Two-step Continuous-flow Synthesis of 1,2-dimethyl-3-methylsulfanylbenzene via Diazotization and Methanethiolation

Abstract: 1,2-Dimethyl-3-methylsulfanylbenzene is the key intermediate of topramezone. This work designed a two-step continuous-flow device to synthesize 1,2-dimethyl-3-methylsulfanylbenzene via diazotization and methanethiolation. The results showed that compared with the batch process, the continuous-flow method greatly shortened the residence time to 1 minute, avoided the accumulation of large amounts of diazonium salts to reduce decomposition and increased the product yield to 91.7%. At the same time, the continuous-flow process improved the safety and efficiency of the reactions, saved reaction time and had good prospects for industrial application.