Conversion of D-Arabinose into 2-Deoxy D-Ribose and 3-Deoxy D-Xylose

2-DEOXY D-ribose is of considerable importance since it is the carbohydrate constituent of the de-oxyribonucleic acid of cell nucleal material, and we have been interested in its preparation for structural and synthetic studies. Although we have made some improvements in the standard method of its synthesis from D-arabinal, we are exploring alternative routes. A possible method resulted from the work of Newth, Overend and Wiggins1 on the ring scission of 2 : 3-anhydro 4 : 6-benzylidene α-methyl alloside (I) with halogen acids, because hydrobromic acid in aqueous acetone solution effected scission of the anhydro ring in this substance to give 2-bromo α-methyl altroside (one part) and 3-bromo α-methyl glucoside (4 parts). On this finding it was clear that a similar ring scission of 2 : 3-anhydro β-methyl D-riboside (II) would give rise to 2-bromo β-methyl D-arabinoside (III) and 3-bromo β-methyl D-xyloside (IV), although it is our experience2 that, as yet, it would be inexpedient to predict the relative proportions of the isomers that could be produced in this reaction. The halogen sugars (III) and (IV) on reductive dehalogenation would afford 2-deoxy β-methyl D-riboside (arabinoside) and 3-deoxy β-methyl D-riboside (xyloside). Thus if 2-bromo β-methyl D-arabinoside (III) was the main product of the ring-opening of 2 : 3-anhydro β-methyl D-riboside, this procedure would furnish a new method of preparation of 2-deoxy β-methyl D-riboside and of 2-deoxy D-ribose itself. We have found, however, that (III) was only the minor constituent of the ring-scission products, 3-bromo β-methyl D-xyloside being the main product. We have, however, obtained 2-deoxy β-methyl D-riboside and 2-deoxy D-ribose by this procedure, although the method clearly has no preparative value.