AUTHOR OF THIS BLOG

DR ANTHONY MELVIN CRASTO, WORLDDRUGTRACKER
Jul 302017
 

Ecocatalyzed Suzuki cross coupling of heteroaryl compounds

Green Chem., 2017, Advance Article
DOI: 10.1039/C7GC01672G, Paper
Guillaume Clave, Franck Pelissier, Stephane Campidelli, Claude Grison
A bio-based EcoPd was developed for the Suzuki cross coupling of heteroaryl compounds.

Ecocatalyzed Suzuki cross coupling of heteroaryl compounds

 

Abstract

A bio-based EcoPd was developed for the Suzuki cross coupling of heteroaryl compounds. Based on the ability of Eichhornia crassipes to bioconcentrate Pd in its roots, we addressed the transformation of plant-derived Pd metals to green catalysts. The methodology is based on eco-friendly procedures. It allowed the preparation of a wide range of heterocyclic biaryl and heterocyclic–heterocyclic biaryl compounds, with a low Pd catalyst loading. EcoPd was found to have the ideal microstructure to promote complex Suzuki reactions without ligands or additives. For the first time, post-reaction solution was treated by rhizofiltration. The resulting EcoPd has been reused with the same performance. This work has established the ecocatalysis concept as a powerful strategy for Pd sustainability, with the development of homogeneous catalysts that are easily recycled and reused.

str4 str5 str6

2-Bromothiophene (20 g, 125 mmol), Phenyl boronic acid (16.8 g, 138 mmol), potassium carbonate (20.7 g, 150 mmol) and EcoPd1 (113 mg, 125 µmol of Pd, 13.3 mg of Pd, EcoPd1 at 11.7 wt% of Pd) were suspended into degassed glycerol (200 mL). The mixture was stirred at 120°C for 4h thanks to an oil bath under an argon atmosphere. The reaction was checked for completion by TLC (cyclohexane) and GCMS analysis after a short extraction of the organic material: 10 µL of the crude were added into a 1 mL microtube containing a mixture of water and AcOEt (800 µL, 1:1, v/v) ; the microtube was vortexed before using the organic layer to perform analysis. Deionised water (500 mL) and AcOEt (500 mL) were added into the flask and the mixture filtered through fritted glass to isolate black Pd for recycling. The organic layer was further washed by deionised water (500 mL x 3) before drying over Na2SO4. The organic layer was filtered and concentrated under vacuum. The residue was then purified by chromatography on a silica gel column (250 g) with pure cyclohexane as the mobile phase, giving the desired coupled compound as a white powder (18 g, 112.5 mmol, yield 90%) Rf = 0.7 (cyclohexane).

1H NMR (300 MHz, CDCl3):  = 7.10- 7.13 (m, 2H), 7.44-7.26 (m, 5H), 7.38-7.33 (m, 1H).

13C NMR (75.5 MHz, CDCl3):  = 123.0, 124.8, 125.9, 127.4, 128.0, 128.8, 134.4, 144.4.

MS (EI): m/z = 160 (M+ , 100%), 128 (21%), 115 (54%), 89 (17%) calcd for C10H8S: 159.99.

 

////////

Share

Catalytic carbonyl hydrosilylations via a titanocene borohydride-PMHS reagent system

 spectroscopy, SYNTHESIS  Comments Off on Catalytic carbonyl hydrosilylations via a titanocene borohydride-PMHS reagent system
Jul 142017
 

 

DOI: 10.1039/C7CY01088E, Paper
Godfred D. Fianu, Kyle C. Schipper, Robert A. Flowers II
Catalytic amounts of titanocene(III) borohydride, generated under mild conditions from commercially available titanocene dichloride, in concert with a stoichiometric hydride source is shown to effectively reduce aldehydes and ketones to their respective alcohols in aprotic media.
  • Catalysis Science & Technology

Catalytic carbonyl hydrosilylations viaa titanocene borohydride–PMHS reagent system

 Author affiliations

Abstract

Reduction of a wide range of aldehydes and ketones with catalytic amounts of titanocene borohydride in concert with a stoichiometric poly(methylhydrosiloxane) (PMHS) reductant is reported. Preliminary mechanistic studies demonstrate that the reaction is mediated by a reactive titanocene(III) complex, whose oxidation state remains constant throughout the reaction.

