(S)-2-[[(2S,3S,5R)-3-Azido-5-(5-methyl-2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-tetrahydro-furan-2-ylmethoxy]-(2,2,2-trifluoro-ethoxy)-phosphorylamino]-3-methyl-butyric acid methyl ester AIDS-214731 AIDS214731