Synthesis of heterocyclic compounds from o-aminobenzenethiol and ammonium thiocarbamate

The reaction of o-aminobenzenethiol with carbonyl sulfide in the presence of triethylamine afforded an alternate route for the synthesis of 2-benzothiazolinone ( 1 ) in 97–98% yield. The reaction of ammonium thiocarbamate ( 2 ) with 2-chlorocyclohexanone furnished the novel 4,5,6,7-tetrahydro-2-benzothiazolinone ( 3 ). 3-Ethoxy-2H-1,4-benzothiazin-2-one ( 7 ) was prepared by the reaction of o-aminobenzenethiol with diethyl oxalate. Possible pathways and supporting nmr, ir and mass spectra are discussed.