Conversion of pyrroles into bis-1,2,5-thiadiazoles: a new route to biheterocycles

Abstract

Trithiazyl trichloride 1 converts 1-aryl-2,5-diphenylpyrroles 2c into isothiazole imines 3c, but 1-alkyl-2,5-diphenylpyrroles (e.g. 4) react very differently to give the bis-1,2,5-thiadiazole 5 in which two N–S–N units have been fused onto the pyrrole and the alkyl–N unit has been excised, in a new dissection of the pyrrole ring, thus providing a novel route to an aromatic biheterocycle.