| abstract |
A compound of the formula (I) or its pharmaceutically acceptable salt or ester: <CHEM> wherein each of <CHEM> which are the same or different, is an aryl group or a heteroaromatic ring group; A is a C3-8 linear saturated or unsaturated aliphatic hydrocarbon group which may have substituent(s) selected from the group consisting of a lower alkyl group, a hydroxyl group, a lower alkoxy group, a carboxyl group, an aryl group and an aralkyl group; Q is a single bond or a group of the formula -CO-O-, -O-CO-, -CH2CH2-, -CH=CH-, -OCH2-, -SCH2-, -CH2O- or -CH2S-; each of R<1>, R<2>, R<3> and R<4> which are the same or different, is a hydrogen atom, a halogen atom, a lower alkyl group, a hydroxyl group, a lower alkoxy group, or an aryl or heteroaromatic ring group which may have substituent(s) selected from the group consisting of a halogen atom, a lower alkyl group and a lower alkoxy group; each of R<5>, R<6> and R<7> which are the same or different, is a hydrogen atom or a lower alkyl group; and R<8> is a hydrogen atom, a lower alkyl group, a lower alkenyl group, a lower alkynyl group or an aralkyl group, provided that when Q is a single bond, <CHEM> are not simultaneously 4-chlorophenyl groups.a |