Synthesis of new trihalomethylated and non-symmetrical substituted 2-(1H-pyrazolyl)-5-(1H-pyrazolylcarbonyl)pyridines

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.