Synthesis of {2-[1-(4-bromophenyl)-5-oxopyrrolidin-3-yl]-1H -benzimidazol-1-yl}acetic acid hydrazide derivatives

First of all, condensation reactions of acetohydrazide with different aldehydes were carried out, 7 hydrazones were obtained. In the presence of acetic acid as a catalyst, reactions of acetohydrazide with 2,4-pentanedione and 2,5-hexanedione yielded pyrazole and pyrrole derivatives, respectively. The reaction of acetohydrazide and carbon disulphide in the presence of potassium hydroxide was carried out, and potassium dithiocarbazate was obtained. The cyclization reaction of potassium dithiocarbazate with hydrazine monohydrate gave 4-amino-1,2,4-triazole. The cyclization reaction of potassium dithiocarbazate was investigated in an acidic medium; 1,3,4-oxadiazole was formed. By the use of regular heating, in the reaction of acetohydrazide with triethyl orthoformate ethyl formohydrazonate was obtained. Triazine was prepared by heating at reflux a mixture of acetohydrazide, ammonium acetate, 1,2-diphenyl-1,2-ethanedione and using 2-propanol as a solvent. In reactions of acetohydrazide with phenyl isocyanate or phenyl thiocyanate, the N -substituted semicarbazide or thiosemicarbazide derivatives were synthesized, respectively. The cyclization reactions of semicarbazide and thiosemicarbazide were carried out in acidic medium - 1,3,4-oxadiazole and 1,3,4-thiadiazole were obtained. Also cyclization reactions of semicarbazide and thiosemicarbazide were investigated in alkaline medium – 1,2,4-triazole derivatives were forme. DOI: http://dx.doi.org/10.5755/j01.ct.67.1.15829