All About Drugs

Tout sur les médicaments הכל על תרופות كل شيئ عن الأدوية Все о наркотиках 关于药品的一切 డ్రగ్స్ గురించి అన్ని 마약에 관한 모든 것 Όλα για τα Ναρκωτικά Complete Tracking of Drugs Across the World by Dr Anthony Melvin Crasto, Worldpeacepeaker, worlddrugtracker, PH.D (ICT), MUMBAI, INDIA, Worlddrugtracker, Helping millions, 9 million hits on google on all websites, 2.5 lakh connections on all networks, “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

N-Butylpyrrolidinone as a dipolar aprotic solvent for organic synthesis

SYNTHESIS, Uncategorized Comments Off

Jul 292016

N-Butylpyrrolidinone as a dipolar aprotic solvent for organic synthesis

Green Chem., 2016, 18,3990-3996
DOI: 10.1039/C6GC00932H, Paper

James Sherwood, Helen L. Parker, Kristof Moonen, Thomas J. Farmer, Andrew J. Hunt
N-Butylpyrrolidinone (NBP) has been demonstrated as a suitable safer replacement solvent for N-Methylpyrrolidinone (NMP) in selected organic syntheses.

N-Butylpyrrolidinone as a dipolar aprotic solvent for organic synthesis

James Sherwood,^a Helen L. Parker,^a Kristof Moonen,^b Thomas J. Farmer^a and Andrew J. Hunt*^a

*Corresponding authors

^aGreen Chemistry Centre of Excellence, Department of Chemistry, University of York, UK
E-mail: andrew.hunt@york.ac.uk

^bEastman Chemical Company, Pantserschipstraat 207 – B-9000, Gent, Belgium

Green Chem., 2016,18, 3990-3996

http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC00932H?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract
DOI: 10.1039/C6GC00932H

Dipolar aprotic solvents such as N-methylpyrrolidinone (or 1-methyl-2-pyrrolidone (NMP)) are under increasing pressure from environmental regulation. NMP is a known reproductive toxin and has been placed on the EU “Substances of Very High Concern” list. Accordingly there is an urgent need for non-toxic alternatives to the dipolar aprotic solvents. N-Butylpyrrolidinone, although structurally similar to NMP, is not mutagenic or reprotoxic, yet retains many of the characteristics of a dipolar aprotic solvent. This work introduces N-butylpyrrolidinone as a new solvent for cross-coupling reactions and other syntheses typically requiring a conventional dipolar aprotic solvent.

//////////////N-Butylpyrrolidinone, dipolar aprotic solvent, organic synthesis\

Bhandardhara, maharashtra, India

भंडारदरा

Bhandardara

Village in India

Bhandardara is a holiday resort village on the western ghat of India. The village is located in the Ahmednagar district of the state of Maharashtra, about 185 kilometers from Mumbai. Wikipedia

/////////

Carboxylative cyclization of substituted propenyl ketones using CO2: transition-metal-free synthesis of [small alpha]-pyrones

SYNTHESIS Comments Off

Jul 292016

Carboxylative cyclization of substituted propenyl ketones using CO2: transition-metal-free synthesis of [small alpha]-pyrones

Green Chem., 2016, 18,4181-4184

DOI: 10.1039/C6GC01346E, Communication

Wen-Zhen Zhang, Ming-Wang Yang, Xiao-Bing Lu
Carboxylative cyclization of substituted 1-propenyl ketones via [gamma]-carboxylation using CO₂ provides an efficient, straightforward, and transition-metal-free access to [small alpha]-pyrone compounds.

http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC01346E?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

Carboxylative cyclization of substituted propenyl ketones using CO₂: transition-metal-free synthesis of α-pyrones

Wen-Zhen Zhang,*^a Ming-Wang Yang^a and Xiao-Bing Lu^a

*Corresponding authors

^aState Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, P. R. China
E-mail: zhangwz@dlut.edu.cn

Green Chem., 2016,18, 4181-4184

DOI: 10.1039/C6GC01346E

Carbon dioxide is a green carboxylative reagent due to its non-toxic and renewable properties. Described herein is a carboxylative cyclization of substituted 1-propenyl ketones via γ-carboxylation using CO₂, which provides an efficient, transition-metal-free and straightforward access to important α-pyrone compounds from easily available substrates and CO₂.

////////////Carboxylative cyclization, substituted propenyl ketones, CO2, transition-metal-free synthesis, [small alpha]-pyrones

Rapid, metal-free and aqueous synthesis of imidazo[1,2-a]pyridine under ambient conditions

Uncategorized Comments Off

Jul 292016

Rapid, metal-free and aqueous synthesis of imidazo[1,2-a]pyridine under ambient conditions

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC01601D, Communication

Open Access

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.

