A selective synthesis of 2‐arylamino‐4<i>H</i>‐1,3,4‐thiadiazino[5,6‐<i>b</i>]‐quinoxalines and mesoionic triazolo[4,3‐<i>a</i>]quinoxaline

Abstract

Abstract The reaction of the 6‐chloro‐2‐(1‐methyl‐2‐thiocarbamoylhydrazino)quinoxaline 4‐oxides 3a‐d with trifluoroacetic anhydride gave the 2‐( N ‐aryl)trifluoroacetamido‐8‐chloro‐4‐methyl‐4 H ‐1,3,4‐thiadiazino‐[5,6‐ b ]quinoxalines 7a‐d , respectively, while the reflux of compounds 3a‐c in N,N ‐dimethylformamide afforded the mesoionic triazolo[4,3‐ a ]quinoxaline 4 . Hydrolysis of compounds 7a‐d with triethylamine/water provided the 2‐arylamino‐8‐chloro‐4‐methyl‐4 H ‐1,3,4‐thiadiazino[5,6‐ b )]quinoxalines 8a‐d , respectively.