Synthesis of the related substances of deferasirox

To perform the quality control of deferasirox and establish its quality criterion, three related substances which were determined by analyzing the synthetic route were synthesized, and their structures were confirmed by ¹H NMR and MS. These substances were 2-(2-hydroxyphenyl)-4H-benzo［1, 3-e］oxazin-4-one(A), 2-hydroxy-N-(2-hydroxyben-zoyl)-benzamide(B), and methyl-4-［3, 5-bis(2-hydroxyphenyl)- 1H- ［1, 2, 4］triazol-1-yl］-benzoate(C).