(S)-2-({1-[3-Azido-5-(5-methyl-2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-tetrahydro-furan-2-ylmethoxycarbonyl]-methanoyl}-amino)-4-methyl-pentanoic acid AIDS-122346 AIDS122346 AZT ANALOGS AZT-Leu