1H,3H,7H-Pyrano[3,4-g][1,5]dioxecin-9-carboxylicacid, 12-(b-D-glucopyranosyloxy)-4,5,8,8a,12,12a-hexahydro-4-hydroxy-4-(hydroxymethyl)-1,5-dimethyl-3,7-dioxo-,methyl ester, [1S-(1R*,4R*,5R*,8aR*,12R*,12aR*)]-