Michael R. Chapman, Maria H. T. Kwan, Georgina E. King, Benjamin A. Kyffin, A. John Blacker, Charlotte E. Willans, Bao N. Nguyen
A route to access the privileged imidazo[1,2-a]pyridine scaffold in one step, 1-10 minutes using only aqueous NaOH, is reported.

Rapid, metal-free and aqueous synthesis of imidazo[1,2-a]pyridine under ambient conditions

Michael R. Chapman,^a Maria H. T. Kwan,^a Georgina E. King,^a Benjamin A. Kyffin,^a A. John Blacker,^a Charlotte E. Willans*^a and Bao N. Nguyen*^a

*Corresponding authors

^aInstitute of Process Research and Development, School of Chemistry, University of Leeds, Leeds, UK
E-mail: b.nguyen@leeds.ac.uk

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC01601D

see………..http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC01601D?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

see http://pubs.rsc.org/en/content/articlehtml/2016/gc/c6gc01601d

A novel, rapid and efficient route to imidazo[1,2-a]pyridines under ambient, aqueous and metal-free conditions is reported. The NaOH-promoted cycloisomerisations of N-propargylpyridiniums give quantitative yield in a few minutes (10 g scale). A comparison of common green metrics to current routes showed clear improvements, with at least a one order of magnitude increase in space-time-yield.

Scheme 1 Synthetic methods to assemble imidazo[1,2-a]pyridines.

Fig. 1 A scaled up reaction setup. (a) before reaction; (b) during addition of 1a (zoomed in); (c) phase separation at the end of the reaction (zoomed in).

2-Aminopyridine (6.12 g, 65.0 mmol), propargyl bromide (11.6 g of an 80 wt.% solution in toluene, 78 mmol, 1.2 equiv) and 2-propanol (200 mL) charged to a round bottomed flask and stirred at 50 C for 2 hours. After which, a pale yellow solid precipitated from solution. This was filtered and washed with diethyl ether (2 x 30 mL) followed by drying in vacuo to give product 1a in 11.1 g (52 mmol, 80% isolated yield). To a stirring solution of NaOH (1.90 g, 47.5 mmol) in deionised H2O (70 mL) was added 2-amino-1- (2-propynyl)pyridinium bromide 1a (10.0 g, 47.0 mmol) via powder addition funnel (a) over a period of 5 minutes. Immediately upon addition, the solution phase turned yellow (b – d) and a yellow oil became dispersed as a distinct separate phase (e). The oil (product) was subsequently extracted into EtOAc (2 × 30 mL) (f), dried over anhydrous MgSO4, filtered and concentrated under reduced pressure to afford imidazo[1,2-a]pyridine 2a as a spectroscopically pure pale yellow oil. Yield: 6.12 g, 98% yield.

2-Amino-1-(2-propynyl)pyridinium bromide 1a: 1

1 M. Bakherad, H. N. –Isfahani, A. Keivanloo, N. Doostmohammadi, Tetrahedron Lett. 2008, 49, 3819-3822

2-Aminopyridine was reacted according to the general procedure (vide supra), affording the product as a colourless solid. Yield: 0.88 g, 83% yield.

1H NMR (300 MHz, D2O): δ (ppm) 8.08 (d, J = 6.9 Hz, 1H, pyH), 7.93 (t, J = 16.2, 8.4 Hz, 1H, pyH), 7.17 (d, J = 8.4 Hz, 1H, pyH), 7.01 (t, J = 14.1, 6.9 Hz, 1H, pyH), 5.06 (d, J = 2.7 Hz, 2H, CH2), 3.18 (t, J = 5.1, 2.7 Hz, 1H, C≡CH).

13C{1H} NMR (100 MHz, D2O): δ (ppm) 153.8, 143.1, 138.5, 115.2, 113.9, 78.6, 73.2, 43.5.

HR-MS (ESI+ ): m/z 133.0756 [C8H9N2] + , calcd. [M – Br]+ 133.0760.

Anal. calcd. (%) for C8H9N2Br: C 45.10, H 4.26, N 13.15; found C 45.40, H 4.30, N 13.20.

Lit. data:1 1H NMR (500 MHz, DMSO-d6) 8.72 (s, 2H, NH2), 8.23 – 6.85 (m, 4H, pyH), 5.12 (s, 2H, CH2), 3.85 (s, 1H, CH).

