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

Metal-free synthesis of polysubstituted oxazoles via a decarboxylative cyclization from primary α-amino acids

Scheme 1

Control experiments.

The ubiquitous oxazoles have attracted more and more attention in both industrial and academic fields for decades. This interest arises from the fact that a variety of natural and synthetic compounds which contain the oxazole substructure exhibit significant biological activities and antiviral properties. Although various synthetic methodologies for synthesis of oxazols have been reported, the development of milder and more general procedure to access oxazoles is still desirable.

Initially, compound A, formed by the substitution reaction of 1a with 2a, which can be transformed following two pathways: (a) I+, generated by the oxidation of iodine, could oxidize A to radical intermediate B, which eliminates one molecular of CO2 to generate radical C, which is further oxidized to imine Dor its isomer E. Subsequently, F is obtained by intramolecular nucleophilic addition of E. Finally, the desired product (3a) is given by deprotonation and oxidation of F; (b) G is formed from the oxidation of A. Then 3a is obtained through H, I, J, K following a process similar to path a.

Scheme 2

Plausible mechanism.

General procedure for the synthesis of polysubstituted oxazoles

1a (105.8 mg, 0.7 mmol), 2a (99.5 mg, 0.5 mmol), I2 (50.8 mg, 0.2 mmol), DMA (2 mL) and TBHP (70% aqueous solution, 1 mmol) were placed in a tube (10 mL) and sealed with a thin film. Then the reaction mixture was stirred at 25°C for 4 h, heated up to 60°C and stirred at this temperature for another 4 h. After that, the resulting mixture was cooled to the room temperature, diluted with water, extracted with ethyl acetate. The organic phase was washed with saturation sodium chloride solution, dried and filtrated. The solvent was evaporated under reduced pressure and the residue was purified by silica gel column separation (petroleum ether:ethyl acetate = 10:1) to give 3a(154.7 mg, 70%) as light yellow solid, mp = 70–72°C.

2,5-diphenyloxazole (3a) [1]

Synthesized according to typical procedure and purified by column chromatography (petroleum ether:ethyl acetate = 10:1) to give light yellow solid (154.7 mg, 70%), mp = 70-72 °C.

1H NMR (300 MHz, CDCl3): δ 8.12-8.09 (m, 2 H), 7.72-7.69 (m, 2 H), 7.50-7.40 (m, 6 H), 7.35-7.24 (m, 1 H).

13C NMR (75 MHz, CDCl3): δ 161.3, 151.4, 130.4, 129.0, 128.9, 128.5, 128.1, 127.6, 126.4, 124.3, 123.6.

HRMS (APCI-FTMS) m/z: [M + H]+ calcd for C15H12NO: 222.0913, Found: 222.0911.

D1 D2

The scope of the reaction. Standard conditions: 0.7 mmol of amino acids (1a1h), 0.5 mmol of2a2j, 0.1 mmol of I2, 1 mmol of TBHP, 2 mL of DMA, were stirred at 25°C for 4 h then slowly raised to 60°C for 4 h. Catalysts amount and isolated yields were based on 2.

Metal-free synthesis of polysubstituted oxazoles via a decarboxylative cyclization from primary α-amino acids

Yunfeng Li, Fengfeng Guo, Zhenggen Zha and Zhiyong Wang*

Zhiyong Wang

Department of Chemistry, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China

Sustainable Chemical Processes 2013, 1:8  doi:10.1186/2043-7129-1-8

The electronic version of this article is the complete one and can be found online at:http://www.sustainablechemicalprocesses.com/content/1/1/8

ADDITIONAL SPECTRAL DATA FROM NET

WANG Zhiyong(汪志勇)


Ph.D., University of Science and Technology of China (USTC) (1992); M.S., USTC (1989); B.S., Anhui Normal University (1982).

