PCT No. PCT / JP97 / 02858 Sec. 371 Date Oct. 30, 1997 Sec. 102(e) Date Oct. 30, 1997 PCT Filed Aug. 19, 1997 PCT Pub. No. WO98 / 07705 PCT Pub. Date Feb. 26, 1998A compound of the formula: wherein Q is an optionally substituted
carbon atom or N(O)p wherein p is 0 or 1; Y is an optionally substituted
methylene group, S(O)q wherein q is an integer of 0 to 2, or an optionally substituted imino group; Z1 is a C1-3 alkylene group which may have an oxo group or a thioxo group and may contain etherified
oxygen or
sulfur within the
carbon chain; Z2 is an optionally substituted C1-3 alkylene group; Ar is an optionally substituted carbocyclic group or an optionally substituted heterocyclic group; one of R1 and R2 is a
hydrogen atom, a
halogen atom, a hydroxyl group, an optionally substituted lower
alkyl group, or an optionally substituted lower
alkoxy group; the other is a
halogen atom, a hydroxyl group, an optionally substituted lower
alkyl group, or an optionally substituted lower
alkoxy group; or R1 and R2 taken together with adjacent -c=c- form a ring; and ring A is a
benzene ring which may be substituted in addition to R1 and R2; or a salt thereof.