalovinyl or tetrahalopropenyl and one R2 is fluorine and the other R2 is phenoxy. The latter preferred compounds are isomeric mixtures having the common name “cyfluthrin” when R1 is dichlorovinyl, n is 2 and one R2 is fluorine. When R1 is dichlorovinyl, n is 1 and R2 is phenoxy, the mixtures have the common name “cypermethrin.”

Cypermethrin contains four cis and four trans isomers designated I-VIII as follows:

cis isomers I. (S) (α-cyano)(3-phenoxyphenyl)methyl 1R, cis-3-

(2,2-dichloroethenyl)-2,2-dimethylcyclopropane- carboxylate (abbreviated 1R, cis S)

II. (R)(α-cyano)(3-phenoxyphenyl)methyl 1S, cis-3- (2,2-dichloroethyl)-2,2-dimethylcyclopropane- carboxylate (abbreviated 1S, cis R)

III. (S)(α-cyano)(3-phenoxyphenyl)methyl 1S, cis-3- (2,2-dichloroethenyl)-2,2-dimethylcyclopropane- carboxylate (abbreviated 1S, cis S)

IV. (R)(α-cyano)(3-phenoxyphenyl)methyl 1R, cis-3-

(2,2-dichloroethenyl)-2,2-dimethylcyclopropane- carboxylate (abbreviated 1R, cis R)

trans isomers V. The trans isomer of I (abbreviated 1R, trans S)

VI. The trans isomer of II (abbreviated 1S,trans R)

VII. The trans isomer of III (abbreviated 1S,trans S)

VIII. The trans isomer of IV (abbreviated 1R, trans R)

Cyfluthrin and other pyrethroids to which the invention is applicable comprise similar isomericmixtures.

It is known that the most insecticidally active isomers of the foregoing eight isomers are I and V, and that enantiomer pairs I/II (abbreviated cis-2) and V/VI (abbreviated trans-2) are more insecticidally active than the enantiomer pairs III/IV (abbreviated cis-1) and VII/VIII (abbreviated trans-1). It is extremely difficult and commercially impractical to separate the more active isomers such as I and V from the complex isomer mixtures produced in the usual pyrethroid synthesis. Accordingly, efforts to produce more pesticidally active pyrethroids have focused on techniques for converting less active isomers in the synthesis product mixtures to more active isomers, i.e., to enrich isomeric mixtures with respect to the more active isomers, thus avoiding complex resolution procedures and the loss represented by discard of less active isomers.

Nevertheless, even when the isomeric mixtures have been converted rather than resolved, the conversion procedures have not been commercially practical because of poor yields, usually due to production of undesired by-product, often comprising as many isomers as the desired product, and because of time-consuming multiple steps, high temperatures and/or the need to recover expensive reagents. In the case of cypermethrin the major by-product is (R,S)-2-oxo-1,2-bis(3-phenoxyphenyl) ethyl cis- and trans-3-(2,2-dichloroethenyl)-2,2- dimethylcyclopropanecarboxylate, an eight isomer mixture commonly called the “benzoin by-product.” Similar byproducts are encountered in the synthesis of other pyrethroids such as cyfluthrin. Representative of prior efforts to convert isomer mixtures to more active species are the procedures disclosed in U.S. Patents 4,213,916, 4,308,279, 4,544,510, 4,544,508, 4,512,931, 4,427,598, 4,670,646 and 4,681,969 and the two PCT patent publications cited above.

Usage

Deltamethrin products are among the most popular and widely used insecticides in the world[citation needed] and have become very popular with pest control operators and individuals in the United States.[1] This material is a member of one of the safest classes of pesticides: synthetic pyrethroids. This pesticide is highly toxic to aquatic life, particularly fish, and therefore must be used with extreme caution around water. Although generally considered safe to use around humans, it is still neurotoxic to humans. Deltamethrin is able to pass from a woman’s skin through her blood and into her breast milk.[2]

There are many uses for deltamethrin, ranging from agricultural uses to home pest control. Deltamethrin has been instrumental in preventing the spread of diseases carried by tick-infested prairie dogsrodents and other burrowing animals[citation needed]. It is helpful in eliminating and preventing a wide variety of household pests, especially spidersfleastickscarpenter antscarpenter bees,cockroaches and bed bugs. Deltamethrin is also one of the primary ingredients in ant chalk.

Production

Deltamethrin is a pyrethroid composed of a single isomer of 8 stereoisomers selectively prepared by the esterification of (1R,3R)- orcis-2,2-dimethyl-3-(2,2-dibromovinyl)cyclopropanecarboxylic acid with (alpha,S)- or (+)-alpha-cyano-3-phenoxybenzyl alcohol or by selective recrystallization of the racemic esters obtained by esterification of the (1R,3R)- or cis-acid with the racemic or (alphaR,alphaS, or alphaR/S)- or + or − alcohol.

 

Chemical structure for deltamethrin

…………………………….

Evolution of an industrial process: deltamethrin synthesis
Chemistry&Industry (London, United Kingdom) (1984), (6), 199-204

……………………….

http://www.sciencedirect.com/science/article/pii/S0040402001801307

Very efficient enantioselective syntheses of (1R)--and -hemicaronaldehydes precursors of (1R)-trans chrysanthemic acid and its (1R)-cis dibromovinyl analogue starting from natural tartaric acid or D-mannitol are described. They are based on the reaction between isopropylidenetriphenylphosphorane or isopropylidenediphenylsulfurane and chiral γ-alkoxy-α,β-unsaturated esters. The general problem of the diastereoselective addition to such esters is discussed.

………………………….

http://www.sciencedirect.com/science/article/pii/0040403988853413

Isopropylidenediphenylsulfurane reacts with γ-alkoxy α,β-unsaturated esters and produces γ-alkoxy cyclopropane carboxylates. This reaction is almost stereospecific and takes place with very high asymmetric induction. The stereochemistry of the resulting cyclopropane derivative proved independent of the stereochemistry of the carbon-carbon double bond of the starting ester. This reaction has been successfully applied to the enantioselective synthesis of deltamethrin (the most biologically active insecticide) from natural tartaric acid.

(+)-4 α-Acetyl-2-carene (6), readily available from (+)-3-carene (5), was converted to (1R)--(+)-3-(2′,2′-dihalovinyl)-2, 2-dimethyl-cyclopropane-1-carboxylic acids (21) and (22) in eleven steps and in overall yields of 23% and 14%, respectively. Alternatively, (-)-5-keto-3-carene (23), an oxidation product of (+)-3-carene (5) was converted to (1R)--(-)-permethrin (1) in five steps and in an overall yield of 20%. in yet another flexible approach, (-)-(23) was converted to (1R)--(+)-(21) and (1R)--(+)-(22) in seven steps and in an overall yields of 33% and 23%, respectively. These results coupled with the literature reports for the conversion of (1R)--(+)-(21) and (22) to (1R)--(-)-(1), (1R)-cis-(+)-cypermethrin (2) and (1R)--(+)-deltamethrin (decis) (3) constitute two efficient methods for the synthesis of (1R)--synthetic pyrethroid from (+)-3-carene (5).

………………………..

1R-cis-2,2-Dimethyl-3-(2,2-dibromovinyl)cyclopropane carboxylic acid1 (1), the acid moiety of the highly potent photostable pyrethroid deltamethrin (2) has been obtained either by a Wittig reaction on 1R-cis-caronaldehyde ester (3) employing 1, 1-dibromomethylenetriphenylphosphorane or from the bicyclic tribromo-lactone2,3 (4) by reaction with zinc and acetic acid. Lactone (4) is thus an important intermediate in the deltamethrin synthesis.

http://www.tandfonline.com/doi/abs/10.1080/00397918908050947#.VESwr2eSyvM

 

Physical and Chemical Properties

    Technical grade deltamethrin contains more than 98% deltamethrin
(FAO/WHO, 1981).  It is stable to heat (6 months at 40 °C), light,
and air, but unstable in alkaline media (FAO/WHO, 1981; Meister et
al., 1983; Worthing & Walker, 1983).  Some physical and chemical
properties are listed in Table 1, and the chemical composition of
various stereoisomeric mixtures is shown in Table 2. 

Table 1.  Some physical and chemical properties of deltamethrin
------------------------------------------------------------------- 
Physical state            crystalline powder 
Colour                    colourless
Odour                     odourless
Density (20 °C)           0.5 g/cm3
Relative molecular mass   505.24
Melting point (°C)        98-101
Boiling point             decomposes above 300 °C
Water solubility (20 °C)  < 0.002 mg/litre (practically insoluble)
Solubility in organic     solublea
 solvents
Vapour pressure (25 °C)   2.0 x 10-6 Pa
 n-Octanol-water           5.43
 partition coefficient 
 (Log Pow) 
-------------------------------------------------------------------  
a Acetone (500 g/litre), ethanol (15 g/litre), cyclohexanone (750 
  g/litre), dioxane (900 g/litre), xylene (250 g/litre), ethyl 
  acetate.

2.3  Analytical Methods

    Methods for the determination of deltamethrin residues and the 
analysis of environmental samples, and products are summarized in 
Table 3. 

    To analyse technical grade deltamethrin, a mixture of 
deltamethrin and diphenylamine (an internal standard) was injected 
in a high-performance liquid chromatograph equipped with a UV-
detector (Mourot et al., 1979). 

    The Joint FAO/WHO Codex Alimentarius Commission has published 
recommendations for methods for the determination of deltamethrin 
residues (FAO/WHO 1985b).  A further review of analytical methods 
for deltamethrin has been made by Vaysse et al. (1984). 

Table 2.  Chemical identity of deltamethrins of various stereoisomeric compositions
---------------------------------------------------------------------------------------------------------------
Common name           CA Index name (9CI)                        Stereoisomeric  Synonyms and trade names
CAS Registry No.                                                 compositionc    
NIOSH Accession No.a  Stereospecific nameb
--------------------------------------------------------------------------------------------------------------- 
Deltamethrin          Cyclopropanecarboxylic acid,               (4)             Decamethrin, Decis,
52918-63-5            3-(2,2-dibromovinyl)-2,2-dimethyl-,                        K-Othrine, NRDC 161,
GZ1233000a            alpha-cyano(3-phenoxyphenyl)methyl ester,                  WHO 1998, K-Obiol, Butox
                      [1R-[1 (S*), 3 R]]-,                                       Butoflin, Cislin, FMC 45498
                                                                                 RU 22974

                      (S)-alpha-cyano-3-phenoxybenzyl
                      (1R,  cis)-2,2-dimethyl-3-(2,2-di-
                      bromovinyl)cyclopropanecarboxylate

d- cis-Deltamethrin    same as deltamethrin                       -               Decamethrin, Decis
52820-00-5   
GZ1240000a            (S)-alpha-cyano-3-phenoxybenzyl
                      (d,  cis)-2,2-dimethyl-3-(2,2-di-
                      bromovinyl)cyclopropanecarboxylate
---------------------------------------------------------------------------------------------------------------  
a Registry of Toxic Effects of Chemical Substances (RTECS) (1981-82 edition).
b (1R), d, (+) or (1S), 1, (-) in the acid part of deltamethrin signifies the same stereospecific conformation, 
  respectively.
c The number in the parenthesis identifies the structure shown in the figures of stereoisomers.

