AUTHOR OF THIS BLOG

DR ANTHONY MELVIN CRASTO, WORLDDRUGTRACKER
Nov 102017
 
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Abstract

The synthesis of monocyclic, spirocyclic and fused bicyclic secondary amines bearing a gem-difluorocyclopropane moiety via difluorocyclopropanation of unsaturated N-Boc derivatives using the trifluoromethyl(trimethyl)silane/sodium iodide [CF3SiMe3-NaI] system is described. The relative order of the substrate reactivity is established. It is shown that for the reactive alkenes the standard reaction conditions can be used, whereas for the substrates with low reactivity, slow addition of the Ruppert–Prakash reagent is necessary.

Gram-Scale Synthesis of Amines Bearing a gem-Difluorocyclopropane Moiety

Authors., Pavel S. Nosik,

DOI: 10.1002/adsc.201700857

Pavel S. Nosik,a.b Andrii O. Gerasov,a Rodion O. Boiko,a Eduard Rusanov,b Sergey V. Ryabukhin,c Oleksandr O. Grygorenko,c * Dmitriy M. Volochnyukb

a Spectrum Info Ltd., Life Chemicals Inc., Murmanska Street 5, Kyiv 02094, Ukraine

b Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanska Street 5, Kyiv 02660, Ukraine

c National Taras Shevchenko University of Kyiv, Volodymyrska Street 64, Kyiv 01601, Ukraine

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* Corresponding author. E-mail: gregor@univ.kiev.ua.

 

Oleksandr Grygorenko at National Taras Shevchenko University of Kyiv

Oleksandr Grygorenko

Ph D
Professor (Associate)
National Taras Shevchenko University of Kyiv, Volodymyrska Street 64, Kyiv 01601, Ukraine
National Taras Shevchenko University of Kyiv

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Dmitriy M. Volochnyuk

Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanska Street 5, Kyiv 02660, Ukraine

Dmitriy M. Volochnyuk was born in 1980 in Irpen, Kyiv region, Ukraine. He graduated from Kyiv State Taras Shevchenko University in 2002 and was awarded his M.S. degree in chemistry. He received his Ph.D. in organic chemistry in 2005 from the Institute of Organic Chemistry, National Academy of Sciences of Ukraine under the supervision of Dr. A. Kostyuk for research on the chemistry of enamines. At present, he divides his time between the Institute of Organic Chemisty, as Deputy Head of Organophosphorus Department and Senior Researcher, and Enamine Ltd (Kyiv, Ukraine), as Director of Chemistry. His main scientific interests are related to fluoroorganic, organophosphorus, heterocyclic and combinatorial chemistry, and multistep organic synthesis. He is a coauthor of more than 80 papers

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  • Given that the incorporation of small fluorinated fragments in drug-like molecules continues to rise, this has created an onus on the synthetic community to provide robust, scalable routes to these molecules of interest. Grygorenko and co-workers have reported on a synthesis of amines featuring a gem-difluorocyclopropane moiety using the readily available Ruppert–Prakash reagent ( Adv. Synth. Catal. 201710.1002/adsc.201700857).
  • Evaluating a series of olefins under the standard reaction conditions in refluxing THF indicated that only the most reactive olefins (gem-disubstituted) provided good yields of the desired cyclopropane, while other solvents proved to be ineffective. Conducting a control experiment omitting the substrate demonstrated that the key issue herein was competitive decomposition of the TMSCF3 to a series of gaseous byproducts under the reaction conditions.
  • Whereas continuous flow provides a potential to mitigate against this, the current report demonstrated that slow addition of the reagent to the reaction mixture also provided a practical solution to this problem.
  • Employing this approach enabled not only excellent conversions and yields to be realized but also allowed reactivity trends to be identified. In general, gem-disubstituted are the most reactive with the trend correlating with steric hindrance.
  • For other classes of olefins, electronics are the major factor with the ability of the substituents to stabilize a positive charge in the transition state consistent with a nonsynchronous formation of the two sigma bonds in the cycloaddition the key consideration. The removal of the Boc-protecting group under standard acidic conditions provided the amines as their hydrochloride salts.
  • Eduard Rusanov at Institute of Organic Chemistry National Academy of Sciences of Ukraine
  • Eduard Rusanov

