Synthesis of novel pyridine-, pyrindine- and isoquinoline-substituted α- and β-C-nucleosides of 2-deoxy-D-ribose

The novel imido esters of 2-deoxy-alpha- and -beta-D-ribose 8 and 9 have been synthesized and successfully transformed to the protected 1,2,4-triazine-C-nucleosides 11 and 12 using an inverse type Diels-Alder reaction with the 1,2,4,5-tetrazine 10. The electron deficient diazadiene system of both C-nucleosides 11 and 12 proved to be highly reactive in a consecutive [4+2] cycloaddition with inverse electron demand towards several electron rich dienophiles yielding after successful deprotection the novel pyridine-, pyrindine- and isoquinoline-C-nucleosides 15, 18 and 21 of 2-deoxy-alpha-D-ribose and 23, 25 and 27 of 2-deoxy-beta-D-ribose.