Godfred Fianu

Godfred Fianu

Robert A Flowers

Robert A Flowers

Danser Distinguished Faculty Chair in Chemistry and Deputy Provost for Faculty Affairs
Lehigh University
Bethlehem, United States
Phenyl methanol (2-c)
Phenyl methanol (2-c) was prepared from benzaldehyde (1-c) by the procedure outlined
in GP1. NMR analysis showed 100% conversion in 1 hour. 86% isolated yield of alcohol
product was obtained after complete workup.
1H NMR (400 MHz, CDCl3) δ 7.37 – 7.26 (m,5H), 4.59 (s, 2H), 2.99 (s, 1H).
13C NMR (101 MHz, CDCl3) δ 140.92, 128.56, 127.60, 127.07,77.52, 77.20, 76.88, 65.04.
STR1 STR2

//////////////

Share

Control of stereoselectivity of benzylic hydroxylation catalysed by wild-type cytochrome P450BM3 using decoy molecules

 SYNTHESIS, Uncategorized  Comments Off on Control of stereoselectivity of benzylic hydroxylation catalysed by wild-type cytochrome P450BM3 using decoy molecules
Jul 142017
 

 

Control of stereoselectivity of benzylic hydroxylation catalysed by wild-type cytochrome P450BM3 using decoy molecules

Catal. Sci. Technol., 2017, Advance Article
DOI: 10.1039/C7CY01130J, Paper
Kazuto Suzuki, Joshua Kyle Stanfield, Osami Shoji, Sota Yanagisawa, Hiroshi Sugimoto, Yoshitsugu Shiro, Yoshihito Watanabe
The benzylic hydroxylation of non-native substrates was catalysed by cytochrome P450BM3, wherein “decoy molecules” controlled the stereoselectivity of the reactions.
  • Catalysis Science & Technology

Control of stereoselectivity of benzylic hydroxylation catalysed by wild-type cytochrome P450BM3 using decoy molecules

Abstract

The hydroxylation of non-native substrates catalysed by wild-type P450BM3 is reported, wherein “decoy molecules”, i.e., native substrate mimics, controlled the stereoselectivity of hydroxylation reactions. We employed decoy molecules with diverse structures, resulting in either a significant improvement in enantioselectivity or clear inversion of stereoselectivity in the benzylic hydroxylation of alkylbenzenes and cycloalkylbenzenes. For example, supplementation of wild-type P450BM3 with 5-cyclohexylvaleric acid-L-phenylalanine (5CHVA-Phe) and Z-proline-L-phenylalanine yielded 53% (R) ee and 56% (S) ee for indane hydroxylation, respectively, although 16% (S) ee was still observed in the absence of any additives. Moreover, we performed a successful crystal structure analysis of 5CHVA-L-tryptophan-bound P450BM3 at 2.00 Å, which suggests that the changes in selectivity observed were caused by conformational changes in the enzyme induced by binding of the decoy molecules.

M2 Kazuto Suzuki \ suzuki.kazuto*c.mbox.nagoya-u.ac.jp

Yoshihito Watanabe yoshi*nucc.cc.nagoya-u.ac.jp

/////////////////

Share

2,2,5,5-Tetramethyltetrahydrofuran (TMTHF): a non-polar, non-peroxide forming ether replacement for hazardous hydrocarbon solvents

 SYNTHESIS  Comments Off on 2,2,5,5-Tetramethyltetrahydrofuran (TMTHF): a non-polar, non-peroxide forming ether replacement for hazardous hydrocarbon solvents
Jul 132017
 

 

2,2,5,5-Tetramethyltetrahydrofuran (TMTHF): a non-polar, non-peroxide forming ether replacement for hazardous hydrocarbon solvents

Green Chem., 2017, Advance Article
DOI: 10.1039/C7GC01392B, Paper
Fergal Byrne, Bart Forier, Greet Bossaert, Charly Hoebers, Thomas J. Farmer, James H. Clark, Andrew J. Hunt
An inherently non-peroxide forming ether solvent, 2,2,5,5-tetramethyltetrahydrofuran (2,2,5,5-tetramethyloxolane), has been synthesized from readily available and potentially renewable feedstocks, and its solvation properties have been tested

2,2,5,5-Tetramethyltetrahydrofuran (TMTHF): a non-polar, non-peroxide forming ether replacement for hazardous hydrocarbon solvents

 

http://pubs.rsc.org/en/Content/ArticleLanding/2017/GC/C7GC01392B?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

Abstract

An inherently non-peroxide forming ether solvent, 2,2,5,5-tetramethyltetrahydrofuran (2,2,5,5-tetramethyloxolane), has been synthesized from readily available and potentially renewable feedstocks, and its solvation properties have been tested. Unlike traditional ethers, its absence of a proton at the alpha-position to the oxygen of the ether eliminates the potential to form hazardous peroxides. Additionally, this unusual structure leads to lower basicity compared with many traditional ethers, due to the concealment of the ethereal oxygen by four bulky methyl groups at the alpha-position. As such, this molecule exhibits similar solvent properties to common hydrocarbon solvents, particularly toluene. Its solvent properties have been proved by testing its performance in Fischer esterification, amidation and Grignard reactions. TMTHF’s differences from traditional ethers is further demonstrated by its ability to produce high molecular weight radical-initiated polymers for use as pressure-sensitive adhesives.