13C NMR (125 MHz, DMSO-d6) 154.5, 143.6, 139.8, 115.8, 114.0, 80.5, 76.0, 43.9.

1H NMR BELOW 1a

2-Methylimidazo[1,2-a]pyridine 2a:1 2-Amino-1-(2-propynyl)pyridinium bromide (1a) was reacted according to the general procedure (vide supra), affording the product as a colourless oil which solidifies under vacuum at room temperature. Yield: 0.13 g, 100% yield.

1H NMR (300 MHz, CDCl3): δ (ppm) 8.24 (dt, J = 6.6, 2.1, 0.9 Hz, 1H, pyH), 7.58 (d, J = 9.0 Hz, 1H, pyH), 7.49 (s, 1H, imH), 7.20 (m, 1H, pyH), 6.80 (td, J = 9.0, 6.6, 0.9 Hz, 1H, pyH), 2.41 (d, J = 0.9 Hz, 3H, CH3).

13C{1H} NMR (75 MHz, CDCl3): δ (ppm) 143.2, 140.2, 126.5, 126.1, 115.2, 113.3, 110.2, 13.1.

HR-MS (ESI+ ): m/z 133.0759 [C8H9N2] + , calcd. [M + H]+ 133.0760.

Anal. calcd. (%) for C8H8N2: C 72.70, H 6.10, N 21.10; found C 72.70, H 6.50, N 20.75.

Lit. data:1 1H NMR (500 MHz, DMSO-d6) 8.29 (s, 1H, CH), 7.59 – 7.03 (m, 4H, pyH), 1.21 (s, 3H, CH3).

13C NMR (125 MHz, DMSO-d6) 148.0, 140.0, 137.1, 130.8, 130.1, 116.2, 114.5, 34.1.

1 M. Bakherad, H. N. –Isfahani, A. Keivanloo, N. Doostmohammadi, Tetrahedron Lett. 2008, 49, 3819-3822

//////////

Ring-locking enables selective anhydrosugar synthesis from carbohydrate pyrolysis

SYNTHESIS Comments Off

Jul 292016

Ring-locking enables selective anhydrosugar synthesis from carbohydrate pyrolysis

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC01600F, Paper

Li Chen, Jinmo Zhao, Sivaram Pradhan, Bruce E. Brinson, Gustavo E. Scuseria, Z. Conrad Zhang, Michael S. Wong
The nonselective nature of glucose pyrolysis chemistry can be controlled by preventing the sugar ring from opening and fragmenting.

Ring-locking enables selective anhydrosugar synthesis from carbohydrate pyrolysis

Li Chen,^a Jinmo Zhao,^b Sivaram Pradhan,^a Bruce E. Brinson,^b Gustavo E. Scuseria,^b Z. Conrad Zhang*^c and Michael S. Wong*^a^b^d^e

*Corresponding authors

^aDepartment of Chemical and Biomolecular Engineering, Rice University, Houston, USA
E-mail: mswong@rice.edu

^bDepartment of Chemistry, Rice University, Houston, USA

^cDalian National Laboratory of Clean Energy, Dalian Institute of Chemical Physics, Dalian, China
E-mail: zczhang@dicp.ac.cn

^dDepartment of Civil and Environmental Engineering, Rice University, Houston, USA

^eDepartment of Materials Science and NanoEngineering, Rice University, Houston, USA

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC01600F

see ………………..http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC01600F?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

The selective production of platform chemicals from thermal conversion of biomass-derived carbohydrates is challenging. As precursors to natural products and drug molecules, anhydrosugars are difficult to synthesize from simple carbohydrates in large quantities without side products, due to various competing pathways during pyrolysis. Here we demonstrate that the nonselective chemistry of carbohydrate pyrolysis is substantially improved by alkoxy or phenoxy substitution at the anomeric carbon of glucose prior to thermal treatment. Through this ring-locking step, we found that the selectivity to 1,6-anhydro-β-D-glucopyranose (levoglucosan, LGA) increased from 2% to greater than 90% after fast pyrolysis of the resulting sugar at 600 °C. DFT analysis indicated that LGA formation becomes the dominant reaction pathway when the substituent group inhibits the pyranose ring from opening and fragmenting into non-anhydrosugar products. LGA forms selectively when the activation barrier for ring-opening is significantly increased over that for 1,6-elimination, with both barriers affected by the substituent type and anomeric position. These findings introduce the ring-locking concept to sugar pyrolysis chemistry and suggest a chemical-thermal treatment approach for upgrading simple and complex carbohydrates.

////////Ring-locking , selective anhydrosugar, carbohydrate pyrolysis, synthesis