Lewis acid promoted spiro annulation for the one-pot synthesis of novel pyrrole–quinazoline hybrid molecules as described.

Herein; we report protocols for the synthesis of 1,2,4‐triazoles and 1,3,4‐ thiadiazinones by [3+2] and [3+3] domino annulation reactions of nitrile imines with succinimide and thiazolidine‐2,4‐dione, respectively, using a base (1.5 equivalents) and alcohol as a solvent. In these reactions, notably, alcohol serves not only as a solvent but also as a reactant participating in the formation of ester functionality in products. These methodologies provide metal‐free and direct approaches to the synthesis of 1,2,4‐triazoles and 1,3,4‐thiadiazinones under mild conditions with a wide substrate scope and high yields.