194280-07-4Relevant academic research and scientific papers
Synthesis of novel pyridine-C-nucleosides of 2,3-dideoxyribose by "inverse" [4+2]-cycloaddition
Seitz, Gunther,Siegl, Johanna
, p. 851 - 858 (1997)
The anomeric imido esters 5 and 6, appropriate precursors for C-nucleoside synthesis, were prepared and utilized as heterodienophiles in a Diels-Alder reaction with inverse electron demand to yield the novel, protected 1.2.4-triazine C-nucleosides 8 and 9. They could be deprotected by treatment with 70% trifluoroacetic acid to furnish the free C-nucleosides 10 and 11. The triazine "aglycon" of 8 contains an electron deficient diazadiene system, highly activated to react with various electron rich dienophiles such as enamines, enol ethers and several cyclic ketene acetals in an "inverse" [4+2]-cycloaddition reaction. The Diels-Alder adducts spontaneously eliminate N2 and after follow-up reactions the O-TBDPS protected pyridine-C-nucleosides 13, 15, 17, 19, 21 and 23 are formed. Removal of the protecting group by treatment with CF3CO2H/H2O leads to the corresponding 2′,3′-dideoxy-β-D-ribofuranosyl-pyridines.
