(9R,10R)-3-(Bromomethyl)-8,8-dimethyl-2-oxo-9-(4,7,7-trimethyl-2-oxa-3-oxobicyclo[2.2.1]heptylcarbonyloxy)pyrano[6,5-f]chroman-10-yl 4,7,7-trimethyl-2-oxa-3-oxobicyclo[2.2.1]heptanecarboxylate AIDS-108624 AIDS108624