On purpose to develop highly safe PDE IV inhibitors excellent in antiasthmatic effect, the invention provides compounds represented by the general formula (1) or medicinally acceptable salts thereof, which have excellent PDE IV inhibiting activity and are useful as antiasthmatics: (1) wherein A is methylene, (lower alkyl)methylene, carbonyl, or the like; Y is a 5− or 6−membered heteroaryl group containing one or two heteroatoms selected from among nitrogen, sulfur and oxygen; and Z is (i) a fused ring composed of a 5− or 6−membered heteroaryl group and a benzene ring or (ii) phenyl which may be substituted with nitro, amino, a group containing amino nitrogen, or the like, with the proviso that the substituent on this phenyl group is amino or a group containing amino nitrogen when A is methylene, Y is a 5− or 6−membered heteroaryl group selected from among pyrrolyl, pyridyl and so on, and Z is optionally substituted phenyl.
