Ring-locking enables selective anhydrosugar synthesis from carbohydrate pyrolysis

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

*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

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

N-Butylpyrrolidinone as a dipolar aprotic solvent for organic synthesis

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

*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.
STR1

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

2-Bromo-1,4-benzenedimethanol

(2-bromo-4-hydroxymethylphenyl)methanol.png

(2-bromo-4-hydroxymethylphenyl)methanol;

 CAS 89980-92-7; 

2-Bromo-1,4-benzenedimethanol;

Molecular Formula: C8H9BrO2
Molecular Weight: 217.05986 g/mol

(2-Bromo-4-hydroxymethylphenyl)methanol (3).

To a solution of commercially available 2-bromoterephthalic acid (2) (575 g, 2.34 mol) in THF (5.75 L), a THF solution of BH3 (1.0 M, 5.86 L) was added at 0 °C dropwise for 2.5 h, and the mixture was stirred for 1 h at 0 °C. The mixture was gradually warmed up to 35 °C over 3.5 h. The reaction mixture was cooled to 0 °C and quenched by dropwise addition of MeOH (1.15 L) over 30 min. Then, the mixture was concentrated in vacuo. The residue was dissolved in MeOH (1.72 L), and then water (10.3 L) was added; the mixture was then stirred at 0 °C for 30 min. The off-white solid was filtered and washed with water (1.15 L × 3) and heptanes (2.30 L) to obtain 3 (426 g, 84%) as a white crystal;

mp 108–109 °C;

1H NMR (400 MHz, DMSO-d6) δ: 4.47 (2H, d, J = 5.6 Hz), 4.49 (2H, d, J = 5.4 Hz), 5.29 (1H, t, J = 5.6 Hz), 5.39 (1H, t, J = 5.4 Hz), 7.31 (1H, d, J = 7.8 Hz), 7.47 (1H, d, J = 7.8 Hz), 7.48–7.49 (1H, m);

13C NMR (100 MHz, DMSO-d6) δ: 61.9, 62.5, 120.8, 125.5, 127.9, 129.7, 139.1, 143.4;

HRMS (EI) calcd for C8H9BrO2 [M]+ 215.9786, found 215.9787.

1H NMR

1H NMR (400 MHz, DMSO-d6) δ: 4.47 (2H, d, J = 5.6 Hz), 4.49 (2H, d, J = 5.4 Hz), 5.29 (1H, t, J = 5.6 Hz), 5.39 (1H, t, J = 5.4 Hz), 7.31 (1H, d, J = 7.8 Hz), 7.47 (1H, d, J = 7.8 Hz), 7.48–7.49 (1H, m); 

13C NMR

13C NMR (100 MHz, DMSO-d6) δ: 61.9, 62.5, 120.8, 125.5, 127.9, 129.7, 139.1, 143.4;

MASS PREDICT

1H/13C PREDICT

J. Org. Chem.201681 (5), pp 2148–2153

DOI: 10.1021/acs.joc.5b02734

///////////c1(cc(c(cc1)CO)Br)CO

An efficient Passerini tetrazole reaction (PT-3CR)

Green Chemistry International

Graphical abstract: An efficient Passerini tetrazole reaction (PT-3CR)

An efficient Passerini tetrazole reaction (PT-3CR)

Green Chem., 2016, 18,3718-3721

DOI: 10.1039/C6GC00910G, Communication

Ajay L. Chandgude, Alexander Domling

A sonication accelerated, catalyst free, simple, high yielding and efficient method for the Passerini-type three-component reaction (PT-3CR) has been developed.

http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC00910G?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

A sonication accelerated, catalyst free, simple, high yielding and efficient method for the Passerini-type three-component reaction (PT-3CR) has been developed. It comprises the reaction of an aldehyde/ketone, an isocyanide and a TMS-azide in methanol : water (1 : 1) as the solvent system. The use of sonication not only accelerated the rate of the reaction but also provided good to excellent quantitative yields. This reaction is applicable to a broad scope of aldehydes/ketones and isocyanides.

An efficient Passerini tetrazole reaction (PT-3CR)

*
Corresponding authors
a
Department of Drug Design, University of Groningen, Antonius Deusinglaan 1, 9713 AV…

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Oxidation of refractory sulfur compounds with molecular oxygen over a Ce-Mo-O catalyst

Green Chemistry International


Oxidation of refractory sulfur compounds with molecular oxygen over a Ce-Mo-O catalyst

 Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC01357K, Paper
Yawei Shi, Guozhu Liu, Bofeng Zhang, Xiangwen Zhang
A Ce-Mo-O catalyst showed remarkable performance for aerobic oxidative desulfurization without sacrificial agents at 100 [degree]C and atmospheric pressure.

Oxidation of refractory sulfur compounds with molecular oxygen over a Ce–Mo–O catalyst

Yawei Shi,a   Guozhu Liu,*a   Bofeng Zhanga and  Xiangwen Zhang*a  
*
Corresponding authors
a
Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
E-mail: gliu@tju.edu.cnzhangxiangwen@tju.edu.cn
Fax: +86 22 27892340
Tel: +86 22 27892340
Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC01357K

http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC01357K?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

A Ce–Mo–O catalyst prepared by a simple sol–gel method was proved to…

View original post 100 more words

Visible-light-activated copper(I) catalyzed oxidative Csp–Csp cross-coupling reaction: efficient synthesis of unsymmetrical conjugated diynes without ligands and base

Green Chemistry International

A novel visible-light-promoted copper-catalysed process for the Csp–Csp cross-coupling reaction of terminal alkynes at room temperature is described. The current photochemical method is simple, highly functional group compatible, and more viable towards the construction of bio-active 1,3-unsymmetrical conjugated diynes without the need of bases/ligands, additives and expensive palladium/gold catalysts.

Visible-light-activated copper(I) catalyzed oxidative Csp-Csp cross-coupling reaction: efficient synthesis of unsymmetrical conjugated diynes without ligands and base

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC01463A, Communication
Arunachalam Sagadevan, Ping-Chiang Lyu, Kuo Chu Hwang
An efficient and eco-friendly approach to Csp-Csp cross-coupling of terminal alkynes for the construction of unsymmetrical conjugated diynes via a visible-light-induced CuCl catalysed process at room temperature is described.
Communication

Visible-light-activated copper(I) catalyzed oxidative Csp–Csp cross-coupling reaction: efficient synthesis of unsymmetrical conjugated diynes without ligands and base

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Microbial cyclosophoraose as a catalyst for the synthesis of diversified indolyl 4H-chromenes via one-pot three component reactions in water

Green Chemistry International

Green Chem., 2016, 18,3620-3627
DOI: 10.1039/C6GC00137H, Paper
Someshwar D. Dindulkar, Daham Jeong, Eunae Cho, Dongjin Kim, Seunho Jung
A novel biosourced saccharide catalyst, microbial cyclosophoraose, a cyclic [small beta]-(1,2) glucan, was used for the synthesis of indolyl 4H-chromenes via a one pot three-component Knoevenagel-Michael addition-cyclization reaction in water under neutral conditions.

Microbial cyclosophoraose as a catalyst for the synthesis of diversified indolyl 4H-chromenes via one-pot three component reactions in water

 *corresponding authors
a
Institute for Ubiquitous Information Technology and Applications (UBITA) & Center for Biotechnology Research in UBITA (CBRU), Konkuk University, Seoul 143-701, South Korea
E-mail: shjung@konkuk.ac.kr
b
Nelson Mandela African Institution of Science and Technology, PO box 447, Arusha, Tanzania
c
Department of Bioscience and Biotechnology…

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