الفهرس 
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Abstract
Bromination of pyranulose glycoside 3 with bromine and carbon tetrachloride at room temperature afforded pyranulose 4, which was treated with hydrochloric acid in acetonitrile and gave bromofurfural derivative 5. Formation of 5 proceeded through the formation of the ring-opened intermediate γ-diketone 4’, which subsequently underwent ring closure to the five-membered ldehyde 5. On the other hand, treatment of bromo compound 4 with trifluoroacetic acid in dioxane at room temperature afforded a mixture of 5-hydroxy-2-(2,3,5- tri-O-benzoyl-β-D-ribofuranosyl)pyran-4-one 6 and its furan derivative 5-hydroxy-2-{5- [(benzoyloxy)methyl]furan-2-yl}pyran-4-one 7. Acetylation of the mixture with acetic anhydride facilitated product separation to give the corresponding acetates 5-acetoxy-2- (2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)pyran-4-one 8 and 5-acetoxy-2-{5- [(benzoyloxy)methyl]furan-2-yl}pyran-4-one11 9.