This study aimed for the synthesis of new heterocyclic compounds incorporating sulfamoyl moiety suitable for use as antimicrobial agents via a versatile, readily accessible N-[4-(aminosulfonyl)phenyl]- 3-oxobutanamide (1). Butanamide coupled with arenediazonium salts to afford hydrazones. The latter react with dimethylformamide dimethyl acetal (DMF-DMA) to afford the substituted 1,4 dihydropyridazine. Several new thiophene, pyridine, nicotinamide, and pyrazole derivatives have been synthesized by the reactions of butanamide with malononitrile and elemental sulfur, 1,3-diphenylpropenone, arylidenecyanothioacetamide, nitrogen nucleophiles, respectively. Refluxing of butanamide with a mixture of p methoxybenzaldehyde and thiourea afforded 4 (4 methoxyphenyl)-6-methyl- N (4 sulfamoylphenyl)-2-thioxo-1,2-dihydropyrimidine-5-carboxamide which heated with chloroacetyl chloride give N-[4-(aminosulfonyl)phenyl]-7-methyl-5-(4- methoxyphenyl)-3-oxo-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxamide. Treatment of butanamide with phenyl isothiocyanate afforded the intermediate salt which reacted in situ with 2-bromo-1-phenylethanone to afford N-[4- (aminosulfonyl)phenyl]-2-(3,4-diphenyl-3H-thiazol-2-ylidene)-3-oxobutanamide. The some selected products were evaluated for both their in vitro antibacterial and antifungal activities and showed promising results. In addition, the anti-cancer activity of some selected products against human liver (HEPG2) cell line was determined and the results revealed high activities of compounds 5a, 6 and 14.