An Efficient One Pot Synthesis of Fused Pyrazolo [3’, 4’:4, 5] Pyrimido [2,1-b][1,3] Benzothiazole and its 2-Substituted Derivatives

Pyrazolo pyrimido benzothiazoles (4a-i) were prepared by the reaction of compound 3-cyano-4-imino-2-methylthio-8-methyl-4H-pyrimido[2,1-b] benzothiazole (3) with hydrazine hydrate, substituted phenyl hydrazine, 2-hydrazino benzothiazole and 6-substituted 2-hydrazino benzothiazole in N,N-dimethyl formamide and catalytic amount of potassium carbonate. The synthesized compounds were characterized by elemental analysis, IR, PMR and Mass data.