主权项 |
1. A compound of formula A: or a salt or solvate thereof, wherein: R1 is hydrogen, hydroxy, substituted or unsubstituted alkyl, or halogen; R2 is hydrogen or α-hydroxy; R4 is substituted or unsubstituted alkyl or halogen; R5 is hydrogen; R6 is hydrogen; R7 is hydrogen, substituted or unsubstituted alkyl, or hydroxy; R11 is hydroxyl, OSO3H, OSO3−, OCOCH3, OPO3H, OPO32− or hydrogen; R12 is hydroxyl, OSO3H, OSO3−, OCOCH3, OPO3H, OPO32− or hydrogen, or taken together R11 and R12 form a carbonyl; m is 0, 1, or 2; n is 0 or 1; o is 0 or 1; and p is 1, wherein m+n+o=3. |