Table 3.  Analytical methods for deltamethrin
---------------------------------------------------------------------------------------------------------------------------------
Sample         Extraction    Sample preparation                     Determination:         MDCb     % Recovery          Reference
               solvent       -----------------------------------                           (mg/kg)  (fortification
                             Partition     Clean up                 GLC or HPLC                     level in
                                           column      elution      condition; detector,            mg/kg)  
                                                                    carrier flow, column,
                                                                    temp, R.T.a
---------------------------------------------------------------------------------------------------------------------------------
RESIDUE ANALYSIS

apple           n-hexane/     ext.sol.c/    silica gel  CH2Cl2       ECD-GC; N2;            0.01     105(0.1), 100(1.0)  1
               acetone       H2O                                    50 ml/min; 1 m 
               (1/1)                                                3% OV-7; 235 °C
pear                                                                                       0.01     125(0.1), 98(1.0)   
cabbage                                                                                    0.01     130(0.1), 118(1.0) 
potato                                                                                     0.01     126(0.1), 97(1.0) 

apple,         acetonitrile  petroleum     Florisil    ether/       EDC-GC; 1.2 m          0.005    85-100(0.02-0.1)    2 
peach,                       ether/H2O                  n-hexane     DC-200, OV-1 or 
grape,                                                 (1/4)        OV-101; 245 °C,  
tomato                                                              10-12 min

wheat          methanol       n-hexane      alumina                  HPLC; 235 nm;                   87(2.0)             3
grain                                                               30 cm; uBondapak;
                                                                    C 18; methanol/H2O
                                                                    (4/1); 2.5 ml/min

wheat                         n-hexane      Florisil    ether/       ECD-GC; N2;                     91                  4
                                                       petroleum    75 ml/min; 0.6 m 
                                                       ether (1/9)  5% SE-30; 215 °C

meat           ethyl ether/  acetonitrile  gel         diisopropyl  ECD-GLC; N2;           0.001    90-95% at 0.01      5
               petroleum                   permeation  ether        40 ml/min; 1.8 m
               ether                       column                   SE-30 1% on gas 
                                           (Styragel)               Chrom. PAW

milk           hexane        acetonitrile  Florisil +  benzene/     ECD-GLC; N2;           0.01     83-87% at 0.1       5
                                           cellulose/  hexane       40 ml/min; 1.8 m  
                                           charcoal    (1/1)        SE-30 1% on gas
                                                                    Chrom. PAW 
---------------------------------------------------------------------------------------------------------------------------------

Table 3.  (contd.)
-----------------------------------------------------------------------------------------------------------------------------------
Sample         Extraction    Sample preparation                     Determination:           MDCb     % Recovery          Reference
               solvent       -----------------------------------                             (mg/kg)  (fortification
                             Partition     Clean up                 GLC or HPLC                       level in
                                           column      elution      condition; detector,              mg/kg)  
                                                                    carrier flow, column,
                                                                    temp, R.T.a
-----------------------------------------------------------------------------------------------------------------------------------
ENVIRONMENTAL ANALYSIS

locust          n-hexane                    Florisil    ether/       ECD-GC; N2;                       92                  4
                                                       petroleum    75 ml/min; 0.6 m 5%
                                                       ether (1/9)  SE-30; 215 °C 

sea water      XAD-2         ext.sol.c/    alumina                  ECD-GC; N2;                                           6
               resin          n-hexane                               70 ml/min; 1.5 m 
               acetone                                              4% SE-30; 207 °C

water           n-hexane                    alumina                  ECD-GC; N2;                                           6
                                                                    70 ml/min; 1.5 m 
                                                                    4% SE-30; 207 °C 

water          petroleum                   Florisil    petroleum    ECD-GLC; 1 m OV          0.0001   97 at 0.010         8
               ether/                                  ether/       1-3% on Chromosorb
               diethyl-                                diethyl-     W.A.W. HMDS 60/80
               ether (1/1)                             ether   
                                                       (80/20)

soil           acetone,                    acid        hexane       ECD-GLC; 5.2%            0.001    > 91%               9
               acetone/                    alumina     ether        OV-210 with AR/CH4
               hexane (1/1)                            hexane 
               hexane                                  (5-10%)

               acetone,                    acid        hexane/      ECD-GLC; N2;             0.0001   > 91%               5
               acetone/                    alumina     ethyl ether  40 ml/min; 1.8 m 
               hexane (1/1)                            (90/10)      SE-30 1% on gas 
               hexane                                               Chrom. PAW

cotton          n-hexane                                             transesterification                                   7
foliage                                                             followed by ECD-GC; 
(dislodgeable                                                       31 ml/min; 0.45 m    
residue)                                                            5% SE-30; 120 °C
----------------------------------------------------------------------------------------------------------------------------------- 

Table 3.  (contd.)
-----------------------------------------------------------------------------------------------------------------------------------
Sample         Extraction    Sample preparation                     Determination:           MDCb     % Recovery          Reference
               solvent       -----------------------------------                             (mg/kg)  (fortification
                             Partition     Clean up                 GLC or HPLC                       level in
                                           column      elution      condition; detector,              mg/kg)  
                                                                    carrier flow, column,
                                                                    temp, R.T.a
-----------------------------------------------------------------------------------------------------------------------------------
PRODUCT ANALYSIS

Technical                                                           HPLC, 230 nm; 15 cm                                   10
grade                                                               Lichrosorb Si-60; 
                                                                     n-hexane/diisopropyl 
                                                                    ether (93/7); 80 ml/h; 
                                                                    7.6 min    

               isoctane/                                            HPLC - UV detector                                    5
               dioxane                                              254 nm (230 nm for
               (80/20)                                              conc. <0.5%) Silica-60; 
                                                                    100ml/h; isooctane/ 
                                                                    dioxane (95/5)   
-----------------------------------------------------------------------------------------------------------------------------------
a R.T.:  retention time;
b MDC: minimum detectable concentration;
c ext .sol.: extraction solvent.

References

1. Baker & Bottomley (1982); 2. Mestres et al. (1978a); 3. Noble et al. (1982); 4. Pansu et al. (1981); 5. Vaysse et al. (1984); 
6. Zitko et al. (1979); 7. Estesen et al. (1979); 8. Mestres et al. (1978b); 9. Hill (1982); 10. Mourot et al. (1979). 
3.  SOURCES OF ENVIRONMENTAL POLLUTION AND ENVIRONMENTAL LEVELS

3.1  Industrial Production

    Deltamethrin was first marketed in 1977.  Production volumes in 
recent years are shown in Table 4. 

Table 4.  Worldwide production of deltamethrin
-------------------------------------------------
Year  Production  Reference
      (tonnes)
-------------------------------------------------
1979  75          Wood Mackenzie (1980)
1980  100         Wood Mackenzie (1981)
1981  100         Wood Mackenzie (1982, 1983)
1982  115         Wood Mackenzie (1983)
1987  250         Information from Roussel Uclaf
-------------------------------------------------

 

Malaria control

Deltamethrin plays key role in controlling malaria vectors, and is used in the manufacture of long-lasting insecticidal mosquito nets. It is used as one of a battery of pyrethroid insecticides in control of malarial vectors, particularly Anopheles gambiae, and whilst being the most employed pyrethroid insecticide, can be used in conjunction with, or as an alternative to, permethrincypermethrin and other organophosphate-based insecticides, such as malathion and fenthion. Resistance to deltamethrin (and its counterparts) is now extremely widespread and threatens the success of worldwide vector control programmes.

Resistance to deltamethrin

Resistance has been characterised in several insects, including important vectors of malaria like the mosquito Anopheles gambiae as well as non-disease carrying pests like bed bugs.

Mosquitoes

Methods of resistance include thickening of the cuticle of the insect to limit permeation of the insecticide, metabolic resistance via overexpression of metabolising P450 mono-oxygenases and glutathione-S-transferases, and the knockdown resistance (kdr) sodium channel mutations which render the action of insecticides ineffectual, even when co-administered with piperonyl butoxide. Characterisation of the different forms of resistance among mosquitoes has become a top priority in groups studying tropical medicine due to the high mortality of those who reside in endemic areas.[3]

Bed Bugs

Two mutations, the Valine to Leucine mutation (V419L) and the Leucine to Isoleucine mutation (L925I) in voltage-gated sodium channel α-subunit gene, have been identified as responsible for knockdown resistance to deltamethrin in bed bugs. One study found that 88% of bed bug populations in the US had one, the other, or both mutations, meaning that deltamethrin resistance among bed bugs is currently making this insecticide obsolete.[4]

Poisoning

In humans

Since deltamethrin is a neurotoxin, it temporarily attacks (in medical terms, “insults”) the nervous system of any animal with which it comes into contact. Skin contact can lead to tingling or reddening of the skin local to the application. If taken in through the eyes or mouth, a common symptom is facial paraesthesia, which can feel like many different abnormal sensations, including burning, partial numbness, “pins and needles”, skin crawling, etc. There are no reports indicating that chronic intoxication from pyrethroid insecticides causes motor neuron damage or motor neuron disease.[5] However, in 2011, a case report was published that demonstrated pathologically proven motor-neuron death in a Japanese woman after acute massive ingestion of pesticides containing pyrethroids and organochlorine. [6]

Recently, in South Africa, residues of deltamethrin were found in breast milk, together with DDT, in an area that used DDT treatment for malaria control, as well as pyrethroids in small-scale agriculture.[7]

There are no antidotes, and treatment must be symptomatic, as approved by a physician. Over time, deltamethrin is metabolized, with a rapid loss of toxicity, and passed from the body. A poison control center should be contacted in the event of an accidental poisoning.

In domestic animals

Cases of toxicity have been observed in cattle, following use of agricultural deltamethrin preparation in external application in tick control. Symptoms appeared 36 hours after the application, and included muscular tremors that lead to decubitus 12 hours later. After 12 hours, there was spontaneous recovery and the animal could stand up again, although the muscular tremors persisted. The body temperature was then 38.3°C. (normal range 38.0 to 39.5°C.).