    PhD
    Head of Crystallographic Lab./Director of the crystallographic facility Nat. Acad. of Sci. Ukraine ‘Single Mjlecule Crystallography’ at IOC
    Institute of Organic Chemistry… · DEPARTMENT OF PHYSICOCHEMICAL INVESTIGATIONS

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tert-Butyl 1,1-difluoro-6-azaspiro[2.5]octane-6-carboxylate (10a):

Yield: 66.7 g (91%) (Method A); off-white crystalline powder: mp 46–48 8C;

1H NMR (CDCl3 , 400 MHz): d= 3.57–3.42 (m, 2H), 3.40–3.27 (m, 2H), 1.66–1.47 (m, 4H), 1.44 (s, J=2.3 Hz, 9H), 1.08 (t, J=8.3 Hz, 2H);

13C NMR (CDCl3, 101 MHz): d=154.2, 115.4 (t, J=288.1 Hz), 79.3, 42.8, 28.4, 28.1, 26.8 (t, J=10.0 Hz), 21.0 (t, J=10.1 Hz);

19F NMR (CDCl3 , 376 MHz): d=@140.6;

MS (EI): m/z= 247 (M+ ), 192 (M+@t-Bu), 174 (M+@t-BuO), 147 (M+@Boc), 127 (M+@Boc@HF);

Anal. calcd. for C12H19F2NO2 : C 58.29, H 7.74, N 5.66; found: C 58.49, H 8.02, N 5.30.

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Nov 092017
 

STR3

2-Phenylfuran

17113-33-6 cas

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2-Phenylfuran (3v) [15]: According to the general procedure I and purification by column chromatography (100% PE) yielded 3v (35.9 mg, 50%) and the general procedure II yielded 3s (35.1 mg, 49%) as a white solid . 1 H NMR (400 MHz, CDCl3) δ 7.68-7.66 (m 2H), 7.46 (s, 1H), 7.40-7.35 (m, 2H), 7.26-7.23 (m, 1H), 6.645-6.639 (m, 1H), 6.461-6.457 (m, 1H). LRMS (ESI) calcd for [M+H]+ C10H9O 145.1, found 145.1.

15 Zhou, C.-Y.; Chan, P. W. H.; Che, C.-M. Org. Lett. 2006, 8, 325.

Visible-Light Photoredox in Homolytic Aromatic Substitution: Direct Arylation of Arenes with Aryl Halides

Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering, and Materials Science, Soochow University, 199 RenAi Road, Suzhou, Jiangsu 215123, China
Org. Lett.201315 (11), pp 2664–2667
DOI: 10.1021/ol400946k

Abstract

Abstract Image

Direct arylation of unactivated arenes or heteroarenes with aryl halides could be carried out in the presence of potassium tert-butoxide and dimethyl sulfoxide under visible-light irradiation. Ir(ppy)3was found to be an effective photoredox catalyst for this reaction. The reactions of aryl iodides occurred at room temperature. Elevated temperature was required for aryl bromides. Homolytic aromatic substitution was proposed to be the operative reaction pathway.

Predicts

1H NMR

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13C NMR

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http://pubs.acs.org/doi/10.1021/ol400946k

more info

Open Babel bond-line chemical structure with annotated hydrogens.<br>Click to toggle size.

<sup>1</sup>H NMR spectrum of C<sub>10</sub>H<sub>8</sub>O<sub></sub> in CDCL3 at 400 MHz.<br>Click to toggle size.

Shifts

Index Name Shift (ppm)
19 H7 6.582
1 H1 7.655
5 H5 7.655
15 H6 6.885
11 H2 7.415
7 H4 7.415
9 H3 7.362
17 H8 7.471

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

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Nov 092017
 

Zhong-Xia WANG

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N,N-dimethyl-4-biphenylamine

Molecular Formula, C14H15N
Molecular Weight, 197.28
CAS Number, 1137-79-7

(1) N,N-dimethyl-[1,1′-biphenyl]-4-amine (3a) 5,6

Elute: EtOAc/petroleum ether: 1/100 (v/v), white solid, yield 97.8 mg (99%).

