AUTHOR OF THIS BLOG

DR ANTHONY MELVIN CRASTO, WORLDDRUGTRACKER

Yonkenafil

 phase 2  Comments Off on Yonkenafil
Jun 292016
 

Yonkenafil

Mw 487.61, MF C₂₄H₃₃N₅O₄S,

Cas 804518-63-6

4H-Pyrrolo[2,3-d]pyrimidin-4-one, 2-[2-ethoxy-5-[(4-ethyl-1-piperazinyl)sulfonyl]phenyl]-3,7-dihydro-5-methyl-7-propyl-,

2- [2-ethoxy –5- (4 – ethylpiperazine -1– sulfonyl) phenyl] -5 – methyl – 7 – n-Propyl-3 7 – PYRROLINE [2, 3 – d] pyrimidin – 4 – one

Phase2  Erectile dysfunction

扬子江药业 (Originator), 天士力制药 (Originator)

phosphodiesterase type 5 (PDE5) inhibitor

  • Originator Tasly Pharmaceutical Group; Yangtze River Pharmaceutical Group
  • Class Erectile dysfunction therapies
  • Mechanism of Action Type 5 cyclic nucleotide phosphodiesterase inhibitors

str1.jpg

Yonkenafil Hydrochloride

Molecular Weight 524.08
Formula C24H33N5O4S • HCl

804518-63-6 (Yonkenafil);
804519-64-0 (Yonkenafil Hydrochloride);

4H-Pyrrolo[2,3-d]pyrimidin-4-one, 2-[2-ethoxy-5-[(4-ethyl-1-piperazinyl)sulfonyl]phenyl]-3,7-dihydro-5-methyl-7-propyl-, hydrochloride (1:1)

2- [2-ethoxy –5- (4 – ethylpiperazine -1– sulfonyl) phenyl] -5 – methyl – 7 – n-Propyl-3 7 – PYRROLINE [2, 3 – d] pyrimidin – 4 – one

Yonkenafil hydrochloride, useful for treating erectile dysfunction and other PDE-5 mediated diseases eg female sexual dysfunction, benign prostatic hyperplasia, hypertension, allergic asthma, bronchitis, glaucoma, gastrointestinal motility disorders or Alzheimer’s Ydisease.

Yangtze River Pharmaceutical, under license from Jilin University, is developing yonkenafil (appears to be first disclosoed in WO2004108726), a PDE-5 inhibitor, for treating male erectile dysfunction.

In June 2016, yonkenafil was reported to be in phase 2 clinical development.

Yonkenafil hydrochloride is in phase II clinical trials for the treatment of erectile dysfunction (ED).

The compound was co-developed by Yangtze River Pharmaceutical and Tianjin Tasly Pharm.

Yonkenafil is a novel phosphodiesterase type 5 (PDE5) inhibitor. Here we evaluated the effect of yonkenafil on ischemic injury and its possible mechanism of action. Male Sprague-Dawley rats underwent middle cerebral artery occlusion, followed by intraperitoneal or intravenous treatment with yonkenafil starting 2h later. Behavioral tests were carried out on day 1 or day 7 after reperfusion. Nissl staining, Fluoro-Jade B staining and electron microscopy studies were carried out 24h post-stroke, together with an analysis of infarct volume and severity of edema. Levels of cGMP-dependent Nogo-66 receptor (Nogo-R) pathway components, hsp70, apaf-1, caspase-3, caspase-9, synaptophysin, PSD-95/neuronal nitric oxide synthases (nNOS), brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) and nerve growth factor (NGF)/tropomyosin-related kinase A (TrkA) were also measured after 24h. Yonkenafil markedly inhibited infarction and edema, even when administration was delayed until 4h after stroke onset. This protection was associated with an improvement in neurological function and was sustained for 7d. Yonkenafil enlarged the range of penumbra, reduced ischemic cell apoptosis and the loss of neurons, and modulated the expression of proteins in the Nogo-R pathway. Moreover, yonkenafil protected the structure of synapses and increased the expression of synaptophysin, BDNF/TrkB and NGF/TrkA. In conclusion, yonkenafil protects neuronal networks from injury after stroke.

Erectile dysfunction (Erectile dysfunction, ED) refers to the duration can not be achieved, and (or) maintain an erection sufficient for satisfactory sexual life. ED can be divided according to different causes psychogenic, organic and mixed three categories, which are closely related to the aging process, but it is not inevitable disease with age.

The primary risk factors for ED include: high blood pressure, high cholesterol, diabetes, coronary and peripheral vascular disease, spinal cord injury or pelvic organs or surgery. According to statistics worldwide about 150 million men suffer from varying degrees of ED, 2025 the number of patients will double. More ED treatment options, such as oral medications phosphodiesterase 5 (PDE5) inhibitors, dopaminergic activator, a receptor blocker, intracavernous injection therapy, vacuum devices treatment, penile prosthesis treatment Wait. Wherein the selective phosphodiesterase 5 (PDE5) inhibitors are the most sophisticated study based on ED treatment, clinical treatment for ED is the first-line drugs. Has now approved the listing of these drugs were five sildenafil (Sildenafil), Tadalafil (Tadalafil), vardenafil (Vardenafil), to that of non-black (Udenafil) and Miro that non-( Mirodenafil).

In 2004 the Chinese patent CN03142399. X discloses a series pyrrolopyrimidine ketone compound of the structure and for the treatment of sexual dysfunction in animals, including humans, in particular male erectile dysfunction and TOE5 function-related diseases use; wherein the compound 1-HC1, i.e. 2- [2_ ethoxy-5- (4-ethyl-piperazine-1-sulfonyl) phenyl] -5-methyl-7-n-propyl -3 , 7-dihydro-pyrrolo [2, 3-d] pyrimidine-4-one monohydrochloride salt has been used as CN03142399. X Example features are disclosed compound named hydrochloride that non-gifted grams. This patent only to the preparation of the compounds have been described

 

PATENT

WO2004108726

http://www.google.co.in/patents/WO2004108726A1?cl=en

Example 1

Preparation of 2-[2-ethoxyl-5-(4-ethylpiperazinyl-1-sulfonyl)phenyl] -5-methyl-7-n-propyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one, its monohydrochloride and dihydrochloride

Route of synthesis

 

    • Figure imgb0011
      Figure imgb0012
      • (1a)2-amino-3-cyano-4-methylpyrrole;
      • (1b)N-propyl-2-amino-3-cyano-4-methylpyrrole;
      • (2)2-ethoxylbenzoyl chloride;
      • (3a)N-(3-cyano-4-methyl-1H-pyrrol-2-yl)-2-ethoxylbenzamide;
      • (3b)N-(3-cyano-4-methyl-1-n-propyl-1H-pyrrol-2-yl)-2-ethoxylbenzami de;
      • (4a) 2-(2-ethoxylbenzamido)-4-methyl-1H-pyrrolo-3-formamide;
      • (4b) 2-(2-ethoxylbenzamido)-4-methyl-1-n-propyl-1H-pyrrolo-3-formamide;
      • (5) 2-(2-ethoxylphenyl)-5-methyl-3,7-dihydro-pyrrolo[2,3-d]pyrimidin -4-one;
      • (6)2-(2-ethoxylphenyl)-5-methyl-7-n-propyl-3,7-dihydropyrrolo[2,3-d ]pyrimidin-4-one;
      • (7)4-ethoxyl-3-(5-methyl-4-oxy-7-n-propyl-3,7-dihydropyrrolo[2,3-d] pyrimidin-2-yl)benzenesulfonyl chloride;
      • (8)2-[2-ethoxyl-5-(4-ethylpiperazinyl-1-sulfonyl)phenyl]-5-methyl-7 -n-propyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one.

Preparation 1N-(3-cyano-4-methyl-1H-pyrrol-2-yl)-2-ethoxylbenzamide (3a) and N-(3-cyano-4-methyl-1-n-propyl-1H-pyrrol-2-yl)-2-ethoxylbenzamide (3b)

2-ethoxyl benzoic acid (10.0g, 60.2mmol) was added into thionyl chloride (20ml), and the mixture was refluxed with agitation for 40 minutes, and the excess amount of thionyl chloride was evaporated under reduced pressure. The residual was dissolved into dichloromethane (150ml). Within 30 minutes and being stirred on ice bath, the afore-obtained solution of 2-ethoxyl benzoyl chloride was dropped into the compound (1a) (7.0g, 56.8mmol) dissolved in tetrahydrofuran (80ml) and triethylamine (8.5ml, 61.0mmol). After completion, the mixture was stirred for 1 hour at 0°C . After being washed with water and filtrated with diatomaceous earth, the reaction solution was mixed with 20g of silica gel and evaporated to dryness. The resulting residual was eluted with dichloromethane by using silica gel(80g) column to obtain 7.5g of solid product (3a) with the yield of 48%. Furthermore, the sample for analysis was prepared by column chromatography (developing agent: dichloromethane: n-hexane=1:2) and recrystallization (dichloromethane: n-hexane=1:5).

mp 183~184°C (sublimation 162°C);\

IR (cm-1) : 3326, 3309, 2981, 2938, 2915, 2854, 2208, 1647, 1593, 1471, 1309, 1302, 1232, 1039, 923, 727, 655, 648;1H NMR (CDCl3) : δ 1.70 (t, J=7.0Hz, 3H), 2.15 (s, 3H), 4.32 (q, J=7.0Hz, 2H), 6.24 (s, 1H), 7.04 (d, 1H), 7.10 (m, 1H), 7.51 (dd, 1H), 8.20 (dd, J=7.9 and 1.8Hz, 1H), 10.69 (brs, 1H), 10.80 (s, 1H);13CNMR (CDCl3) : δ (CH3) 10.6, 15.0; (CH2) 65.7; (CH) 110.3, 112.3, 121.4132.1, 134.2; (C) 78.7, 115.6, 119.2, 119.4, 136.7, 157.0, 163.2;

MS (ES+) : m/z 287 (M+NH4) .

