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

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.

Automated summary

In this study, protocols for the synthesis of 1,2,4-triazoles and 1,3,4-thiadiazinones were developed using [3+2] and [3+3] domino annulation reactions of nitrile imines with succinimide and thiazolidine-2,4-dione, respectively. The reactions were conducted in the presence of a base and alcohol as a solvent. Notably, the alcohol also reacted to form ester functionality in the products. These methodologies provide a metal-free and direct approach to the synthesis of 1,2,4-triazoles and 1,3,4-thiadiazinones with high yields and a wide range of substrates under mild conditions.