| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject new compound useful as a raw material a (S)- benzoxazine derivative which is an intermediate for producing levofloxacin having a strong antibacterial action. SOLUTION: A compound of formula I (X1, X2 are each a halogen; R is a lower alkyl). For example, an N-[(2S)-2-(6-methoxynaphthyl-2-oyl)propionyl]-(3 S)-7, 8-difluoro-2, 3-dihydro-3-methyl-4H[1,4]benzoxazine compound. A compound of formula II among the compound of formula I is obtained by dissolving a (RS)-7, 8-difluoro-2,3-dihydro-3-methyl-4H[1,4]benzoxazine derivative racemic compound in dichloromethane, dropwisely adding (S)-2-(6-methoxynaphthyl-2-oyl) propionyl chloride at room temperature, stirring the mixture, adding hydrochloric acid, washing the organic layer with water, drying over MgSO4, treating the dry organic layer with activated carbon, filtering, removing the solvent, adding hexane and then filtering the obtained solid.
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