Elemental analysis (C15H15N3O2) : C 66.90%; H 5.61%; N 15.60%; 0 11.88%. The compound (3b) was prepared from compound (1b) according to the above-mentioned method with the yield of 41%.

mp 58~61°C;

IR (cm-1) : 3596, 3336, 2969, 2937, 2877, 2216, 1676, 1658, 1603, 1571, 1537, 1475, 1431, 1292, 1232, 1122, 1037, 927, 789, 752, 577;1H NMR (CDCl3): δ 0.88 (t, J=7.4Hz, 3H), 1.58 (t, J=7.0Hz, 3H), 1.75(m, 2H), 2.16 (s, 3H), 3.73 (t, J=7.4Hz, 2H),4.30 (q, J=7.0Hz, 2H), 6.36 (s, 1H), 7.04 (d, 1H), 7.11 (m, 1H), 7.48 (dd, 1H), 8.23 (dd, J=7.9 and 1.8Hz, 1H), 9.62 (brs, 1H) ;13C NMR (CDCl3) : δ (CH3) 11.1, 14.8; (CH2) 23.6, 48.3, 65.2; (CH) 112.5,117.0, 121.3, 132.5, 134.1; (C) 89.2, 115.6, 119.8, 120.5, 131.2, 157.1, 165.0;MS (ES+): m/z 329 (M+NH4).

 

Preparation 2

2-(2-ethoxylbenzamido)-4-methyl-1H-pyrrolo-3-formamide (4a) and 2-(2-ethoxylbenzamido)-4-methyl-1-n-propyl-1H-pyrrolo-3-formamide(4 b);

A mixture of N-(3-cyano-4-methyl-1H-pyrrol-2-yl)-2-ethoxylbenzamide(3a) (2.00g, 7.44mmol) or N-(3-cyano-4-methyl-1-n-propyl-1H-pyrrol-2-yl)-2 -ethoxylbenzamide(3b) (2.30g, 7.44mmol) of preparation 1 and 85% phosphoric acid (14.8ml) was stirred for 20 minutes at 130°C, cooled and poured into crushed ice (80g). The precipitations were filtrated and dried to give dark red solid of compound (3a) or (3b) with the yield of 80%. The product(3a) and (3b) of this step may be directly used for the next step without further purification.

Preparation 32-(2-ethxoylphenyl)-5-methyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one(5) and 2-(2-ethoxylphenyl)-5-methyl-7-n-propyl -3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one(6)

A mixture of 2-(2-ethoxylbenzamido)-4-methyl-1H-pyrrolo-3-formamide (4a) (7.0g, 25.5mmol) of preparation 2 and dimethyl cyclohexylamine (20ml) was refluxed with agitation for 11 hours in N,N-dimethyl formamide (100ml). After evaporation the solvent by distillation under reduced pressure, the residual was extracted with dichloromethane, and the dichloromethane extraction was washed with water. the resultant extraction was dried with anhydrous sodium sulfate. n-hexane (80ml) was added into the residual and ground to give product (5) (6.0g) by filtration with the yield of 91%.

mp 219~221°C

IR (cm-1) : 3187, 3114, 3062, 2978, 2923, 1658, 1587, 1460, 1321, 1292, 1250, 1044, 771, 763;

1H NMR (DMSO-d6) : δ 1.35 (t, J=6.9Hz, 3H), 2.29 (s, 3H), 4.13 (q, J=7.0Hz, 2H), 6.79 (s, 1H), 7.05 (t, 1H), 7.14 (d, 1H), 7.45 (dd, 1H), 7.76 (dd, 1H), 11.35 (brs, 1H), 11.54 (brs, 1H);

13C NMR (DMSO-d6) : δ (CH3) 11.2, 14.5; (CH2) 64.2; (CH) 113.0, 118.0, 120.6, 130.1, 131.9, (C) 105.0, 113.6, 121.9, 148.5, 149.8, 156.5, 159.2; MS(ES+) : m/z 287 (M+NH4) .

The compound (6) was prepared from compound(4b) according to the above-mentioned method with the yield of 85%

mp 124~127°C

IR (cm-1) : 3234, 3184, 3141, 3103, 3056, 2956, 2943, 2869, 1654, 1595, 1567, 1468, 1311, 1267, 1243, 1191, 1118, 1047, 758;

1H NMR (CDCl3) : δ 0.88 (t, J=7.5Hz, 3H), 1.23 (t, 3H), 1 . 80 (q, 2H), 2. 42 (s, 3H), 4.08 (t, J=7.2Hz, 2H), 4.22 (q, 2H), 6.60 (s, 1H), 7.01 (d, J=8.3Hz, 1H), 7.08 (t, 1H), 7.40 (m, 1H), 8.35 (dd, J=8.0 and 1.9 Hz, 1H), 11.02 (brs, 1H).

Preparation 42-(2-ethxoylphenyl)-5-methyl-7-n-propyl-3,7-dihydro-pyrrolo[2,3-d] pyrimidin-4-one(6):

A mixture of compound (5) (1.5g, 5.57mmol) of preparation 3, n-propyl bromide (2.0g, 16.3mmol) and potassium carbonate (5g, 36.2mmol) was dissolved in acetone (15ml), refluxed with agitation by heating for 15 hours, after the solids were filtrated out, the filtrate was dried under reduced pressure. The resultant was developed by column chromatography, using dichloromethane as mobile phase to obtain 0.6g of product (6) with yield of 35%. The physical/chemical data were identical with that of the above-mentioned.

Preparation 54-ethoxyl-3-(5-methyl-4-oxy-7-n-propyl-4,7-dihydropyrrolo[2,3-d] pyrimidin-2-yl)benzenesulfonyl chloride(7):

2-(2-ethxoylphenyl)-5-methyl-7-n-propyl-3,7-dihydropyrrolo[2,3-d] pyrimidin-4-one(6) (1.25g, 4.01mmol) of preparation 4 was added into chlorosulfonic acid (4ml) that was dissolved in acetic ether (20ml), stirred at 0°C by two batches. The obtained solution was stirred at 0 °C for 30 minutes, and then reacted with agitation at room temperature for 3 hours. The resultant solution was poured into the a mixture of icy water (50ml) and acetic ether (50ml) . The organic layer was separated, washed with cold water (5ml), desiccated with anhydrous sodium sulfate and concentrated to dryness to afford 1.33g of product as yellow foam. The yield was 81%. The product was used directly for the next reaction.

Compound 1:

BASE

2-[2-ethoxyl-5-(4-ethyl-piperazinyl-1-sulfonyl)phenyl]-5-methyl-7-n -propyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one (8):

4-ethoxyl-3-(5-methyl-4-oxy-7-n-propyl-4,7-dihydro-3H-pyrrolo[2,3-d ]pyrimidin-2-yl)benzenesulfonyl chloride(7) (1.00g, 2.44mmol) of Preparation 5 was dissolved into dichloromethane (20ml), stirred at 0 °C, into which 1-ethyl piperazine (0.78ml, 6.10mmol) was added slowly. Reactant solution was stirred at 0°C for 5 minutes, and then sequentially stirred at room temperature for 5 hours. The crude product was washed with water and dried with anhydrous sodium sulfate to give 1. 2g of product as yellow foam. Continuously, the product was refined by column chromatography (acetic ether: methanol=20:1) to afford 0.89g of product as a yellow solid with yield of 75%.

mp: 174~176°C (EtOAc);

IR (cm-1) : 3324, 2960, 2923, 2869, 2862, 2767, 1682, 1560, 1458, 1355, 1282, 1247, 1172, 1149, 739, 615, 588, 555;

1H NMR(CDCl3) : δ 0.89(t,J=7.4Hz, 3H), 0.99(t, J=7.2Hz, 3H), 1.61(t,J=7.0Hz,3H),1.77-1.86(m, 2H), 2.35(m, 2H), 2.41(s, 3H), 2.50(brs, 4H), 3.05(brs,4H), 4.08(t, J=7.0Hz, 2H), 4.29-4.37(q, 2H), 6.61(s, 1H), 7.11(d, J=8.8Hz,1H), 7.77(dd, J=8.7 and2.2Hz, 1H), 8.74(d, J=2.2, 1H), 10.63(brs, 1H);

13C NMR(CDCl3) : δ (CH3) 11.0, 11.3, 11.8, 14.3; (CH2)23.8, 45.9, 46.1, 51.6, 51.7, 65.8; (CH)112.9, 121.1, 130.6, 131.3;(C)105.7,114.6, 121.4, 127.8, 146.8, 147.3, 159.3, 159.6;MS(ES+): m/z 505(M+NH4).

