| 摘要 |
<p>A process for the preparation of (-)-1,4-benzothiazine-2-acetic acid derivatives, characterized by conducting the optical resolution of a racemic modification of a 1,4-benzothiazine-2-acetic acid derivative represented by general formula (I) by forming a salt of the (-)-enantiomer of the derivative with an optically active substance: (wherein R?1 and R2¿ are each hydrogen or the like; R3 is carboxyl or the like; R?4, R5, R6 and R7¿ are each hydrogen, halogeno, or the like; and X is oxygen or the like). This process makes it possible to separate (-)-1,4-benzothiazine-2-acetic acid derivatives respectively from the corresponding (±)-1,4-benzothiazine-2-acetic acid derivatives in high yield and at high optical purity.</p> |
