Síntese de 2-(1h-pirazol-1-il)-5-(1h-pirazol-1-il-1-carbonil) piridinas

Abstract

This work describes the synthesis of a new series of 2-[3-alkyl(aryl/heteroaryl)-5-trihalomethyl-5-hydroxy-4,5-dihydro-1H-pyrazol-1-il]-5-[3-alkyl(aryl/heteroaryl)-5-trihalomethyl-5-hydroxy-4,5-dihydro-1H-pyrazol-1-il-1-carbonyl]pyridines by the cyclocondensation reaction of 1,1,1-trihalo-4-alkoxy-4-alkyl(aryl/heteroaryl)-3-alken-2- ones [CX3C(O)CH=CR1OR, where R = Me, Et; R1 = H, Me, Ph, 4-MeOPh, 4-NO2Ph, 4,4 -Biphenyl, 1-Naftyl, 2-Furyl, 2-Thienyl and X = F, Cl] with 6-hydraninonicotinic hydrazide hydrate. Yields of 67 to 97% was obtained when the reactions were performed in ethanol as a solvent to 78 oC for 4 hours. In a subsequent step are described the reactions of dehydration intramolecular of 2- (1H-pyrazol-1-yl)-5-(1H pyrazol-1-yl-1-carbonyl)pyridines. These reactions 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-trihalomethyl-1H- pyrazol-1-yl]-5-3-alkyl (aryl/heteroaryl)-5-trihalomethyl-1H-pyrazol-1-yl-1-carbonyl]pyridine, with yields of 64 to 86%. All compounds were characterized by analytical experiments 1Hs and 13Cs, 2DCOLOQ NMR, mass spectrometry (GC-MSD) and its purities they were determined by CHN elemental analysis.