HALOGENATION OF 3-HYDROXY-1H-PYRIDO[2,1-B]BENZOTHIAZOL-1-ONE: SYNTHESIS OF TWO NEW RING SYSTEMS

Abstract

3-Hydroxy-1H-pyrido[2,1-b]benzothiazol-1-one (1) reacts with sulphuryl chloride to give the 2-chloro derivative II. Bromination of I yields the 4-bromo derivative VIII. Each of II and VIII condenses with thiourea to afford 2-amino-11H-thiazolo[4′,5′:4,5]pyrido[2,1-b]benzothiazol-11-one (IV) and 2-amino-5H-thiazolo[4′,5′: 4,3]pyrido[2,1-b]benzothiazol-5-one (V), respectively. The structures of the newly synthesised compounds are proved by chemical and spectral methods.

Key Words:

• Pyridobenzothiazole
• chlorination
• bromination
• coupling