(9-Amino-3-(3,5-dimethyl-2,4-dioxo(1,3-diazinyl))-2,6-dioxa-7,7-dioxo-4-(1,1,2,2-tetramethyl-1-silapropoxy)-7-thiaspiro[4.4]non-8-enyl)methyl acetate AIDS-057891 AIDS057891