NMR SPECTROSCOPIC INVESTIGATIONS WITH ETHYL 1-(HETERO)ARYL-5-HYDROXY-1H-PYRAZOLE-4-CARBOXYLATES

摘要

The synthesis of a series of ethyl N-1-(hetero)aryl-5-hydroxy-1H-pyrazole-4-carboxylates by reaction of diethyl ethoxymethylenemalonate with the appropriate hydrazines is described. According to nmr-spectroscopic investigations (H-1- and C-13-nmr) the title compounds exist as 5-hydroxy tautomers in deuteriochloroform as well as in deuteriodimethyl sulfoxide solution. [References: 30]