4-ACYL-5-HYDROXY-1-PHENYL-3-TRIFLUOROMETHYL-PYRAZOLES:SYNTHESIS AND NMR SPECTRAL INVESTIGATIONS

摘要

The title compounds were prepared by reaction of l-phenyl-3-trifluoromethyl-lH-pyrazol-5-ol with trimethyl orthoacetate,triethyl orthopropionate and triethyl orthobenzoate,respectively,followed by hydrolytic cleavage of the primarily formed condensation products.Detailed NMR spectroscopic investigations with the obtained products are presented,revealing the title compounds to be present as 5-hydroxypyrazoles stabilized by an intramolecular hydrogen bond in CDCl_3 solution.