 

Deltamethrin
Deltamethrin
Deltamethrin
Identifiers
CAS number 52918-63-5 Yes
ChemSpider 37079 Yes
UNII 2JTS8R821G Yes
KEGG D07785 Yes
ChEBI CHEBI:4388 Yes
ChEMBL CHEMBL1593566 
ATC code P03BA03,QP53AC11
Jmol-3D images Image 1
Properties
Molecular formula C22H19Br2NO3
Molar mass 505.20 g mol−1
Density 1.5 g cm−3
Melting point 98 °C (208 °F; 371 K)
Boiling point 300 °C (572 °F; 573 K)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)

 

 

References

  1.  “Deltamethrin Odorless Synthetic Pyrethroid Insecticides”. PestProducts.com. Retrieved 2008-09-26.
  2. Bouwman, B. Sereda and H.M. Meinhardt, H.; B. Sereda and H.M. Meinhardt (December 2006). “Simultaneous presence of DDT and pyrethroid residues in human breast milk from a malaria endemic area in South Africa”Environmental Pollution 144 (3): 902–917. doi:10.1016/j.envpol.2006.02.002PMID 16564119. Retrieved 2008-09-26.
  3. Muller, Pie, et al. (2008). Field caught Permethrin-Resistant Anopheles gambiae overexpress CYP6P3, a P450 that metabolises pyrethroids,PLoS Genetics 4(11)).
  4.  Zhu, F.; Wigginton, J.; Romero, A.; Moore, A.; Ferguson, K.; Palli, R.; Potter, M. F.; Haynes, K. F.; Palli, S. R. (2010). “Widespread distribution of knockdown resistance mutations in the bed bug,Cimex lectularius(Hemiptera: Cimicidae), populations in the United States”. Archives of Insect Biochemistry and Physiology: n/a. doi:10.1002/arch.20355.
  5.  Doi, et al (2006). “Motor neuron disorder simulating ALS induced by chronic inhalation of pyrethroid insecticides”. Neurology 67 (10). pp. 1894–1895.doi:10.1212/01.wnl.0000244489.65670.9f.
  6.  Doi, et al (2006). “Motor neuron disorder simulating ALS induced by chronic inhalation of pyrethroid insecticides”. Neurology 67 (10). pp. 1894–1895.doi:10.1212/01.wnl.0000244489.65670.9f.
  7.  Bouwman, B. Sereda and H.M. Meinhardt, H.; B. Sereda and H.M. Meinhardt (December 2006). “Simultaneous presence of DDT and pyrethroid residues in human breast milk from a malaria endemic area in South Africa”Environmental Pollution 144 (3): 902–917. doi:10.1016/j.envpol.2006.02.002PMID 16564119. Retrieved 2008-09-26.

External links

 

Literature References:

Synthetic pyrethroid insecticide. Prepn of racemic mixture: M. Elliot et al., DE 2439177 (1975 to NRDC),C.A. 83, 73519z (1975); of decamethrin and isomers: eidem,

Pestic. Sci. 9, 105 (1978). Activity: eidem, Nature 248, 710 (1974);eidem, Pestic. Sci. 9, 112 (1978).

Absolute configuration: J. D. Owen, J. Chem. Soc. Perkin Trans. 1 1975, 1865.

Photochemistry: L. O. Ruzo et al., J. Agric. Food Chem. 25, 1385 (1977).

Metabolism: eidem, ibid. 26, 918 (1978). Toxicology: R. Kavlock et al., J. Environ. Pathol. Toxicol. 2, 751 (1979).

Pharmacological effects on central nervous system: P. H. Chanh et al.,Arzneim.-Forsch. 34, 175 (1984).

Review of toxicology and human exposure: Toxicological Profile for Pyrethrins and Pyrethroids(PB2004-100004, 2003) 332 pp.

file:///C:/Users/Inspiron/Downloads/molecules-17-13989-v2.pdf

 

1. Elliott, M., Farnham, A. W., Janes, N. F., Needham, P. H., and Pulman, D. A., Nature, 244, 456 (1973).
2. Elliott, M., Farnham, A. W., Janes, N. F., Needham, P. H., Pulman, D. A., and Stevenson, J. H., Nature, 246, 169 (1973).
3. Elliott, M., Farnham, A. W., Janes, N. F., Needham, P. H., Pulman, D. A., and Stevenson, J. H., Proc. Seventh Br. Ins. Fung. Conf. (Brighton) 721 (1973).
4. Cahn, R. S., Ingold, C., and Prelog, V., Angew. Chem. int. Ed. Engl., 5, 385 (1966).
5. Brown, D. G., Bodenstein, O. F., and Norton, S. J., J. agric. Fd Chem., 21, 767 (1973).
6. Lock, G., and Kempter, F. H., Ml Chem., 67, 24 (1935).
7. Elliott, M., Farnham, A. W., Janes, N. F., Needham, P. H., and Pearson, B. C., Nature, 213, 493 (1967).
8. Elliott, M., Chem. and Ind., 776 (1969).
9. Elliott, M., Bull. Wld Hlth Org., 44, 315 (1971).
10. Becker, W., and Pfeifl, E., J. Am. chem. Soc., 88, 4299 (1966).
11. Chemistry of Carbon Compounds (edit. by Rodd, E. H.) III, 902 (Elsevier, 1956).
12. Barnes, J. M., and Verschoyle, R. D., Nature, 248, 711 (1974).

 

6-19-1985
Stabilized mixtures of carbamate insecticides and synthetic pyrethroids
8-8-1984
Pesticides
10-20-1983
Stabilized mixtures of carbamate insecticides and synthetic pyrethroids. STABILIZED MIXTURES OF CARBAMATE INSECTICIDES AND SYNTHETIC PYRETHROIDS
11-11-1981
Stabilized cyandhydrin ester
7-23-1980
Conversion of stereoisomer into its diastereoisomer
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Oct 252014
 

 

 

The continuous flow synthesis of carboxylic acids using CO2 in a tube-in-tube gas permeable membrane reactor

A. Polyzos, M. O’Brien, T. Pugaard-Petersen, I.R. Baxendale, S.V. Ley, Angew. Chem. Int. Ed. 2011, 50, 1190-1193.

http://onlinelibrary.wiley.com/doi/10.1002/anie.201006618/abstract

http://onlinelibrary.wiley.com/store/10.1002/anie.201006618/asset/supinfo/anie_201006618_sm_miscellaneous_information.pdf?v=1&s=eeb1de81511ff2fac7a88009df9f45da49384532

Keep it simple: A gas–liquid flow reactor has been developed based on a gas permeable tube-in-tube configuration which effectively delivers gas to a liquid substrate stream in a safe, continuous fashion. A series of carboxylic acids were prepared from the reaction of CO2with a range of Grignard reagents (see picture).

The gas-liquid reactor assembly is comprised of a 1 m section of Teflon AF-
2400 tubing (0.8 mm o.d.; 0.6 mm i.d.) placed within PTFE tubing (3.2 mm o.d.; 1.6
mm i.d). These tubings were coiled and each end fastened to a 1/8” stainless steel tube
fitting, which was fixed onto an aluminium base plate. One section of the Teflon AF-
2400 membrane tubing was passed through to a stainless steel T-piece (Swagelok 2 ×
1/8”, 1 × 16” fittings) that was united with PTFE tubing (1/16”), forming the liquid
inlet. The other section of the Teflon AF-2400 was passed through a 4-way stainless
steel connector (Swagelok, 3 × 1/8”, 1 × 16” fittings) and directly united with a
second piece of PTFE tubing (1/16”), forming the liquid outlet. One of the 1/8”
fittings on the 4-way connector was attached to a fine needle release valve (Swagelok)
used to purge the reactor of excess gas. The remaining connector was attached to
another stainless steel T-piece (Swagelok 3 × 1/8” fittings) that was connected to a
pressure gauge (Swagelok, 10 Bar) and a gas pressure regulator valve (10 bar
maximum) via stainless steel tubing (1/8”) (Figure S1).

Inline image 1

Inline image 2

 

Two flow streams driven by the Vapourtec R4/R2+; stream 1 containing a
solution of 1a (1.0 M in THF, 1.0 equiv, 1.0 mmol) loaded into a 2mL PEEK loop
and stream 2 containing the dry THF, were mixed at a T-piece before entering the
gas-liquid tube-in-tube reactor at room temperature. A back pressure regulator (75
psi) was placed immediately after the gas-liquid reactor to prevent out-gassing of the
dissolved CO2 from the solvent stream in the reactor. The flow stream was collected
in a flask containing a biphasic mixture of saturated ammonium chloride solution and
diethyl ether (1:1) (20 mL). The solution was acidified with HCl (1.0 M) and the
product was extracted with EtOAc (2 × 10 mL), dried (Na2SO4) and solvent removed
in vacuo to give the crude product 1b.

 

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DIISOPROPYLAMINE SPECTROSCOPY TAUGHT BY MOM, AUNT

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Oct 182014
 

 

MOM

DIISOPROPYLAMINE

C6H15N

MW 101

the degree of unsaturation: the answer is 0. The molecule has no double bonds or rings.

IR Spectrum

Since the molecule has a nitrogen, look for a band in the region 3400-3250 – there is a single small band at 3384, which probably indicates the N-H stretch of a secondary amine. (Recall that tertiary amines will not show a band in this region because they do not have any N-H’s to stretch.)

 

 

 

NMR Spectrum

 

Diisopropylamine(108-18-9)1HNMR

 

 

Amine protons show up from 0.5-3.0 ppm if the amine is not on an aromatic ring; the small “buried” peak at 1 ppm indicates a secondary amine peak:

There are only two other types of protons in the molecule: the doublet at 1 ppm indicates 12 hydrogens adjacent to one hydrogen and the septet at 2.9 ppm indicates 2 hydrogens adjacent to 6 hydrogens. The only way the molecule can be “put together” is to have each R group coming off the nitrogen to be the same, and to be -CH(CH3)2.

13C NMR

MASS

 

Summary

Example is diisopropylamine:

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PRISMANE 棱晶烷

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Oct 172014
 
Chemical structure of prismane
PRISMANE

650-42-0 cas

Tetracyclo[2.2.0.02,6.03,5]hexane

Prismane is a polycyclic hydrocarbon with the formula C6H6. It is an isomer of benzene, specifically a valence isomer. Prismane is far less stable than benzene. The carbon (and hydrogen) atoms of the prismane molecule are arranged in the shape of a six-atomtriangular prismAlbert Ladenburg proposed this structure for the compound now known as benzene.[1] The compound was not synthesized until 1973.[2]
Prismane
Chemical structure of prismane Chemical structure of prismane
CPK model of prismane
Identifiers
CAS number 650-42-0 
ChemSpider 16736515 Yes
Jmol-3D images Image 1
Properties
Molecular formula C6H6
Molar mass 78.11 g mol−1

History

In the mid 19th century, investigators proposed several possible structures for benzene which were consistent with its empirical formula, C6H6, which had been determined by combustion analysis. The first, which was proposed by Kekulé in 1867, later proved to be closest to the true structure of benzene. This structure inspired several others to propose structures that were consistent with benzene’s empirical formula; for example, Ladenburg proposed prismane, Dewar proposed Dewar benzene, and Koerner and Claus proposedClaus’ benzene. Some of these structures would be synthesized in the following years. Prismane, like the other proposed structures for benzene, is still often cited in the literature, because it is part of the historical struggle toward understanding the mesomeric structures and resonance of benzene. Some computational chemists still research the differences between the possible isomers of C6H6.[3]

Properties

Prismane is a colourless liquid at room temperature. The deviation of the carbon-carbon bond angle from 109° to 60° in a triangle leads to a high ring strain, reminiscent of that of cyclopropane but greater. The compound is explosive, which is unusual for a hydrocarbon. Due to this ring strain, the bonds have a low bond energy and break at a low activation energy, which makes synthesis of the molecule difficult; Woodward and Hoffmann noted that prismane’s thermal rearrangement to benzene is symmetry-forbidden, comparing it to “an angry tiger unable to break out of a paper cage.”[4]

The substituted derivative hexamethylprismane (in which all six hydrogens are substituted by methyl groups) has a higher stability, and was synthesized by rearrangement reactionsin 1966.[5]

Synthesis

Synthesis of Prismane

The synthesis starts from benzvalene (1) and 4-phenyltriazolidone, which is a strong dienophile. The reaction is a stepwise Diels-Alder like reaction, forming a carbocation as intermediate. The adduct (2) is then hydrolyzed under basic conditions and afterwards transformed into a copper(II) chloride derivative with acidic copper(II) chloride. Neutralized with a strong base, the azo compound (3) could be crystallized with 65% yield. The last step is a photolysis of the azo compound. This photolysis leads to a biradical which forms prismane (4) and nitrogen with a yield of less than 10%. The compound was isolated by preparative gas chromatography.

