(S)-2-[3-Azido-5-(5-methyl-2,4-dioxo-tetrahydro-pyrimidin-1-yl)-tetrahydro-furan-2-ylmethoxy]-methoxy-phosphorylamino}-3-(1H-indol-3-yl)-propionic acid methyl ester AIDS-104749 AIDS104749 AZT Phosphoramidates