InChI=1S/C13H20O9/c1-6(4-2-3-5-7(14)15)21-13-10(18)8(16)9(17)11(22-13)12(19)20/h2,4,6,8-11,13,16-18H,3,5H2,1H3,(H,14,15)(H,19,20)/b4-2-