Sunday 8 May 2016

A pot-economical and diastereoselective synthesis involving catalyst-free click reaction for fused-triazolobenzodiazepines

Green Chem., 2016, 18,2642-2646
DOI: 10.1039/C6GC00497K, Communication
Xiaofeng Zhang, Sanjun Zhi, Wei Wang, Shuai Liu, Jerry P. Jasinski, Wei Zhang
A pot-economical synthesis involving two [3 + 2] cycloadditions for diastereoselective synthesis of novel triazolobenzodiazepine-containing polycyclic compounds.
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A pot-economical and diastereoselective synthesis involving catalyst-free click reaction for fused-triazolobenzodiazepines



A pot-economical and diastereoselective synthesis involving catalyst-free click reaction for fused-triazolobenzodiazepines

Xiaofeng Zhang,a   Sanjun Zhi,b   Wei Wang,c   Shuai Liu,a  Jerry P. Jasinskid and   Wei Zhang*a  
*
Corresponding authors
a
Centre for Green Chemistry and Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston, USA 
E-mail: wei2.zhang@umb.edu
b
Jiangsu Key Laboratory for the Chemistry of Low-Dimensional Materials, Huaiyin Normal University, Huaian, PR China
c
School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, PR China
d
Department of Chemistry, Keene State College, Keene, USA
Green Chem., 2016,18, 2642-2646

DOI: 10.1039/C6GC00497K





















A pot-economical synthesis involving sequential [3 + 2] cycloadditions of an azomethine ylide and an azide–alkyne (click reaction) has been developed for diastereoselective synthesis of novel triazolobenzodiazepine-containing polycyclic compounds. A new example of catalyst-free click chemistry of non-strained alkynes is also disclosed.







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Saturday 9 April 2016

9-(1H-indol-3-yl)-5-methoxy-3,3- dimethyl-2,3,4,9-tetrahydro-1H-xanthen-1-one



  • Green Chem., 2016, Advance Article
    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


 http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC00137H?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

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, Microbial Carbohydrate Resource Bank (MCRB), Konkuk University, Seoul 143-701, South Korea
Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC00137H




















 As a novel biosourced saccharide catalyst, microbial cyclosophoraose, a cyclic β-(1,2) glucan, was used for the synthesis of therapeutically important versatile indolyl 4H-chromenes via a one pot three-component Knoevenagel–Michael addition–cyclization reaction of salicylaldehyde, 1,3-cyclohexanedione/dimedone, and indoles in water under neutral conditions. A possible reaction mechanism through molecular complexation is suggested based on 2D ROESY NMR spectroscopic analysis. Moreover, green chemistry metric calculations were carried out for a model reaction, indicating the satisfactory greener approach of this method, with a low E-factor (0.18) and high atom economy (AE = 91.20%). The key features of this protocol are based on two critical factors where the first is to use a novel eco-friendly supramolecular carbohydrate catalyst and the second is its fine green properties such as compatibility with various substituted reactants, recyclability of the catalyst, chromatography-free purification, high product selectivity, and clean conversion with moderate to excellent yields in an aqueous medium.



 9-(1H-indol-3-yl)-5-methoxy-3,3- dimethyl-2,3,4,9-tetrahydro-1H-xanthen-1-one (4a):


 (2-hydroxy-3-methoxybenzaldehyde 1, Dimedone 2








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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 Chem., 2016, Advance Article
    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


 http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC00137H?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

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, Microbial Carbohydrate Resource Bank (MCRB), Konkuk University, Seoul 143-701, South Korea
Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC00137H




















 As a novel biosourced saccharide catalyst, microbial cyclosophoraose, a cyclic β-(1,2) glucan, was used for the synthesis of therapeutically important versatile indolyl 4H-chromenes via a one pot three-component Knoevenagel–Michael addition–cyclization reaction of salicylaldehyde, 1,3-cyclohexanedione/dimedone, and indoles in water under neutral conditions. A possible reaction mechanism through molecular complexation is suggested based on 2D ROESY NMR spectroscopic analysis. Moreover, green chemistry metric calculations were carried out for a model reaction, indicating the satisfactory greener approach of this method, with a low E-factor (0.18) and high atom economy (AE = 91.20%). The key features of this protocol are based on two critical factors where the first is to use a novel eco-friendly supramolecular carbohydrate catalyst and the second is its fine green properties such as compatibility with various substituted reactants, recyclability of the catalyst, chromatography-free purification, high product selectivity, and clean conversion with moderate to excellent yields in an aqueous medium.



