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 O2 and 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.