2-(5-Methyl-2,6-dioxo-3-{4-(1,1,2,2-tetramethyl-1-silapropoxy)-5-[(1,1,2,2-tetramethyl-1-silapropoxy)methyl]oxolan-2-yl}-1,3-dihydropyrimidinyl)acetic acid AIDS-111353 AIDS111353