AIDS-153255 AIDS153255 NSC699494 Phosphoric acid 5-(5-fluoro-4-octadecylamino-2-oxo-2H-pyrimidin-1-yl)-3-hydroxy-tetrahydro-furan-2-ylmethyl ester 5-(4-imino-2-oxo-3,4-dihydro-2H-pyrimidin-1-yl)-tetrahydro-furan-2-ylmethyl ester