Professor of Chemistry
Department of Chemistry
School of Chemistry and Materials Science
University of Science and Technology of China
Hefei, Anhui 230026, P. R. China

Tel: 86-551-63603185
Fax: 86-551-63603185
E-mail: zwang3@ustc.edu.cn
Personal Homepage:
http://staff.ustc.edu.cn/~zwang3/default.htm

  • RESEARCH INTERESTS
    Research in our group will focus on the general areas of reaction development and chemical synthesis. Our studies will be driven by the discovery of new and useful catalysts. By virtue of the developed organic reactions various organic ligands are synthesized and used as probes in biological progress. Brief summaries of three research directions illustrating these objectives are shown below:
    1) The preparation of heterogeneous catalysts;
    2) The theoretical calculation for the mechanism of organic reactions;
    The application of organic ligands as probes or inhibitors to explore the molecular mechanism of HIV transcription.

    PUBLICATIONS
    http://www.researcherid.com/rid/F-7955-2010

    WANG Zhiyong, Professor
    Name: Zhiyong Wang(汪志勇)
    Born: June, 1962, Anhui, P. R. China
    Address: Department of Chemistry, University of Science and Technology of China, 230026 Hefei, P. R. China
    Tel: 86-551-63603185
    Fax: 86-551-63603185
    E-mail: zwang3@ustc.edu.cn
    EDUCATION AND RESEARCH EXPERIENCE
     1978-1982 B.S., Anhui Normal University
     1982-1986 Lecturer, South Anhui Agricultural College, China
     1986-1989 M.S., University of Science and Technology of China
     1989-1992 Ph.D., University of Science and Technology of China
     1992-1997 Lecturer, Associate Professor, University of Science and Technology of China
     1997-1999 Research Fellow, Tulane University & Brandeis University
     1999-Now Professor of Chemistry, University of Science and Technology of China
    RESEARCH INTERESTS
    1) Organic reactions in aqueous media and development of synthetic methodology;
    2) Supramolecular assembly under the control of organic ligands;
    3) Drug design on the base of PCAF bromodomain.
    CURRENT RESEARCH PROJECTS
    1) Organic reactions in water mediated by nano-metals and its application in asymmetric synthesis, National Natural Science Foundation (2004-2006)
    2) Crystal Engineering under control of organic ligands, Foundation from Education Department of Anhui Province (2003-2005)
    REPRESENTATIVE PUBLICATIONS
    1) C-F. Pan, M. Meze, S. Mujtaba, M. Muller, L. Zeng, J-M. Li, Z-Y. Wang,* M-M. Zhou*
    “Structure-Guided Optimization of Small Molecules Selectively Inhibiting HIV-1 Tat and PCAF Association” J. Med. Chem., 2007, 50, 2285
    2) Y. Xie, Z-P. Yu, X-Y. Huang, Z-Y. Wang,* L-W. Niu, M-K. Teng, J. Li
    “Rational Design on the MOFs Constructed from modified Aromatic Amino Acids”
    Chem. Eur. J., 2007, 13, 9399
    3) Z-H. Zhang, C-F. Pan, Z-Y. Wang* “Synthesis of chromanones: a novel palladium-catalyzed Wacker-type oxidative cyclization involving 1,5-hydride alkyl to palladium migration” Chem. Commun, 2007, 4686
    4) Y. Xie, Y. Yan, H-H. Wu, G-P. Yong, Y. Cui, Z-Y. Wang*, L. Pan, J. Li “Homochiral Metal-organic Coordination Networks from L-Tryptophan” Inorg. Chim. Acta., 2007, 360,1669
    5) Y. Xie, H-H. Wu, G-P. Yong,, Z-Y. Wang*, R. Fan , R-P. Li, G-Q. Pan, Y-C. Tian, L-S. Sheng, L. Pan, J. Li “Synthesis, Crystal Structure, Spectroscopic and Magnetic Properties of Two Cobalt Molecules Constructed from Histidine” J. Mol. Struct., 2007, 833, 88
    6) Z-H. Zhang, Z-Y. Wang* “Diatomite-Supported Pd Nanoparticles: An Efficient Catalyst for Heck and Suzuki Reactions” J. Org. Chem., 2006, 71, 7485
    7) Z-H. Zhang, Z-G. Zha, C-S. Gan, C-F. Pan, Y-Q. Zhou, Z-Y. Wang*, M-M. Zhou* “Catalysis and Regioselectivity of the Aqueous Heck Reaction by Pd(0) Nanoparticles under Ultrasonic Irradiation”
    J. Org. Chem., 2006, 71, 4339