 9-(1H-indol-3-yl)-5-methoxy-3,3- dimethyl-2,3,4,9-tetrahydro-1H-xanthen-1-one (4a):


 (2-hydroxy-3-methoxybenzaldehyde 1, Dimedone 2








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Monday 21 March 2016

Probing the mechanism of benzaldehyde reduction to chiral hydrobenzoin on the CNT surface under near-UV light irradiation


Green Chem., 2016, 18,1482-1487
DOI: 10.1039/C5GC02168E, Paper
Yunwei Wang, Pengju Ren, Xianmo Gu, Xiaodong Wen, Yingyong Wang, Xiangyun Guo, Eric R. Waclawik, Huaiyong Zhu, Zhanfeng Zheng
For the first time, metal-free CNTs is found to be an effective photocatalyst working under near-UV light (400 nm)

Probing the mechanism of benzaldehyde reduction to chiral hydrobenzoin on the CNT surface under near-UV light irradiation

Yunwei Wang,a   Pengju Ren,ab   Xianmo Gu,a   Xiaodong Wen,ab  Yingyong Wang,a   Xiangyun Guo,a   Eric R. Waclawik,c  Huaiyong Zhuc and   Zhanfeng Zheng*a  

*
Corresponding authors
a
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, CAS, Taiyuan, China
E-mail: zfzheng@sxicc.ac.cn
Fax: +86-351-4040605
b
National Energy Center for Coal to Liquids, Synfuels China Co., Ltd, Huairou District, Beijing, China
c
School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Australia
Green Chem., 2016,18, 1482-1487

DOI: 10.1039/C5GC02168E
Received 13 Sep 2015, Accepted 21 Dec 2015

























http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C5GC02168E?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract



Metal-free CNTs exhibit high activity (conversion rate 99.6%, 6 h) towards the synthesis of chiral hydrobenzoin from benzaldehyde under near-UV light irradiation (320–400 nm). The CNT structure before and after the reaction, the interaction between the molecule and the CNT surface, the intermediate products, the substitution effect and the influence of light on the reaction were examined using various techniques. A photo-excited conduction electron transfer (PECET) mechanism for the photocatalytic reduction using CNTs has been proposed. This finding provides a green photocatalytic route for the production of hydrobenzoin and highlights a potential photocatalytic application of CNTs.






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Sunday 13 March 2016

Breaking the symmetry of dibenzoxazines: a paradigm to tailor the design of bio-based thermosets

Green Chem., 2016, Advance Article
DOI: 10.1039/C5GC03102H, Paper
L. Puchot, P. Verge, T. Fouquet, C. Vancaeyzeele, F. Vidal, Y. Habibi
Asymmetric di-benzoxazine monomers from naturally occurring phenolic compounds - cardanol and vanillin - were synthesized to obtain a processable and self-supported bio-thermoset with valuable properties. Such strategy constitutes an efficient and versatile route for the elaboration of biobased thermoset from a wide range of phenolic compounds derived from renewable resources.

