Solvent- and halide-free synthesis of pyridine-2-yl substituted ureas through facile C-H functionalization of pyridine N-oxides

Solvent- and halide-free synthesis of pyridine-2-yl substituted ureas through facile C-H functionalization of pyridine N-oxides

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC02556K, Paper

Valentin A. Rassadin, Dmitry P. Zimin, Gulnara Z. Raskil’dina, Alexander Yu. Ivanov, Vadim P. Boyarskiy, Semen S. Zlotskii, Vadim Yu. Kukushkin

A solvent- and halide-free atom-economical synthesis of practically useful pyridine-2-yl substituted ureas utilizes pyridine N-oxides and dialkylcyanamides.

Solvent- and halide-free synthesis of pyridine-2-yl substituted ureas through facile C–H functionalization of pyridine N-oxides

 *Corresponding authors

aInstitute of Chemistry, Saint Petersburg State University, Universitetskaya Nab. 7/9, 199034 Saint Petersburg, Russia

bUfa State Petroleum Technological University, Kosmonavtov 1, Ufa, Bashkortostan, Russia

cResearch Park SPbSU, Center for Magnetic Resonance, Saint Petersburg State University, Universitetskaya Nab. 7/9, 199034 Saint Petersburg, Russia

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC02556K

A novel solvent- and halide-free atom-economical synthesis of practically useful pyridine-2-yl substituted ureas utilizes easily accessible or commercially available pyridine N-oxides (PyO) and dialkylcyanamides. The observed C–H functionalization of PyO is suitable for the good-to-high yielding synthesis of a wide range of pyridine-2-yl substituted ureas featuring electron donating and electron withdrawing, sensitive, or even fugitive functional groups at any position of the pyridine ring (63–92%; 19 examples). In the cases of 3-substituted PyO, the C–H functionalization occurs regioselectively providing a route for facile generation of ureas bearing a 5-substituted pyridine-2-yl moiety.

1,1-Dimethyl-3-(pyridin-2-yl)urea

1,1-Dimethyl-3-(pyridin-2-yl)urea (4a)3 : From pyridine 1-oxide (1a) (95.0 mg, 1.00 mmol) and dimethylcyanamide (2a) (105 mg, 1.50 mmol), compound 4a (147 mg, 89%) was obtained according to GP1 as a yellow oil, which was then crystalized in the freezer to give pale yellow solid, m.p. = 42.6–43.5 °C, lit.4 m.p. = 44–47 °C (EtOAc/hexane), Rf = 0.25 (EtOAc). 1H NMR (400 MHz, CDCl3): δ = 3.00 (s, 6 H, NCH3), 6.88 (ddd, J = 7.3, 5.0, 0.9 Hz, 1 H), 7.30 (br. s, 1 H), 7.60 (ddd, J = 8.5, 7.3, 1.9 Hz, 1 H), 8.02 (dt, J = 8.5, 0.9 Hz, 1 H), 8.14 (ddd, J = 5.0, 1.9, 0.9 Hz, 1 H) ppm. 13C NMR (101 MHz, CDCl3): δ = 36.3 (2 С, CH3), 113.0 (CH), 118.1 (CH), 138.0 (CH), 147.3 (CH), 152.8 (C), 154.8 (C) ppm. NMR data are consistent with previously reported.3 HRMS (ESI), m/z: [M + H]+ calcd. for C8H12N3O+ : 166.0975; found: 166.0977.

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A catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles: an easy access to five-ring-fused tetrahydroisoquinolines

A catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles: an easy access to five-ring-fused tetrahydroisoquinolines

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC02517J, Communication

Xihong Liu, Dongxu Yang, Kezhou Wang, Jinlong Zhang, Rui Wang

A catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles has been reported under mild conditions.

A catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles: an easy access to five-ring-fused tetrahydroisoquinolines

Xihong Liu,a   Dongxu Yang,a   Kezhou Wang,a  Jinlong Zhanga and   Rui Wang*ab  

*Corresponding authors

aSchool of Life Sciences, Institute of Biochemistry and Molecular Biology, Lanzhou University, Lanzhou 730000, P. R. China

bState Key Laboratory of Chiroscience, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, P. R. China

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC02517J

We have reported herein a catalyst-free 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines and 3-nitroindoles by which a series of five-ring-fused tetrahydroisoquinolines featuring an indoline scaffold were obtained as single diastereomers in moderate to high yields without any additives under mild conditions. Moreover, the current method provides a novel and convenient approach for the efficient incorporation of two biologically important scaffolds (tetrahydroisoquinoline and indoline).

ethyl 13b-nitro-8-tosyl-8,8a,13b,13c-tetrahydro-5H-indolo[2′,3′:3,4]pyrazolo[5,1- a]isoquinoline-9(6H)-carboxylate

ethyl 13b-nitro-8-tosyl-8,8a,13b,13c-tetrahydro-5H-indolo[2′,3′:3,4]pyrazolo[5,1- a]isoquinoline-9(6H)-carboxylate:

White solid, m.p. 153 – 154 oC; 94% yield; 1H NMR (300 MHz, CDCl3) δ 7.86 (d, J = 8.2 Hz, 2H), 7.78 (d, J = 7.9 Hz, 1H), 7.30 – 7.13 (m, 5H), 7.1 (s, 1H), 7.05 – 6.94 (m, 1H), 6.94 – 6.87 (m, 1H), 6.59 (t, J = 7.6 Hz, 3H), 6.28 (d, J = 7.6 Hz, 1H), 4.78 (s, 1H), 4.37 (q, J = 7.1 Hz, 2H), 2.80 – 2.58 (m, 2H), 2.33 (s, 3H), 2.31 – 2.11 (m, 2H), 1.41 (t, J = 7.1 Hz, 3H) ppm;

13C NMR (75 MHz, CDCl3) δ 152.1, 144.6, 142.6, 134.0, 132.1, 129.3, 129.0, 128.7, 128.3, 127.5, 127.3, 126.2, 122.8, 121.1, 115.5, 104.5, 84.9, 70.7, 62.8, 48.5, 29.1, 21. 6, 14.3 ppm;

HRMS (ESI): C27H26N4NaO6S [M + Na]+ calcd: 557.1465, found: 557.1476.

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Simultaneous rapid reaction workup and catalyst recovery

Simultaneous rapid reaction workup and catalyst recovery

Green Chem., 2016, 18,5769-5772

DOI: 10.1039/C6GC02448C, Communication

Zhichao Lu, Zofia Hetman, Gerald B. Hammond, Bo Xu

By combining reaction work-up and catalyst recovery into a simple filtration procedure we have developed a substantially faster technique for organic synthesis.

By combining reaction work-up and catalyst recovery into a simple filtration procedure we have developed a substantially faster technique for organic synthesis. Our protocol eliminates the time-consuming conventional liquid–liquid extraction and is capable of parallelization and automation. Additionally, it requires only minimal amounts of solvent.

Simultaneous rapid reaction workup and catalyst recovery

Zhichao Lu,a   Zofia Hetman,a   Gerald B. Hammond*a and  Bo Xu*b  

 *Corresponding authors

aDepartment of Chemistry, University of Louisville, Louisville, USA

bCollege of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China

E-mail: bo.xu@dhu.edu.cn

Green Chem., 2016,18, 5769-5772

DOI: 10.1039/C6GC02448C

http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC02448C?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

. General procedure for a reaction Step 1. Reaction setup. The reaction is conducted in the usual way with the supported catalyst. Porelite® (typically 1 mL for every 0.1 gram of product) is added to the reaction mixture under stirring, Step 2. Reaction quench and rigid solvent extraction. If needed, the reaction is quenched with a suitable aqueous solution (e.g. NaHCO3 solution). • If the solvent used in the reaction is water-miscible (eg., DMF, methanol, etc.), a minimum amount of water immiscible solvent (e.g. 3 mL ether for every 1 g of product) is added to help organic material become entrenched in Porelite. • If the reaction is conducted in a water immiscible solvent (e.g. toluene, DCM), no extra solvent is needed in most cases. The excess amount of solvent is removed by rotavapor or by nitrogen/air purging (no need to remove the water from the mixture). The reaction mixture is filtered to remove aqueous-soluble components (starting materials, by-products, etc.) and washed with water (or HCl or Na2CO3 solution to remove basic or acidic byproducts. Vacuum is applied to dry the filtrate for 2 minutes to remove any remaining aqueous and volatile solvents. (For automatic flash chromatographic separation, an empty loading cartridge can be used, which can be directly attached to the commercial system. For manual chromatographic separation, a regular Büchner filter can be used). Step 3. Sample loading to chromatographic system. • The loading cartridge can be directly attached to the commercial flash chromatographic system (e.g., CombiFlash Rf series). • For manual chromatographic separation, the polymer powder is loaded directly onto a manual flash silica gel column (dry loading).

