Using Triazolobenzodiazepine as the Cyclic Imine in Various Types of Joullié–Ugi Reactions
Mohammad Taghi Nazeri, Maryam Ghasemi, Masoomeh Ahmadi, Ahmad Shaabani, Behrouz Notash
Abstract
The triazolobenzodiazepine as a cyclic imine was employed in a variety of Joullié–Ugi reactions, and three new families of unique triazolobenzodiazepine connected to carboxamide and tetrazole products were synthesized via a three-component reaction of the cyclic imine and isocyanides with each species of a carboxylic acid/water/TMSN 3 under mild conditions in high yields. Furthermore, triazolobenzodiazepine imine was used in an interesting strategy based on the modified Ugi reaction (pseudo-Joullié–Ugi reaction) of cyclic imines with an isocyanide and acetylenedicarboxylates under catalyst-free conditions for the synthesis of triazolobenzodiazepine-fused pyrroles. Mechanistic investigation reveals that triazolobenzodiazepine-fused pyrroles have been generated via a surprising route. Significantly, the use of triazolobenzodiazepine in the Joullié–Ugi, azido-Joullié–Ugi, and pseudo-Joullié–Ugi reactions of a broad scope of biological scaffolds occurred under mild, simple conditions without any catalyst.