“…Reaction of compound 5, independently, with each of dimethyl sulphate (DMS), diethyl sulphate (DES) and benzyl chloride (PhCH 2 Cl) in the presence of K 2 CO 3 , by a simple physical grinding of the reaction mixture in a mortar with a pestle under solvent-free conditions for 10-15 min at room temperature, followed by processing, gave respectively 1-methyl-2-methylthiobenzimi-dazole (6a, i.e., R = CH 3 ), 1-ethyl-2methylthiobenzimidazole (6b, i.e., R = C 2 H 5 ), 1-benzyl-2methylthiobenzimidazole (6c, i.e., R = PhCH 2 ), as the products identical with the ones reported in the earlier methods 9,10 in all respects (m.p. m.m.p.…”