Multicomponent Synthesis of Benzothiazepinones

Significance

Reported is an efficient three-component synthesis of benzo[e][1,4]thiazepin-2-(1H,3H,5H)-ones in water under microwave irradiation. A plausible mechanism is proposed which involves initial electrophilic ortho-substitution by the aromatic aldehyde, followed by reaction with mercaptoacetic acid. Certain substrates (deactivated aldehydes bearing EWGs) generated thiazolidinone products; results which are rationalized by initial reaction of the aromatic aldehyde and the aniline to form an imine, which then undergoes ­reaction with mercaptoacetic acid. The formation of thiazolidinones was also achieved by the use of aprotic solvents. A detailed investigation to support the proposed mechanism would ensure the full utility of this work.