Elemental analysis (C24H33N5O4S) : theoretical value C 59.12%; H 6.82%; N 14.36%; practically measured value C59.38%; H 7.10%; N 14.12%.

Compound 1-HCl:

2-[2-ethoxyl-5-(4-ethylpiperazinyl-1-sulfonyl)phenyl]-5-methyl-7-n-propyl-3,7-dihydropyrrolo[2,3-d]pyrimidin-4-one monohydrochloride (9) :

The free alkali (compound 1) (1.00g, 2.05mmol) was dissolved into ether (10ml) and dichloromethane (10ml), into which the solution of 4M hydrochloric acid (HC1)- dioxane (0.51ml, 2.04mmol) diluted with ethyl ether (10ml) was dropped with agitation. After completion, the resulting solution was continued to stir at room temperature for 20 minutes, filtrated and dried to give 1.01g of monohydrochloride with yield of 94%.

mp: 147~150°C;

IR(cm-1): 2964, 2931, 2675, 2599, 2462, 1668, 1574, 1456, 1348, 1167, 933, 588;

1H NMR(D2O): δ 0.72(m, 3H),1.24(t, J=7.3Hz, 3H), 1.45(m, 3H), 1.59(m, 2H), 2.04(s, 3H), 2.77-3.81(all brs, 8H), 3.20(q, 2H), 3.75(m, 2H), 4.20(m, 2H), 6.62(m, 1H), 7.17(m, 1H), 7.73(m, 1H), 8.22(s, 1H).

Elemental analysis (C24H33N5O4S. HCl) : theoretical value C 55.00%; H 6.54%; N 13.36%; practically measured value C55.28%; H 6.41%; N 13.07%.

 

PATENT

WO 2016095650

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2016095650&redirectedID=true

Example 1:
At room temperature, preferably hydrochloride grams that non-B polymorph (1.0g, prepared as described in its comparative) and 95% by volume aqueous ethanol (6mL) added to the flask and stirred for 2h, isolated by filtration, and the resulting solid dried under reduced pressure to give hydrochloride gifted grams that non-A type polymorph (0.8g). Its X-RD diffraction as shown in Figure 1, as shown in Figure 2. DSC.

 

SEE

https://www.google.com/patents/CN1552714A?cl=en

 

Spectral Analysis

str2 STR3

STR3

 

13C NMR PREDICT

str2

str2

COSY PREDICT

str2

 

CN1552714A * Jun 6, 2003 Dec 8, 2004 天津倍方科技发展有限公司 2-substituted benzyl-5,7-dihydrocarbyl-3,7-dihydro pyrroline [2,3-d] pyromidine-4-one derivative ,its preparation and medicinal use
CN102970965A * Apr 4, 2011 Mar 13, 2013 Sk化学公司 Composition containing PDE5 inhibitor for relieving skin wrinkles
WO2007067570A1 * Dec 5, 2006 Jun 14, 2007 Biomarin Pharmaceutical Inc. Methods and compositions for the treatment of disease

//////////yonkenafil, Phase 2,  Erectile dysfunction , phosphodiesterase type 5 (PDE5) inhibitor, Tasly Pharmaceutical Group; Yangtze River Pharmaceutical Group

Cc4cn(CCC)c1c4N/C(=N\C1=O)c2cc(ccc2OCC)S(=O)(=O)N3CCN(CC3)CC

Gisadenafil

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Jan 312014
 

 

Lodenafil carbonate

UNII-29X84F932D, CRIS-031  

bis-(2-{4-[4-ethoxy-3-(1-methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-benzenesulfonyl]piperazin-1-yl}-ethyl)carbonate

5-{2-ethoxy-5-[(4-hydroxyethyl-1-piperazinyl)sulfonyl]phenyl}-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazole[4,3-d]pyrimidin-7-one. IS THE NAME OF MONOMER

398507-55-6  CAS

Cristalia (Originator)

C47 H62 N12 O11 S2= MF
 Molecular Weight 1035.199

Lodenafil is a drug belonging to a class of drugs called PDE5 inhibitor, which many other erectile dysfunction drugs such as sildenafiltadalafil, and vardenafil also belong to. Like udenafil and avanafil it belongs to a new generation of PDE5 inhibitors.

Lodenafil is formulated as a dimerlodenafil carbonate, which breaks down in the body to form two molecules of the active drug lodenafil. This formulation has higher oral bioavailability than the parent drug.[1]

It is manufactured by Cristália Produtos Químicos e Farmacêuticos in Brazil and sold there under the brand-name Helleva.[2]

Helleva (Lodenafil Carbonate) - 80mg (4 Tablets)

Helleva (Lodenafil Carbonate) is an oral PDE5 inhibitor prescribed to treat men suffering from erectile dysfunction. It operates by relaxing muscles and dilating blood vessels in the penis to increase circulation making it easier to attain and maintain an erection.

It has undergone Phase III clinical trials,[3][4][5] but is not yet approved for use in the United States by the U.S. Food and Drug Administration.

lodenafil

………..

SYNTHESIS

WO 2002012241 OR US7148350

MONOMER synthesis

PIPERAZINE

AND

ETHYL CHLORO ACETATE

WILL GIVE

Ethyl 1-piperazinylacetateChemSpider 2D Image | Ethyl 1-piperazinylacetate | C8H16N2O2

SEE RXN 1 BELOW

Reaction 1:

Synthesis of Piperazine Ethyl Acetate

To a reaction blend containing 100 g (3 Eq, 0.515 mol, MW=194) of piperazine, 26.3 mL (1.1 Eq, 0.189 mol, MW=101, d=0.726) of triethylamine in 200 mL of isopropanol, add to a solution previously prepared of 18.4 mL (1 Eq., 0.172 mol, MW=122.55, d=1.15) of chloroacetate of ethyl in 140 mL of isopropanol under stirring, at room temperature. Keep the reaction medium under stirring, monitoring the reaction termination by means of a chromatography of the thin layer (about 2–3 hours). Add a solution of 40.6 g (0.344 mol) of succinic acid in 140 mL of isopropanol. Keep the system under stirring for about 30 minutes to assure total precipitation of the succinate salt of piperazine formed. Filter this salt and concentrate the filtrate containing the mono and dialkyled derivatives. We obtain a slightly yellowish oil, which is used in later phases without purification.

Mass obtained=33 g

GC/MS: Monoalkylated derivative 72%, and dialkylated 22%.

NEXT

ChemSpider 2D Image | Ethyl 1-piperazinylacetate | C8H16N2O2Piperazine Ethyl Acetate

AND

5-(5-Chlorosulfonyl-2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one Structure

5-(5-chlorosulfonyl-2-ethoxyphenyl)-1-methyl-3n-propyl-1,6-dihydro-7H-pyrazole[4,3-d]pyrimidin-7-one

WILL REACT TO GIVE… 5-{2-ethoxy-5-[(4-ethyl acetate 1-piperazinyl)sulfonyl]phenyl}-1-methyl-3-n-propyl-1,6-di-hydro-7H-pyrazole[4,3-d]pyrimidin-7-one AS IN RXN 4 BELOW

Reaction 4:

Synthesis of 5-{2-ethoxy-5-[(4-ethyl acetate 1-piperazinyl)sulfonyl]phenyl}-1-methyl-3-n-propyl-1,6-di-hydro-7H-pyrazole[4,3-d]pyrimidin-7-one.

Suspend 24.6 g (60 mmol, MW=410.9) of 5-(5-chlorosulfonyl-2-etoxyphenyl)-1-methyl-3n-propyl-1,6-dihydro-7H-pyrazole[4,3-d]pyrimidin-7-one in 900 mL of ethanol absolute. Under stirring and at room temperature, add at only one time, a solution containing 31.0 g (3 Eq., 180 mmol MW=172) of N-piperazine ethyl acetate (Reaction 1) dissolved in 150 mL of ethanol absolute. In an interval of 2–10 minutes, all solid is consumed, forming a clean and homogeneous solution, and after that starts the precipitation of the expected product. At the end of the reaction, which lasts 2–3 hours (monitored by chromatography of thin layer), the product is vacuum filtered and the solid is washed with two portions of 50 mL of iced absolute ethanol. 29 g are obtained (yielding=89%) from the product as a white solid of MP=165.5–166.5° C.

Reaction 7:

Intermediate 1

5-{2-ethoxy-5-[(4-hydroxyethyl-1-piperazinyl)sulfonyl]phenyl}-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazole[4,3-d]pyrimidin-7-one.  IS MONOMER

please note during LAH redn  …………. the PIP CH2-C=O-O CH2 CH3     BECOMES        PIP-CH2CH2-OH

To a suspension of lithium aluminum hydride (0.74 g 2.2 Eq. MW=37.9) in 25 mL of THF, slowly add, under stirring and at room temperature, a suspension of 5.0 g (9.1 mmol, MW=546.6) of 5-{2-ethoxy-5-[(4-ethyl acetate 1-piperazinyl)sulfonyl]phenyl}-1-methyl-3-n-propyl-1,6-di-hydro-7H-pyrazole[4,3-d]pyrimidin-7-one in 50 mL of THF. The system is maintained under stirring, monitoring the consumption of the product by chromatography of thin layer, until the complete consumption of the starting reagent (about 5–6 hours). Slowly add water to the reaction medium and, when there is no longer release of H2, add HCl 1M regulating pH for 7. Extract the product with 3 200 mL-portions of chloroform, dry with anhydrous sodium sulfate and vacuum concentrate the product. It is obtained 3.8 g of the product as a cream solid MP=183–187° C. yielding 83%. The same was crystallized from methanol and DMF yielding a slightly yellowish solid with melting point at 189–192° C.

