The synthesis of 4-bromo-, 4-chh1ro-, 4, S-dichloro-, 4-fluoro-, and 4-methyl-2H-1, 3 (:~ H)- oxazitie-2, 6-dione, as well as an improved synthesis of 2H-1,:~(3H)-oxazine-2,~-dione, t) y reaction of trimethylsilyl azide with the corresponding maleic anhydride is described. This route is superior to other methods for preparation of 4-substituted oxazinediones. N- Methylation of the oxazinedione rinr may he readily accomplished with dimethyl sulfate ...
