1-(2-Hydroxy-2-thioxo(1,3,6,2-dioxazaphosphaperhydroocin-6-yl))-18-{[2-(2-hydroxy-2-thioxo(1,3,6,2-dioxazaphosphaperhydroocin-6-yl))-2-oxoethyl]amino}octadecan-1-one AIDS-104823 AIDS104823