2-((((5-(Azadiazomvinyl)-3-(5-methyl-2,4-dioxo(3H-1,3-diazinyl))(2-oxolanyl))methoxy)(hydroxyphosphoryl)oxy)(hydroxyphosphoryl)oxy)-1-(octadecylthiomethyl)ethyl hexadecanoate AIDS-051763 AIDS051763 AZT 5'-diphosphate-rac-1-S-octadecyl-2-O-palmitoyl-1-thioglycerol