Synthesis and Antimicrobial Activity of Novel Pyrazole Derivatives

Abstract

This work aimed to synthesis of some new different heterocyclic compds. based on 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxaldehyde reacted with cyanoacetohydrazide to afford N'-[(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)methylene]-2-cyanoacetohydrazide I [R = HNC(O)CH2CN]. Compd. I [R = HNC(O)CH2CN] was cyclized by acetyl acetone and arom. aldehyde, resp., to give pyrazolo-pyridone I [R = 3-cyano-4,6-dimethyl-2-oxo-1-pyridyl] and substituted pyrazolochromene II [R1 = H; R2 = H, MeO, Br; R1R2 = (CH)2] resp. Pyrazolo-triazole I [R = (5-amino-1-(4-fluorophenyl)triazole-4-carbonyl)amino] was obtained by coupling of 1-azido-4-fluorobenzene with compd. I [R = HNC(O)CH2CN], which was diazotized by 3-(chlorodiazenyl)-4,6-dimethyl-1H-pyrazolo[3,4-b]pyridine to give pyrazolo-pyridine deriv. III [R3 = 2-(5,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-yl)hydrazino]. N,N-Dimethylformamide di-Me acetal reacted with compd. I [R = HNC(O)CH2CN] to afford [(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)methylene]-2-cyano-3-(dimethylamino)-acrylohydrazide III [R3 = HCN(Me)2]. The reaction of compd. III [R3 = HCN(Me)2] with hydrazine hydrate in 1,4-dioxane resulted in formation of substituted pyrazole-4-carbohydrazide I [R = (3-amino-1H-pyrazole-4-carbonyl)amino]. The reaction of compd. III [R3 = HCN(Me)2] with benzenediazonium chloride derivs. resulted in formation of substituted pyrazole-4-carbohydrazide III [R3 = NNHPh, 4-ClC6H4NHN]. Also, compd. I [R = HNC(O)CH2CN] reacted with PhNCS in the presence of KOH and furnish compd. III [R3 = 4-oxo-3-phenyl-thiazolidin-2-ylidene]. All the synthesized compds. were established using IR, 1H-NMR. All the synthesized compds. were screened for their antimicrobial activities. [on SciFinder(R)]