| 摘要 |
in which R1, R2, R3, R4 R5, R6 are independently selected from the group consisting of H, methyl, ethyl, propyl, OH, OMe, OEt, COOH, COOR7, in which R7 is selected from linear or branched C1-C7 alkyl, and CONR8R9, in which R8 and R9 are independently selected from hydrogen and straight or branched C1-C4 alkyl; or any two adjacent substituents R2-R6 together form a ring of 5 or 6 members; and n is 1 or 0. |
