Synthetic diversification of tryptanthrin through its C6-hydrazone

Abstract

Three effective methods for diversification of tryptanthrin through its C6-hydrazone is described. Pyrazoles were produced through the cyclocondensation of C6-hydrazone with α, β-unsaturated carbonyl substrates, catalyzed by triflic acid. A range of diversifications at the C6 position of tryptanthrin were achieved from a triazole, produced from an oxidative transformation of C6-hydrazone, by UV-A irradiation in the presence of different solvents. Finally, Mannich adducts were produced through the reaction of two equivalents of ketones and C6-hydrazone.