Hefei, Anhui China

////Metal-free,  Synthesis,  Oxazoles, Oxidation,  Decarboxylative cyclization,  α-amino acids

An efficient and inexpensive device for undergraduate chemistry classes aiming teaching the photolytic synthesis concepts

Quim. Nova 2014, 37(1), 164-167,  2014

Um reator fotoquímico barato e eficiente para experimentos de química

Ramon Kenned Sousa AlmeidaI; Cláudia MartelliI; Gilson Herbert Magalhães DiasI; Julio Cesar Araujo da SilvaII, *

An efficient and inexpensive device for undergraduate chemistry classes aiming teaching the photolytic synthesis concepts. This device presents simplicity, low costs, class-compatible reaction times and good yields.

Ramon Kenned Sousa Almeidaa , Cláudia Martellia , Gilson Herbert Magalhães Diasa e Julio Cesar Araujo da Silvab,* a Instituto de Química, Universidade Estadual de Campinas, 13083-970 Campinas – SP, Brasil b Instituto Federal de Ciência e Tecnologia de Santa Catarina, Estrada do Senadinho, s/no , Centro, 88625-000 Urupema – SC, Brasil

A CHEAP AND EFFICIENT PHOTOCHEMICAL REACTOR FOR CHEMICAL EXPERIMENTS. In this work, we present an efficient and inexpensive device for undergraduate chemistry classes aimed at teaching and learning the photolytic synthesis concepts. A photochemical reactor was tested for the synthesis of the organometallic compound enneacarbonyldiiron from iron pentacarbonyl in acetic acid, and its formation evidenced by FTIR analysis. Although similar devices have been described in other studies, none of these offered the simplicity, low cost, class-compatible reaction times and good yields afforded by the procedure reported herein.

Keywords: photochemistry; reactor; enneacarbonyldiiron.

 

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Instituto de Química, Universidade Estadual de Campinas

 

    1. Map of state university of meadows institute of chemistry

 

Instituto Federal de Ciência e Tecnologia de Santa Catarina, Estrada do Senadinho

Campus Palhoça-Bilingue. Atualizado por Rafael Batista. O Instituto Federal de Educação, Ciência e Tecnologia de Santa Catarina …

 

 

Aberto o concurso do Instituto Federal de Educação, Ciência e Tecnologia de Santa Catarina (IFSC). A seleção visa prover um total de 145 vagas.

 

Instituto Federal de Educação, Ciência e Tecnologia – Campus Rio do Sul – Cantagalo

One-pot triangular chemoenzymatic cascades for the syntheses of chiral alkaloids from dopamine

One-pot triangular chemoenzymatic cascades for the syntheses of chiral alkaloids from dopamine

Green Chem., 2015, 17,852-855
DOI: 10.1039/C4GC02325K, Communication
*Corresponding authors
aDepartment of Biochemical Engineering, University College London, Bernard Katz Building, Gordon Street, London, UK
bDepartment of Chemistry, University College London, Christopher-Ingold Building, 20 Gordon Street, London, UK
Green Chem., 2015,17, 852-855

