4H-Furooxazine-2(1H),4-dione. A Furan Analogue of Isatoic Anhydride

Article abstract of DOI:10.1021/jo00332a018

The title compound 2 was prepared in four steps from diethyl 3,4-furandicarboxylate.Reactions of 2 with nitrogen and oxygen nucleophiles occur exclusively at the nitrogen carbonyl to give ureido acids 6 or carbamato acids 8 under a variety of reaction conditions.The results are in contrast to the reactions of isatoic anhydride 1.In order to achieve substitution at the carbonyl adjacent to the furan ring, carbamato acid 8a was derivatized with subsequent deprotection of the amine.In this manner, furo<3,4-d><1,3>oxazines 14a-d were prepared.Several possible reasons for the reactivity of 2 are presented.