2-Hydroxy-2-methyl-thiopropionic acid -(2-{[3-azido-5-(5-methyl-2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-tetrahydro-furan-2-ylmethoxy]-[2-(2-hydroxy-2-methyl-propanoylsulfanyl)-ethoxy]-phosphoryloxy}-ethyl) ester AIDS-107249 AIDS107249 SATE AZT ANALOG