Affordable Access

Publisher Website

Fluorocarbohydrates:Part XVI. The synthesis of 3-deoxy-3-flouro- D-xylose and 3-deoxy-3-fluoro-β- D-arabinose

Carbohydrate Research
Publication Date
DOI: 10.1016/s0008-6215(00)82209-0


Abstract The action of potassium hydrogen fluoride (KHF 2) in ethane-1,2-diol on methyl 2,3-anhydro-4- O-benzyl-β- D-ribopyranoside ( 1) and methyl 2,3-anhydro-5- O-benzyl-α- D-lyxofuranoside ( 7) has been examined. In both cases the expected trans scission of the epoxide ring occurs to yield methyl 4- O-benzyl-3-deoxy-3-fluoro-β- D-xylopyranoside ( 2) and methyl 5- O-benzyl-3-deoxy-3-fluoro-α- D-arabinofuranoside ( 8) respectively. The structure of compound ( 2) was established by catalytic hydrogenation, which removed the benzyl group, to yield a crystalline glycoside ( 3) which did not consume periodate. Acid hydrolysis of methyl 3-deoxy-3-fluoro-β- D-xylopyranoside ( 3) yielded syrupy 3-deoxy-3-fluoro-αβ- D-xylose ( 5) as a syrup characterized as the 2,5-dichlorophenylhydrazone. Acid hydrolysis of compound ( 8) yielded a reducing sugar ( 9), characterised as the phenylhydrazone. Compound ( 9) consumed 1 mol. of periodate and liberated formic acid which is consistent with the structure 5- O-benzyl-3-deoxy-3-fluoro-αβ- D-arabinose. Catalytic hydrogenation of the fluorohydrin ( 8) removed the benzyl group to give methyl 3-deoxy-3-fluoro-α- D-arabinofuranoside ( 10) which, on acid hydrolysis, yielded crystalline 3-deoxy-3-fluoro-β- D-arabinose ( 13). The β-configuration was assigned to compound ( 13) on the basis of its mutarotation. This method of introducing fluorine into carbohydrates affords reasonable yields of uncontaminated fluorohydrins and is considered to have general applicability.

There are no comments yet on this publication. Be the first to share your thoughts.