Conversion of 2-aminomethylbenzothiazoles into imidazo[5, 1-b]benzothiazoles

A number of substituted 2-aminomethylbenzothiazoles ate synthesized. The corresponding ureas or thioureas are also obtained by reaction with arylisocyanates or arylisothiocyanates. Heating the substituted ureas or thioureas at temperatures above their melting points cyclizes them to 9-substituted 2-hydroxy- or 2-mercaptoimidazo[5, 1-b]benzothiazoles, which are derivatives of a new heterocyclic system.