Concise synthesis of -thiomethyl benzoimidazoles through base-promoted sequential multicomponent assembly.

An efficient method for the synthesis of -thiomethyl benzimidazoles from -phenylenediamines, thiophenols, and aldehydes C-N/C-S bond formation under metal-free conditions is described. A broad range of functional groups attached to the substrates were well tolerated in this reaction system. Stable and low-toxicity paraformaldehyde was used as the carbon source.