STR1

[TMTHF].

1H NMR (400 MHz, CDCl3): δ 1.81 (s, 4H), 1.21 (s, 12H);

13C NMR (400 MHz, CDCl3): δ 29.75, 38.75, 80.75;

IR 2968, 2930, 2968, 1458, 1377, 1366, 1310, 1265, 1205, 1144, 991, 984, 885, 849, 767 cm−1;

m/z (%): (ESI–MS) 128 (40) [M+ ]

STR1

 

Fergal Byrne

Fergal Byrne

PHD Researcher at Green Chemistry Centre of Excellence

University of York

York, United Kingdom

University of York

Green Chemistry Centre of Excellence, University of York, York YO10 5DD, UK 

 

Andrew Hunt

Andrew Hunt

Catalysis, Environmental Chemistry, Green Chemistry

////////////

NMR predict

[TMTHF].

1H NMR (400 MHz, CDCl3): δ 1.81 (s, 4H), 1.21 (s, 12H);

STR1 STR2

13C NMR (400 MHz, CDCl3): δ 29.75, 38.75, 80.75;

Share

KemInnTek Laboratories, helps you synthesize in mg to multi-kg scale.

 regulatory, SYNTHESIS, Uncategorized  Comments Off on KemInnTek Laboratories, helps you synthesize in mg to multi-kg scale.
May 122017
 

STR0

 

Image result for waitThe presentation will load below


KemInnTek Laboratories

Image result for presentation animation

 

Welcome to Keminntek Laboratories

Keminntek Laboratories is a Hyderabad (India) based Contract Research Organization in Pharmaceutical sector in specific Pharmaceutical Intermediates, Speciality Chemicals, Impurities and Active Pharmaceutical Ingredients. Promoters of Keminntek Laboratories are Young and Dynamic Technocrats and established with a vision to provide a best-in class pharmaceutical services. Keminntek Laboratories would be a value-added and innovative-in –approach business partner. It has a strong talent pool of qualified and experienced scientists drawn from the national and international institutes and industry. It has a capability to synthesize in mg to multi-kg scale.

About Us

Vision
Our vision is to build Keminntek Laboratories into a world class leading pharmaceutical service provider based on innovation while keeping health and prosperity in mind. Imperatively, we will continue our business with high standards of ethics in the interest of society and environment.Mission
We are committed towards improving people’s health through science and innovation. Our mission is to provide better access of the affordable medicines to the patients and positively impact prosperity.

Team

  • Promoters of this company are very well qualified and experienced personalities in Pharmaceutical sector

  • We have a team consisting

    • Ph.Ds from premier Indian Institutes and postdocs from abroad

    • M. Sc (Chemistry) with 2-12 years pharmaceutical industry experience

  • Our team expertise lies in process R&D of pharmaceutical intermediates, NCEs (Medicinal Chemistry) development, pharmaceutical impurities, and custom synthesis of specialty chemicals

http://keminnteklabs.com/

keminnteklabs@gmail.com

 

Kolupula Srinivas

Kolupula Srinivas

Co-Founder & Chief Scientific Officer at Keminntek Laboratories

logo
Visit

Plot No: 10/11, Road No: 5,
IDA Nacharam, Hyderabad,
India – 500076.
 +91 9515 053 169 / 68
 keminnteklabs@gmail.com
 keminnteklabs@gmail.com

 

Image result for presentation animation

//////////////KemInnTek Laboratories, srinivas kolupula, hyderabad, blog, cro, custom, synthesis

Share

Dr. Vinayak Pagar( GUEST BLOGGER) Development of a Povarov Reaction/Carbene Generation Sequence for Alkenyldiazocarbonyl Compounds

 cancer, new drugs, spectroscopy, SYNTHESIS  Comments Off on Dr. Vinayak Pagar( GUEST BLOGGER) Development of a Povarov Reaction/Carbene Generation Sequence for Alkenyldiazocarbonyl Compounds
Apr 282017
 

Discussing my paper……..

