134947-26-5Relevant articles and documents
Formation and dehydration of a series of 5-hydroxy-5-trifluoromethyl-4,5-dihydropyrazoles
Singh, Shiv P.,Kumar, Dalip,Jones, Brian G.,Threadgill, Michael D.
, p. 199 - 203 (2007/10/03)
Reaction of five (3-oxo-4,4,4-trifluorobutanoyl)heterocycles with hydrazine hydrate under mild conditions gave the corresponding 3-heterocyclyl-5-hydroxy-5-trifluoromethyl-4,5-dihydropyrazoles. Thermal elimination of water from the 3-(thien-2-yl), 3-(pyridin-2-yl) and 3-(pyridin-4-yl) compounds readily gave the corresponding pyrazoles but acid catalysis was required to form 3-(benzothiazol-2-yl)-5-trifluoromethylpyrazole and 3-(1-methylbenzimidazol-2-yl)-5-trifluoromethylpyrazole. More forcing conditions were required for the analogous dehydration/aromatisations giving 3,5-bis(trifluoromethyl)-1-(4-nitrophenyl)pyrazole and 3,5-bis(trifluoromethyl)-1-pentafluorophenylpyrazole.