90772-66-0Relevant articles and documents
Cu/CuxOyNPs architectured COF: a recyclable catalyst for the synthesis of oxazolidinedioneviaatmospheric cyclizative CO2utilization
Sarkar, Somnath,Ghosh, Swarbhanu,Mondal, Jahangir,Islam, Sk. Manirul
supporting information, p. 12202 - 12205 (2020/10/20)
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.
Ru-catalyzed highly chemo- and enantioselective hydrogenation of γ-halo-γ,δ-unsaturated-β-keto esters under neutral conditions
Ma, Xin,Li, Wanfang,Li, Xiaoming,Tao, Xiaoming,Fan, Weizheng,Xie, Xiaomin,Ayad, Tahar,Ratovelomanana-Vidal, Virginie,Zhang, Zhaoguo
supporting information; experimental part, p. 5352 - 5354 (2012/06/30)
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.
Synthetic approaches to the microtubule-Sabilizing sponge alkaloid ceratamine A and desbromo analogues
Nodwell, Matt,Pereira, Alban,Riffell, Jenna L.,Zimmerman, Carla,Patrick, Brian O.,Roberge, Michel,Andersen, Raymond J.
experimental part, p. 995 - 1006 (2009/07/18)
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.
