Some nucleophilic reactions of 2-isothiocyanatobenzyl bromide. A new simple synthesis of 2-substituted 4H-benzo[d][1,3]thiazines

Abstract

N-Bromosuccinimide reacts with o-tolyl isothiocyanate to afford 2-isothiocyanatobenzyl bromide, a new type of bifunctional synthon. Nucleophiles I-, SCN-, 4-CH3C6H4SO2- and hexamethylenetetramine yield substitution products of bromine. Amines and phenols react exclusively with the NCS grouping under formation of unstable thioureas, which in turn cyclize to the corresponding 4H-benzo[d][1,3]thiazines. Structure of these compounds was corroborated by IR, 1H, 13C NMR and mass spectral data and backed by elemental analysis.