Development of large-scale oxidative Bromination with HBr-DMSO by using a continuous-flow microwave system for the subsequent synthesis of 4-Methoxy-2-methyldiphenylamine

Copper-promoted oxidative mono- and di-bromination of 8-aminoquinoline amides with HBr and DMSO

An efficient and convenient method for oxidative mono- and di-bromination of 8-aminoquinoline amides is presented, utilizing hydrogen bromide (HBr) as the brominating reagent and dimethyl sulfoxide (DMSO) as a mild oxidant. Copper salts act as Lewis acid catalysts, facilitating the bromination process. The formation of C5-monobrominated products is promoted by copper sulfate (CuSO4·5H2O), whereas the generation of C5, C7-dibrominated products necessitates the participation of copper nitrate (Cu(NO3)2·3H2O). A wide range of substrates bearing diverse functional groups undergo smooth transformation, resulting in brominated products with good to excellent yields.

Impact of Microwaves on Organic Synthesis and Strategies toward Flow Processes and Scaling Up

Microwave-assisted organic synthesis has been widely studied and deliberated, opening up some controversial issues as well. Nowadays, microwave chemistry is a mature technology that has been well demonstrated in many cases with numerous advantages in terms of the reaction rate and yield. The strategies toward scaling up find an ally in continuous-flow reactor technology comparing dielectric and conductive heating.