4,8,8-Trimethyl-2-oxo-9-(((4,7,7-trimethyl-3-oxo-2-oxabicyclo[2.2.1]hept-1-yl)carbonyl)oxy)-9,10-dihydro-2H,8H-pyrano[2,3-f]chromen-10-yl 4,7,7-trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carboxylate AIDS-161577 AIDS161577 NSC700281