Synonyms: Dispiro[6,11b-(epoxymethano)-6a,9-methano-1H-cyclohepta[a]naphthalene-8(7H),1'-cyclobutane-2',8''(7''H)-[6,11b](epoxymethano)[6a,9]methano[1H]cyclohepta[a]naphthalene]-7,7''-dione,3,3''-bis(acetyloxy)-4,4''-bis[(acetyloxy)methyl]eicosahydro-5,5'',6,6''-tetrahydroxy-4,4''-dimethyl-,[3S-[3a,4b,4aa,5a,6b,6ab,8b(3''R*,4''S*,4''aR*,5''R*,6''R*,6''aR*,8''S*,9''S*,11''aR*,11''bS*),9b,11aa,11bb]]-; Maoecrystal M