 

note …………. the PIP CH2-C=O-O CH2 CH3 BECOMES  PIP-CH2CH2-OH

 

HOMODIMER CARBONATE

 

EXAMPLE 1B

Homodimer Carbonate of Intermediate 1—Alternative Method

A phosgene solution (3.5 g, 35 mmol) dissolved in 20 mL of toluene was added dropwise to a solution of 2.02 g (4 mmol) of 5-{2-ethoxy-5-[(4-hydroxyethyl-1-piperazinyl)sulfonyl]phenyl}-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazole[4,3-d]pyrimidin-7-one, suspended in 44 mL of toluene. The reaction mixture resulting is stirred and followed by chromatography analysis of thin layer every hour until the reagent conversion in its chloroformate was completed. When the analysis indicates the complete consumption of 5-{2-ethoxy-5-[(4-hydroxyethyl-1-piperazinyl)sulfonyl]phenyl}-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazole[4,3-d]pyrimidin-7-one, the volatile compounds of the reaction are vacuum removed (solvents and phosgene), yielding the esther chloroformate raw derivative of 5-{2-ethoxy-5-[(4-hydroxyethyl-1-piperazinyl)sulfonyl]phenyl}-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazole[4,3-d]pyrimidin-7-one.

The raw chloroformate obtained above (4.0 mmol, 2.27 g) is dissolved in about 30 mL of dichloromethane, to which is added 2.07 g (4.1 mmol) of 5-{2-ethoxy-5-[(4-hydroxyethyl-1-piperazinyl)sulfonyl]phenyl}-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazole[4,3-d]pyrimidin-7-one, followed by the addition of 4 mL of dichloromethane containing 450 mg of triethylamine. The reaction mixture is maintained under stirring, being followed by chromatography of thin layer every hour until this indicates the end of the reaction (disappearing of chloroformate derivative). The reaction mixture is then diluted with 60 mL of dichloromethane, washed with NaCl saturated solution, after with sodium bicarbonate saturated solution and again with NaCl saturated solution. Organic phase is separated and dry with anhydrous sodium sulfate. The solvent is then evaporated to dry, yielding the dimer carbonate as a slightly yellowish solid.

This compound is re-crystallized from ethanol:DMF, yielding a pale white solid. Yielding m=3.2 g (76%)

Microanalysis: Theoretical C, (54.53%); H, (6.04%); N, (16.24%);

Obtained C, (54.45%); H, (6.02%); N, (16.17%).

 

INFO ABOUT INTERMEDIATE

5-(5-Chlorosulfonyl-2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one Structure

5-(5-chlorosulfonyl-2-ethoxyphenyl)-1-methyl-3n-propyl-1,6-dihydro-7H-pyrazole[4,3-d]pyrimidin-7-one

CAS No. 139756-22-2
Chemical Name: 5-(5-Chlorosulfonyl-2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one
Synonyms: Sildenafil Chlorosulfone IMpurity;Sildenafil Chlorosulfonyl IMpurity;5-(5-CHLOROSULFONYL-2-ETHOXY PHENYL)-1-METHYL-3-N-PROPYL-1;3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1 H-pyrazolo-(4-3-d)-pyrimidine-5;5-(5-Chlorosulfonyl-2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one;3-(4,7-Dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-4-ethoxy-benzenesulfonyl Chloride;4-Ethoxy-3-(1-Methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyriMidin-5-yl)benzene-1-sulfonyl chloride
CBNumber: CB11175931
Molecular Formula: C17H19ClN4O4S

http://www.chemicalbook.com/ChemicalProductProperty_EN_CB11175931.htm

…………..

SYNTHESIS OF

Figure US06362178-20020326-C00096

http://www.google.co.in/patents/US6362178

2-butyrylamino-propionic acid
EXAMPLE 1A 2-Butyrylaminopropionic acid 

Figure US06362178-20020326-C00052

 

22.27 g (250 mmol) of D,L-alanine and 55.66 g (550 mmol) of triethylamine are dissolved in 250 ml of dichloromethane, and the solution is cooled to 0° C. 59.75 g (550 mmol) of trimethylsilyl chloride are added dropwise, and the solution is stirred for 1 hour at room temperature and for 1 hour at 40° C. After cooling to −10° C., 26.64 g (250 mmol) of butyryl chloride are added dropwise, and the resulting mixture is stirred for 2 hours at −10° C. and for one hour at room temperature.

With ice-cooling, 125 ml of water are added dropwise and the reaction mixture is stirred at room temperature for 15 minutes. The aqueous phase is evaporated to dryness, the residue is titrated with acetone and the mother liquor is filtered off with suction. The solvent is removed and the residue is chromatographed. The resulting product is dissolved in 3N aqueous sodium hydroxide solution and the resulting solution is evaporated to dryness. The residue is taken up in conc. HCl and once more evaporated to dryness. The residue is stirred with acetone, precipitated solid is filtered off with suction and the solvent is removed under reduced pressure. This gives 28.2 g (71%) of a viscous oil which crystallizes after some time.

200 MHz 1H-NMR (DMSO-d6): 0.84, t, 3H; 1.22, d, 3H; 1.50, hex, 2H; 2.07, t, 2H; 4.20, quin., 1H; 8.09, d, 1H.

EXAMPLE 3A 2-Ethoxybenzonitrile 

Figure US06362178-20020326-C00054

 

25 g (210 mmol) of 2-hydroxybenzonitrile are refluxed with 87 g of potassium carbonate and 34.3 g (314.8 mmol) of ethyl bromide in 500 ml of acetone overnight. The solid is filtered off, the solvent is removed under reduced pressure and the residue is distilled under reduced pressure. This gives 30.0 g (97%) of a colourless liquid.

200 MHz 1H-NMR (DMSO-d6): 1.48, t, 3H; 4.15, quart., 2H; 6.99, dt, 2H; 7.51, dt, 2H.

 2-ethoxybenzamidine hydrochloride
EXAMPLE 4A 2-Ethoxybenzamidine hydrochloride 

Figure US06362178-20020326-C00055

 

21.4 g (400 mmol) of ammonium chloride are suspended in 375 ml of toluene, and the suspension is cooled to 0° C. 200 ml of a 2M solution of trimethylaluminium in hexane are added dropwise, and the mixture is stirred at room temperature until the evolution of gas has ceased. After addition of 29.44 g (200 mmol) of 2-ethoxybenzonitrile, the reaction mixture is stirred at 80° C. (bath) overnight.

With ice-cooling, the cooled reaction mixture is added to a suspension of 100 g of silica gel and 950 ml of chloroform, and the mixture is stirred at room temperature for 30 minutes. The mixture is filtered off with suction, and the filter residue is washed with the same amount of methanol. The mother liquor is concentrated, the resulting residue is stirred with a mixture of dichloromethane and methanol (9:1), the solid is filtered off with suction and the mother liquor is concentrated. This gives 30.4 g (76%) of a colourless solid.

200 MHz 1H-NMR (DMSO-d6): 1.36, t, 3H; 4.12, quart., 2H; 7.10, t, 1H; 7.21, d, 1H; 7.52, m, 2H; 9.30, s, broad, 4H.

EXAMPLE 10A 2-(2-Ethoxy-phenyl)-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one

 

Figure US06362178-20020326-C00061

 

7.16 g (45 mmol) of 2-butyrylamino-propionic acid and 10.67 g of pyridine are dissolved in 45 ml of THF and, after addition of a spatula tip of DMAP, heated to reflux. 12.29 g (90 mmol) of ethyl oxalyl chloride are slowly added dropwise, and the reaction mixture is refluxed for 3 hours. The mixture is poured into ice-water and extracted three times with ethyl acetate and the organic phase is dried over sodium sulphate and concentrated using a rotary evaporator. The residue is taken up in 15 ml of ethanol and refluxed with 2.15 g of sodium bicarbonate for 2.5 hours. The cooled solution is filtered.

With ice-cooling, 2.25 g (45 mmol) of hydrazine hydrate are added dropwise to a solution of 9.03 g (45 mmol) of 2-ethoxybenzamidine hydrochloride in 45 ml of ethanol, and the resulting suspension is stirred at room temperature for another 10 minutes. The ethanolic solution described above is added to this reaction mixture, and the mixture is stirred at a bath temperature of 70° C. for 4 hours. After filtration, the mixture is concentrated, the residue is partitioned between dichloromethane and water, the organic phase is dried over sodium sulphate and the solvent is removed under reduced pressure.

