3-2',3',5'-tri-O-benzyl-β-D-ribofuranosyl-2-(2-furyl)pyrido<1,2-a>pyrimidin-4-one

3-2',3',5'-tri-O-benzyl-β-D-ribofuranosyl-2-ethoxypyrido<1,2-a>pyrimidin-4-one

3-2',3',5'-tri-O-benzyl-β-D-ribofuranosyl-2-ethoxy-9-methylpyrido<1,2-a>pyrimidin-4-one

ethyl 3,6-anhydro-4,5,7-tri-O-benzyl-2-chloro-2-deoxy-D-allo-heptonate

2-ethoxy-3-(β-D-ribofuranosyl)pyrido<1,2-a>pyrimidin-4-one