Sustainable routes for quantitative green selenocyanation of activated alkynes
摘要:
Most organic reactions require the usage of volatile organic compounds in the synthesis, work-up and purification processes, thus resulting in major environmental pollution and high manufacturing cost. By using cheap biomass lactic acid as the reaction media and catalyst, a sustainable protocol for the synthesis of Z-3-selenocyanatoacrylates and analogues through green selenocyanation of activated alkynes has been achieved. A principal advantage of this protocol is that the usage of organic volatile compounds can be avoided entirely, as the conversion of substrate is almost quantitative or quantitative with a minimal amount of lactic acid employed as reaction media, and the pure products can be conveniently collected through water precipitation. (C) 2019 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.
Improved preparation of aliphatic propynoic esters
作者:L. Balas、B. Jousseaume、B. Langwost
DOI:10.1016/s0040-4039(01)80735-8
日期:1989.1
An improved procedure of esterification of propynoic acid, based on the N, N′-dicyclohexylcarbodiimide 4-dimethylaminopyridine condensation, is presented, which gives good results with primary, secondary, allylic and homoallylic alcohols. Reactions conditions are mild. Some limitations are given.
A novel and selective protocol for the synthesis of 1-allyl-2-ethynylbenzenes has been developed by palladium-catalyzed decarboxylative coupling of allylic alkynoates with arynes. This new route allows for both sp−sp2 and sp2−sp3 couplings of allylic alkynoates with arynes in one pot involving a decarboxylation process.
A convenient and efficient approach to (E)-2-iodo-3-(methylthio)acrylate has been developed through direct iodothiomethylation of alkynes with aqueous HI and DMSO under mild conditions. This novel protocol has demonstrated a unique difunctionalization of electron-deficient alkynes with a broad substrate scope and excellent functional-group tolerance. Preliminary mechanistic studies indicated that prior
通过在温和条件下用 HI 和 DMSO水溶液直接碘硫甲基化炔烃,开发了一种方便有效的 ( E )-2-iodo-3-(甲硫基)丙烯酸酯方法。这种新颖的协议证明了缺电子炔烃的独特双功能化,具有广泛的底物范围和出色的官能团耐受性。初步机理研究表明,先对炔烃进行二碘化,然后用原位产生的 DMS 进行亲核取代,导致形成 ( E )-2-iodo-3-(methylthio) 丙烯酸酯。
Palladium-Catalyzed Oxidative Diarylating Carbocyclization of Enynes
作者:Min Jiang、Tuo Jiang、Jan-E. Bäckvall
DOI:10.1021/ol301551x
日期:2012.7.6
efficient palladium-catalyzedoxidativediarylatingcarbocyclization of enynes is described. The reaction tolerates a range of functionalized arylboronic acids to give diarylated products in good yields. Control experiments suggest that the reaction starts with an arylpalladation of the alkyne, followed by carbocyclization, transmetalation, and reductive elimination to afford the diarylated product.
Dihydropyridine derivatives of the following formula, analogs thereof and pharmaceutically acceptable salts thereof have an activity of selectively inhibiting the action of N-type calcium channel. They are used as remedies for various diseases relating to the N-type calcium channel such as encephalopathies caused by the ischemia in the acute phase after the onset of cerebral infarction, cerebral hemorrhage or the like, Alzheimer's disease, etc.