1H NMR (400 MHz, CDCl3): δ 7.56 (d, J = 7.8 Hz, 2H), 7.51 (d, J = 8.8 Hz, 2H), 7.40 (t, J = 7.7 Hz, 2H), 7.30–7.21 (m, 1H), 6.81 (d, J = 8.8 Hz, 2H), 3.00 (s, 6H).

13C NMR (101 MHz, CDCl3): δ 150.09, 141.34, 129.37, 128.78, 127.84, 126.43, 126.12, 112.90, 40.97.

5 Yang, X.; Wang, Z.-X. Organometallics 2014, 33, 5863.

(6) Stibingerova, I.; Voltrova, S.; Kocova, S.; Lindale, M.; Srogl, J. Org. Lett. 2016, 18, 312.

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Transition-Metal-Free Cross-Coupling of Aryl and Heteroaryl Thiols with Arylzinc Reagents

Bo Yang and Zhong-Xia Wang* 
 CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
 Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, P. R. China
Org. Lett., Article ASAP
DOI: 10.1021/acs.orglett.7b03145

Abstract

Abstract Image

Cross-coupling of (hetero)arylthiols with arylzinc reagents via C–S cleavage was performed under transition-metal-free conditions. The reaction displays a wide scope of substrates and high functional-group tolerance. Electron-rich and -deficient (hetero)arylthiols and arylzinc reagents can be employed in this transformation. Mg2+ and Li+ ions were demonstrated to facilitate the reaction.

In summary, we developed a transition-metal-free coupling reaction of (hetero)arylthiols with arylzinc reagents to form bi(hetero)aryls. The reaction exhibited wide substrate scope and good compatibility of functional groups. Electron-rich and -poor aryl or heteroaryl thiols can be converted. Various arylzinc reagents, including electron-rich and electron-poor reagents, can be employed as the coupling partners. Preliminary mechanistic studies suggest a nucleophilic aromatic substitution pathway, and Mg2+ and Li+ ions play important roles in the process of reaction. This study provides an example of S2– as a leaving group in an aromatic system and an effective methodology for the synthesis of bi(hetero)aryls including pharmaceutical molecules without transition-metal impurities.

Zhong-Xia WANG

Department: Department of Chemistry
Mailing Address:
Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Rd, Hefei, Anhui, 230026, PR China
Postal Code:
230026
Phone:
+86-551-63603043
Fax:
Homepage:
http://chem.ustc.edu.cn/szdw_16/bd/201210/t20121023_142877.html
Zhong-Xia Wang is a professor in the Department of Chemistry at the University of Science and Technology 
of China. He received his BS degree (1983) and MS degree (1986) from Nankai University, 
and PhD degree (1997) from the University of Sussex, UK. Since July 1986, Wang has been working 
at the University of Science and Technology of China (USTC) successively as Assistant, 
Lecturer, Associate Professor, and Professor. From Aug. 1993 to Oct. 1996, he pursued his doctoral 
studies at the University of Sussex, UK, and from Oct. 1999 to Oct. 2000, he was a Research Associate 
at the Chinese University of Hong Kong.

 学 系
Department of Chemistry

Predicts

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http://pubs.acs.org/doi/10.1021/acs.orglett.7b03145

 

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

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Nov 032017
 

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1-benzyl-2, 4, 5-triphenyl-1H-imidazole

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. 1-Benzyl-2,4,5-triphenyl-1H-imidazole (5a, n = 1).

Off-white solid; m.p.: 160–162 °C;

anal. calcd. for C28H22N2: C, 87.01, H, 5.74, N, 7.25%. Found: C, 87.13, H, 5.70, N, 7.19%;

UV (λmax, ethanol) = 280 nm;

FT-IR (KBr, cm−1 ): 3060 (C–H stretch), 3031, 1600 (CN), 1497, 1483, 1447 (CC), 1352 (C–N stretch), 769, 697 (C–H band);