This residue is dissolved in 60 ml of 1,2-dichloroethane and, after addition of 7.5 ml of phosphorus oxychloride, refluxed for 2 hours. The mixture is diluted with dichloromethane and neutralized by addition of sodium bicarbonate solution and solid sodium bicarbonate. The organic phase is dried and the solvent is removed under reduced pressure. Chromatography using ethyl acetate and crystallization afford 4.00 g (28%) of a colourless solid, Rf=0.42 (dichloromethane/methanol=95:5)

200 MHz 1H-NMR (CDCl3): 1.02, t, 3H; 1.56, t, 3H; 1.89, hex, 2H; 2.67, s, 3H; 3.00, t, 2H; 4.26, quart., 2H; 7.05, m, 2H; 7.50, dt, 1H; 8.17, dd, 1H; 10.00, s, 1H.

EXAMPLE 15A 4-Ethoxy-3-(5-methyl-4-oxo-7-propyl-3,4-dihydro-imidazo[5,1-f][1,2,4]triazin-2-yl)-benzenesulphonyl chloride

 

Figure US06362178-20020326-C00066

 

At 0° C., 2.00 g (6.4 mmol) of 2-(2-ethoxy-phenyl)-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one are slowly added to 3.83 ml of chlorosulphonic acid. At room temperature, the reaction mixture is stirred ovemight, and then poured into ice-water and extracted with dichloromethane. This gives 2.40 g (91%) of a colourless foam.

200 MHz 1H-NMR (CDCl3): 1.03, t, 3H; 1.61, t, 2H; 1.92, hex, 2H; 2.67, s, 3H; 3.10, t, 2H; 4.42, quart., 2H; 7.27, t, 1H; 8.20, dd, 1H; 8.67, d, 1H; 10.18, s, 1H.

Example 22 2-[2-Ethoxy-5-(4-hydroxyethyl-1-amino-piperazine-1-sulphonyl)-phenyl]-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one

 

Figure US06362178-20020326-C00096

 

By the same method, starting with 0.04 g (0.097 mmol) of 4-ethoxy-3-(5-methyl-4-oxo-7-propyl-3,4-dihydro-imidazo[5,1-f][1,2,4]triazin-2-yl)-benzenesulphonyl chloride and 0.04 g (0.29 mmol) of 1-amino-4-hydroxyethylpiperazine, 46 mg (91%) of 2-[2-ethoxy-5-(4-hydroxyethyl-1-amino-piperazine-1-sulphonyl)-phenyl]-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one are obtained.

Rf=0.08 (dichloromethane/methanol=19:1)

200 MHz 1H-NMR (CDCl3): 1.02, t, 3H; 1.59, t, 3H; 1.90, sex., 2H; 2.49, m, 6H; 2.62, s, 3H; 2.71, m, 4H; 3.00, t, 2H; 3.55, t, 2H; 4.31, quart., 2H; 7.14, d, 1H; 8.05, dd, 1H; 8.60, d, 1H.

…………..

Methods of analysis

The development of lodenafil carbonate was reported by Toque et al. (2008). They observed the effects of lodenafil carbonate on rabbit and human corpus cavernosum relaxation, activity of PDE5 in human platelets, stability and metabolic studies in comparison with sildenafil and lodenafil, as well as the pharmacological evaluation of lodenafil carbonate after intravenous and oral administration in male beagles.

The determination of PDE activity, stability of lodenafil carbonate in human, dog and rat plasma and the pharmacokinetic parameters after a single intravenous or oral dose was carried out by LC-MS/MS analysis

Codevilla et al. (2011a) developed a stability-indicating reversed-phase liquid chromatography method using ultraviolet (UV) detection for the quantitative determination of lodenafil carbonate in tablets. The method can be useful for routine quality control assay and stability studies.

Another study for the determination of lodenafil carbonate in tablets was developed by Codevilla et al. (2011b). As an alternative to the LC method the authors suggested a UV-spectrophotometric method for the analysis of lodenafil carbonate in pharmaceutical form. The UV method offers advantages over other analytical methods due to its rapidity, simplicity, and lower cost. Recently, Codevilla et al. (2012) developed and validated a capillary zone electrophoresis (CZE) method for determination of lodenafil carbonate in drug products. There are some advantages to use the CZE method, such as rapid analysis, small sample and reagent consumption, high separation efficiency (Furlanetto et al., 2001; Yang et al., 2010). The results obtained from the UV-spectrophotometric method and CZE method were compared statistically with the LC method (Codevilla et al., 2011a) and the results showed no significant difference between these methods.

 

References

  1.  Toque HA, Teixeira CE, Lorenzetti R, Okuyama CE, Antunes E, De Nucci G (September 2008). “Pharmacological characterization of a novel phosphodiesterase type 5 (PDE5) inhibitor lodenafil carbonate on human and rabbit corpus cavernosum”. European Journal of Pharmacology 591 (1–3): 189–95. doi:10.1016/j.ejphar.2008.06.055PMID 18593576.
  2.  Cristália Product page. Retrieved on September 16, 2009.
  3.  ukmedix Lodenafil article. Retrieved on September 16, 2009.
  4.  Glina S, Toscano I, Gomatzky C, de Góes PM, Júnior AN, Claro JF, Pagani E (February 2009). “Efficacy and tolerability of lodenafil carbonate for oral therapy in erectile dysfunction: a phase II clinical trial”. The Journal of Sexual Medicine 6 (2): 553–7. doi:10.1111/j.1743-6109.2008.01079.x.PMID 19040623.
  5.  Glina S, Fonseca GN, Bertero EB, Damião R, Rocha LC, Jardim CR, Cairoli CE, Teloken C, Torres LO, Faria GE, da Silva MB, Pagani E (February 2010). “Efficacy and Tolerability of Lodenafil Carbonate for Oral Therapy of Erectile Dysfunction: A Phase III Clinical Trial”. The Journal of Sexual Medicine 7 (5): 1928–1936. doi:10.1111/j.1743-6109.2010.01711.xPMID 20214718.
  6. Toque H A et al., (2008) European Journal of Pharmacology, 591(1-3):189-95.
  7. Exploring the role of PDE5 inhibition in the treatment of muscular dystrophy
    Drugs Fut 2011, 36(4): 321

 

 

 

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Jan 292014
 

Figure imgf000081_0001Dasantafil

569351-91-3 CAS NO

405214-79-1 (racemate)

UNII-48P711MI2G, SCH 446132, D03657,
Molecular Formula: C22H28BrN5O5
Molecular Weight: 522.39222
Merck & Co. (Originator) IN PHASE 2

THERAPEUTIC CLAIM       treatment of erectile dysfunction (phosphodiesterase (PDE) 5 isoenzyme inhibitor)

CHEMICAL NAMES

  1. 1H-purine-2,6-dione, 7-[(3-bromo-4-methoxyphenyl)methyl]-1-ethyl-3,7-dihydro-8-[[(1R,2R)-2-hydroxycyclopentyl]amino]-3-(2-hydroxyethyl) 
  2. 7-(3-bromo-4-methoxybenzyl)-1-ethyl-8-[[(1R,2R)-2-hydroxycyclopentyl]amino]-3-(2-hydroxyethyl)-3,7-dihydro-1H-purine-2,6-dione

7-[(3-bromo-4-methoxyphenyl)methyl]-l-ethyl-8-[[(lR,2R)-2- hydroxycyclopentyl]amino]-3-(2-hydroxyethyl)purine-2,6-dione

Treatment of Erectile Dysfunction , Phosphodiesterase PDE5A Inhibitors

Dasantafil (SCH-446132) is a phosphodiesterase type 5 (PDE5) inhibitor which had been in early clinical development at Merck & Co. for the treatment of erectile dysfunction (ED); however, no recent development has been reported for this research. Phosphodiesterases regulate the tissue concentration of cyclic guanosine monophosphate (cGMP), which in turn triggers smooth muscle relaxation, allowing blood to flow into the penis and resulting in erection. PDE5 is the most abundant phosphodiesterase in the human corpus cavernosum, and as such its inhibition by dasantafil enhances erectile function by increasing the concentration of cGMP.

DASANTAFIL

 

PDE V inhibitor compounds and their use in treating a variety of physiological conditions are described in a number of patents {e.g., U.S. Pat. Nos. 5,409,934, 5,470,579, 5,939,419 and 5,393,755) and foreign publications (e.g., WO 93/23401 , WO 92/05176, WO 92/05175, and WO 99/24433).

Specific PDE V inhibitors have been found useful for specific indications. For example, the use of PDE V inhibitors for treating impotence has met with commercial success with the introduction of sildenafil citrate, vardenafil, and tadalafil (i.e., Viagra®, Levitra®, and Cialis®, respectively). The chemistry and use of Viagra®, including its mechanism of action in treating erectile dysfunction, are taught in EP 0 702 555 B1. Accordingly, it is an object of this invention to provide a method of using a PDE V inhibitor to treat a patient who has, or is at risk of, congestive heart failure, and/or other cardiovascular conditions.

