C-Nucleosides. Part 13. Synthesis of 5-nitro-2-(β-D-ribofuranosyl)furan
Abstract
The synthesis of 5-nitro-2-(β-D-ribofuranosyl)furan (4) from the glycosylfuran (1) is described. Treatment of compound (1) with acetyl nitrate in acetonitrile afforded compound (2) in quantitative yield. When compound (2) was treated with pyridine, acetic acid was lost from the molecule to afford the protected nitrofuran (3) in 95% yield. Deprotection of compound (3) with methanolic sodium hydroxide afforded three products, nitrofuran (4) and the unexpected spiro compounds (5a, b) in 29, 4, and 9% yield, respectively. The configuration of the spiro-carbon in (5a) and (5b) was established by NOE experiments.