1 H NMR (400 MHz, DMSO): 5.16 (s, 2H, CH2), 6.74–7.67 (m, 20H, Ar–H) ppm;

13C NMR (100 MHz, DMSO): 47.6 (CH2, C8), 125.1 (CHarom, C28), 126.0 (CHarom, C26), 126.2 (CHarom, C30), 126.4 (CHarom, C11), 127.0 (CHarom, C15), 127.1 (CHarom, C16), 127.7 (CHarom, C20), 128.0 (CHarom, C21), 128.1 (CHarom, C25), 128.4 (CHarom, C13), 128.5 (CHarom, C18), 128.6 (CHarom, C27), 128.8 (C1), 128.8 (CHarom, C12), 128.9 (CHarom, C14), 130.1 (CHarom, C17), 130.3 (CHarom, C19), 130.5 (CHarom, C22), 130.7 (CHarom, C24), 131.0 (CHarom, C29), 134.4 (CHarom, C9), 135.1 (CHarom, C23), 136.8 (CHarom, C7), 137.0 (CHarom, C10), 137.2 (CHarom, C6), 145.4 (C2), 147.0 (C4) ppm;

MS: m/z = 387.5 (M + H)+

An efficient green protocol for the synthesis of tetra-substituted imidazoles catalyzed by zeolite BEA: effect of surface acidity and polarity of zeolite

*Corresponding authors

Abstract

In the present study, the catalytic activity of various medium (H-ZSM-5) and large pore (H-BEA, H-Y, H-MOR) zeolites were studied as solid acid catalysts. The zeolite H-BEA is found to be an efficient catalyst for the synthesis of 1-benzyl-2,4,5-triphenyl-1H-imidazoles through one-pot, 4-component reaction (4-CR) between benzil, NH4OAc, substituted aromatic aldehydes and benzyl amine. The hydrophobicity, Si/Al ratio and acidic properties of zeolite BEA were well improved by controlled dealumination. The synthesized materials were characterized by various characterization techniques such as XRD, ICP-OES, BET, NH3-TPD, FT-IR, pyridine FT-IR, 27Al and 1H MAS NMR. It has been observed that the dealumination of the parent zeolite H-BEA (12) results in the enhanced strength of Brønsted acidity up to a certain Si/Al ratio which is attributed to the inductive effect of Lewis acidic EFAl species, leading to the higher activity of the zeolite BEA (15) catalyst towards the synthesis of 1-benzyl-2,4,5-triphenyl-1H-imidazoles under thermal solvent-free conditions with good to excellent yields. Using the present catalytic synthetic protocol, diverse tetra-substituted imidazoles, which are among the significant biologically active scaffolds, were synthesized in high yield within a shorter reaction time. The effect of polarity, surface acidity and extra framework Al species of the catalysts has been well demonstrated by means of pyridine FT-IR, and 27Al and 1H MAS NMR. The solvent-free synthetic protocol makes the process environmentally benign and economically viable.

Graphical abstract: An efficient green protocol for the synthesis of tetra-substituted imidazoles catalyzed by zeolite BEA: effect of surface acidity and polarity of zeolite
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Image result for S. V. National Institute of Technology, Ichchhanath, Surat
Image result for S. V. National Institute of Technology, Ichchhanath, Surat
Image result for S. V. National Institute of Technology, Ichchhanath, Surat
S. V. National Institute of Technology, Ichchhanath, Surat
Image result for Mandvi Science College, Mandvi – 394160, Surat, India
Image result for Mandvi Science College, Mandvi – 394160, Surat, India
Mandvi Science College, Mandvi – 394160, Surat, India

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DISCLAIMER

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent
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Diethyl Isosorbide (DEI)

 spectroscopy, SYNTHESIS, Uncategorized  Comments Off on Diethyl Isosorbide (DEI)
Oct 162017
 

STR1 STR2 str3 str4

Diethyl Isosorbide (DEI): []D 20 +95.9 (c 1, in MeOH);

1H NMR (400 MHz; CDCl3; Me4Si):  4.63 (t, J = 4.2 Hz, 1H, H-4), 4.51 (d, J = 4.1 Hz, 1H, H-3), 4.06–3.90 (m, 5H, H- 1, H-2, H-5, H-6), 3.80–3.69 (m, 1H, CH2-OC-5), 3.63–3.49 (m, 4H, H-6, CH2-OC-5, CH2- OC-2), 1.23 ppm (dt, J = 17.8, 7.0 Hz, 6H, CH3CH2O-C-2, CH3CH2O-C-5);

