Thiosemicarbazone derivatives 3a-e were synthesized by the reaction of various aldehydes 1a-e with 4-methyl thiosemicarbazide 2 in 78% to 90% yield. Then, the thiazole moieties of the target materials 5a-e were obtained in high yields (71-93%) using the Hantzsch reaction utilizing thiosemicarbazone derivatives 3a-e with ethyl-2-chloroacetoacetic ester. The substituted nitrile derivatives 7a-e were obtained in moderate to high yield (58-84%) from the reaction of compounds 5a-e with chloroacetonitrile by the nucleophilic aliphatic substitution reaction in the presence of anhydrous potassium carbonate. Finally, substituted 2-amino-1,3,4-thiadiazole compounds 9a-e were obtained in moderate to good yields (51-62%) from the reaction of thiosemicarbazide with substituted nitrile derivatives 7a-e. As a result, compounds that all share a high disposition for biological activities were obtained. The structures of the newly synthesized compounds were confirmed by IR, H-1 NMR, C-13 NMR, elemental analysis, and mass spectrometric techniques.