Patent ID: 7288654

Claim:
A compound represented by the formula: wherein R 1 is a 5- or 6-membered ring which may be substituted; R 3 is a hydrogen atom, a lower alkyl group which may be substituted or a lower alkoxy group which may be substituted; Z 1 is a 5- or 6-membered aromatic ring which may be further substituted; Z 2 is a group represented by -Z 2a -W 1 -Z 2b - wherein Z 2a and Z 2b are each O, S(O) m (wherein m is 0, 1 or 2), a substituted imino group, or a bond; and W 1 is an alkylene chain which may be substituted, an alkenylene chain which may be substituted, or a bond; n is 2; Y is or NR 4 (wherein R 4 is a hydrogen atom, a hydrocarbon group which may be substituted, a heterocyclic group which may be substituted, or an acyl group which may be substituted); and R 2 is (1) a substituted amino group, in which the nitrogen atom may be converted to a quaternary ammonium or an oxide, (2) a nitrogen-containing heterocyclic group which may be substituted and may contain a sulfur atom or an oxygen atom as a ring-constituting atom, in which the nitrogen atom may be converted to a quaternary ammonium or an oxide, (3) a group represented by the formula: wherein k is 0 or 1; when k is 0, the phosphorus atom may form a phosphonium salt; R 5 and R 6 are each a hydrocarbon group which may be substituted, a substituted hydroxy group or an amino group which may be substituted; or R 5 and R 6 may be bonded to each other to form a ring with the adjacent phosphorus atom, or a salt thereof.