| 摘要 |
Compounds of the general formula (I) <CHEM> (in which X represents a halogen atom; R<1> and R<2> respectively represent a hydroxy group and a hydrogen atom, a halogen atom and a hydrogen atom, or a hydrogen atom and a halogen atom; and R<3> and R<4>, which may be the same or different, represent halogen atoms or hydroxy groups; at least one of R<1>, R<2> and R<3> representing a halogen atom; II with the proviso that when R<2>, R<3> and R<4> all represent chlorine atoms, X does not represent a chlorine atom). |