Processes for preparing PDE V inhibitor compounds can be found in US

6,207,829, US 6,066,735, US 5,955,611 , US 5,939,419, US 5,393,755, US 5,409,934, US 5,470,579, US 5,250,534, WO 02/24698, WO 99/24433, WO 93/23401 , WO 92/05176, WO 92/05175, EP 740,668 and EP 702,555. One type of PDE V inhibitor compound contains a xanthine functionality in its structure. Xanthines can be prepared as described by Peter K. Bridson and Xiaodong Wang in 1 -Substituted Xanthines, Synthesis, 855 (July, 1995), which is incorporated herein by reference in its entirety. WO 02/24698, which is incorporated herein by reference in its entirety, teaches a class of xanthine PDE V inhibitor compounds useful for the treatment of impotence. A general process disclosed therein for preparing xanthine PDE V inhibitor compounds having the formula (I) follows:

 

(III) (I) (i) reacting a compound having the formula (III) with an alkyl halide in the presence of a base (introduction of R11 or a protected form of R11); (ii) (a) debenzylating and then (b) alkylating the compound resulting from step (i) with an alkyl halide, XCH2R1“; (iii) (a) deprotonating and then (b) halogenating the compound resulting from step (ii);

(iv) reacting the compound resulting from step (iii) with an amine having the formula RlvNH2; and (v) removing a protecting portion of Rn, if present, on the compound resulting from step (iv) to form the compound having the formula (I). R1, R”, Rm and Rlv correspond to R1, R2, R3 and R4, respectively, in WO02/24698, and are defined therein. WO 02/24698 (pages 44 and 68-73) also teaches a synthesis for the following xanthine compound (identified therein as Compound 13 or Compound 114 of Table II): 1-ethyl-3,7-dihydro-8-[(1 R,2R)- (hydroxycyclopentyl) amino]-3-(2-hydroxyethyl)-7-[(3-bromo-4- methoxyphenyl)methyl]-1 H-purine-2,6-dione:

 

Compound 13. It would be beneficial to provide an improved process for preparing polycyclic xanthine PDE V inhibitor compounds

………………….

Patent description

Links

WO2006055573A2

entry 129 is dasantafil

Figure imgf000050_0001

…………………

SYNTHESIS

Links

WO2002024698A1

Figure imgf000069_0001

14X CHs ‘ B” tX is Experimental Procedure: Compound 114 in Table II (13)

1 (20.0 g, 74.0 mmol) was dissolved in dimethylformamide (370 mL) under nitrogen and (2-bromoethoxy)-terf-butyldimethylsilane (31.8 mL, 148 mmol) was added dropwise. The reaction was stirred at room temperature for 115 hrs., then diluted with ethyl acetate and washed with water several times.

The organic mixture was dried over potassium carbonate, filtered and concentrated under vacuum. Purification via flash chromatography (30/70 ethyl acetate/hexanes) yielded 2 (28.1 g, 88%).

1H NMR (400 MHz, CDCI3): δ 7.52 (s, 1 H), 7.29-7.39 (m, 5H), 5.49 (s,

2H), 4.25 (t, 2H, J = 6.0 Hz), 4.07 (q, 2H, J = 7.2 Hz), 3.93 (t, 2H, J =

6.0 Hz), 1.24 (t, 3H, J = 7.2 Hz), 0.75 (s, 9H), 0.08 (s, 6H). HRMS: Calcd for C22H32N403Si (M+H): 429.2322. Found: 429.2329.

To a solution of 2 (2.10 g, 4.89 mmol) in methanol (375 mL) was added ammonium formate (4.64g, 73.6 mmol) and 20% palladium hydroxide on carbon (980 mg). The reaction was heated to reflux for 1.5 hrs., then cooled to room temperature, filtered and concentrated under vacuum. Purification via flash chromatography (50/50 ethyl acetate/hexanes) yielded 3 (1.26 g, 94%).

1H NMR (400 MHz, CDCI3): δ 7.82 (s, 1 H), 4.33 (t, 2H, J = 6.0 Hz), 4.16

(q, 2H, J = 7.2 Hz), 3.99 (t, 2H, J = 6.0 Hz), 1.29 (t, 3H, J = 7.2 Hz),

0.78 (s, 9H), 0.06 (s, 6H). HRMS: Calcd for Cι5H26N4O3Si (M+H): 339.1852. Found: 339.1864. To 3 (970 mg, 2.86 mmol) was added dimethylformamide (25 mL), 3- bromo-4-methoxybenzyl bromide 15 (1.62 g, 5.79 mmol), and potassium carbonate (800 mg, 5.79 mmol) under nitrogen. The reaction mixture was stirred at room temperature for 21 hrs., then diluted with ethyl acetate and washed with water several times. The organic mixture was dried over potassium carbonate, filtered and concentrated under vacuum. Purification by flash chromatography (30/70 ethyl acetate/hexanes) yielded 10 (1.55 g, 100%).

1H NMR (400 MHz, CDCI3): δ 7.52 (s, 1 H), 7.51 (d, 1 H, J = 2.4 Hz),

7.30 (dd 1 H, J = 2.0 Hz, J = 8.4 Hz), 6.87 (d, 1 H, J = 8.8 Hz), 5.40 (s,

2H), 4.25 (t, 2H, J = 6.0 Hz), 4.07 (q, 2H, J = 7.0 Hz), 3.93 (t, 2H, J =

6.0 Hz), 3.88 (s, 3H), 1.25 (t, 3H, J = 7.0 Hz), 0.75 (s, 9H), 0.08 (s, 6H).

HRMS: Calcd for C23H33BrN4O4Si (M+H): 537.1533. Found: 537.1540.

To solution of 10 (1.50 g, 2.80 mmol) in tetrahydrofuran (24 mL) under nitrogen at -78 °C (dry ice/acetone bath) was added lithium diisopropylamide (2M in THF/heptane, 2.2 mL, 4.33 mmol). After stirring for thirty minutes, 1 ,2- dibromotetrafluoroethane (0.69 mL, 5.77 mmol) was added dropwise over five minutes. The reaction was stirred for 1.25 hrs. at -78 °C then quenched with saturated aqueous sodium bicarbonate and warmed to room temperature.

The mixture was extracted with dichloromethane, dried over potassium carbonate, filtered and concentrated under vacuum. Purification via flash chromatography (30/70 ethyl acetate/hexanes) yielded 11 (600 mg, 34%). 1H NMR (400 MHz, CDCI3): δ 7.60 (d, 1 H, J = 2.4 Hz), 7.35 (dd, 1 H, J =

2.0 Hz, J = 8.4 Hz), 6.84 (d, 1 H, J = 8.4 Hz), 5.45 (s, 2H), 4.21 (t, 2H, J = 5.6 Hz), 4.07 (q, 2H, J = 6.8 Hz), 3.90 (t, 2H, J = 5.6 Hz), 3.87 (s, 3H), 1.24 (t, 3H, J = 6.8 Hz), 0.73 (s, 9H), 0.08 (s, 6H). HRMS: Calcd for C23H32Br2N4O4Si (M+H): 615.0638. Found: 615.0633.

To 11 (1.89 g, 3.07 mmol) was added the amino alcohol hydrochloride salt (1.31 g, 12.27 mmol), diisopropylethylamine (15.4 mL), and 1-methyl-2- pyrrolidinone (15.4 mL). The reaction mixture was heated to 160 °C in a sealed tube for 13 hrs., then cooled to room temperature. Water was added, then the mixture was extracted with ethyl acetate and washed with water several times. The organic mixture was dried over potassium carbonate, filtered and concentrated under vacuum. Purification via flash chromatography (3/97 methanol/dichloromethane) yielded 12 (1.77 g, 90%).

1H NMR (400 MHz, CDCI3): δ 7.45 (d, 1 H, J = 2.0 Hz), 7.17 (dd, 1 H, J =

2.4 Hz, J = 8.6 Hz), 6.86 (d, 1 H, J = 8.4 Hz), 5.18-4.34 (m, 3H), 4.00- 4.23 (m, 5H), 3.86-3.98 (m, 6H), 3.69-3.79 (m, 1 H), 2.10-2.21 (m, 1 H), 1.99-2.10 (m, 1 H), 1.60-1.84 (m, 3H), 1.32-1.43 (m, 1 H), 1.24 (t, 3H, J = 7.2 Hz), 0.75 (s, 9H), 0.07 (d, 6H, J = 4.0 Hz). HRMS: Calcd for C28H43BrN5θ5Si (M+H): 636.2217. Found: 636.2207.

12 (1.77 g, 2.78 mmol) was dissolved in tetrahydrofuran (28 mL) under nitrogen and tetrabutylammonium fluoride (1M in THF, 28 mL) was added dropwise. The reaction was stirred at room temperature for 15 hrs., then diluted with dichloromethane and washed with water several times. The organic mixture was dried over potassium carbonate, filtered and concentrated under vacuum. Purification via flash chromatography (3/97 methanol/dichloromethane) yielded 13 (compound no. 114 in Table II) (760 mg, 52%).

DASANTAFIL

1H NMR (400 MHz, CDCI3):

δ 7.47 (d, 1 H, J = 2.0 Hz), 7.19 (dd, 1 H, J =2.0 Hz, J = 8.4 Hz), 6.88 (d, 1 H, J = 8.4 Hz), 5.25 (s, 2H), 5.09 (s, 1H), 4.21-4.27 (m, 3H), 4.06 (q, 2H, J = 7.0 Hz), 3.90-3.97 (m, 3H), 3.89 (s, 1 H), 3.74-3.82 (m, 1 H), 3.08 (s, 1 H), 2.12-2.22 (m, 1 H), 1.98-2.08 (m, 1 H), 1.60-1.86 (m, 3H), 1.33-1.43 (m, 1 H), 1.25 (t, 3H, J = 7.0 Hz),1.06-1.22 (m, 3H). HRMS: Calcd for C22H28BrN5O5 (M+H): 522.1352. Found: 522.1346.

