Preparation of novel tricyclic ring systems containing the pyridazinone ring

Abstract

Abstract Novel tricyclic ring systems, irmdazo[3,4‐ d ]pyridazino[4,5‐ b ][1,4]thiazines 3 , imidazo[2,1‐ b ]pyridazino[4,5‐e][1,3,4]thiadiazines 15 and 18 were prepared by the reaction of 5‐amino‐4‐chloropyridazin‐3(2 H )‐ones 1 and 5(4)‐(1‐methylhydrazino)‐4(5)‐chloropyridazin‐3(2 H )‐ones 13 (16) with isothiocyanates 2 and 7 .