Fused 1,2,4‐triazole heterocycles. IV. Synthesis of four new heterocyclic ring systems of [1,2,4]triazolo[1,3]thiazinoquinolines

Abstract

Syntheses of 5H‐[1,2,4]triazolo[5′,1′:2,3][1,3]thiazino[5,4‐c]quinolines 8, 5H‐[1,2,4]triazolo[3′,4′:2)3][1,3]thiazino[5,4‐c]quinolines 9, 5H‐[1,2,4]triazolo[5′,1′:2,3][1,3]thiazino[5,6‐c]quinolines 14 and 5H‐[1,2,4]triazolo[3′,4′:2,3][1,3]thiazino[5,6‐c]quinolines 15 are described starting from 4‐chloro‐3‐chloromethylquinaldine (4) and 1,2,4‐triazole‐5‐thiols 5 taking advantage of different reactivity of the chlorine atoms of 4 under different reaction conditions. The structures of products 8, 9, 14 and 15 and the intermediates leading to them were confirmed by desulfurization, unequivocal syntheses and nmr spectroscopy as well.