Redox condensation of o-halonitrobenzenes, sulfur and isothiocyanates: access to 2-aminobenzothiazoles

Abstract

The elemental sulfur and isothiocyanate (S₈/RNCS) couple was found to undergo redox condensation with o-halonitrobenzenes in the presence of N-methylpiperidine as a base in N-methylpyrrolidin-2-one to provide step- and redox-economical access to 2-aminobenzothiazoles. Alternatively, dithiocarbamate salts generated in situ from addition of amines and CS₂ could be used in place of the S₈/RNCS couple.