(-)-Methylthyrsiflorin A InChI=1/C24H38O4/c1-21(2)9-6-10-23(4)17(21)8-7-16-13-18(28-20(26)14-19(25)27-5)22(3)11-12-24(16,23)15-22/h16-18H,6-15H2,1-5H3/t16-,17-,18+,22-,23-,24-/m0/s methyl (4aR,6aR,8S,9R,11aR,11bR)-4,4,9,11b-tetramethyltetradecahydro-9,11a-methanocyclohepta[a]naphthalen-8-yl rel-malonate propanedioic acid, methyl (4aS,6aS,8R,9S,11aS,11bS)-tetradecahydro-4,4,9,11b-tetramethyl-9,11a-methano-11aH-cyclohepta[a]naphthalen-8-yl ester