13C NMR (101 MHz; CDCl3; Me4Si):  86.57 (C-3), 84.45 (C-2), 80.36 (C-5), 80.27 (C-4), 73.64 (C-1), 69.81 (C-6), 66.28 (CH2-O-C-5), 65.24 (CH2-O-C-2), 15.49 ppm (CH3-CH2OC-5), 15.44 (CH3-CH2OC-2);

MS (70 eV): m/z 202 (M+ , 6%), 157 (1), 113 (17), 89 (33), 69 (100), 57 (11), 44 (39).

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Total synthesis of (-)-aritasone via the ultra-high pressure hetero-Diels-Alder dimerisation of (-)-pinocarvone

 organic chemistry, spectroscopy, SYNTHESIS  Comments Off on Total synthesis of (-)-aritasone via the ultra-high pressure hetero-Diels-Alder dimerisation of (-)-pinocarvone
Oct 102017
 

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Total synthesis of (-)-aritasone via the ultra-high pressure hetero-Diels-Alder dimerisation of (-)-pinocarvone

Org. Biomol. Chem., 2017, Advance Article

DOI: 10.1039/C7OB02204B, Paper
Maliha Uroos, Phillip Pitt, Laurence M. Harwood, William Lewis, Alexander J. Blake, Christopher J. Hayes
The total synthesis of aritasone via the proposed biosyntheic hetero-Diels-Alder [4 + 2] cyclodimerisation of pinocarvove, has been achieved under ultra-high pressure (19.9 kbar) conditions

Total synthesis of (−)-aritasone via the ultra-high pressure hetero-Diels–Alder dimerisation of (−)-pinocarvone

 Author affiliations

Christopher Hayes

Abstract

This paper describes a total synthesis of the terpene-derived natural product aritasone via the hetero-Diels–Alder [4 + 2] cyclodimerisation of pinocarvove, which represents the proposed biosyntheic route. The hetero-Diels–Alder dimerisation of pinocarvone did not proceed under standard conditions, and ultra-high pressure (19.9 kbar) was required. As it seems unlikely that these ultra-high pressures are accessible within a plant cell, we suggest that the original biosynthetic hypothesis be reconsidered, and alternatives are discussed.

STR1 STR2
Aritasone (1) A solution of pinocarvone (()-2) (100 mg, 0.66 mmol) in dichloromethane (5 mL) was pressurized to 19.9 kbar for 120 h. The 1H NMR spectrum of the crude reaction mixture showed significant change in the composition as compared to the starting material. The solvent was evaporated and the residue was purified by column chromatography (pentane/Et2O; 25/1) to afford aritasone (1) (20 mg, 40%) as a white solid; mp 101- 103 C; (lit3 mp 105-106 °C); []D 26 26.1 (c 0.40 in CHCl3); (lit3 []D 9 118); max/cm-1 (CHCl3) 2926, 2359, 1722, 1689, 1601, 1467, 1372, 1305, 1152; H (400 MHz; CDCl3, 298 K) 2.67 (2H, app dd, J 4.8, 2.5, H-2a, H-2b), 2.45-2.32 (3H, m, H-7a, H-15a, H-3), 2.15-2.01 (4H, m, H-10, H-12, H-15b, H-16a), 1.91-1.80 (2H, m, H-4, H-16b), 1.66 (1H, ddd, J 13.8, 6.4, 3.4, H-7b), 1.38 (3H, s, CH3), 1.29-1.22 (7H, br s, CH3, H-13a, H-13b, H-8a, H- 8b), 0.90 (3H, s, CH3), 0.80 (3H, s, CH3); C (100 MHz; CDCl3, 298 K) 209.5 (C), 142.9 (C), 112.8 (C), 80.8 (C), 45.2 (CH), 44.3 (CH), 43.7 (CH2), 40.9 (CH), 40.5 (C), 39.4 (CH), 38.3 (C), 33.2 (CH2), 32.7 (CH2), 27.7 (CH3), 27.3 (CH2), 27.3 (CH3), 26.3 (CH3), 22.5 (CH2), 22.1 (CH2), 20.9 (CH3); HRMS m/z (ES+ ) found 301.2162 (M + H) C20H29O2 requires 301.2162 and 323.1981 (M + Na) C20H28O2Na requires 323.1982. These data were consistent to those previously reported, 5, 7 however the value of the specific rotation5 differs significantly from that measured during the original isolation work.3