 

SYNTHESIS
Chemical structure
MeLi, CH2Cl2, 
Et2O
-45 °C, 45 %
Chemical structure

+

Chemical structure

Et2O, Dioxane
0 °C to RT, 60 min, 50-60 %

Chemical structure
KOH, 
MeOH, H2O
Reflux, 24 h
Chemical structure
CuCl2, HCl,
H2O
65 % (2 steps)
Chemical structure
hν, 
PhMe
30 °C, 5 h, 8 %
Chemical structure
References

 

 

https://www.beilstein-journals.org/bjoc/single/printArticle.htm?publicId=1860-5397-7-30

 

 

http://chemistry.stackexchange.com/questions/8898/does-benzene-have-isomers-and-resonance-structures

References

  1. Ladenburg A. (1869). “Bemerkungen zur aromatischen Theorie“. Chemische Berichte 2: 140–2. doi:10.1002/cber.18690020171.
  2. Katz T. J., Acton N. (1973). “Synthesis of Prismane”. Journal of the American Chemical Society 95 (8): 2738–2739. doi:10.1021/ja00789a084.
  3.  UD Priyakumar, TC Dinadayalane, GN Sastry (2002). “A computational study of the valence isomers of benzene and their group V hetero analogs”New J. Chem. 26 (3): 347–353.doi:10.1039/b109067d.
  4. R. B. Woodward and R. Hoffmann, Angew. Chem., Int. Ed. Engl.8, 789, (1969)
  5.  Lemal D. M., Lokensgard J. P. (1966). “Hexamethylprismane”. Journal of the American Chemical Society 88 (24): pp 5934–5935. doi:10.1021/ja00976a046.
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Highly potent APIs: can lean manufacturing ever be safe?

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Oct 092014
 

ALL ABOUT DRUGS
 

Highly potent APIs: can lean manufacturing ever be safe?

By Fiona Barry +, 09-Oct-2014

The phrase “lean manufacturing” conjures up job cuts and not much more for many people, but managers can use the method to drastically simplify HPAPI (highly potent active pharmaceutical ingredients) production, says an expert.

http://www.in-pharmatechnologist.com/Processing/Highly-potent-APIs-can-lean-manufacturing-ever-be-safe

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Green chemistry makes ‘cents’ for cost-focused API firms says expert

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Oct 092014
 

 

 

Green chemistry makes ‘cents’ for cost-focused API firms says expert

By Gareth MacDonald+, 07-Oct-2014

Making drugs generates a huge amount of waste but industry is showing signs of cleaning up its act according to Paul Anastas, the Yale scientist who coined the phrase “green chemistry.”

http://www.in-pharmatechnologist.com/Ingredients/Green-chemistry-makes-cents-for-cost-focused-API-firms-says-expert

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Oct 082014
 
Dr. Rafael "Rafi" Boritzer

DR RAFAEL BORITZER

Global Biotech Marketer, Serial Entrepreneur, Academician, Chair of Bioinfomedical Ltd. (www.bioinfomedical.com)
WE SALUTE YOU, SIR ……for your enormous contribution to society

WE SALUTE YOU SIR

His public appeal in his own words
Aloha Bio Research-Education Friends and Colleagues,I appreciate your recent linking to me on the LinkedIn network and directly at [email protected] Our Mission is to provide molecular biological product support, for research and development of Biosimilars, Personalized Medicine, and Traditional Pharma.Through our networks and relationships in over 60 countries, we help engage the scientific community in the cure and treatment of life-threatening and newly emerging diseases. You can find us at www.bioinfomedical.com , where our enterprise guarantees the highest levels of purity at “budget-constrained” prices. If you prefer to “buy the machine” instead of the product, we do offer the technology to produce any of our over 3,500 recombinant proteins and antibodies. If you do not find what you need in our online catalog (bottom right of landing page), we will be happy to entertain custom orders.With our accumulated experience in graduate and distance learning, we actively encourage, participate, and support American biotechnology and biological sciences education (Certificate, Masters, and Ph.D.). Our hybrid formats integrate short campus residency at first rate “bricks and mortar” campuses, on-line synchronous and asynchronous instruction, and the use of strategically located research labs in the U.S.A., Europe, and Asia.We look forward to meeting your needs.Thank you,
Dr. Rafi

Dr. Rafael "Rafi" Boritzer

Dr. Rafael “Rafi” Boritzer

Global Biotech Marketer, Serial Entrepreneur, Academician, Chair of Bioinfomedical Ltd.

CURRENT
  1. ThinkTech Hawaii,
  2. Bioinfomedical Ltd. / InfoMedical L.L.C.http://www.linkedin.com/in/doctorboritzer

 

Chairman of the Board of Directors

Bioinfomedical Ltd. / InfoMedical L.L.C. 

Started and built entrepreneurial venture that began as a consulting firm and grew into a successful business engaged in the global transfer of medical/gerontological technologies and software, marketing of research cytokines, and strategic alliances with bio-similar producers. Fostered relationships in Hawaii, Central/Southeast Asia, Oceania, Central Europe, Middle East, and East Africa, to accelerate growth of the business and further its objectives. Created differentiation strategies designed to cope with competitive marketing pressures primarily in long-term healthcare, specialty medical institutions and pharmaceutical distributors in the U.S. and Southeast Asia.

 

Dr. Rafi on Sociology at the University of Hawaii

Dr. Rafi on Sociology at the University of Hawaii

 

 

ABOUT HIM BY HIM

Over the course of my 20+ year career as an interdisciplinary and multicultural university educator, social scientist, marketer, entrepreneur and administrator, I have directed organizations, programs and initiatives that promote academic excellence, improve student performance, and strengthen educational outcomes. I have taught at Professor levels in the disciplines of healthcare administration, healthcare management information systems, sociology, global marketing and more. I have a track record in leading and participating in accreditation requirements, and in driving the design and development of curriculum and course offerings, at both graduate and undergraduate levels. My international experience encompasses five continents and I have an in-depth understanding of geopolitical contexts of business and effects on global and local economy and education.

Complementing my teaching and administrative background is executive and research experience in healthcare, geriatrics, entrepreneurship, and marketing, including the conceptualization, startup, and growth of a successful firm engaged in the global transfer of medical/gerontological technologies and software, marketing of research cytokines, and strategic alliances. InfoMedical Biotechnology (www.bioinfomedical.com) satisfies customers’ demand for high quality cytokine products. The use of medical diagnostics is growing in importance, as bigger proportion of the world’s population age and the cost of healthcare continues to rise. The company provides scientists with tools to investigate the genetic and molecular basis for human development and disease; knowledge that is applied in development, discovery and manufacture of new drugs.

Specialties: Education Program Development; Teaching; Student Recruitment-Retention; Distance Learning Modalities; Research & funding; Community Health; Sustainable Entrepreneurship; Strategic Planning; Sociology; Disruptive Innovation; and Global Business Strategies.

Senior project presentations at University of Hawaii Entrepreneurship Baccalaureate

Senior project presentations at University of Hawaii Entrepreneurship Baccalaureate

Live Life Aloha Obesity Reduction

Live Life Aloha Obesity Reduction

 

More about him

TV Talk Show Host

ThinkTech Hawaii

 – Present (10 months)Honolulu, HawaiiDr. Rafi conducts the weekly broadcast of Boritzer’s Bio Briefings. The hourly show focuses on the Biotechnological, Health and Medical sectors that are changing the way we live, eat, work, and socialize in the 21st Century. www.thinktechhawaii.com (live streaming on Mondays @ 15:00 Hawaiian Standard Time). Available after 24 hours (http://tinyurl.com/lnulduz).

From New York to Singapore, "Hospitals I've Learned to Love" with Dr. Rafi Boritzer

From New York to Singapore, “Hospitals I’ve Learned to Love” with Dr. Rafi Boritzer

Dr. Rafi Reveals IUI, IVF & Transactions at the Sperm Bank

Dr. Rafi Reveals IUI, IVF & Transactions at the Sperm Bank

Live, Life with Aloha - Obesity Reduction MadeEasy- Dr. Rafi Boritzer

Live, Life with Aloha – Obesity Reduction MadeEasy- Dr. Rafi Boritzer

The Health Care Highway -From Kolkata to Kapolei with Dr. Rafael Boritzer

The Health Care Highway -From Kolkata to Kapolei with Dr. Rafael Boritzer

Tele Medicine Systems - Dr. Rafi Boritzer with Dr. Dan Davis

Tele Medicine Systems – Dr. Rafi Boritzer with Dr. Dan Davis

In Telomere Research, SIZE is Everything-Dr. Rafi and Prof. Richard Allsopp

In Telomere Research, SIZE is Everything-Dr. Rafi and Prof. Richard Allsopp

If You Are A Baby Boomer, The Future is Now

If You Are A Baby Boomer, The Future is Now

Dr. Rafi chats with Prof. Tom Huang, Lab Director @ Pacific InVitro Fertilization

Dr. Rafi chats with Prof. Tom Huang, Lab Director @ Pacific InVitro Fertilization

Dr. Rafi and Prof. Clair Wright discuss "Pregnancy Dangers and Outcomes"

Dr. Rafi and Prof. Clair Wright discuss “Pregnancy Dangers and Outcomes”

Islands of Health- Dr Rafi on Fiji, Timor-Leste, Singapore, Madagascar, and Sicily

Islands of Health- Dr Rafi on Fiji, Timor-Leste, Singapore, Madagascar, and Sicily

Dr. Rafi Chases Ambulances from Honolulu to Tahrir Square

Dr. Rafi Chases Ambulances from Honolulu to Tahrir Square

Who is following you when you check into a long term care facility - Boritzer's Bio Briefings

Who is following you when you check into a long term care facility – Boritzer’s Bio Briefings

Cuban Healthcare: Can you achieve more with less?

Cuban Healthcare: Can you achieve more with less?

VITEC POSTER

 

 

Canoe Blessing 1 of 2

Canoe Blessing 1 of 2

Canoe Blessing 2 of 2

Canoe Blessing 2 of 2

Dr. Rafi on Globalization at University of Hawaii

Dr. Rafi on Globalization at University of Hawaii

Dr. Rafi on Entrepreneurship at the University of Hawaii

Dr. Rafi on Entrepreneurship at the University of Hawaii

  1. Advice for Contacting Dr. Rafael “Rafi”

    As as an academic and consultant, I am available for year round consulting projects and visiting professor assignments. Contact: [email protected] , LinkedIn messages, Facebook messages.

