2-{(4S,2R,5R)-2-(2,4-Dioxo(1,3-dihydropyrimidinyl))-4-(1,1,2,2-tetramethyl-1-silapropoxy)-5-[(1,1,2,2-tetramethyl-1-silapropoxy)methyl]-3-2,4,5-trihydrofurylidene}ethanenitrile AIDS-149787 AIDS149787 NSC685187