Because the polymer pad may contain some trapped air, it is recommended to start with the least polar solvent (e.g., hexane) during chromatographic separation to remove the trapped air.

1-(biphenyl-4-yl)ethanone

1-(biphenyl-4-yl)ethanone

Han, W.; Liu, C.; Jin, Z.-L. Organic Letters 2007, 9, 4005-4007

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Photobiocatalytic alcohol oxidation using LED light sources

Green Chem., 2017, Advance Article
DOI: 10.1039/C6GC02008A, Communication
Photobiocatalytic alcohol oxidation using LED light sources
Open Access Open Access
Creative Commons Licence  This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
M. Rauch, S. Schmidt, I. W. C. E. Arends, K. Oppelt, S. Kara, F. Hollmann
The photocatalytic oxidation of NADH using a flavin photocatalyst and a simple blue LED light source is reported.
The photocatalytic oxidation of NADH using a flavin photocatalyst and a simple blue LED light source is reported. This in situ NAD+ regeneration system can be used to promote biocatalytic, enantioselective oxidation reactions. Compared to the traditional use of white light bulbs this method enables very significant reductions in energy consumption and CO2 emission.

Photobiocatalytic alcohol oxidation using LED light sources

M. Rauch,a   S. Schmidt,a   I. W. C. E. Arends,a   K. Oppelt,b  S. Karac and   F. Hollmann*a  
*Corresponding authors
aDepartment of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ Delft, The Netherlands
E-mail: f.hollmann@tudelft.nl
bInstitute of Inorganic Chemistry, Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, Austria
cInstitute of Technical Biocatalysis, Hamburg University of Technology, Denickestrasse 15, 21073 Hamburg, Germany
Green Chem., 2017, Advance Article

DOI: 10.1039/C6GC02008A

///////////Photobiocatalytic,  alcohol oxidation, LED light sources

ENZYMES AS GREEN CATALYSTS FOR PHARMACUETICAL INDUSTRY

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ENZYMES AS GREEN CATALYSTS FOR PHARMACUETICAL INDUSTRY

‘Green’ Catalysts for ‘greener’ reactions
– Dr. Dinesh Nair, Regional Business Manager at Novozymes South Asia Pvt. Ltd

 

 

 

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/////////Novozymes, ENZYMES, GREEN CATALYSTS, PHARMACEUTICAL INDUSTRY, ‘Green’ Catalysts, ‘greener’ reactions

Identifying “green chemistry” industrialisation barriers through case-studies

Nitesh Mehta

Nitesh Mehta

Convenor of Industrial Green Chemistry World and Founder – Director of Newreka Green Synth Technologies Pvt Ltd

nitesh.mehta@newreka.co.in

Identifying “green chemistry” industrialisation barriers through case-studies
– Mr. Nitesh Mehta, Founder Director, Newreka Green Synth Technologies Pvt. Ltd., India

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///////green chemistry, industrialisation barriers,  case-studies, Nitesh Mehta, Founder Director, Newreka Green Synth Technologies Pvt Ltd, India

Green Solvent – A sustainable option – Dr. Denis Prat, SANOFI, France

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Dr. Denis Prat

Head of Process Safety & Automated Chemistry Chemistry & Biotechnology Development, SANOFI, France

Sanofi-Aventis SA

54 Rue La Boetie

Paris, Île-de-France 75008

France

Green Solvent – A sustainable option
– Dr. Denis Prat, Head of Process Safety & Environment, Chemistry & Biochemistry, SANOFI, France

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Prof. Andrea Larson

 

/////////Green Solvent, sustainable option, Denis Prat, SANOFI, France