This was my tribute to a great living legend

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Oct 022014
 

 

Lanoconazole

READ AT http://newdrugapprovals.org/2014/10/02/lanoconazole/

  • Latoconazole, Lanoconazole, TJN-318, NND-318, Astat,

Nihon Nohyaku (Originator), Tsumura (Licensee)

Synonym: 2-[4-(2-Chlorophenyl)-1,3-dithiolan-2-ylidene]-2-imidazol-1-yl-acetonitrile
Application: An antifungal compound
CAS Number: 101530-10-3
Molecular Weight: 319.83
Molecular Formula: C14H10ClN3S2

Brief background information

Technical Information
Appearance: Crystalline
Physical State: Solid
Solubility: Soluble in chloroform, and methanol. Insoluble in water.
Storage: Store at -20° C
Melting Point: 129-132 °C
Boiling Point: ~477.6 °C at 760 mmHg (Predicted)
Density: ~1.4 g/cm3 (Predicted)
Refractive Index: n20D 1.73 (Predicted)
pK Values: pKb: 3.76 (Predicted)
Safety and Reference Information
WGK Germany: 3
RTECS: NI3393500
PubChem CID: 3002820
Merck Index: 14: 5357
MDL Number: MFCD00865590
Beilstein Registry: 4819111
Salt ATC Formula MM CAS
D01 14 H 10 ClN 3 S 2 319.84 g / mol 101530-10-3

Lanoconazole

Application

  • antifungal

Synthesis pathway

Synthesis a)

 

Synthetic route
The reaction of 2- (1-imidazolyl) acetonitrile (I) with CS2 and KOH in DMF gives the dithiolate (II), which is then cyclized with 1- (2-chlorophenyl) -1,2-di (methanesulfonyloxy) ethane . (III) A column chromatography over silicagel allows the separation of the (E) -.? and (Z) -isomers (1-5)
Description Crystals, mp 141-5 Manufacturer Nihon Nohyaku Co., Ltd. (Japan) and Tsumura Juntendo (Japan).
References 1. Seo, A., Kanno, H., Hasegawa, N. et al. (Nihon Nohyaku Co., Ltd.). Antimycotic agent and fungicidal agent. US 4738976. 2. Seo, A ., Sugano, H., Hasegawa, C., Ikeda, K., Munechica, Y., Konoe, T., Konaka, M. (Nihon Nohyaku Co., Ltd.). Antifungal agent. JP 87093227. 3. Seo , A., Sugano, H., Hasegawa, C., Ikeda, K., Nishimura, A., Miyashiro, Y. (Nihon Nohyaku Co., Ltd.). Non-medicinal bactericidal agents and method for their preparation. JP 87093204. 4. Seo, A., Sugano, H., Hasegawa, C., Miyashiro, Y., Nishimura, A., Ikeda, K. (Nihon Nohyaku Co., Ltd.). Ketene S, S-acetals. JP 85218387. 5. Seo, A., Kanno, H., Hasegawa, N. et al. (Nihon Nohyaku Co., Ltd.). A novel ketene S, S-acetal deriv., a process for manufacturing thereof and a method for curing mycosis by administering it. EP 218736.

 

Trade Names

Country Trade name Manufacturer
Japan Astatine Tsumura
Ukraine No No

Formulations

  • 1% cream;
  • 1% ointment;
  • 1% solution

Links

  • EP 218 736 (Nihon Nohyaku; EP-prior. 9.10.1985).
References

1. Oka, H., et al., 1992. Therapeutic efficacy of latoconazole in formulations of clinical use on experimental dermatophytosis in guinea pigs. Arzneimittel-Forschung. 42(3): 345-9. PMID: 1497697
2. Niwano, Y., et al., 1994. Therapeutic efficacy of lanoconazole, a new imidazole antimycotic agent, for experimental cutaneous candidiasis in guinea pigs. Antimicrobial agents and chemotherapy. 38(9): 2204-6. PMID: 7811048

http://aac.asm.org/content/38/9/2204.full.pdf

References 1. Seo, A., Kanno, H., Hasegawa, N. et al. (Nihon Nohyaku Co., Ltd.). Antimycotic agent and fungicidal agent. US 4738976. 2. Seo, A ., Sugano, H., Hasegawa, C., Ikeda, K., Munechica, Y., Konoe, T., Konaka, M. (Nihon Nohyaku Co., Ltd.). Antifungal agent. JP 87093227. 3. Seo , A., Sugano, H., Hasegawa, C., Ikeda, K., Nishimura, A., Miyashiro, Y. (Nihon Nohyaku Co., Ltd.). Non-medicinal bactericidal agents and method for their preparation. JP 87093204. 4. Seo, A., Sugano, H., Hasegawa, C., Miyashiro, Y., Nishimura, A., Ikeda, K. (Nihon Nohyaku Co., Ltd.). Ketene S, S-acetals. JP 85218387. 5. Seo, A., Kanno, H., Hasegawa, N. et al. (Nihon Nohyaku Co., Ltd.). A novel ketene S, S-acetal deriv., a process for manufacturing thereof and a method for curing mycosis by administering it. EP 218736.

 

Title: Lanoconazole
CAS Registry Number: 101530-10-3
CAS Name: (E)-(±)-a-[4-(2-Chlorophenyl)-1,3-dithiolan-2-ylidene]-1H-imidazole-1-acetonitrile
Additional Names: latoconazole
Manufacturers’ Codes: TJN-318; NND-318
Trademarks: Astat (Nihon Nohyaku)
Molecular Formula: C14H10ClN3S2
Molecular Weight: 319.83
Percent Composition: C 52.57%, H 3.15%, Cl 11.08%, N 13.14%, S 20.05%
Literature References: Prepn: A. Soe et al., JP Kokai 85 218387idem et al., US 4636519 (1985, 1987 both to Nihon Nohyaku).In vivo antifungal activity: H. Oka et al., Arzneim.-Forsch. 42, 345 (1992); Y. Niwano et al., Antimicrob. Agents Chemother. 38,2204 (1994). Toxicity study: P. L. Munt et al., Oyo Yakuri 43, 195 (1992).
Properties: Light yellow crystals, mp 141.5°. LD50 in male, female mice, rats (mg/kg): 3224, 2715, 993, 652 orally; 2158, 1743, 1655, 2596 i.p.; >5000 both species s.c. LD50 dermally in rats: >5000 mg/kg (Munt).
Melting point: mp 141.5°
Toxicity data: LD50 in male, female mice, rats (mg/kg): 3224, 2715, 993, 652 orally; 2158, 1743, 1655, 2596 i.p.; >5000 both species s.c.; LD50 dermally in rats: >5000 mg/kg (Munt)
Therap-Cat: Antifungal.
Keywords: Antifungal (Synthetic); Imidazoles.
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New Route to Paricalcitol

 Uncategorized  Comments Off on New Route to Paricalcitol
Sep 102014
 

Paricalcitol3Dan.gif

thumbnail image: New Route to Paricalcitol

Synthesis offers potential routes to analogues of vitamin-D-based drug

Paricalcitol, an A-ring-modified 19-nor analogue of 1α,25-dihydroxyvitamin D2, is currently used for the treatment and prevention of secondary hyperparathyroidism associated with chronic renal failure.

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http://www.chemistryviews.org/details/ezine/6508291/New_Route_to_Paricalcitol.html

 

Paricalcitol.svg

Zemplar; 131918-61-1; 19-Nor-1alpha,25-dihydroxyvitamin D2; Compound 49510; Paracalcin; Zemplar (TN); 19-Nor-1,25-(OH)2D2; CHEBI:7931
Molecular Formula: C27H44O3   Molecular Weight: 416.63646
Abbott (Originator), Tetrionics (Bulk Supplier)
launched 1998
(1R,3R)-5-[(2E)-2-[(1R,3aS,7aR)-1-[(E,2R,5S)-6-hydroxy-5,6-dimethylhept-3-en-2-yl]-7a-methyl-2,3,3a,5,6,7-hexahydro-1H-inden-4-ylidene]ethylidene]cyclohexane-1,3-diol
For treatment of secondary hyperparathyroidism associated with chronic kidney disease (CKD) Stage 3 and 4

Paricalcitol (chemically it is 19-nor-1,25-(OH)2-vitamin D2. Marketed by Abbott Laboratories under the trade name Zemplar) is a drugused for the prevention and treatment of secondary hyperparathyroidism (excessive secretion of parathyroid hormone) associated withchronic renal failure. It is an analog of 1,25-dihydroxyergocalciferol, the active form of vitamin D2 (Ergocalciferol).

Paricalcitol is a synthetic vitamin D analog. Paricalcitol has been used to reduce parathyroid hormone levels. Paricalcitol is indicated for the prevention and treatment of secondary hyperparathyroidism associated with chronic renal failure.

Chemical structure for paricalcitol

Medical uses

Its primary use in medicine is in the treatment of secondary hyperparathyroidism associated with chronic kidney disease.[2] In three placebo-controlled studies, chronic renal failure patients treated with paricalcitol achieved a mean parathyroid hormone (PTH) reduction of 30% in six weeks. Additionally there was no difference in incidence of hypercalcemia or hyperphosphatemia when compared to placebo.[3] A double-blind randomised study with 263 dialysis patients showed a significant advantage over calcitriol (also known as activated vitamin D3; a similar molecule to 1,25-dihydroxyergocalciferol, adding a methyl group on C24 and lacking a double-bond in the C22 position). After 18 weeks, all patients in the paricalcitol group had reached the target parathormone level of 100 to 300 pg/ml, versus none in the calcitriol group.[4] Combination therapy with paricalcitol and trandolapril has been found to reduce fibrosis inobstructive uropathy.[5] Forty-eight week therapy with paricalcitol did not alter left ventricular mass index or improve certain measures of diastolic dysfunction in 227 patients with chronic kidney disease.[6]

Patents

Country Patent Number Approved Expires (estimated)
United States 6136799 1998-10-08 2018-10-08
United States 5246925 1995-04-17 2012-04-17

Mechanism of action

3D structure of paricalcitol

Like 1,25-dihydroxyergocalciferol, paricalcitol acts as an agonist for the vitamin D receptor and thus lowers the bloodparathyroid hormone level.[1]

Pharmacokinetics

Within two hours after administering paricalcitol intravenous doses ranging from 0.04 to 0.24 µg/kg, concentrations of paricalcitol decreased rapidly; thereafter, concentrations of paricalcitol declined log-linearly. No accumulation of paricalcitol was observed with multiple dosing.[9]

 

vitamin D is a fat-soluble vitamin. It is found in food, but also can be formed in the body after exposure to ultraviolet rays. Vitamin D is known to exist in several chemical forms, each with a different activity. Some forms are relatively inactive in the body, and have limited ability to function as a vitamin. The liver and kidney help convert vitamin D to its active hormone form. The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain healthy bones.

