- Cu/CuxOyNPs architectured COF: a recyclable catalyst for the synthesis of oxazolidinedioneviaatmospheric cyclizative CO2utilization
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The present study describes the favourable construction of a crystalline covalent organic framework (COF) with exceptional surface area, tunable pore size and huge CO2capture efficiency to facilitate a novel multicomponent cyclization by introducing CO2into extremely reactive organic skeletons. In the presence of a catalytic Cu/CuxOyNP-loaded COF, several 2-bromo-3-alkylacrylic acids combined with several amine derivatives and CO2(0.1 MPa) are converted to the desired oxazolidinediones in excellent yields (up to 96%) under alkali-free conditions and ambient temperature.
- Sarkar, Somnath,Ghosh, Swarbhanu,Mondal, Jahangir,Islam, Sk. Manirul
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supporting information
p. 12202 - 12205
(2020/10/20)
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- Chemical fixation of carbon dioxide by copper catalyzed multicomponent reactions for oxazolidinedione syntheses
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The quest to reduce greenhouse gases has triggered the development of new chemical fixation of carbon dioxide. Given the importance of CO2 based transformation chemistry, we demonstrate the fixation of CO2 for oxazolidinedione synthesis via a novel multicomponent synthesis. In the presence of a catalytic amount of Cu2O, various 2-bromo-3-phenylacrylic acid derivatives reacted with CO2 and amines are transformed to the corresponding oxazolidinedione derivatives in high yields. This journal is
- Sharma, Siddharth,Singh, Ajay K.,Singh, Devendra,Kim, Dong-Pyo
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supporting information
p. 1404 - 1407
(2015/03/18)
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- Ru-catalyzed highly chemo- and enantioselective hydrogenation of γ-halo-γ,δ-unsaturated-β-keto esters under neutral conditions
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Finely-tuned ruthenium-catalyzed highly chemoselective and enantioselective hydrogenation of γ-halo-γ,δ-unsaturated-β-keto esters at the carbonyl group was achieved under neutral reaction conditions (ee up to 97%). Both olefin and alkenyl halogen moieties, which are labile under hydrogenation conditions, remained untouched during the reaction.
- Ma, Xin,Li, Wanfang,Li, Xiaoming,Tao, Xiaoming,Fan, Weizheng,Xie, Xiaomin,Ayad, Tahar,Ratovelomanana-Vidal, Virginie,Zhang, Zhaoguo
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supporting information; experimental part
p. 5352 - 5354
(2012/06/30)
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- Simple and efficient copper-catalyzed approach to 2,4-disubstituted imidazolones
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(Figure Presented) Some imidazolone derivatives are biological and pharmaceutical active molecules and the chromophores of the fluorescent proteins. In this communication, a simple and efficient approach to 4-arylidene-2-alkyl-4,5-dihydro-1H-imidazol-5-ones (2,4-disubstituted imidazolones) has been developed, and the protocol uses readily available 2-bromo-3-alkylacrylic acids and amidines as the starting materials without addition of any ligand or additive. The reactions were performed under mild conditions. Therefore, the present method will be of wide application in organic chemistry and medicinal chemistry.
- Gong, Xiaoyu,Yang, Haijun,Liu, Hongxia,Jiang, Yuyang,Zhao, Yufen,Fu, Hua
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supporting information; experimental part
p. 3128 - 3131
(2010/09/04)
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- Synthetic approaches to the microtubule-Sabilizing sponge alkaloid ceratamine A and desbromo analogues
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Two synthetic approaches to the microtubule-stabilizing ceratamine alkaloids are described. The first approach involved attempts to graft an aminoimidazole moiety onto an azepine ring to form partially hydrogenated versions of the unprecedented aromatic imidazo[4,5-d]azepine core of the ceratamines. This route ultimately failed because it was not possible to aromatize the partially hydrogenated ceratamine intermediates. A second approach started with tribromoimidazole that was sequentially metalated and functionalized to efficiently generate a key imidazole intermediate containing vinyl bromide and amide functionalities. An intramolecular Buchwald vinyl amidation reaction converted this key intermediate into a bicyclic imidazo[4,5-d]azepine that was at the same oxidation state as the aromatic core of the ceratamines. The 2-amino functionality present on the imidazole ring of the ceratamines was installed using a Buchwald/Hartwig amination reaction on a 2-chloroimidazole precursor. Deprotection and aromatization resulted in the first synthesis of desbromoceratamine A (55) and desmethyldesbromoceratamine A (60). An unanticipated addition of atmospheric oxygen was encountered during deprotection of the imidazole ring in the last step of the synthesis leading to C-11 oxygenated ceratamine analogues as byproducts. Evaluation of the synthetic ceratamines in a TG3 cell-based assay for mitotic arrest revealed that the C-14 and C-16 bromine substituents in ceratamine A (1) play a major role in the antimitotic potency of the natural product. The synthetic route to ceratamine analogues has provided sufficient quantities of desbromoceratamine A (55) for testing in mouse models of cancer.
- Nodwell, Matt,Pereira, Alban,Riffell, Jenna L.,Zimmerman, Carla,Patrick, Brian O.,Roberge, Michel,Andersen, Raymond J.
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experimental part
p. 995 - 1006
(2009/07/18)
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