Christopher Hayes

Contact

Biography

Prof. Christopher Hayes began his academic career here in Nottingham with his B.Sc. in July 1992. Remaining at Nottingham, he completed his Ph.D. studies in organic chemistry, under the supervision of Professor Gerald Pattenden, in September 1995. In January 1996, on a NATO Postdoctoral Fellowship, he moved to the University of California at Berkeley where he worked in the group of Professor Clayton H. Heathcock. In September 1997, he returned to Nottingham as a Lecturer in Organic Chemistry, and has subsequently been promoted to Reader (2003), Associate Professor (2006) and Professor of Organic Chemistry (2011).

Research Summary

Research is centred in main-stream synthetic organic chemistry, focusing on the organic chemistry of biologically active molecules. His current research interests span a number of areas such as (i)… read more

Recent Publications

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A green route for methanol carbonylation

 spectroscopy, SYNTHESIS  Comments Off on A green route for methanol carbonylation
Oct 092017
 

 

Catal. Sci. Technol., 2017, Advance Article
DOI: 10.1039/C7CY01621B, Paper
Youming Ni, Lei Shi, Hongchao Liu, Wenna Zhang, Yong Liu, Wenliang Zhu, Zhongmin Liu
Halide-free and noble metal-free pyridine-modified H-mordenites exhibit high stability and selectivity in methanol carbonylation to acetic acid.

A green route for methanol carbonylation

 Author affiliations

Abstract

Acetic acid is one of the most important bulk commodity chemicals and is currently manufactured by methanol carbonylation reactions with rhodium or iridium organometallic complexes and halide-containing promoters named Monsanto or BP Cativa™ homogeneous processes, respectively. Developing a halide-free catalyst and a heterogeneous process for methanol carbonylation is of great importance and has recently attracted extensive research attention. Here, we report a green route for direct synthesis of acetic acid via vapor-phase carbonylation of methanol with a stable, selective, halide-free, and noble metal-free catalyst based on pyridine-modified H-mordenite zeolite. Methanol conversion and acetic acid selectivity can reach up to 100% and 95%, respectively. Only little deactivation is observed during the 145 hour reaction.

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A Fully Continuous-Flow Process for the Synthesis of p-Cresol: Impurity Analysis and Process Optimization

 PROCESS, spectroscopy, SYNTHESIS  Comments Off on A Fully Continuous-Flow Process for the Synthesis of p-Cresol: Impurity Analysis and Process Optimization
Oct 092017
 

Abstract Image

A fully continuous-flow diazotization–hydrolysis protocol has been developed for the preparation of p-cresol. This process started from the diazotization of p-toluidine to form diazonium intermediate. The reaction was then quenched by urea and subsequently followed by a hydrolysis to give the final product p-cresol. Three types of byproducts were initially found in this reaction sequence. After an optimization of reaction conditions (based on impurity analysis), side reactions were eminently inhibited, and a total yield up to 91% were ultimately obtained with a productivity of 388 g/h. The continuous-flow methodology was used to avoid accumulation of the highly energetic and potentially explosive diazonium salt to realize the safe preparation for p-cresol.

 

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1H NMR (400 MHz, (CD3)2SO) δ/ppm: 9.06 (br s, 1H, −OH), 6.94 (d, J = 8.0 Hz, 2H, Ar–H), 6.62 (d, J = 8.0 Hz, 2H, Ar–H), 2.17 (s, 3H, −CH3).

13C NMR (CDCl3) δ/ppm: 153.0, 129.9, 115.1, 20.5.

 

Literature data:(3b) 1H NMR (300 MHz, CDCl3) δ/ppm: 7.03 (d, J = 8.2 Hz, 2H), 6.73 (dd, J = 8.2, 2.0 Hz, 2H), 4.75 (s, 1H, OH), 2.27 (s, 3H, CH3).