DOI: 10.1039/C4GC02325K

Royal Society of Chemistry
image file: c4gc02325k-s1.tif
Scheme 1 Overview of the biocatalytic and non-enzymatic cascades presented in this work, including the ‘triangular’ cascade.
image file: c4gc02325k-u1.tif
image file: c4gc02325k-u2.tif
image file: c4gc02325k-s2.tif
Scheme 2 One-pot chemoenzymatic synthesis of (S)-4 and (S)-5. Reaction conditions: (a) 20 mM 2, 10 mM sodium pyruvate, 500 μg mL−1 NCS and 20% v.v−1 CV2025 lysate, 50 mM HEPES pH 7.5, 37 °C, 3 h. (b) 40 mM formaldehyde, 1 M sodium phosphate, pH 6, 30 min, 37 °C.
Prof Helen Hailes
Appointment
  • Professor of Chemical Biology
  • Dept of Chemistry
  • Faculty of Maths & Physical Sciences
Research Summary
Research activity in our group is focused on the use of synthetic organic chemistry to probe and solve biological problems. Current projects include the use of water as a reaction solvent and the use of catalytic and biocatalytic synthetic strategies. Also novel kinase inhibitors, cytosine-based hydrogen-bonding polymers and new lipid design for use in a ternary gene delivery vector.
Academic Background
1991 PhD Doctor of Philosophy – Organic Chemistry University of Cambridge
1987 BA Bachelor of Arts – Chemistry and Metallurgy University of Cambridge

publications..total 146

https://iris.ucl.ac.uk/iris/browse/profile?upi=HCHAI24

9 Research Activities
Status

Zinc-Catalyzed Reactions of Ethenetricarboxylates with 2-(Trimethylsilylethynyl)anilines Leading to Bridged Quinoline Derivatives

Zinc-Catalyzed Reactions of Ethenetricarboxylates with
2-(Trimethylsilylethynyl)anilines Leading to Bridged Quinoline Derivatives

Shoko Yamazaki, Satoshi Morikawa, Kazuya Miyazaki, Masachika Takebayashi
Yuko Yamamoto, Tsumoru Morimoto, Kiyomi Kakiuchi, Yuji Mikata
Org. Lett. 2009, 11,13, 2796-2799.

http://pubs.acs.org/doi/abs/10.1021/ol900960q

Highlighted in .
ChemInform 2009, 40(46)http://onlinelibrary.wiley.com/doi/10.1002/chin.200946157/abstract

Zinc Lewis acid-catalyzed cyclization of ethenetricarboxylate derivatives 1 with 2-ethynylanilines has been examined. Reaction of 1,1-diethyl 2-tert-butyl ethenetricarboxylate1b with 2-(trimethylsilylethynyl)aniline substrates in the presence of Zn(OTf)2 gave bridged quinoline derivatives in 43−85% yield. The reaction of 1b with 2′-aminoacetophenone also gave the bridged quinoline derivative in 41% yield. Thermal reaction of bridged quinolines (180−190 °C) afforded indole derivatives in moderate to good yields.

Regioselective Rapid Synthesis of Fully-substituted 1,2,3-Triazoles Mediated by Propargyl Cations

Regioselective Rapid Synthesis of Fully-substituted 1,2,3-Triazoles Mediated by Propargyl Cations
Huan Zhang, Hiroki Tanimoto, Tsumoru Morimoto, Yasuhiro Nishiyama, Kiyomi Kakiuchi
Org. Lett. 2013, 15, 5222-5225.

http://pubs.acs.org/doi/abs/10.1021/ol402387w

Regioselective rapid triazole syntheses at low temperature are described. Organic azides and propargyl cations generated by acids gave fully substituted 1H-1,2,3-triazoles. Most reactions could be performed in 5 min at not only rt but also −90 °C. Both terminal and internal alkynes were acceptable, and the sterically bulky substituents could afford the products smoothly. Various types of three-component coupling reactions were demonstrated, and the presence of allenylaminodiazonium intermediates was indicated.

Going for Gold in Chiral Amine Synthesis

thumbnail image: Going for Gold in Chiral Amine Synthesis

Going for Gold in Chiral Amine Synthesis
A diphosphine binuclear gold(I) chloride complex catalyzes the asymmetric hydroamination of alkenes

Amines are synthesized most effectively by hydroamination of unactivated alkenes, the enantioselective version of which is best achieved by metal catalysis. Binuclear gold(I) complexes can catalyze the hydroamination of alkenes, however, the harsh and stringent reactions conditions required have prevented full development of this metal for synthesis of chiral amines. In addition, the exact catalytic species involved and whether the activating silver salt participates haChiral Amine Synthesis remained a mystery.

Read more

http://www.chemistryviews.org/details/ezine/6518601/Going_for_Gold_in_Chiral_Amine_Synthesis.html