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

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. [ABSTRACT FROM AUTHOR]