One-Pot Synthesis of 3,4,5-Trisubstituted 1,2,4-Triazoles via the Addition of Hydrazides to Activated Secondary Amides

A general
approach has been developed for the one-pot synthesis
of 3,4,5-trisubstituted 1,2,4-triazoles from secondary amides and
hydrazides via triflic anhydride activation followed by microwave-induced
cyclodehydration. In addition, the 1,2,4-triazole moiety is shown
to be a useful directing group for Ru-catalyzed C–H arylation.
Access to 1,2,4-triazolophenanthridine can be achieved from the reaction
products using a Pd-catalyzed intramolecular C–H functionalization
reaction.