Metal-catalyzed cycloadditions of alkenyldiazo reagents are useful tools to access carbo- and heterocycles.[1] These diazo compounds are chemically sensitive toward both Brønsted orLewis acids. Their reported cycloadditions rely heavily on the formation of metal carbenes to initiate regio- and stereoselective [3+n] cycloadditions (n=2–4) with suitable dipolarophiles.[2–4] A noncarbene route was postulated for a few copper-catalyzed cycloadditions of these diazo species, but they resulted in complete diazo decomposition.[3a, 4a, 5] oyle and co-workers reported[4a] a [3+2] cycloaddition of the alkenylrhodium carbene A with imines to give dihydropyrroles (Scheme 1a). We proposed a cycloaddition the tetrahydroquinoline derivatives 3 and 3’, as well as the tetrahydro-1H-benzo[b]azepine species 4. Access to these frameworks are valuable

Access to these frameworks are valuable for the preparation of several bioactive molecules including 2-phenyl-2,3-
dihydroquinolone,[8a] L-689,560,[8b] torcetrapib,[8c] martinellic acid,[8d] OPC-31260,[8e] OPC-51803,[8f] and tetraperalone A (Figure 1).[8g] Their specific biological functions have been well documented.[8]

str2

Spectral data for ethyl 2-diazo-2-(2-phenyl-1,2,3,4-tetrahydroquinolin-4-yl) acetate (2a)

Yellow Semi-Solid;

IR (KBr, cm-1 ): 3542 (m), 2117 (s), 3015 (s), 1737 (s), 1564 (s), 1334 (m), 1137 (s), 817 (s);

1H NMR (600 MHz, CDCl3): δ 7.41 (d, J = 7.3 Hz, 2 H), 7.36 ~ 7.33 (m, 2 H), 7.30 (t, J = 7.3 Hz, 2 H), 7.07 (d, J = 7.6 Hz, 1 H), 7.04 (t, J = 7.6 Hz, 1H), 6.71 (t, J = 7.2 Hz, 1H), 6.55 (d, J = 7.9 Hz, 1H) 4.56 (dd, J = 11.0, 2.3 Hz, 1H ), 4.25 (q, J = 7.1 Hz, 2H ), 4.21 (dd, J = 11.0, 5.3 Hz, 1H ), 4.01 (s, 1H) 2.36 ~ 2.33 (m, 1H), 2.00 (dd, J = 11.8, 2.3 Hz, 1H ), 1.28 (t, J = 7.1 Hz, 3H);

13C NMR (150 MHz, CDCl3): δ 167.2, 145.3, 142.9, 128.6, 128.0, 127.8, 126.5, 126.4, 118.8, 117.9, 114.4, 60.9, 59.5, 56.2, 36.8, 32.6, 14.4.

HRMS calcd for C19H19N3O2: 321.1477; found: 321.1483.

Development of a Povarov Reaction/Carbene Generation Sequence for Alkenyldiazocarbonyl Compounds

Authors, Appaso Mahadev Jadhav, Vinayak Vishnu Pagar, and Rai-Shung Liu*, DOI: 10.1002/anie.201205692

 We thank the National Science Council, Taiwan, for financial support of this work., [*] A. M. Jadhav, V. V. Pagar, Prof. Dr. R.-S. Liu

Department of Chemistry, National Tsing Hua University
Hsinchu (30013) (Taiwan)
E-mail: rsliu@mx.nthu.edu.tw

Abstract

original image

Rings aplenty: A HOTf-catalyzed (Tf=trifluoromethanesulfonyl) Povarov reaction of alkenyldiazo species has been developed and delivers diazo-containing cycloadducts stereoselectively (see scheme). The resulting cycloadducts provide access to six- and seven-membered azacycles through the generation of metal carbenes as well as the functionalization of diazo group.

