(1S.2S.6S.9R)-9-hydroxy-9-(hydroxymethyl)-2-[(2S.3R.4S.5R.6R)-3.4.5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-3-oxabicyclo[4.3.0]nona-4.7-diene-5-carboxylic acid