A Multicomponent Approach toward Angularly Fused/Linear Bitriazoles: A Cascade Cornforth Rearrangement and Triazolization.

A multicomponent reaction of triazoloketones, primary amines, and 4-nitrophenyl azide was developed for the synthesis of hitherto unknown angularly fused/linear bitriazoles. The two-stage mechanism was well proven by the isolation of the intermediate. This sequential reaction consists of Cornforth rearrangement and triazolization, which has also been demonstrated in a one-pot manner.

BOPAHY: a doubly chelated highly fluorescent pyrrole-acyl hydrazone -BF chromophore.

New easily functionalisable and highly fluorescent BOPAHY chromophores are synthesised via a one-pot two-step reaction starting from commercially available pyrrole-2-carbaldehydes and respective acyl hydrazides in the presence of BF·OEt. Most importantly, all BOPAHY dyes show excellent photophysical properties with quantum yields up to 0.92.