2-Bromo-4-methyl anisole 14 (2.2 mL, 14.9 mmol) was dissolved in dichlomethane (30 mL) and N-bromosuccinimide (3.75 g, 16.4 mmol) was added followed by AIBN (26.0 mg). The reaction was heated to reflux for 19 hrs., then cooled to room temperature and the precipitate was filtered off. The filtrate was diluted with dichloromethane and washed with 0.5 M aqueous sodium bicarbonate, followed by water. The organic mixture was dried over sodium sulfate, filtered and concentrated under vacuum to yield 15 (4.16 g,

100%). The benzyl bromide was used as the crude material without further purification.

1H NMR (400 MHz, CDCI3): δ 7.59 (d, 1 H, J = 2.0 Hz), 7.30 (dd, 1 H, J =

2.4 Hz, J = 8.4 Hz), 6.85 (d, 1 H, J = 8.4 Hz), 4.37 (s, 2H), 3.90 (s, 3H).

General Synthesis of Compound No. 114 in Table II (13) a) Reacting 1 with an alkyl halide and base to form 2; b) Debenzylation of 2 to form 3; c) Alkylation of 3 with a benzyl halide to form 10; d) Deprotonation of 10 followed. by addition of a brominating agent to form 11 ; e) Displacement of bromo 11 with an amine to form 12; and f) Silyl ether cleavage of 12 to form compound no. 114 in Table II (13).

114 IN TABLE II./(13)

Figure imgf000045_0001

……………

Links

WO2003101992A1

GENERAL SCHEME

Figure imgf000018_0001

 

SYNTHESIOS

1A

Figure imgf000027_0001

9A                                                                                                                   13A DASANTAFIL

 

SYNTHESIS

Compound 1A:

glycine-A/-r(4-methoxyphenyl)methyl1 ethyl ester

To a mixture of glycine ethyl ester hydrochloride (about 1.4 equiv) and potassium carbonate (about 1.0 equiv) was added anhydrous ethanol. The mixture

was stirred at about 40-45 °C for about 3 hours. Then, p-anisaldehyde (about 1.0

equiv.) was added, and the reaction mixture was stirred for a minimum of about 3 hours to provide an imine (not shown). Upon reaction completion (about <5.0 % p- anisaldehyde remaining by GC analysis), the reaction mixture was cooled to about 0-

10 °C. Then, an aqueous solution of sodium borohydride (about 0.50 equiv) was

added to the reaction mixture at a temperature of between about 0 °C and about 20

°C, and stirred for about 1 hour to provide Compound 1 A. Upon completion of the

reduction reaction, the reaction mixture was quenched with the slow addition of an aqueous solution of aqueous glacial acetic acid. After quenching, the reaction mixture was warmed to room temperature and filtered to remove solids. The filtrate was then concentrated under vacuum, followed by the addition of toluene and water to facilitate layer separation. Aqueous potassium carbonate solution was added to adjust the pH of the mixture to about 8-9. The organic layer was separated and the aqueous layer was extracted with toluene. The combined toluene extracts were concentrated to provide the product in about a 80-85% yield (based on GC and HPLC in solution assay). 1H NMR 400 MHz (CDCI3): δ 7.23 (d, J = 8.5 Hz, 2H), 6.85 (d, J = 8.5 Hz, 2H),

4.17 (q, J = 7.1 Hz, 2H), 3.78 (s, 3H), 3.73 (s, 2H), 3.38 (s, 2H), 1.88 (s, br, 1 H), 1.26

(t, J = 7.1 Hz, 3H); 13C NMR 100 MHz (CDCI3): δ 172.8, 159.2, 132.0, 129.9, 114.2,

61.1, 55.6, 53.1 , 50.4, 14.6.

Compound 2:

/V-cvanomethanimidic acid ethyl ester

To cyanamide (about 1.2 mole) was added triethylorthoformate (about 1.33 mole), and the reaction mixture was heated to about 85-95 °C for approximately 2 hours to form Compound 2. Estimated in-solution yield was about 95-100%. The product was optionally purified by vacuum distillation.

1H NMR 400 MHz (CDCI3): δ 8.38 (s, 1H), 4.28 (t, J = 6.7 Hz, 2H), 1.29 (t, J =

6.8 Hz, 3H); 13C NMR 100 MHz (CDCI3): δ 171.5, 113.4, 65.5, 13.1.

Compound 3A:

Figure imgf000051_0001

cis- and frans-glvcine Λ/-r(cvanoimino,methyl1-Λ/-r(4- methoxyphenvDmethvπ ethyl ester

A solution of Compound 1A (about 1.0 mole) in toluene was concentrated under vacuum to distill off toluene. Anhydrous tetrahydrofuran (“THF”) was added to the concentrate, then Compound 2 (about 1.2 moles, obtained above) was added to that, and the solution was heated at reflux for about 1 hour. At this stage, the formation of Compound 3A was complete. Estimated in-solution yield was about

95% (about 2:1 mixture of cis and trans isomers). Compound 4A: 1H-imidazole-5-carboxylic acid, 4-amino-1-[(4- methoxyphenvDmethvn ethyl ester

Compound 3A (obtained above) was concentrated by distilling off THF. Then, anhydrous ethanol was added to afford a reaction mixture solution. Separately, potassium t-butoxide (about 0.15 mole) was dissolved in anhydrous ethanol to afford a solution. The potassium t-butoxide solution was added to the reaction mixture solution and heated to about 75-85 °C for about 1 hour. The overall in-solution yield of Compound 4A was about 85-90%.

Figure imgf000051_0002

1H NMR 400 MHz (CDCI3): δ 7.16 (s, 1H), 7.08 (d, J = 8.6 Hz, 2H), 6.82 (d, J

=8.7 Hz, 2H), 5.23 (s, 2H), 4.93 (s, br, 2H), 4.23 (q, J = 7.1 , 2H), 3.76 (s, 3H), 1.26 (t,

J = 7.1 Hz, 3H); 13C NMR 400 MHz (CDCI3): δ 160.9, 159.2, 139.0, 128.6, 128.5,

114.0, 101.8, 59.5, 55.2, 50.1 , 14.4.

Compound 5AK:

Figure imgf000052_0001

4A                                                                                                                             5AK

1 -ethyl-3,7-dihydro-7-F(4-methoxyphenyl)methvπ-1 H-Purine-2.6- dione potassium salt

The reaction mixture containing Compound 4A in ethanol (obtained above) was added to diglyme and distilled under vacuum to remove the ethanol. After being cooled to room temperature, Λ/-ethylurethane (about 1.2 equiv.) was added and the

reaction mixture was heated to about 110-120 °C. A solution of potassium t-butoxide

(2.2 equiv.) in diglyme was added to the hot solution. The reaction mixture was cooled to room temperature. THF was added to precipitate additional product, which was filtered and washed to provide Compound Salt 5AK in 55-65% overall yield. The wet cake can be used as such for conversion to Compound 6A.

1H NMR (DMSO-de, 400 MHz): δ 7.73 (s, 1H) 7.31 (d, J = 8.6 Hz , 2H) 6.86 (d,

J = 8.6 Hz, 2H) 5.24 (s, 1 H) 3.88 (q, J = 6.8 Hz, 2H) 3.71 (s, 3H) 1.07 (t, J = 6.8 Hz, 3H); 13C NMR (DMSO-d6, 100 MHz): δ 161.1 , 159.0, 158.4, 157.2, 141.4, 131.0,

129.5, 114.1 , 105.6, 55.4, 48.2, 34.4, 14.3.

Optional Neutralization of Compound Salt 5AK to Compound 5A: Compound 5A: 1-ethyl-3,7-dihvdro-7-r(4-methoχyphenyl,methvπ-1 H-Purine-2,6- dione

The wet cake filtered solid of Compound Salt 5AK (obtained above) was suspended in water and then acidified to a pH of about 5 using glacial acetic acid. The resulting slurry was filtered to obtain the neutralized product, which was then washed with water and dried. The overall isolated yield of neutralized Compound 5A from Compound 1 A was about 45-55%. Spectroscopic data for neutralized Compound 5A was identical to that of Compound Salt 5AK.

Compound 6A:

3-r2-(acetyloxy,ethvn-1-ethyl-3,7-dihvdro-7-r(4- methoxyphenyl,methvπ-1H-purine-2,6-dione

To the wet cake filtered solid of Compound Salt 5AK (obtained above) were added tetrabutylammonium bromide (about 0.05 mole) and 2-bromoethyl acetate

(about 1.2 moles) in THF. After being heated to reflux for about 2 hours, part of the THF was distilled off, and isopropyl alcohol was added to the reaction mixture. The reaction mixture was then concentrated under reduced pressure and cooled to around room temperature. Water was added to precipitate the product. After being cooled to about 0-5 °C for about a few hours, the product was isolated by filtration. The wet cake was washed with aqueous isopropyl alcohol (about 30% in water), and dried under vacuum to afford Compound 6A as a pale yellow solid in about a 45- 55% overall yield (based on Compound 1A). The crude product may be purified further by decolorizing with Darco in methanol, followed by filtration and concentration to afford crystalline Compound 6A.

