(2E,4E)-5-[4-Hydroxy-1-((2R,4S,5R)-4-hydroxy-5-hydroxymethyl-tetrahydro-furan-2-yl)-2-oxo-1,2-dihydro-pyrimidin-5-yl]-penta-2,4-dienoic acid, methyl ester AIDS-186328 AIDS186328