[1] Selected reviews: a) M. P. Doyle,M. A. McKervy, T. Ye, Modern Catalytic Methods for Organic Synthesis with Diazo Compounds,  Wiley, New York, 1998; b) A. Padwa, M. D. Weingarten, Chem. Rev. 1996, 96, 223; c) H. M. L. Davies, J. R. Denton, Chem. Soc. Rev. 2009, 38, 3061; d) M. P. Doyle, R. Duffy, M. Ratnikov, L. Zhou, Chem. Rev. 2010, 110, 704; e) H. M. L. Davies, D. Morton, Chem. Soc. Rev. 2011, 40, 1857; f) Z. Zhang, J. Wang, Tetrahedron
2008, 64, 6577.
[2] Selected examples for carbocyclic cycloadducts, see: a) L. Deng, A. J. Giessert, O. O. Gerlitz, X. Dai, S. T. Diver, H. M. L. Davies, J. Am. Chem. Soc. 2005, 127, 1342; b) H. M. L. Davies, Adv. Cycloaddit. 1999, 5, 119; c) H. M. L. Davies, B. Xing, N. Kong, D. G. Stafford, J. Am. Chem. Soc. 2001, 123, 7461; d) H. M. L. Davies, T. J. Clark, H. D. Smith, J. Org. Chem. 1991, 56, 3819; e) Y. Liu, K. Bakshi, P. Zavalij, M. P. Doyle, Org. Lett. 2010, 12, 4304; f) J. P. Olson, H. M. L. Davies, Org. Lett. 2008, 10, 573.
[3] For oxacyclic cycloadducts, see: a) X. Xu, W.-H. Hu, P. Y. Zavalij, M. P. Doyle, Angew. Chem. 2011, 123, 11348; Angew. Chem. Int. Ed. 2011, 50, 11152; b) M. P. Doyle, W. Hu, D. J. Timmons, Org. Lett. 2001, 3, 3741.

[4] For azacyclic cycloadducts, see selected reviews: a) M. P. Doyle, M. Yan, W. Hu, L. Gronenberg, J. Am. Chem. Soc. 2003, 125, 4692; b) J. Barluenga, G. Lonzi, L. Riesgo, L. A. Lpez, M. Tomas, J. Am. Chem. Soc. 2010, 132, 13200; c) M. Yan, N. Jacobsen, W. Hu, L. S. Gronenberg, M. P. Doyle, J. T. Colyer, D. Bykowski, Angew. Chem. 2004, 116, 6881; Angew. Chem. Int. Ed. 2004, 43, 6713; d) X.Wang, X. Xu, P. Zavalij, M. P. Doyle, J. Am.
Chem. Soc. 2011, 133, 16402; e) Y. Lian, H. M. L. Davies, J. Am. Chem. Soc. 2010, 132, 440; f) X. Xu, M. O. Ratnikov, P. Y. Zavalij, M. P. Doyle, Org. Lett. 2011, 13, 6122; g) V. V. Pagar, A. M. Jadhav, R.-S. Liu, J. Am. Chem. Soc. 2011, 133, 20728; h) R. P. Reddy, H. M. L. Davies, J. Am. Chem. Soc. 2007, 129, 10312.

[5] Y. Qian, X. Xu, X.Wang, P. Zavalij,W. Hu, M. P. Doyle, Angew. Chem. 2012, 124, 6002; Angew. Chem. Int. Ed. 2012, 51, 5900.
[6] Povarov reactions refer to the formal [4+2] cycloadditions of Naryl imines with enol ethers or enamines. See reviews: a) L. S. Povarov, Russ. Chem. Rev. 1967, 36, 656; b) V. V. Kouznetsov, Tetrahedron 2009, 65, 2721; c) D. Bello, R. Ramn, R. Lavilla, Curr. Org. Chem. 2010, 14, 332; d) M. A. McCarrick, Y. D. Wu, K. N. Houk, J. Org. Chem. 1993, 58, 3330; e) A. Whiting, C. M. Windsor, Tetrahedron 1998, 54, 6035.

[7] For Povarov reactions catalyzed by Brønsted acids, see selected examples: a) H. Xu, S. J. Zuend, M. G. Woll, Y. Tao, E. N. Jacobson, Science 2010, 327, 986; b) T. Akiyama, H. Morita, K. Fuchibe, J. Am. Chem. Soc. 2006, 128, 13070; c) H. Liu, G. Dagousset, G. Masson, P. Retailleau, J. Zhu, J. Am. Chem. Soc. 2009, 131, 4598; d) G. Dagousset, J. Zhu, G. Masson, J. Am. Chem. Soc. 2011, 133, 14804; e) H. Ishitani, S. Kobayashi, Tetrahedron Lett. 1996, 37, 7357; f) G. Bergonzini, L. Gramigna, A. Mazzanti, M. Fochi, L. Bernardi, A. Ricci, Chem. Commun.
2010, 46, 327; g) L. He, M. Bekkaye, P. Retailleau, G. Masson, Org. Lett. 2012, 14, 3158.

