Patent ID: 7462628

Claim:
A compound represented by the formula: wherein Ar 1 is a group represented by the formula: L 1 represents a C 4-6 alkylene group which may have a substituent, L 2 represents a C 2-4 alkylene group which may have a substituent, R represents a hydrogen atom or a hydrocarbon group which may have a substituent, X represents a bond, an oxygen atom or NR 1a (wherein R 1a represents a hydrogen atom, a hydrocarbon group which may have a substituent, an acyl group or a heterocyclic group which may have a substituent), and Ar 2 represents an aromatic ring group which may have a substituent, or Ar 2 and R, or Ar 2 and L 2 may, link together to form a ring, or a salt thereof.