Synthesis of 2-substituted pyrimidines and benzoxazoles via a visible-light-driven organocatalytic aerobic oxidation: enhancement of the reaction rate and selectivity by a base
Oxidative Dehydrosulfurative Cross-Coupling of 3,4-Dihydropyrimidine-2-thiones with Alkynes for Access to 2-Alkynylpyrimidines
作者:Ngoc Son Le Pham、Hyunik Shin、Jun Yong Kang、Jeong-Hun Sohn
DOI:10.1021/acs.joc.0c00091
日期:2020.4.3
(DHPMs) via dehydrosulfurative Sonogashira cross-coupling with concomitant oxidative dehydrogenation using a Pd/Cu catalytic system. Together with the ready availability of DHPMs possessing various substituents at the C4–C6 positions, this transformation offers rapid and general access to diverse 2-alkynylpyrimidine derivatives.
描述了一种通过Pd / Cu催化体系通过脱硫Sonogashira交叉偶联与伴随的氧化脱氢从3,4-二氢嘧啶-1 H -2-硫酮(DHPM)一步合成2-炔基嘧啶的反应方法。连同在C4–C6位置具有各种取代基的DHPM的现成可用性,这种转变为获得各种2-炔基嘧啶衍生物提供了快速而通用的途径。
Silica-supported ZnCl<sub>2</sub> — A highly active and reusable heterogeneous catalyst for the one-pot synthesis of dihydropyrimidinones–thiones
chloride catalyst was prepared and investigated for the Biginelli reaction. The key features of the catalyst include rapid reaction with 100% conversion of aldehyde, good catalyst recyclability, and high stability under the reaction conditions (passes hot filtration test successfully). A low catalyst loading (12 mol% of ZnCl2) was required to achieve a quantitative reaction. Other catalysts such as
TaBr5-catalyzed Biginelli reaction: one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones/thiones under solvent-free conditions
作者:Naseem Ahmed、Johan E. van Lier
DOI:10.1016/j.tetlet.2007.06.005
日期:2007.7
An efficient TaBr5 (5–10 mol %)-catalyzed Biginelli reaction under solvent-free conditions for one-pot syntheses of 3,4-dihydropyrimidin-2-(1H)-ones (DHPMs) and their thione analogs is reported. The catalyst is stable at room temperature and employed under mild and environmentally friendly conditions.