[8] a) Y. Xia, Z.-Y. Yang, P. Xia, K. F. Bastow, Y. Tachibana, S.-C. Kuo, E. Hamel, T. Hackl, K.-H. Lee, J. Med. Chem. 1998, 41, 1155; b) R.W. Carling, P. D. Leeson, A. M. Moseley, J. D. Smith, K. Saywell, M. D. Trickelbank, J. A. Kemp, G. R. Marshall, A. C. Foster, S. Grimwood, Bioorg. Med. Chem. Lett. 1993, 3, 65;
c) D. B. Damon, R. W. Dugger, R.W. Scott, U.S. Patent 6,689,897, 2004; d) D. A. Powell, R. A. Batey, Org. Lett. 2002, 4, 2913; e) A. Matsuhisa, K. Kikuchi, K. Sakamoto, T. Yatsu, A. Tanaka, Chem. Pharm. Bull. 1999, 47, 329; f) M. Y. Christopher, E. A. Christine, D. M. Ashworth, J. Barnett, A. J. Baxter, J. D. Broadbridge, R. J. Franklin, S. L. Hampton, P. Hudson, J. A. Horton, P. D. Jenkins, A. M. Penson, G. R.W. Pitt, P. Rivire,
P. A. Robson, D. P. Rooker, G. Semple, A. Sheppard, R. M.Haigh, M. B. Roe, J. Med. Chem. 2008, 51, 8124; g) C. Li, X. Li, R. Hong, Org. Lett. 2009, 11, 4036.

About author( Me)

Dr. Vinayak Pagar

Dr. Vinayak Pagar

Postdoctoral Research Fellow at The Ohio State University

Vinayak Vishnu Pagar was born in Nasik, Maharashtra (India) in 1983. He obtained his BSc and MSc degrees in chemistry from the University of Pune (India) in 2004 and 2006, respectively. From 2006–2010, he worked as Research Associate in pharmaceutical companies like Jubilant Chemsys Ltd. and Ranbaxy Laboratories Ltd. (India). In 2010, he joined the group of Professor Rai-Shung Liu to pursue his PhD degree in National Tsing Hua University (Taiwan) and completed it in 2014. Subsequently, he worked as a postdoctoral fellow in the same group for one year. Currently, he is working as a Research Scientist at The Ohio State University, Columbus, Ohio USA. His research focused on the development of new organic reactions by using transition-metal catalysis such Gold, Silver, Rhodium, Zinc, Cobalt, Nickel and Copper metals which enables mild, diastereoselective, enantioselective and efficient transformations of variety of readily available substrates to wide range of synthetically useful nitrogen and oxygen containing heterocyclic products which are medicinally important. He published his research in a very high impact factor international Journals includes  J. Am. Chem. Soc.,  Angew. Chem. Int. Ed.,  J. Org. Chem.,  Chem- A. Eur. Journal,  Org. Biomol. Chem., and Synform (Literature Coverage).

Dr. Vinayak Pagar

Postdoctoral Researcher

Department of Chemistry and Biochemistry

The Ohio State University

100 West 18th Avenue

Columbus, Ohio 43210 USA

vinayak.pagar@gmail.com

/////////Vinayak Pagar, Postdoctoral Research Fellow, The Ohio State University, blog, Povarov Reaction, Carbene Generation Sequence,  Alkenyldiazocarbonyl Compounds

Share

Towards nitrile-substituted cyclopropanes – a slow-release protocol for safe and scalable applications of diazo acetonitrile

 spectroscopy, SYNTHESIS  Comments Off on Towards nitrile-substituted cyclopropanes – a slow-release protocol for safe and scalable applications of diazo acetonitrile
Apr 222017
 

Towards nitrile-substituted cyclopropanes – a slow-release protocol for safe and scalable applications of diazo acetonitrile

 Green Chem., 2017, Advance Article
DOI: 10.1039/C7GC00602K, Communication
Katharina J. Hock, Robin Spitzner, Rene M. Koenigs
Applications of diazo acetonitrile in cyclopropa(e)nation reactions are realized in a slow-release protocol with bench-stable reagents. Cyclopropyl nitriles are obtained in one step in good diastereoselectivity on a gram-scale providing an efficient entry into this class of fragrances and drug-like molecules.
STR1
STR2
trans-2-phenylcyclopropane-1-carbonitrile
colorless solid (46 mg, 81%);
m.p. = 29°C;
1 H-NMR (600 MHz, CDCl3): δ = 7.34 – 7.30 (m, 2H), 7.28 – 7.24 (m, 1H), 7.12 – 7.08 (m, 2H), 2.63 (ddd, J = 9.2, 6.7, 4.7 Hz, 1H), 1.62 (dt, J = 9.2, 5.4 Hz, 1H), 1.55 (ddd, J = 8.7, 5.5, 4.8 Hz, 1H), 1.45 (ddd, J = 8.8, 6.7, 5.3 Hz, 1H);
13C-NMR (151 MHz, CDCl3): δ = 137.55, 128.76, 127.41, 126.31, 121.05, 24.90, 15.24, 6.63;
HRMS (ESI): m/z calc. for [C10H9NNa]: 166.06272, found 166.06276;
IR (KBr): νmax/cm-1 = 3044, 2235, 2098, 1761, 1600, 1461, 1220, 1051, 920, 705.
The analytical data is in correspondence with the literature [2]
STR1 STR2
[2] M. Gao, N. N. Patwardhan, P. R. Carlier, J. Am. Chem. Soc., 2013, 135 (38), 14390–14400