Breaking the symmetry of dibenzoxazines: a paradigm to tailor the design of bio-based thermosets


http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C5GC03102H?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

With the ongoing efforts to promote the development of bio-based dibenzoxazine thermosets, we explore herein a new strategy aiming at the synthesis of asymmetric dibenzoxazine monomers from naturally occurring phenolic compounds, cardanol and vanillin. By taking advantage of the low reactivity of cardanol, a monosubstituted cardanol-based benzoxazine monomer was prepared and further coupled with vanillin to yield vanillin–cardanol di-benzoxazines. The structural features of the resulting products were substantiated by 1H NMR and HR-MS. The occurrence of the thermally-induced ring-opening polymerization was monitored by rheological measurements and DSC. At 190 °C the new asymmetric monomers showed a moderate gelation time (8 min) compared to 30–31 min revealed for cardanol-based (di-card) dibenzoxazines. Once polymerized, they exhibited a high Tg (129 °C), while the di-card flew under heating because of its low cross-linking density. Asymmetric monomers also exhibited lower melting temperatures than their symmetrical congeners based on vanillin, which significantly enlarge the processing window between the melting and polymerization temperatures up to 126 °C instead of 7 °C for symmetric vanillin-based dibenzoxazines. Therefore, such a strategy constitutes an efficient and versatile route for an easy elaboration of biobased monocomponent thermosets and can be applied to a wide range of phenolic compounds derived from renewable resources.







Breaking the symmetry of dibenzoxazines: a paradigm to tailor the design of bio-based thermosets

L. Puchot,ab   P. Verge,*a   T. Fouquet,c   C. Vancaeyzeele,b  F. Vidalb and   Y. Habibi*a  
*
Corresponding authors
a
Luxembourg Institute of Science and Technology (LIST), 5 avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg 
E-mail: Pierre.verge@list.lu, Youssef.habibi@list.lu
b
Laboratoire de Physicochimie des Polymères et des Interfaces (LPPI – EA 2528), I-Mat, Université de Cergy-Pontoise, 5 mail Gay-Lussac, 95031 Cergy-Pontoise, France
c
Environmental Measurement Technology Group, Environmental Management and Research Institute (EMRI), National Institute of Advanced Industrial Science and Technology (AIST), Onogawa 16-1, Tsukuba, Japan
Green Chem., 2016, Advance Article

DOI: 10.1039/C5GC03102H  //////////

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Saturday 12 March 2016

Water-Soluble Pd–Imidate Complexes: Broadly Applicable Catalysts for the Synthesis of Chemically Modified Nucleosides via Pd-Catalyzed Cross-Coupling

Abstract Image


A broadly applicable catalyst system consisting of water-soluble Pd–imidate complexes has been enployed for the Suzuki–Miyaura cross-coupling of four different nucleosides in water under mild conditions. The efficient nature of the catalyst system also allowed its application in developing a microwave-assisted protocol with the purpose of expediting the catalytic reaction. Preliminary mechanistic studies, assisted by catalyst poison tests and stoichiometric tests performed using an electrospray ionization spectrometer, revealed the possible presence of a homotopic catalyst system.
 


Water-Soluble Pd–Imidate Complexes: Broadly Applicable Catalysts for the Synthesis of Chemically Modified Nucleosides via Pd-Catalyzed Cross-Coupling

Institute of Chemical Technology, Mumbai Nathalal Road, Matunga, Mumbai 400019, India
Rasayan, Inc. 2802 Crystal Ridge Road, Encinitas, California 92024-6615, United States
§ Departamento de Ingeniería Minera, Geológica y Cartográfica, Universidad Politécnica de Cartagena, Área de Química Inorgánica, Regional Campus of International Excellence “Campus Mare Nostrum”, Universidad Politécnica de Cartagena, 30203 Cartagena, Spain
Departamento de Química Inorgánica, Regional Campus of International Excellence “Campus Mare Nostrum”, Universidad de Murcia, 30071 Murcia, Spain
Ernst-Moritz-Arndt-Universität Greifswald, Institut für Biochemie, Felix-Hausdorff-Strasse 4, 17489 Greifswald, Germany
J. Org. Chem., Article ASAP
DOI: 10.1021/acs.joc.5b02475
Publication Date (Web): February 27, 2016
Copyright © 2016 American Chemical Society

 http://pubs.acs.org/doi/abs/10.1021/acs.joc.5b02475
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