1H NMR (CDCI3 , 400 MHz): δ 7.54 (s, 1 H) 7.32 (d, J = 8.6 Hz, 2H) 6.90 (d, J =

8.6 Hz, 2H) 5.43 (s, 2H) 4.41 (m, 2H) 4.38 (m, 2H) 4.10 (q, J = 7.2 Hz, 2H) 3.79 (s,

3H) 1.96 (s, 3H) 1.25 (t, J = 7.2 Hz, 3H); 13C NMR (CDCI3 , 100 MHz): δ 171.1 ,

160.2, 155.3, 151.4, 148.9, 140.9, 130.1 , 127.7, 114.8, 107.5, 61.7, 55.6, 50.2, 42.4, 36.9, 21.2, 13.6.

After Optional Neutralization of Compound Salt 5AK to Compound 5A:

Compound 6A:

3-r2-(acetyloxy.ethvπ-1-ethyl-3,7-dihvdro-7-r.4- methoxyphenyl)methyn-1H-purine-2,6-dione

Acetonitrile was added to a mixture of Compound 5A (about 1.0 mole), anhydrous potassium carbonate (about 1.5 moles) and tetrabutylammonium hydrogen sulfate (about 0.05 mole). 2-bromoethyl acetate (about 1.5 moles) was added in three separate portions (0.72 mole in the beginning, another 0.45 mole after about 2 hours of reaction, and then the remaining 0.33 mole after about another

1 hour of reaction) during the course of the reaction at about 80-85 °C. The total reaction time was about 7 hours. The reaction mixture was cooled to about room temperature and filtered. The filtrate was concentrated. Aqueous isopropanol was added to crystallize the product. The product was filtered, washed with aqueous isopropanol, and dried to provide Compound 6A in about a 75-80% yield. Compound 7A: 8-bromo-1 -ethyl-3-r2-(acetyloxy)ethvπ-3,7-dihvdro-7-r(3-bromo-4- methoxyphenyl)methvπ-1 – -Purine-2,6-dione

Compound 6A (about 1 mole) and NBS (about 2.8 moles) were dissolved in

dry acetonitrile and agitated at about 15-20 °C. To this reaction mixture, a solution of

sulfuric acid (about 0.03 mol) in acetonitrile was added, while maintaining the

reaction temperature below about 25 °C. The reaction mixture was agitated at about

20-25 °C for about 12-15 hours until complete consumption of the starting material

was indicated. The reaction mixture was cooled to about 0-5 °C and a cold (about 5-

10 °C) aqueous solution of sodium sulfite was added, keeping the temperature below

about 10 °C. The reaction was agitated for about 2 hours at about 0-10 °C, and then

filtered. The isolated cake was washed with water, followed by methanol, then dried under a vacuum to obtain Compound 7A in about an 85% yield.

Figure imgf000053_0001

1H NMR (CDCIs, 400 MHz): D 7.60 (d, J=2.0 Hz, 1H), 7.35 (dd, J=8.4 Hz, 2.0 Hz, 1 H), 6.83 (d, J=8.4 Hz, 1 H), 5.43 (s, 2H), 4.35 (m, 4H), 4.05 (q, J=7.0 Hz, 2H), 3.85 (s, 3H), 1.96 (s, 3H), 1.23 (t, J=7.0 Hz, 3H); 13C NMR (CDCI3, 100 MHz): D 171.0, 156.2, 154.2, 150.8, 148.2, 138.3, 128.9, 128.7, 127.5, 112.1 , 112.0, 109.1 , 61.5, 56.5, 49.3, 42.5, 37.0, 21.0, 13.3. MS (ES) m/e 545.2 (M+H)+.

Compound 13A:

1-ethyl-3.7-dihvdro-8-r(1f?,2 )-(hvdroxycvclopentyl)amino1-3-(2- hvdroxyethvπ-7-r(3-bromo-4-methoxyphenvhmethvπ-1/–purine-2.6-dione

Compound 7A (about 1 mole) was combined with (R,R)-2-amino-1- cyclopentanol hydrochloride (Compound 8A, about 1.2 moles) and sodium bicarbonate (about 3 moles). To this reaction mixture was added N,N- dimethylacetamide (“DMA”), and the reaction mixture was agitated at about 135-140 °C for about 15-17 hours until complete consumption of the starting material was

indicated.

Figure imgf000053_0002

 

Compound 9A is an intermediate that is formed, but not isolated, from the

reaction mixture. The reaction mixture was then cooled to about 45-50 °C, and

tetrabutylammonium hydroxide (about 0.05 moles of about a 40% solution in water) was charged therein, followed by methanol. The reaction mixture was refluxed at

about 80-85 °C for about 8-9 hours until complete deprotection of the acetate group

was indicated. The reaction mixture was cooled to about 40-45 °C and concentrated

under vacuum. The pH of the reaction mixture was adjusted to about 5-6 with dilute

acetic acid, and the reaction mixture was heated to about 55-65 °C, and seeded with

a small amount of Compound 13A. The reaction mixture was then cooled to about

30-35 °C over a period of about 2 hours, and water was added over a period of

about 1 hour. The reaction mixture was further cooled to about 0-5 °C over a period

of about 1 hour, and agitated at that temperature for about 4 hours. The Compound 13A product was isolated by filtration, washed with water and dried to provide about an 85-90% yield.

Figure imgf000054_0002

9A                                                                                                                                 13A DASANTAFIL

1H NMR (CDCI3, 400 MHz): D 7.47 (d, J=2.1 Hz, 1 H), 7.18 (dd, J=8.4 Hz, 2.0 Hz, 1 H), 6.87 (d, J=8.4 Hz, 1H), 5.23 (s, 2H), 5.01 (s, 1 H), 4.22 (m, 2H), 4.15 (m, 1H), 4.05 (q, J=7.0 Hz, 2H), 3.93 (m, 3H), 3.88 (s, 3H), 3.77 (m, 1H), 2.95 (m, 1H), 2.15 (m, 1H), 2.05 (m, 1 H), 1.60-1.80 (m, 4H), 1.35 (m, 1 H), 1.23 (t, J=7.0 Hz, 3H); 13C NMR (CDCI3, 100 MHz): D 156.2, 154.0, 153.5, 151.8, 148.3, 132.6, 129.1 , 127.9, 112.5, 103.2, 79.5, 77.8, 63.2, 61.3, 56.7, 46.5, 45.9, 36.8, 32.9, 31.5, 21.4, 13.8. MS (ES) m/e 523.4 (M+H)+. Micronization

INTERPRETATION

1H NMR (CDCI3, 400 MHz): DELTA

7.47 (d, J=2.1 Hz, 1 H),  SANDWICHED AROM H BETWEEN BROMO AND -CH2-PY RING

7.18 (dd, J=8.4 Hz, 2.0 Hz, 1 H), AROM H ORTHO TO  -CH2-PH RING AND PARA TO BROMO

6.87 (d, J=8.4 Hz, 1H), AROM H  ORTHO TO O ATOM OF PH RING

5.23 (s, 2H),  CH2 OF N-CH2-PH RING

5.01 (s, 1 H),  OH OR NH 1H OUT OF 3 NOS

4.22 (m, 2H), OH OR NH         2H OUT OF 3 NOS

4.15 (m, 1H),     –NCH2CH2OH     1H OUT OF 4 NOS

4.05 (q, J=7.0 Hz, 2H),   CH2 OF NCH2 CH3

3.93 (m, 3H),          —NCH2CH2OH     3H OUT OF 4 NOS

3.88 (s, 3H),     -OCH3

3.77 (m, 1H), OH-CH OF CYCLOPENTANE RING

2.95 (m, 1H),NH-CH OF CYCLOPENTANE RING

2.15 (m, 1H),

2.05 (m, 1 H),   1H ON CYCLOPENTANE RING

1.60-1.80 (m, 4H),    4H ON CYCLOPENTANE RING

1.35 (m, 1 H),                1 H PARA TO SUBS IN CYCLOPENTANE RING

1.23 (t, J=7.0 Hz, 3H)  –NCH2 CH3

 

………………………..

shark

DASANTAFIL

Links

REFERENCES

1 WANG Y ET AL: “DESIGN AND SYNTHESIS OF XANTHINE ANALOGUES AS POTENT AND SELECTIVE PDE5 INHIBITORS” BIOORGANIC & MEDICINAL CHEMISTRY LETTERS, OXFORD, GB, vol. 12, no. 21, 2002, pages 3149-3152, XP009014973 ISSN: 0960-894X

2. Peter K. Bridson and Xiaodong Wang in 1 -Substituted Xanthines, Synthesis, 855 (July, 1995)

PATENTS

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6. WO 2005051368

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8. WO 2003101991

9.WO2006104870A2 , Schering Corp Methods of treating benign prostatic hyperplasia or lower urinary track symptoms by using pde 5 inhibitors

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