| abstract |
A compound having formula (I), wherein R 1 and R 2 independently represent C 1 -C 6 alkyl, R 3 is C 1 -C 6 alkyl, and R 4 is , C 1 -C 18 alkyl or C 4 -C 18 heteroalkyl, m is 0, 1, 2, or 3, n is 1, 2, or 3, j, k, p, q, A compound wherein r and s are independently 0, 1, or 2, provided that at least one of j, k, p, q, r, and s is not 0. [Chemical 1] [Selection figure] None |