Cyclocondensation versus Cyclocondensation Plus Dehydroxylation During the Reaction of Flavones and Hydrazine

Abstract

Concomitant selective dehydroxylation during the transformation of flavones into pyrazoles with hydrazine is determined by the A-ring substitution pattern and propensity to keto enol tautomerization. The obtained pyrazoles show varied tyrosinase inhibition properties, including one nanomolar inhibitor.