| 摘要 |
A process for preparing a compound represented by the following formula: <CHEM> wherein each symbol is as defined below, or a salt thereof, characterized by subjecting a compound represented by the following formula: <CHEM> wherein R<1> is an electron-attracting group; R<2>, R<3>, R<4>, R<5>, R<6> and R<7> are each a hydrogen atom, a halogen atom, an optionally substituted amino group, an optionally substituted hydroxyl group, an optionally substituted thiol group, an optionally substituted hydrocarbon group, or an optionally substituted heterocyclic group, provided that R<6> and R<7> may be united to form a ring; and R<8> is a hydrogen atom or an optionally substituted hydrocarbon group, or a salt thereof, to a ring-closing reaction. |
