Síntese e caracterização estrutural de pirazolinil-tolil-sulfonas trialometil substituídas de interesse antimicrobiano

Abstract

The present research describes the use of b-alcoxyvynil trihalomethyl ketones [CX3C(O)CR2CR1R, where X= Cl, F; R= OMe, OEt; R1: H, Me, Ph, 4-MePh, 4-MeOPh, 4-BrPh, 4-ClPh, 4-FPh; R2= H, Ph] in the regiospecific synthesis of 16 new 3(4)-alkyl(aryl) substituted 5-trihalomethyl-5-hydroxy-4,5-dihydro-1H-1-tosylpyrazoles. These pyrazolines were obtained from the reaction of b-alcoxyvinyl trihalomethyl ketones with tosyl hydrazine (63-92%). In a following phase, aiming to develop an efficient methodology of dehydration. Two 4-methoxy-4-(4-fluorophenyl)-1,1,1-trihalo-3-buten-2-ones were submitted to the reactions with four dinucleophile: semicarbazide hydrochloride, thiosemicarbazide, methyl hydrazinocarboxylate and 2-furoic hydrazide furnishing, eigth new 1-substituted-3-(4-fluorophenyl)-5-trihalomethyl-5-hydroxy-4,5-dihydro-1H-pyrazoles (63-98%). The dehydration reactions carried out in thionyl chloride/pyridine/benzene gave the best yields of 3-(4-fluorophenyl)-5-trihalomethyl-1H-pyrazoles (41-75%). The inhibitory activities of pyrazolinic compounds were tested using the autobiography technique for bacteria and fungis. The tosyl pyrazolinic compounds exhibit a significant activity for gram-positive bacteria and low activity to fungi. Among the tested compounds, 3-(4-fluorphenyl)-5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-tosylpyrazole exhibited the best inhibitory activity against Staphylococcus aureus (0,78 μg/μL). All the compounds were characterized by spectral and analytical experiments 1H s and 13C s NMR, and the purity was demostrated by elemental analyzes and CG/MS.