(S)-2-[[3-Azido-5-(5-methyl-2,4-dioxo-tetrahydro-pyrimidin-1-yl)-tetrahydro-furan-2-ylmethoxy]-(2-cyano-ethoxy)-phosphorylamino]-3-(1H-indol-3-yl)-propionic acid methyl ester AIDS-097620 AIDS097620 AZT Phosphoramidates