InChI=1S/C21H28O7/c1-14(12-22)4-2-5-15(13-23)6-3-7-16(21(27)28)10-20(26)18-11-17(24)8-9-19(18)25/h4,7-9,11,15,22-25H,2-3,5-6,10,12-13H2,1H3,(H,27,28)/b14-4+,16-7-/t15-/m0/s1