(2R,3S,4R)-2-(methoxy((3R,3'R,3a'S,4aR,6aR,6bS,6'S,7a'R,9R,11aS,11bS)-3',6',10,11b-tetramethyl-1,2,3,3a',4,4a,4',5,5',6,6a,6b,6',7,7',7a',8,11,11a,11b-icosahydro-3'H-spiro[benzo[a]fluorene-9,2'-furo[3,2-b]pyridin]-3-yl)amino)tetrahydrofuran-3,4-diol