| 摘要 |
A compound having formula (I), wherein R represents C1-C18 alkyl, C5-C18 cycloalkyl, C3-C18 alkenyl or C3-C18 alkynyl; provided that, when —OR groups are in 2,2′-positions on benzene rings in formula (I), R is not methyl, ethyl, hexyl, octyl or allyl. |
