4,7-Diamino-1,8-dioxa-6-(1,1,2,2-tetramethyl-1-silapropoxy)-9-((1,1,2,2-tetramethyl-1-silapropoxy)methyl)-2-thiaspiro[4.4]non-3-ene-2,2-dione AIDS-057907 AIDS057907 TSAO deriv.