abstract |
A compound having formula (I), n n n n n n n n n n wherein R represents C 1 -C 18 alkyl, C 5 -C 18 cycloalkyl, C 3 -C 18 alkenyl or C 3 -C 18 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. |