Thiosemicarbazides: synthesis and reactions

The utility of thiosemicarbazides in organic synthesis demonstrates their importance in the synthesis of several heterocycles. Their reactions with systems containing C=O and C=N groups is one of the methods for the preparation of biologically active compounds viz. pyrazole, thiazole, triazole, thiadiazole, oxadiazole, triazine and thiadiazine. The formation of C-N and C=N bonds as opposed to the N-N bond formation is reflected in their extensive use for the preparation of these heterocycles in excellent yields (1). [GRAPHICS] .