(S)-2-({1-[3-Azido-5-(5-methyl-2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-tetrahydro-furan-2-ylmethoxycarbonyl]-methanoyl}-amino)-3-methyl-butyric acid AIDS-122348 AIDS122348 AZT ANALOGS AZT-Val