Synthesis of some Pyrazoles derived of 3-Trifluoroacetyl-4,5- dihydrofurane and 3-Trifluoroacetyl-5,6-dihydro-4H-pyrane

Conselho Nacional de Desenvolvimento Científico e TecnológicoThis work presents a simple and versatile strategy for the synthesis of new 4 and N-sustituted 5-trifluoromethyl-pyrazoles. These compounds were obtained by the reaction of 3-trifluoroacetyl-4,5-dihydrofuran and 3-Trifluoroacetyl-5,6-dihydro-4Hpyran with heteroaryl(aryl/alkyl)hydrazines (RNHNH2, where R= COCH₂CN, (4- Py)CO, (3-Py)CO, 4-Py(2-Cl)CO e (4-SO₂NH₂)Ph), in the presence of trifluoroboroetherete in methanol, furnishing the respective 5-trifluoromethyl-4-alkyl-1N-sustitutedpyrazoles, in moderate yields (17-59%). The pyrazoles obtained in this study were identified by NMR 1H, NMR 13C and Mass Espectroscopy.Este trabalho apresenta uma estratégia sintética simples e versátil para a preparação de uma série inédita de 5-trifluormetilpirazóis 4 e 1N-substituídos. Os pirazóis foram obtidos a partir da reação do 3-trifluoracetil-4,5-diidrofurano e 3-trifluoracetil-5,6-diidro-4H-pirano com heteroaril(aril/alquil)hidrazinas (RNHNH2, onde R= COCH₂CN, (4-Py)CO, (3-Py)CO, 4-Py(2-Cl)CO e (4-SO₂NH₂)Ph), com a presença de trifluorboro eterato em metanol, produzindo os respectivos pirazóis 5- trifluormetil-4-alquil-1N-substituídos com rendimentos moderados (17-59%). Os pirazóis obtidos neste trabalho foram identificados por Ressonância Magnética Nuclear de Hidrogênio, Ressonância Magnética Nuclear de Carbono-13 e Espectroscopia de Massas