(1S,4R,5R,8R,9R,12R,13S)-1,5,9-trimethyl-10-[(4-{[(1S,4R,5R, 8R,9R,12R,13S)-1,5,9-trimethyl-11,14,15,16-tetraoxatetracycl o[10.3.1.04,13.08,13]hexadec-10-yl]oxy}-2-butenyl)oxy]-11,14 ,15,16-tetraoxatetracyclo[10.3.1.04,13.08,13]hexadecane NSC724782