Este trabalho apresenta a síntese de uma nova série de 2-[3-alquil (aril/heteroaril)-5-trialometil-5-hidróxi-4,5-diidro-1H-pirazol-1-il]-5-[3-alquil(aril/heteroaril)-5-trialometil-5-hidróxi-4,5-diidro-1H-pirazol-1-il-1-carbonil]piridinas, obtida a partir de reações de ciclocondensação de 4-alcóxi-4-alquil(aril/heteroaril)-1,1,1-trialo-3-alquen-2-onas [CX3C(O)CH=CR¹OR, onde R = Me, Et; R¹ = H, Me, Ph, 4-MeOPh, 4-NO2Ph, 4,4'-Bifenil, 1-Naftil, Fur-2-il e Tien-2-il e X = F, Cl] com hidrato de hidrazida 6-hidrazino-nicotínica. Os melhores rendimentos foram obtidos quando as reações foram executadas em etanol como solvente a 78 ºC por 4 horas (67-97%). Em sequência, são descritas as reações de desidratação de 2-(1H-pirazol-1-il)-5-(1H-pirazol- 1-il-1-carbonil)piridinas. Estas reações foram realizadas em meio piridina / benzeno, na presença de cloreto de tionila e levaram ao isolamento de uma série de 2-[3-alquil(aril/heteroaril)-5-trifluormetil-1H-pirazol-1-il]-5-[3-alquil(aril/heteroaril)-5-trifluormetil-1H-pirazol-1-il-1-carbonil]piridinas, com rendimentos de 64 a 86%.
This paper describes the synthesis of a new series of 2-[3-alkyl(aryl/heteroaryl)- 5-trifluoro(chloro)methyl-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl]-5-[3-alkyl(aryl/heteroaryl)-5-trifluoro(chloro)methyl-5-hydroxy-4,5-dihydro-1H-pyrazol-1-yl-1-carbonyl]pyridines by the cyclocondensation reaction of 4-alkoxy-4-alkyl(aryl/heteroaryl)-1,1,1-trifluoro(chloro)-3-alken- 2-ones [CX3C(O)CH=CR¹OR, where R = Me, Et; R¹ = H, Me, Ph, 4-MeOPh, 4-NO2Ph, 4,4'-Biphenyl, 1-Naphthyl, Fur-2-yl, Thien-2-yl and X = F, Cl] with 6-hydrazinonicotinic hydrazide hydrate. Yields of 62 to 97% were obtained when the reactions were performed in ethanol as solvent at 78 ºC for 4 hours. In a subsequent step, the dehydration reactions of 2-(5-hydroxy-1H-pyrazol-1-yl)-5-(5-hydroxy-1H-pyrazol-1-yl-1-carbonyl)pyridines were carried out in pyridine/benzene in the presence of thionyl chloride and led to the isolation of a series of 2- [3-alkyl(aryl/heteroaryl)-5-trifluoro(chloro)methyl-1H-pyrazol-1-yl]-5-[3-alkyl(aryl/heteroaryl)-5-trifluoro(chloro)methyl-1H-pyrazol-1-yl-1-carbonyl]pyridines, in 64 to 86% yields.