4-Amino-8-(3,5-dimethyl-2,4-dioxo(1,3-diazinyl))-6-((3-methylbut-2-enyloxy)methyl)-1,7-dioxa-9-(1,1,2,2-tetramethyl-1-silapropoxy)-2-thiaspiro[4.4]non-3-ene-2,2-dione AIDS-057898 AIDS057898 TSAO deriv.