Furo[3',4':6,7]naphtho[2,3-d]-1,3-dioxol-6(5aH)-one,9-[(4,6-O-ethylidene-b-D-glucopyranosyl)oxy]-5,8,8a,9-tetrahydro-5-(4-hydroxy-3,5-dimethoxyphenyl)-,[5R-[5a,5aa,8aa,9b(R*)]]-