Reaction of 2-hydroxyethylhydrazine with a trifluoromethyl-β-diketone: Study and structural characterization of a new 5-hydroxy-5-trifluoromethyl-4,5-dihydropyrazole intermediate

The use of β-diketones with strong electron-withdrawing substituents in the reaction with 2-hydroxyethylhydrazine leads to the stable intermediates of pyrazole synthesis, 5-hydroxy-4,5-dihydropyrazoles.