(1S,3R,4aS,8S,8aS)-8-(beta-D-Glucopyranosyloxy)-4,4a,8,8a-tetrahydro-3-hydroxy-1-methyl-1H,3H-pyrano[3,4-c]pyran-5-carboxylic acid methyl ester; methyl (1S,3R,4aS,8S,8aS)-8-(β-D-glucopyranosyloxy)-3-hydroxy-1-methyl-4,4a,8,8a-tetrahydro-1H,3H-pyrano[3,4-c]pyran-5-carboxylate