Synthesis of fused ring 1,2,4‐triazoles by intramolecular cycloaddition of nitrile imines to the nitrile function

Abstract
Treatment of 1‐chlorohydrazones (IIa‐c) with triethylamine gave fused ring 1,2,4‐triazoles arising from an intramolecular cycloaddition of the intermediate nitrile imines (IIIa‐c). This reaction was not observed in the case of one compound (IId) bearing an unactivated nitrile group.