Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / 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. / O presente trabalho descreve a utilização de b-alcoxivinil trialometil cetonas [CX3C(O)CR2CR1R, onde X: Cl, F; R: OMe, OEt; R1: H, Me, Ph, 4-MePh, 4-MeOPh, 4-BrPh, 4-ClPh, 4-FPh; R2: H, Ph] na síntese regioespecífica de 16 novos 3(4)-alquil(aril)-5-trialometil-5-hidroxi-4,5-diidro-1H-1-tosilpirazois. As tosilpirazolinas foram obtidas a partir da reação das b-alcoxivinil trialometil cetonas com tosilhidrazina (63-92%). Em uma segunda etapa, visando desenvolver uma eficiente metodologia para desidratação das pirazolinas trialometil substituídas. Duas 4-metoxi-4-(4-fluorfenil)-1,1,1-trialo-3-buten-2-onas foram submetidas a reações com quatro dinucleófilos: cloridrato de semicarbazida, tiosemicarbazida, carboximetilhidrazina e 2-furanoilhidrazina, originando inicialmente 8 novos 3-(4-fluorfenil)-5-trialometil-5-hidroxi-4,5-diidro-1H-pirazóis (63-98%). As reações de desidratação realizadas em meio cloreto de tionila/piridina/benzeno produziram os melhores rendimentos para 6 novos 3-(4-fluorfenil)-5-trialometil-1H-pirazóis (41-75%). As atividades inibitórias dos compostos foram avaliadas frente bactérias e fungos, utilizando a técnica de autobiografia. Os compostos tosil pirazolínicos evidenciaram significante atividade frente a bactérias gram-positivas e pouco ativas para fungos. Dentre os compostos avaliados, o composto 3-(4-fluorfenil)-5-hidroxi-5-trifluormetil-4,5-diidro-1H-1-tosilpirazol apresentou o melhor resultado, inibindo o crescimento de Staphylococcus áureus (0,78 μg/μL). Os compostos foram caracterizados por experimentos de RMN de 1H e 13C, e sua pureza determinada via Análise Elementar e CG/MS.