| 摘要 |
PURPOSE:To obtain the titled compound useful as an intermediate for preparing alpha-amino acids, etc. in high quality and yield, by cyclizing a beta-phenylserine through dehydration in the presence of a basic substance in acetic anhydride, and treating the reaction mixture with and acid. CONSTITUTION:A beta-phenylserine of formula I (R1 and R2 are H, halogen, etc.) is cyclized through dehydration in the presence of a basic substance, e.g. an alkali metal, in acetic anhydride, and the reaction mixture is then treated with an acid and hydrolyzed without isolating the resultanct 2-methyl-4-benzal-5- oxazolones to afford the aimed compound of formula II (R3 and R4 are H, halogen, lower alkyl, etc.). EFFECT:The reaction proceeds even under mild conditions with almost no formation of coloring impurities, etc. as by-products. The aimed compound formed partially as a by-product in preparing the 2-methyl-4-benzal-5-oxazolones is not lost.
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