The reaction of methyl iodide and allyl-type halides with 2-phenyl-5-oxazolone was carried out in dimethylformamide by use of 50% aqueous solution of potassium hydroxide or triethylamine as a base. When triethylamine was used, better yield was obtained. From methyl iodide, α-benzamino-isobutyric acid was obtained in 49% yield. From allyl halides, disubstituted derivatives (α-benzamino-α, α-diallylacetic acid) were obtained in good yields. Disubstituted derivatives were obtained in good yields (67% or 59%) by the reaction of crotyl bromide or cinnamyl bromide.