Metal-free C-H methylation and acetylation of heteroarenes with PEG-400
The generation of a methyl carbon source from renewable and cheap sources is challenging. Herein, we describe a novel and an efficient route for methylation and acetylation of aza-heteroarenes using PEG-400 under O2and TsOH·H2O for the first time by tuning the reaction conditions using a different set of starting materials. The key features of the current protocol are oxidative C-O and C-C bond scission under metal-free conditions with good functional group tolerance, and a broad substrate scope. The potential applicability of the designed methodology was demonstrated for the synthesis of central nervous system (CNS) depressant and anticonvulsant drug molecules by a one-pot strategy.
Kudale, Vishal Suresh,Wang, Jeh-Jeng
supporting information
p. 3506 - 3511
(2020/06/25)
Palladium-catalyzed four-component carbonylative synthesis of 2,3-disubstituted quinazolin-4(3H)-ones: Convenient methaqualone preparation
A palladium-catalyzed four-component carbonylative cyclization reaction for the synthesis of 2,3-disubstituted quinazolin-4(3H)-ones has been developed. A range of different 2,3-disubstituted quinazolin-4(3H)-one derivatives were prepared in moderate to good yields employing simple and readily accessible 2-iodoanilines, nitro compounds and acid anhydrides as the synthetic precursors. Mo(CO)6 acted both as a solid CO source and a reductant. Notably, methaqualone as a sedative and hypnotic medication can be prepared easily in 68% yield (4b) under our conditions as well.