(2S,3aS,4S,5R,6S)-4-(3,4-Dimethoxybenzyl)-2-(1,3-dioxolan-2-yl)-6-[(2,2-diphenylcyclopentyl)oxy]- 4-ethylhexahydroisoxazolo[2,3-b][1,2]oxazin-5-yl acetate AIDS-153305 AIDS153305 NSC699773