Oxazinone (II) was prepared by cyclization of the unsaturated keto acid (I) with hydroxylamine. Subsequent radical bromination of (II) with N-bromosuccinimide (NBS) provided the alpha-bromobenzyl derivative (III). Alkylation of 3-chlorophenyl piperazine (IV) with N-(2-bromoethyl)phthalimide (V) gave adduct (VI). Further hydrazinolysis of the phthaloyl group of (VI) yielded the primary amine (VII). Finally, condensation between bromide (III) and amine (VII) in refluxing THF furnished the title 5-amino oxazinone derivative.