摘要:
Thiocarbamoylation of 5-aminosalicylic acid with tetramethylthiuram disulfide afforded 5-(N',N'-dimethylthioureido)salicylic acid. Treatment of the latter with mineral acids or Ac2O gave 5-isothiocyanatosalicylic acid, whose reaction with ethanolamine yielded 5-[N'-(2-hydroxyethyl)thioureido]salicylic acid. The latter underwent cyclization under the action of TsOH to form 5-(2-thiazolin-2-ylamino)salicylic acid.