SYNTHESIS OF 2H-[1,2]OXAZINO[3,4-c]QUINOLINE-2,5(6H)-DIONES FROM 6-OXO-6H-1,2-OXAZINE-3-CARBOXYLATES

Abstract

A methodology was developed for the synthesis of 1-ethoxy-6-methyl-2H-[1,2]oxazino[3,4-c]quinoline-2,5(6H)-diones from methyl 4[2-(dimethylamino)phenyl]-5-ethoxy-6-oxo-6H-1,2-oxazine-3-carboxylates by the action of titanium tetrachloride under inert atmosphere. This interaction provides a rare example of demethylation followed by cyclization, yielding several new compounds.