The 19-nor vitamin D analogue, Paricalcitol (I), is characterized by the following formula:

Figure US20070149489A1-20070628-C00001

 

In the synthesis of vitamin D analogues, a few approaches to obtain a desired active compound have been outlined previously. One of the methods is the Wittig-Homer attachment of a 19-nor A-ring phosphine oxide to a key intermediate bicyclic-ketone of the Windaus-Grundmann type, to obtain the desired Paricalcitol, as is shown for example in U.S. Pat. Nos. 5,281,731 and 5,086,191 of DeLuca.

The synthesis of Paricalcitol requires many synthetic steps which produce undesired by-products. Therefore, the final product may be contaminated not only with a by-product derived from the last synthetic step of the process but also with compounds that were formed in previous steps. In the United States, the Food and Drug Administration guidelines recommend that the amounts of some impurities be limited to less than 0.1 percent.

U.S. Pat. Nos. 5,281,731 and 5,086,191 of DeLuca disclose a purification process of Paricalcitol by using a HPLC preparative method.

As the unwanted products have almost the same structure as the final product, it may difficult to get a sufficiently pure drug substance, vitamin D analogue, using this route to purify the drug substance. Moreover, the high polarity of Paricalcitol makes it very difficult to purify by HPLC and to recover the solid product. Furthermore, HPLC preparative methods are generally not applicable for use on industrial scale. There remains a need in the art to provide a method of preparing the vitamin D analogue Paricalcitol in a sufficiently pure form which is applicable for use on an industrial scale.

 

Paricalcitol (chemical name: 19-nor-1α,3β,25-trihydroxy-9,10-secoergosta-5(Z),7(Z),22(E)-triene; Synonyms: 19-nor-1,25-dihydroxyvitamin D2, Paracalcin) is a synthetic, biologically active vitamin D analog of calcitriol with modifications to the side chain (D2) and the A (19-nor) ring. Paricalcitol inhibits the secretion of parathyroids hormone (PTH) through binding to the vitamin D receptor (D. M. Robinson, L. J. Scott, Drugs, 2005, 65 (4), 559-576) and it is indicated for the prevention and treatment of secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD).

Paricalcitol is marketed under the name Zemplar®, which is available as a sterile, clear, colorless, aqueous solution for intravenous injection (each mL contains 2 microgram (2 μg) or 5 μg paricalcitol as active ingredient) or as soft gelatin capsules for oral administration containing 1 μg, 2 μg or 4 μg paricalcitol.

The molecular formula of paricalcitol is C27H44O3 which corresponds to a molecular weight of 416.65. It is a white, crystalline powder and has the following structural formula:

 

 

Historically, nor-vitamin D compounds were described in 1990 as a new class of vitamin D analogs wherein the exocyclic methylene group C(19) in ring A has been removed and replaced by two hydrogen atoms (see e.g. WO 90/10620). So far, two different routes have been discovered for the synthesis of such 19-nor-vitamin analogs which specifically may be used for the preparation of paricalcitol.

The first synthesis of paricalcitol is disclosed in WO 90/10620 (additional patents from patent family: EP patent no. 0 387 077, U.S. Pat. No. 5,237,110, U.S. Pat. No. 5,342,975, U.S. Pat. No. 5,587,497, U.S. Pat. No. 5,710,294 and U.S. Pat. No. 5,880,113) and generally described in Drugs of the Future, 1998, 23, 602-606.

Example 3 of WO 90/10620 provides the preparation of 1α,25-dihydroxy-19-nor-vitamin D2 (Scheme 1) by using experimental conditions analogous to the preparation of 1α,25-dihydroxy-19-nor-vitamin D3. According to this description the starting material 25-hydroxyvitamin D2 is first converted to 1α,25-dihydroxy-3,5-cyclovitamin D2 (a2) using the procedures published by DeLuca et al. in U.S. Pat. No. 4,195,027 and Paaren et al. published in J. Org. Chem., 1980, 45, 3252. Acetylation of compound a2 followed by dihydroxylation of the exocyclic methylene group using osmium tetroxide in pyridine gives the 10,19-dihydroxy compound a4 which is converted with sodium metaperiodate (diol cleavage) to the 10-oxo-intermediate a5. Reduction of the 10-oxo group in a5 is carried out by treatment with sodium borohydride in a mixture of ethanol and water giving the corresponding 10-hydroxy derivative a6. Mesylation of the 10-hydroxy group in a6 (→a7) followed by reduction with lithium aluminium hydride in THF gives the 10-deoxy intermediate a8 wherein the 1-OAcyl group was simultaneously cleaved during the reduction step. Solvolysis (cycloreversion) of a8 by treatment with hot (55° C.) acetic acid results in the formation of two monoacetates (a9 and a10) which are separated and purified by using HPLC. Finally both monoacetates are saponified with aqueous potassium hydroxide in methanol yielding paricalcitol which is purified by HPLC.

The preparation of paricalcitol according to the method provided in WO 90/10620 has several drawbacks:

    • (1) the starting material 25-hydroxyvitamin D2 is one of the major metabolites of vitamin D2 and not readily available in larger amounts. Additional efforts have to be made in order to synthesize the starting material in sufficient amounts resulting in a protractive and unattractive total synthesis of paricalcitol. Examples for the preparation of 25-hydroxyvitamin D2 are described e.g. in U.S. Pat. No. 4,448,721; WO 91/12240; Tetrahedron Letters, 1984, 25, 3347-3350; J. Org. Chem., 1984, 49, 2148-2151 and J. Org. Chem., 1986, 51, 1264-1269;
    • (2) the use of highly toxic osmium tetroxide which requires special precaution for its handling;
    • (3) use of HPLC for separation of isomers and purification of the final compound. As teached in WO 2007/011951 paricalcitol is difficult to purify by HPLC and as a preparative method HPLC is generally not applicable for use on industrial scale;
    • (4) the yields for the preparation of paricalcitol are not described in WO 90/10620. Generally, the provided yields for the preparation of the analogue compound 1α,25-dihydroxy-19-nor-vitamin D3 are very low especially for the corresponding steps 7 to 11 (yield starting from 1α,25-dihydroxy-10-oxo-3,5-cyclo-19-nor-vitamin D3 1-acetate which is the vitamin D3 analogue to a5 in Scheme1: step 7: 63.4%, steps 8-10: 10.7%, step 11: 51.7%; overall yield starting with step 7: 3.5%).

 

 

Another strategy for synthesizing 19-nor vitamin D compounds is disclosed in EP 0 516 410 (and corresponding U.S. Pat. No. 5,281,731, U.S. Pat. No. 5,391,755, U.S. Pat. No. 5,486,636, U.S. Pat. No. 5,581,006, U.S. Pat. No. 5,597,932 and U.S. Pat. No. 5,616,759). The concept is based on condensing of a ring-A unit, as represented by structure b1 (Scheme 2), with a bicyclic ketone of the Windaus-Grundmann type, structure b2, to obtain 19-nor-vitamin D compound (b3).

 

 

Specific methods for synthesizing compounds of formula b1 are shown in Schemes 3, 4 and 5. According to Scheme 3, the route starts with the commercially available (1R,3R,4R,5R)(−)quinic acid (b4). Esterification of b4 with methanol followed by protection of the l- and 3-hydroxygroup using tert.-butyldimethylsilyl chloride (TBDMSCl) gives compound b5. Reduction of the ethyl ester in b5 yields b6 which is subjected to a diol cleavage giving compound b7. The 4-hydroxy group is protected as trimethylsilylether resulting in the formation of b8 which is further converted in a Peterson reaction with ethyl (trimethylsilyl)acetate before being deprotected with dilute acetic acid in tetrahydrofurane (THF). The resulting compound b9 is treated with 1,1-thiocarbonyldiimidazole to obtain b10. Subsequent reaction with tributyltin hydride in the presence of a radical initiator (AIBN) gives b11. Compound b11 is then reduced with DIBAH to the allylalcohol b12 which is then reacted with NCS and dimethyl sulfide giving the allylchloride b13. Finally the ring A synthon b14 is prepared by treatment of the allychloride b13 with lithium diphenylphosphide followed by oxidation with hydrogen peroxide.

In an alternative method for synthesizing the ring A unit (Scheme 3), the intermediate b5 can be also subjected to radical deoxygenation using analogues conditions as previously described, resulting in the formation of b16. Reduction of the ester (→b17), followed by diol cleavage (→b18) and Peterson reaction gives intermediate b11 which can be further processed to b14 as outlined in Scheme 3.

Another modification for the preparation is shown in Scheme 5. As described, b7 can be also subjected to the radical deoxygenation yielding intermediate b18 which can be further processed to b14 as depicted in Schemes 3 and 4.

 

 

 

 

 

 

In EP 0 516 411 (and its counterpart, U.S. Pat. No. 5,086,191) is disclosed the preparation of intermediates useful for the synthesis of 19-nor vitamin D compounds (Scheme 6). The key step is the condensation of compounds c1 which can be prepared in an analogous manner as previously described for e.g. b14 (Scheme 3) with compounds c2, resulting in compounds of formula c3.

 

 

EP 0 516 411 discloses that Grignard coupling of hydroxy-protected 3-hydroxy-3-methylbutylmagnesium bromide with compound c5 (Scheme 7) can give hydroxy-protected 1α,25-dihydroxy-19-nor vitamin D3 or coupling of the corresponding 22-aldehyde c3 (X1=X2=TBDMS, R1=—CHO) with 2,3-dimethylbutyl phenylsulphone can give after desulfonylation, 1α-hydroxy-19-norvitamin d2 in hydroxy-protected form.

 

 

An additional method for preparation of 1α-hydroxy-19-nor-vitamin D compounds is provided in EP 0 582 481 (and corresponding U.S. Pat. No. 5,430,196, U.S. Pat. No. 5,488,183, U.S. Pat. No. 5,525,745, U.S. Pat. No. 5,599,958, U.S. Pat. No. 5,616,744 and U.S. Pat. No. 5,856,536) (Scheme 8). Similar to the strategy as described above and shown in schemes 3 to 7, the basis for preparing 1α-hydroxy-19-nor-vitamin D compounds is an independent synthesis of ring A synthon and ring C/D synthon which are finally coupled resulting in vitamin analogs.

Thus the synthesis of 1α-hydroxy-19-nor-vitamin D compounds comprises the coupling of either the ketone d1 with the acetylenic derivatives d2 or ketone d4 with acetylenic derivatives d3, yielding compounds of formula d5. Partial reduction of the triple bond giving d6 followed by reduction using low-valent titanium reducing agents results in the formation of 7,8-cis and 7,8-trans-double bond isomers (d7). Compounds of formula d7 can be also obtained directly from d5 by reaction of d5 with a metal hydride/titanium reducing agent. The isomeric mixture of compounds of formula d7 may be separated by chromatography to obtain separately the 7,8-trans-isomer. The 7,8-cis-isomer of structure d7 can be isomerized to yield the corresponding 7,8-trans-isomer. Finally any protecting groups, if present, can be then removed to obtain 1α-hydroxy-19-nor-vitamin D compounds.