13C NMR (CDCl3) δ/ppm: 153.2, 130.2, 115.2, 20.6.

3(b) TaniguchiT.ImotoM.TakedaM.NakaiT.MiharaM.IwaiT.ItoT.MizunoT.NomotoA.OgawaA. Heteroat. Chem. 201526411– 416 DOI: 10.1002/hc.21275

A Fully Continuous-Flow Process for the Synthesis of p-Cresol: Impurity Analysis and Process Optimization

National Engineering Research Center for Process Development of Active Pharmaceutical Ingredients, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, P. R. China
Org. Process Res. Dev., Article ASAP
DOI: 10.1021/acs.oprd.7b00250
*Tel.: (+86)57188320899. E-mail: pharmlab@zjut.edu.cn.

http://pubs.acs.org/doi/full/10.1021/acs.oprd.7b00250

 

NMR PREDICT

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Catalyst-free multi-component cascade C-H-functionalization in water using molecular oxygen: an approach to 1,3-oxazines

 spectroscopy, SYNTHESIS  Comments Off on Catalyst-free multi-component cascade C-H-functionalization in water using molecular oxygen: an approach to 1,3-oxazines
Sep 202017
 

 

Catalyst-free multi-component cascade C-H-functionalization in water using molecular oxygen: an approach to 1,3-oxazines

Green Chem., 2017, 19,4036-4042
DOI: 10.1039/C7GC01494E, Communication
Mohit L. Deb, Choitanya D. Pegu, Paran J. Borpatra, Prakash J. Saikia, Pranjal K. Baruah
Synthesis of 1,3-oxazines via catalyst free C-H functionalization using molecular oxygen in water.

Catalyst-free multi-component cascade C–H-functionalization in water using molecular oxygen: an approach to 1,3-oxazines

 Author affiliations

Abstract

Herein, catalyst-free 3-component reactions of naphthols, aldehydes, and tetrahydroisoquinolines to synthesize 1,3-oxazines is reported. The reaction is performed in H2O in the presence of O2 as the sole oxidant at 100 °C, which proceeds through the formation of 1-aminoalkyl-2-naphthols followed by selective α-C–H functionalization of tert-amine.

15-phenyl-7a,12,13,15-tetrahydronaphtho[1′,2′:5,6][1,3]oxazino[2,3- a]isoquinoline (4a):1

White solid; Yield 61 %, 221 mg;

1H NMR (500 MHz, CDCl3): δ 7.79-7.77 (m, 1H), 7.74 (d, J = 8.9 Hz, 1H), 7.43-7.41 (m, 1H), 7.33-7.28 (m, 8H), 7.24-7.19 (m, 3H), 7.11 (d, J = 8.9 Hz, 1H), 5.65 (s, 1H), 5.44 (s, 1H), 3.40-3.26 (m, 2H), 3.12-3.09 (m, 1H), 2.90- 2.86 (m, 1H);

13C NMR (125 MHz, CDCl3): δ 151.9, 142.3, 135.0, 133.0, 132.4, 129.3, 129.1, 128.9, 128.8 (2C), 128.7, 128.6, 128.2, 127.4, 126.5, 126.2, 123.1, 122.7, 118.9, 110.9, 82.2, 62.6, 45.4, 29.4;

HRMS (ESI) exact mass calculated for C26H21NO [M+H]+ : 364.1701; found: 364.1705.

The representative procedure for the synthesis of 4a is as follows: 2-naphthol (1a, 144 mg, 1 mmol), benzaldehyde (2a, 106 mg, 1 mmol), tetrahydroisoquinoline (3, 133 mg, 1 mmol) and water (1.5 mL) were added in a round-bottom flask equipped with a magnetic stirring bar and a reflux condenser. The whole apparatus was efficiently flushed with oxygen gas and then connected to a balloon filled with oxygen. After vigorous stirring at 100 oC for 12 h, water was removed under vacuum and purified the reaction mixture by column chromatography (100-200 mesh silica gel, hexane-ethyl acetate) to obtain the product 4a as white solid. The other 1,3-oxazines were synthesized and purified by following the procedure described above

str4

STR7str6

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