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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Thursday 10 March 2016

Efficient formation of nitriles in the vapor-phase catalytic dehydration of aldoximes


Efficient formation of nitriles in the vapor-phase catalytic dehydration of aldoximes

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC00384B, Paper
Daolai Sun, Eisyun Kitamura, Yasuhiro Yamada, Satoshi Sato
Nitriles were efficiently produced in a vapor-phase dehydration of aldoximes over SiO2 catalysts without external heat supply.
 
A vapor-phase dehydration of acetaldoxime to acetonitrile was investigated over various solid catalysts. Among the tested catalysts, ZrO2, Al2O3 and SiO2 showed high catalytic activity for the formation of acetonitrile from acetaldoxime, while the correlation between catalytic activity and the acid property of the catalysts was not observed. Weak acidic sites such as silanols sufficiently work as catalytic sites for the dehydration, which does not require strong acids such as zeolites. Several SiO2 catalysts with different physical properties were tested, and the SiO2with the smallest pore size and the highest specific surface area showed the highest catalytic activity for the formation of acetonitrile. Because the dehydration of acetaldoxime to acetonitrile is exothermic, a large amount of reaction heat was generated during the reaction, and the reaction temperature was found to be significantly affected by the feed rate of the reactant and the flow rate of the carrier gas. In order to effectively utilize the in situ generated reaction heat, the dehydration of acetaldoxime to acetonitrile without using the external heat supply was conducted. The temperature was controllable even in the absence of the external heat, and the acetonitrile yield higher than 90% could be achieved in such a green operation under the environment-friendly adiabatic conditions.
 
 

Efficient formation of nitriles in the vapor-phase catalytic dehydration of aldoximes

*Corresponding authors
aGraduate School of Engineering, Chiba University, Chiba, Japan
E-mail: satoshi@faculty.chiba-u.jp
Fax: +81 43 290 3401
Tel: +81 43 290 3377
Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC00384B
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Nanopalladium-catalyzed conjugate reduction of Michael acceptors - application in flow


 
Green Chem., 2016, Advance Article
DOI: 10.1039/C5GC02920A, Communication
Anuja Nagendiran, Henrik Sorensen, Magnus J. Johansson, Cheuk-Wai Tai, Jan-E. Backvall
A continuous-flow approach towards the selective nanopalladium-catalyzed hydrogenation of the olefinic bond in various Michael acceptors, which could lead to a greener and more sustainable process, has been developed.
 
A continuous-flow approach towards the selective nanopalladium-catalyzed hydrogenation of the olefinic bond in various Michael acceptors, which could lead to a greener and more sustainable process, has been developed. The nanopalladium is supported on aminofunctionalized mesocellular foam. Both aromatic and aliphatic substrates, covering a variation of functional groups such as acids, aldehydes, esters, ketones, and nitriles were selectively hydrogenated in high to excellent yields using two different flow-devices (H-Cube® and Vapourtec). The catalyst was able to hydrogenate cinnamaldehyde continuously for 24 h (in total hydrogenating 19 g cinnanmaldehyde using 70 mg of catalyst in the H-cube®) without showing any significant decrease in activity or selectivity. Furthermore, the metal leaching of the catalyst was found to be very low (ppb amounts) in the two flow devices
 
 
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3 Gottlieb, H. E.; Kotlyar, V; Nudelman, A. J. Org. Chem. 1997, 62, 7512-7515.
 
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Nanopalladium-catalyzed conjugate reduction of Michael acceptors – application in flow

*Corresponding authors
aDepartment of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
E-mail: jeb@organ.su.se
bBerzelii Centre EXSELENT on Porous Materials, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
cAstraZeneca R&D, Innovative Medicines, Cardiovascular and Metabolic Disorders, Medicinal Chemistry, Pepparedsleden 1, SE-431 83 Mölndal, Sweden
dDepartment of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
Green Chem., 2016, Advance Article
DOI: 10.1039/C5GC02920A
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Monday 7 March 2016

Catalyst-free thiolation of indoles with sulfonyl hydrazides for the synthesis of 3-sulfenylindoles in water


 
Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC00313C, Communication
Yu Yang, Sheng Zhang, Lin Tang, Yanbin Hu, Zhenggen Zha, Zhiyong Wang
A water promoted thiolation of indoles with sulfonyl hydrazides has been developed under mild conditions in water.
 
A catalyst-free thiolation of indoles with sulfonyl hydrazides was efficiently developed in water under mild conditions without any ligand or additive. The reaction provided a variety of 3-sulfenylindoles with good to excellent yields and the only by-products were nitrogen and water.
 