 

 

The main disadvantage of the strategies as shown in Schemes 3 to 8 is the fact that ring A as well as ring C/D of the vitamin D derivative has to be separately synthesized before coupling them to compounds like 1α-hydroxy-nor-vitamin D or a protected precursor thereof. According to literature procedure, the ring fragment C/D can be prepared from vitamin D2 by ozonolysis (see e.g. J. C. Hanekamp et al., Tetrahedron, 1992, 48, 9283-9294) from which the ring A is cleaved (and disposed). This fragment has then to be separately synthesized e.g. by using other sources or starting materials like quinic acid in up to 10 steps or more. Therefore such strategies for the total synthesis of 1α-hydroxy-nor-vitamin D compounds become protractive and unattractive for large scale and according to the procedures provided in these patents, the final compounds are obtained only in amounts of <10 mg and in most cases even <1 mg.

Paricalcitol is an active Vitamin D Analog. Paricalcitol is used for the treatment and prevention of secondary hyperparathyroidism associated with chronic kidney disease.

It has been shown to reduce parathyroid hormone levels by inhibiting its synthesis and secretion.

…………………………….

 

 

………………………………….

 

The 25-hydroxyvitamin D2 (I) is converted into the cyclovitamin D2 acetate (II) according to known methods. The dihydroxylation of the methylene group of (II) with OsO4 in pyridine gives vicinal diol (III), which is oxidized with NaIO4 yielding the ketonic cyclovitamin (IV). The reduction of the ketonic group of (IV) with NaBH4 in ethanol/water affords the corresponding hydroxy derivative (V), which is treated with mesyl chloride and triethylamine to give the mesylate (VI). The reduction of (VI) with LiAlH4 in THF yields the 19-nor-cyclovitamin D (VII), which is treated with hot acetic acid to afford both monoacetates (VIII) and (IX), separated by HPLC. Finally, both monoacetates (VIII) and (IX) are hydrolyzed with KOH in methanol.

…………………………

EXAMPLEShttp://www.google.com/patents/US20070149489

 

HPLC method:
Column: Hypersyl Gold (250 × 4.6 5 μm)
Mobile phase: (A) water (95%)
(B) acetonitrile (5%)
Gradient: From 0 to 10 min (A) isocraticaly
From 10 to 30 min (B) increases from 0 to 55%
From 30 to 40 min (A) isocraticaly
From 30 to 40 min (B) increases from 55 to 100%
Detection: 252 nm
Flow: 2 mL/min
Detection limit: 0.02%

 

Example 1 Crystallization of Paricalcitol from Acetone

500 mg of Paricalcitol were dissolved in 75 ml of acetone in a sonicator at 28° C. over a period of 15 minutes. The clear solution was filtered through glass wool into another flask, and the solution was then concentrated by evaporation, until the volume was 57.5 ml acetone (control by weight). The solution was cooled to −18° C., and the temperature was maintained at −18° C. for 20 hours. The crystals were filtered and washed with 20 ml of cold (−18° C.) acetone, then dried at high vacuum in an oven at 28° C. for 22 hours to obtain a yield of 390 mg (purity of 98.54%).

 

………………………………………………………….

http://www.google.com/patents/US20110184199

 

FIG. 3 is a flow chart showing a detailed example for the synthesis of paricalcitol according to route A1.

FIG. 4 is a flow chart showing the general synthesis of paricalcitol according to route A1.

FIG. 5 is a flow chart showing a detailed example for the synthesis of paricalcitol according to route B1.

FIG. 6 is a flow chart showing the general synthesis of paricalcitol according to route B1.

FIG. 7 is a flow chart showing the general synthesis of paricalcitol using Julia olefination for installation of the side chain according to route B2.

FIG. 8 is a flow chart showing a detailed example for the synthesis of paricalcitol according to route C1.

FIG. 9 is a flow chart showing the general synthesis of paricalcitol according to route C1.

FIG. 10 is a flow chart showing the general synthesis of paricalcitol using Julia olefination for installation of the side chain according to route C2.

 

Example B11Process Step 12Deprotection of IM-A10b(I) and IM-A10b(II) to Paricalcitol

 

 

A mixture consisting of IM-A10b(I) and IM-A10b(II) (41 mg, HPLC purity 54.8%) was dissolved in 1M TBAF in THF (1.5 mL) at temperature 20-25° C. and stirred for 2 h. Then, the reaction mixture was diluted with MeOH (1.5 mL) and 2M aqueous NaOH (0.3 mL) was added. The mixture was stirred for another 2 h and monitored by TLC. Then AcOEt (20 mL) and saturated aqueous NaHCO3 solution (20 mL) were added and the phases separated. The organic phase was washed with brine (20 mL), dried over MgSO4 and concentrated under reduced pressure. The product was purified by column chromatography on silica gel (15 g), with mobile phase cyclohexane/AcOEt (100:0 to 92:8).

Yield 11 mg (81%).

In an additional purification, the product (Paricalcitol, 11 mg) was dissolved in acetone (1 mL) at 35-40° C. The solution was filtered and then cooled to −18° C. to initiate crystallization. The obtained slurry was stirred for 15 min at room temperature (20-25° C.) and again cooled to −18° C. for 3.5 h. The solid material was filtered off, washed with cold (−18° C.) acetone (0.25 mL) and dried in vacuo (6 mbar, 40° C.).

Yield of paricalcitol: 4 mg (36%, HPLC purity 98.3%)

 

Example C7Process Step 12Hydrolysis of IM-A11a to Paricalcitol

 

 

To a solution of IM-A11a(I) and IM-A11a(II) (5.24 g, HPLC-purity 94.2%) in EtOH (80 mL) was added at room temperature (20-25° C.) 2M aqueous NaOH solution (8 mL). The reaction mixture was stirred for 1 h 20 min (TLC monitoring), then EtOAc (8 mL) was added and the mixture was concentrated under reduced pressure to a volume of 40 mL whereupon the crystallization started. Water (50 mL) was added to the suspension and after stirring for 75 min at room temperature the solid was isolated by filtration (pH of the mother liquor measured 8-9). The wet product was slurried in EtOH/H2O (24 g, 1:1) at room temperature, filtered, washed with EtOH/H2O (5 mL, 1:1) and dried (40° C., 10 mbar).

Yield of paricalcitol: 4.26 g (89.5%, HPLC-purity 97.7%).

 

…………………………………………………..

 

US5854390 * Feb 6, 1996 Dec 29, 1998 Lek, Tovarna Farmacevtskih In Kemicnih Izdelkov, D.D. Chromatographic purification of vancomycin hydrochloride by use of preparative HPLC
US6448421 * Jun 16, 1997 Sep 10, 2002 Chugai Seiyaku Kabushiki Kaisha Purifying a crude product derivative through a reverse phase chromatography and then crystallizing from an organic solvent; oxy gonane and indene, cyclohexyl derivatives
US20070149489 * Jul 18, 2006 Jun 28, 2007 Anchel Schwartz Preparation of paricalcitol
US7795459 * Apr 28, 2009 Sep 14, 2010 Alphora Research Inc. Paricalcitol purification
US20110137058 * Feb 15, 2011 Jun 9, 2011 Formosa Laboratories, Inc. Preparation of paricalcitol
DE102009013609A1 Mar 17, 2009 Nov 5, 2009 Formosa Laboratories, Inc. Herstellung von Paricalcitol

References

  1.  “Zemplar (paricalcitol) dosing, indications, interactions, adverse effects, and more”Medscape Reference. WebMD. Retrieved 26 January 2014.
  2.  Rossi, S, ed. (2013). Australian Medicines Handbook (2013 ed.). Adelaide: The Australian Medicines Handbook Unit Trust. ISBN 978-0-9805790-9-3edit
  3.  “Zemplar: Drug Information”
  4.  Schubert-Zsilavecz, M, Wurglics, M, Neue Arzneimittel 2005/2006 (in German).
  5.  Tan, X; He, W; Liu, Y (2009). “Combination therapy with paricalcitol and trandolapril reduces renal fibrosis in obstructive nephropathy”. Kidney international 76 (12): 1248–57.doi:10.1038/ki.2009.346PMID 19759524.
  6.  Thadhani, R; Appelbaum, E; Pritchett, Y; Chang, Y; Wenger, J; Tamez, H; Bhan, I; Agarwal, R et al. (2012). “Vitamin D Therapy and Cardiac Structure and Function in Patients With Chronic Kidney Disease – The PRIMO Randomized Controlled Trial”. JAMA 307 (7): 674–684. doi:10.1001/jama.2012.120PMID 22337679.
  7.  “PARICALCITOL capsule, liquid filled [Teva Pharmaceuticals USA Inc]” (PDF). DailyMed. Teva Pharmaceuticals USA Inc. September 2013. Retrieved 26 January 2014.
  8.  “Zemplar Soft Capsules 1 mcg – Summary of Product Characteristics”electronic Medicines Compendium. AbbVie Limited. 15 April 2013. Retrieved 26 January 2014.
  9.  Rxlist: Zemplar
  10. Anchel Schwartz, Alexei Ploutno, Koby Wolfman, “Preparation of paricalcitol.” U.S. Patent US20070149489, issued June 28, 2007.US20070149489 
Systematic (IUPAC) name
(1R,3R,7E,17β)-17-[(1R,2E,4S)-5-hydroxy-1,4,5-trimethylhex-2-en-1-yl]-9,10-secoestra-5,7-diene-1,3-diol
Clinical data
Trade names Zemplar
AHFS/Drugs.com monograph
MedlinePlus a682335
Pregnancy cat.
Legal status
Routes Oral, Intravenous
Pharmacokinetic data
Bioavailability 72%[1]
Protein binding 99.8%[1]
Metabolism Hepatic[1]
Half-life 14-20 hours[1]
Excretion Faeces (74%), urine (16%)[1]
Identifiers
CAS number 131918-61-1 Yes
ATC code H05BX02
PubChem CID 5281104
IUPHAR ligand 2791
DrugBank DB00910
ChemSpider 4444552 Yes
UNII 6702D36OG5 Yes
 
ChEMBL CHEMBL1200622 Yes
Synonyms (1R,3S)-5-[2-[(1R,3aR,7aS)-1-[(2R,5S)-6-hydroxy-5,6-dimethyl-3E-hepten-2-yl]-7a-methyl-2,3,3a,5,6,7-hexahydro-1H-inden-4-ylidene]ethylidene]-cyclohexane-1,3-diol
Chemical data
Formula C27H44O3 
Mol. mass 416.636 g/mol

more………….

 

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FDA approves Keytruda for advanced melanoma, First PD-1 blocking drug to receive agency approval

 MONOCLONAL ANTIBODIES, Uncategorized  Comments Off on FDA approves Keytruda for advanced melanoma, First PD-1 blocking drug to receive agency approval
Sep 052014
 

September 4, 2014

FDA Release

The U.S. Food and Drug Administration today granted accelerated approval to Keytruda (pembrolizumab) for treatment of patients with advanced or unresectable melanoma who are no longer responding to other drugs.

