4-Amino-8-(3,5-dimethyl-2,4-dioxo(1,3-dihydropyrimidinyl))-6-(methoxymethyl)-1,7-dioxa-9-(1,1,2,2-tetramethyl-1-silapropoxy)-2-thiaspiro[4.4]non-3-ene-2,2-dione AIDS-096293 AIDS096293