Towards nitrile-substituted cyclopropanes – a slow-release protocol for safe and scalable applications of diazo acetonitrile

Author affiliations

Abstract

Diazo acetonitrile has long been neglected despite its high value in organic synthesis due to a high risk of explosions. Herein, we report our efforts towards the transient and safe generation of this diazo compound, its applications in iron catalyzed cyclopropanation and cyclopropenation reactions and the gram-scale synthesis of cyclopropyl nitriles.

Graphical abstract: Towards nitrile-substituted cyclopropanes – a slow-release protocol for safe and scalable applications of diazo acetonitrile
//////////
Share

2,2′-(1-(tert-Butoxycarbonyl)pyrrolidine-3,4-diyl)diacetic Acid

 spectroscopy, SYNTHESIS, Uncategorized  Comments Off on 2,2′-(1-(tert-Butoxycarbonyl)pyrrolidine-3,4-diyl)diacetic Acid
Feb 012017
 

 

STR1

2,2′-(1-(tert-Butoxycarbonyl)pyrrolidine-3,4-diyl)diacetic Acid

STR1 STR2 STR3 str4 str5

2,2′-(1-(tert-Butoxycarbonyl)pyrrolidine-3,4-diyl)diacetic Acid 

as a white solid. Mp: 162–163 °C, % purity: 94.09% (HPLC);
1H NMR (DMSO-d6, 400 MHz) δ: 1.38 (s, 9H), 2.10–2.18 (m, 2H), 2.28–2.32 (m, 2H), 2.49–2.50 (m, 2H, merged with DMSO peak), 2.97–3.03 (m, 2H), 3.33–3.40 (m, 2H), 12.23 (bs, 2H); 1H NMR (CD3OD, 400 MHz) δ: 1.46 (s, 9H), 2.26 (ddd, J1 = 2.8 Hz, J2 = 9.2 Hz, J3 = 16.0 Hz, 2H), 2.43 (dd, J1 = 5.2 Hz, J2 = 16.0 Hz, 2H), 2.69 (m, 2H), 3.16 (dd, J1 = 5.2 Hz, J2 = 10.8 Hz, 2H), 3.49–3.54 (m, 2H);
13C NMR (DMSO-d6, 100 MHz) δ: 28.49, 32.97, 36.49, 37.31, 50.10, 50.20, 78.67, 154.05, 173.96;
IR (KBr): ν = 871, 933, 1143, 1166, 1292, 1411, 1689, 1708, 2881, 2929, 2980, 3001 cm–1;
TOFMS: [C13H21NO6 – H+]: calculated 286.1296, found 286.1031(100%).
HPLC conditions were as follows for compound ; Agilent 1100 series, column: YMC J’SPHERE C18 (150 mm X 4.6 mm) 4µm with mobile phases A (0.05% TFA in water) and B (acetonitrile). Detection was at 210 nm, flow was set at 1.0 mL/min, and the temperature was 30 °C (Run time: 45 min). Gradient: 0 min, A = 90%, B = 10%; 5.0 min, A = 90%, B = 10%; 25 min, A = 0%, B = 100%; 30 min, A = 0%, B = 100%, 35 min, A = 90%, B = 10%; 45 min, A = 90%, B = 10%.
Org. Process Res. Dev., Article ASAP
DOI: 10.1021/acs.oprd.6b00399
/////////
Share

Dimethyl 4,4′-(Benzylazanediyl)(2E,2′E)-bis(but-2-enoate)

 spectroscopy, SYNTHESIS, Uncategorized  Comments Off on Dimethyl 4,4′-(Benzylazanediyl)(2E,2′E)-bis(but-2-enoate)
Jan 312017
 

str5

Dimethyl 4,4′-(Benzylazanediyl)(2E,2′E)-bis(but-2-enoate)

STR1

IR (CHCl3): ν = 758, 1215, 1278, 1437, 1660, 1720, 2806, 2953, 3020, 3421 cm–1;

 