Melanoma, which accounts for approximately 5 percent of all new cancers in the United States, occurs when cancer cells form in skin cells that make the pigment responsible for color in the skin. According to the National Cancer Institute, an estimated 76,100 Americans will be diagnosed with melanoma and 9,710 will die from the disease this year.

Keytruda is the first approved drug that blocks a cellular pathway known as PD-1, which restricts the body’s immune system from attacking melanoma cells. Keytruda is intended for use following treatment with ipilimumab, a type of immunotherapy. For melanoma patients whose tumors express a gene mutation called BRAF V600, Keytruda is intended for use after treatment with ipilimumab and a BRAF inhibitor, a therapy that blocks activity of BRAF gene mutations.

“Keytruda is the sixth new melanoma treatment approved since 2011, a result of promising advances in melanoma research,” said Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “Many of these treatments have different mechanisms of action and bring new options to patients with melanoma.”

The five prior FDA approvals for melanoma include: ipilimumab (2011), peginterferon alfa-2b (2011), vemurafenib (2011), dabrafenib (2013), and trametinib (2013).

The FDA granted Keytruda breakthrough therapy designation because the sponsor demonstrated through preliminary clinical evidence that the drug may offer a substantial improvement over available therapies. It also received priority review and orphan product designation. Priority review is granted to drugs that have the potential, at the time the application was submitted, to be a significant improvement in safety or effectiveness in the treatment of a serious condition. Orphan product designation is given to drugs intended to treat rare diseases.

The FDA action was taken under the agency’s accelerated approval program, which allows approval of a drug to treat a serious or life-threatening disease based on clinical data showing the drug has an effect on a surrogate endpoint reasonably likely to predict clinical benefit to patients. This program provides earlier patient access to promising new drugs while the company conducts confirmatory clinical trials. An improvement in survival or disease-related symptoms has not yet been established.

Keytruda’s efficacy was established in 173 clinical trial participants with advanced melanoma whose disease progressed after prior treatment. All participants were treated with Keytruda, either at the recommended dose of 2 milligrams per kilogram (mg/kg) or at a higher dose of 10 mg/kg. In the half of the participants who received Keytruda at the recommended dose of 2 mg/kg, approximately 24 percent had their tumors shrink. This effect lasted at least 1.4 to 8.5 months and continued beyond this period in most patients. A similar percentage of patients had their tumor shrink at the 10 mg/kg dose.

Keytruda’s safety was established in the trial population of 411 participants with advanced melanoma. The most common side effects of Keytruda were fatigue, cough, nausea, itchy skin (pruritus), rash, decreased appetite, constipation, joint pain (arthralgia) and diarrhea. Keytruda also has the potential for severe immune-mediated side effects. In the 411 participants with advanced melanoma, severe immune-mediated side effects involving healthy organs, including the lung, colon, hormone-producing glands and liver, occurred uncommonly.

Keytruda is marketed by Merck & Co., based in Whitehouse Station, New Jersey.

 

 

 

Pembrolizumab, LambrolizumabMK-3475

STRUCTURAL FORMULA
Heavy chain
QVQLVQSGVE VKKPGASVKV SCKASGYTFT NYYMYWVRQA PGQGLEWMGG 50
INPSNGGTNF NEKFKNRVTL TTDSSTTTAY MELKSLQFDD TAVYYCARRD 100
YRFDMGFDYW GQGTTVTVSS ASTKGPSVFP LAPCSRSTSE STAALGCLVK 150
DYFPEPVTVS WNSGALTSGV HTFPAVLQSS GLYSLSSVVT VPSSSLGTKT 200
YTCNVDHKPS NTKVDKRVES KYGPPCPPCP APEFLGGPSV FLFPPKPKDT 250
LMISRTPEVT CVVVDVSQED PEVQFNWYVD GVEVHNAKTK PREEQFNSTY 300
RVVSVLTVLH QDWLNGKEYK CKVSNKGLPS SIEKTISKAK GQPREPQVYT 350
LPPSQEEMTK NQVSLTCLVK GFYPSDIAVE WESNGQPENN YKTTPPVLDS 400
DGSFFLYSRL TVDKSRWQEG NVFSCSVMHE ALHNHYTQKS LSLSLGK 447
Light chain
EIVLTQSPAT LSLSPGERAT LSCRASKGVS TSGYSYLHWY QQKPGQAPRL 50′
LIYLASYLES GVPARFSGSG SGTDFTLTIS SLEPEDFAVY YCQHSRDLPL 100′
TFGGGTKVEI KRTVAAPSVF IFPPSDEQLK SGTASVVCLL NNFYPREAKV 150′
QWKVDNALQS GNSQESVTEQ DSKDSTYSLS STLTLSKADY EKHKVYACEV 200′
THQGLSSPVT KSFNRGEC 218′
Disulfide bridges
22-96 22”-96” 23′-92′ 23”’-92”’ 134-218′ 134”-218”’ 138′-198′ 138”’-198”’
147-203 147”-203” 226-226” 229-229” 261-321 261”-321” 367-425 367”-425”
Glycosylation sites (N)
Asn-297 Asn-297”
lambrolizumab, or MK-3475

1374853-91-4

C6504H10004N1716O2036S46 (peptide)
MOL. MASS 146.3 kDa (peptide)

Pembrolizumab, Lambrolizumab (also known as MK-3475) is a drug in development by Merck that targets the PD-1 receptor. The drug is intended for use in treating metastatic melanoma.

http://www.ama-assn.org/resources/doc/usan/lambrolizumab.pdf  structureof lambrolizumab, or MK-3475

https://download.ama-assn.org/resources/doc/usan/x-pub/pembrolizumab.pdf  

Statement on a Nonproprietary Name Adopted by the USAN Council. November 27, 2013.

see above link for change in name

may 2, 2013,

An experimental drug from Merck that unleashes the body’s immune system significantly shrank tumors in 38 percent of patients with advanced melanoma, putting the company squarely in the race to bring to market one of what many experts view as the most promising class of drugs in years.

The drugs are attracting attention here at the annual meeting of the American Society of Clinical Oncology, even though they are still in the early stage of testing. Data from drugs developed by Bristol-Myers Squibb and by Roche had already been released.

The drugs work by disabling a brake that prevents the immune system from attacking cancer cells. The brake is a protein on immune system cells called programmed death 1 receptor, or PD-1.

Merck’s study, which was presented here Sunday and also published in the New England Journal of Medicine, involved 135 patients. While tumors shrank in 38 percent of the patients over all, the rate was 52 percent for patients who got the highest dose of the drug, which is called lambrolizumab, or MK-3475.

But that is what is disclosed tonight, as to pembrolizumab, or MK-3475. Wow. With over $44 billion in 2013 worldwide revenue, that disclosure implies (to seasoned SEC lawyers) that spending on this one drug (or, biologic, to be more technical about it — but remember 40 years ago, Merck had no protein chain biologics research & development programs in its pipe — only chemical drug compounds). . . is material, to that number. Normally that would, in turn, mean that the spending is approaching 5 per cent of revenue. So — Merck may be spending $2.2 billion over the next 12 rolling months, on MK-3475. That’s one BIGhairy science bet, given that Whitehouse Station likely already had over $2 billion invested in the program, at year end 2013.

About Pembrolizumab
Pembrolizumab (MK-3475) is an investigational selective, humanized monoclonal anti-PD-1 antibody designed to block the interaction of PD-1 on T-cells with its ligands, PD-L1 and PD-L2, to reactivate anti-tumor immunity. Pembrolizumab exerts dual ligand blockade of PD-1 pathway.
Today, pembrolizumab is being evaluated across more than 30 types of cancers, as monotherapy and in combination. It is anticipated that by the end of 2014, the pembrolizumab development program will grow to more than 24 clinical trials across 30 different tumor types, enrolling an estimated 6,000 patients at nearly 300 clinical trial sites worldwide, including new Phase 3 studies in head and neck and other cancers. For information about Merck’s oncology clinical studies, please click here.
The Biologics License Application (BLA) for pembrolizumab is under priority review with the U.S. Food and Drug Administration (FDA) for the proposed indication for the treatment of patients with advanced melanoma previously-treated with ipilimumab; the PDUFA date is October 28, 2014. Pembrolizumab has been granted FDA’s Breakthrough Therapy designation for advanced melanoma. If approved by the FDA, pembrolizumab has the potential to be the first PD-1 immune checkpoint modulator approved in this class. The company plans to file a Marketing Authorization Application in Europe for pembrolizumab for advanced melanoma in 2014.
About Head and Neck Cancer
Head and neck cancers are a related group of cancers that involve the oral cavity, pharynx and larynx. Most head and neck cancers are squamous cell carcinomas that begin in the flat, squamous cells that make up the thin surface layer (epithelium) of the head and neck (called the). The leading risk factors for head and neck cancer include tobacco and alcohol use. Infection with certain types of HPV, also called human papillomaviruses, is a risk factor for some types of head and neck cancer, specifically cancer of the oropharynx, which is the middle part of the throat including the soft palate, the base of the tongue, and the tonsils. Each year there are approximately 400,000 cases of cancer of the oral cavity and pharynx, with 160,000 cancers of the larynx, resulting in approximately 300,000 deaths.


About Merck Oncology: A Focus on Immuno-Oncology
At Merck Oncology, our goal is to translate breakthrough science into biomedical innovations to help people with cancer worldwide. Harnessing immune mechanisms to fight cancer is the priority focus of our oncology research and development program. The Company is advancing a pipeline of immunotherapy candidates and combination regimens. Cancer is one of the world’s most urgent unmet medical needs. Helping to empower people to fight cancer is our passion. For information about Merck’s commitment to Oncology visit the Oncology Information Center at http://www.mercknewsroom.com/oncology-infocenter.


About Merck
Today’s Merck is a global healthcare leader working to help the world be well. Merck is known as MSD outside the United States and Canada. Through our prescription medicines, vaccines, biologic therapies, and consumer care and animal health products, we work with customers and operate in more than 140 countries to deliver innovative health solutions. We also demonstrate our commitment to increasing access to healthcare through far-reaching policies, programs and partnerships. For more information, visit www.merck.com and connect with us on Twitter, Facebook and YouTube.

 

Hamid, O; Robert, C; Daud, A; Hodi, F. S.; Hwu, W. J.; Kefford, R; Wolchok, J. D.; Hersey, P; Joseph, R. W.; Weber, J. S.; Dronca, R; Gangadhar, T. C.; Patnaik, A; Zarour, H; Joshua, A. M.; Gergich, K; Elassaiss-Schaap, J; Algazi, A; Mateus, C; Boasberg, P; Tumeh, P. C.; Chmielowski, B; Ebbinghaus, S. W.; Li, X. N.; Kang, S. P.; Ribas, A (2013). “Safety and tumor responses with lambrolizumab (anti-PD-1) in melanoma”. New England Journal of Medicine 369 (2): 134–44. doi:10.1056/NEJMoa1305133PMID 23724846

key words
FDA,  approved,  Keytruda,  advanced melanoma, PD-1 blocking drug, pembrolizumab, LambrolizumabMK-3475, Monoclonal antibody

 

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