Y is preferably hydrogen or an alkyl group having 1 to 12 carbon atoms, more preferably hydrogen or an alkyl group having 1 to 6 carbon atoms, further preferably hydrogen or an alkyl group having 1 to 3 carbon atoms, and most preferably hydrogen. [0064] In the formula (I), Z is a halogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an acyl group ha