STR2

13C NMR (CDCl3, 100 MHz) δ: 51.53, 53.42, 58.37, 122.66, 127.28, 128.41, 128.55, 128.76, 138.24, 145.84, 166.58;

 

STR3

1H NMR (CDCl3, 400 MHz) δ: 3.23 (dd, J1 = 1.6 Hz, J2 = 6.0 Hz, 4H), 3.62 (s, 2H), 3.75 (s, 6H), 6.07 (dt, J1 = 1.6 Hz, J2 = 16.0 Hz, 2H), 6.97 (dt, J1 = 6.0 Hz, J2 = 16.0 Hz, 2H), 7.25–7.34 (m, 5H-merged with CDCl3 proton);

 

str4

TOFMS: [C17H21NO4 + H+]: calculated 304.1543, found 304.1703(100%).

str5

 

UPLC conditions were as follows for compound 11; Acquity Waters, column: BEH C18 (2.1 mm X 100 mm) 1.7 µm with mobile phases A (0.05% TFA in water) and B (acetonitrile). Detection was at 220 nm, flow was set at 0.4 mL/min, and the temperature was 30 °C (Run time: 9 min). Gradient: 0 min, A = 90%, B = 10%; 0.5 min, A = 90%, B = 10%; 6.0 min, A = 0%, B = 100%; 7.5 min, A = 0%, B = 100%; 7.6 min, A = 90%, B = 10%; 9.0 min, A = 90%, B = 10%.

 

Dimethyl 4,4′-(Benzylazanediyl)(2E,2′E)-bis(but-2-enoate) (11)

as a yellow oil. % purity: 93.4% (UPLC);
1H NMR (CDCl3, 400 MHz) δ: 3.23 (dd, J1 = 1.6 Hz, J2 = 6.0 Hz, 4H), 3.62 (s, 2H), 3.75 (s, 6H), 6.07 (dt, J1 = 1.6 Hz, J2 = 16.0 Hz, 2H), 6.97 (dt, J1 = 6.0 Hz, J2 = 16.0 Hz, 2H), 7.25–7.34 (m, 5H-merged with CDCl3 proton);
13C NMR (CDCl3, 100 MHz) δ: 51.53, 53.42, 58.37, 122.66, 127.28, 128.41, 128.55, 128.76, 138.24, 145.84, 166.58;
IR (CHCl3): ν = 758, 1215, 1278, 1437, 1660, 1720, 2806, 2953, 3020, 3421 cm–1;
TOFMS: [C17H21NO4 + H+]: calculated 304.1543, found 304.1703(100%).
Org. Process Res. Dev., Article ASAP
DOI: 10.1021/acs.oprd.6b00399
//////
Share

One-Pot Reductive Cyclisations of Nitroanilines to Imidazoles

 spectroscopy, SYNTHESIS, Uncategorized  Comments Off on One-Pot Reductive Cyclisations of Nitroanilines to Imidazoles
Jan 252017
 

Hana and co-workers ( Synlett 2010, 18, 2759−2764) from Genentech have developed a single-step procedure for conversion of 2-nitro aromatic amines to benzimidazoles. Addition of ammonium chloride proved necessary as Fe powder and formic acid alone was ineffective for nitro reduction. These conditions were compatible with a variety of functional groups on the aromatic, including boronate esters. The methodology was also extended to nitro aminopyridines but failed to deliver the desired product with isoxazole or pyrazole reactants.

Mild and General One-Pot Reduction and Cyclization of Aromatic and Heteroaromatic 2-Nitroamines to Bicyclic 2H-Imidazoles

Emily J. Hanan*, Bryan K. Chan, Anthony A. Estrada, Daniel G. Shore, Joseph P. Lyssikatos

*Discovery Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA, Email: hanan.emilygene.com

E. J. Hanan, B. K. Chan, A. A. Estrada, D. G. Shore, J. P. Lyssikatos, Synlett, 2010, 2759-2764.

DOI: 10.1055/s-0030-1259007


see article for more reactions

Abstract

A one-pot procedure for the conversion of aromatic and heteroaromatic 2-nitroamines into bicyclic 2H-benzimidazoles employs formic acid, iron powder, and NH4Cl as additive to reduce the nitro group and effect the imidazole cyclization with high-yielding conversions generally within one to two hours. The compatibility with a wide range of functional groups demonstrates the general utility of this procedure.


see article for more examples

//////////One-Pot, Reductive Cyclisations,  Nitroanilines,  Imidazoles

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This article 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

Share
Follow

Get every new post on this blog delivered to your Inbox.

Join other followers: