ChemInform Abstract: A Synthetic Entry into the Quino(2,1-b) (1,3)benzoxazine Ring System

The double ring closure of N-(2-hydroxybenzyl)anthranilic acids 1 with acetic anhydride or its acyclic analogous (RCH2CO)2O 2b and 2e lead to the formation of novel 12H-quino[2,1-b][1,3]benzoxazin-5-ones. The structure of the obtained compounds was proved with the use of their ir, mass, 1H and 13C nmr spectra. Homo- and heteronuclear two-dimensional nmr experiments were performed to unambiguously assign all proton and carbon chemical shifts.