3H-Imidazo[1,2-a]purine-7-butanoic acid, 4,9-dihydro-β-hydroxy-α-[(methoxycarbonyl)amino]-4,6-dimethyl-9-oxo-3-β-D-ribofuranosyl-, methyl ester, (αS),3H-Imidazo[1,2-a]purine-7-butanoic acid, 4,9-dihydro-β-hydroxy-α-[(methoxycarbonyl)amino]-4,6-dimethyl-9-oxo-3-β-D-ribofuranosyl-, methyl ester, (αS),Uridine