3-((5-(2,4-Dioxo-3,4-dihydro-1(2H)-pyrimidinyl)tetrahydro-2-furanyl)methoxy)-3-oxido-7-oxo-8-(1-piperidinyl)-2,4,6-trioxa-3-phosphaoct-1-yl 1-piperidinylacetate AIDS-149883 AIDS149883 NSC685580