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[1] F.-L. Yang, X.-T. Ma and S.-K. Tian, Chem. Eur. J., 2012, 18, 1582
 
 
 
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Catalyst-free thiolation of indoles with sulfonyl hydrazides for the synthesis of 3-sulfenylindoles in water

Yu Yang,a   Sheng Zhang,a   Lin Tang,a   Yanbin Hu,a  Zhenggen Zhaa and   Zhiyong Wang*a  
 
*Corresponding authors
aHefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry and Department of Chemistry & Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei, P. R. China
E-mail: zwang3@ustc.edu.cn
Fax: (+86) 551-360-3185
Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC00313C
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Pd(II) pincer type complex catalyzed tandem C-H and N-H activation of acetanilide in aqueous media: a concise access to functionalized carbazoles in a single step

 

 
Green Chem., 2016, Advance Article
DOI: 10.1039/C5GC02937F, Paper
Vignesh Arumugam, Werner Kaminsky, Dharmaraj Nallasamy
NNO Pincer type Pd(II) complex catalyzed one-pot synthesis of N-acetylcarbazoles in aqueous media is presented.

One-pot, tandem C–H and N–H activation of acetanilides with aryl boronic acids to realize functionalized carbazoles was conveniently performed under aerobic conditions using a novelNNO pincer type Pd(II) complex [Pd(L)Cl] (where L = nicotinic acid (phenyl-pyridin-2-yl-methylene)-hydrazide or furan-2-carboxylic acid (phenyl-pyridin-2-yl-methylene)-hydrazide) as a catalyst in neat water and a very low (0.01 mol%) amount of catalyst. It is worth noting that recyclability up to six consecutive runs and column chromatography free isolation of the title heterocycles in an excellent yield are achieved.
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Pd(II) pincer type complex catalyzed tandem C–H and N–H activation of acetanilide in aqueous media: a concise access to functionalized carbazoles in a single step

 
 
*Corresponding authors
aInorganic & Nanomaterials Research Laboratory, Department of Chemistry, Bharathiar University, Coimbatore 641 046, India
E-mail: dharmaraj@buc.edu.in
Web: http://ndharmaraj.wix.com/inrl
Fax: +91 4222422387
Tel: +91 4222428316
bDepartment of Chemistry, University of Washington, Seattle, USA
Green Chem., 2016, Advance Article
DOI: 10.1039/C5GC02937F
 
One-pot, tandem C–H and N–H activation of acetanilides with aryl boronic acids to realize functionalized carbazoles was conveniently performed under aerobic conditions using a novelNNO pincer type Pd(II) complex [Pd(L)Cl] (where L = nicotinic acid (phenyl-pyridin-2-yl-methylene)-hydrazide or furan-2-carboxylic acid (phenyl-pyridin-2-yl-methylene)-hydrazide) as a catalyst in neat water and a very low (0.01 mol%) amount of catalyst. It is worth noting that recyclability up to six consecutive runs and column chromatography free isolation of the title heterocycles in an excellent yield are achieved.
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Sunday 6 March 2016

Synthesis of vinyl ethers of alcohols using calcium carbide under superbasic catalytic conditions (KOH/DMSO)



Green Chem., 2016, Advance Article
DOI: 10.1039/C5GC02977E, Communication
Ryosuke Matake, Yusuke Adachi, Hiroshi Matsubara
A convenient preparation of vinyl ethers from alcohols with calcium carbide was developed. This protocol is an alternative to the Favorskii-Reppe reaction without any high pressure device.


 Vinyl ethers are important and useful synthetic building blocks. Using a test tube with a screw cap, a convenient preparation of vinyl ethers from alcohols with calcium carbide under superbasic catalytic conditions (KOH/DMSO) was developed. The vinylation of primary and secondary alcohols was successfully achieved, affording the desired products in good yields. The gram-scale preparation of a vinyl ether was also demonstrated. In this reaction, calcium carbide acts as an acetylene source, constituting a safer alternative to acetylene gas.





 F. de Nanteuil, E. Serrano, D. Perrotta and J. Waser, J. Am. Chem. Soc., 2014, 136, 6239.


1H NMR

1H NMR PREDICT using nmrdb , signals may vary , use your discretion to understand sequence



13C NMR



13 C NMR PREDICT




 

 

 

 

 

 

 

 

 

 

 

 

 

 

Synthesis of vinyl ethers of alcohols using calcium carbide under superbasic catalytic conditions (KOH/DMSO)



*
Corresponding authors
a
Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Japan
E-mail: matsu@c.s.osakafu-u.ac.jp
Green Chem., 2016, Advance Article

DOI: 10.1039/C5GC02977E ////////////////////