D-Altrose → Aldehydo-D-ribose

In another aspect of the second embodiment, D-arabinonic acid reactant 90 may be prepared by decarboxylation 80 of a D-glucose starting material 60 by one or more reactions. Referring to FIG. 2, the starting material can be converted to an arabinonic reactant 90 or a ribonic acid reactant 40 by one or more reaction steps. Preferably, a suitable C-6 sugar starting material is decarboxylated at the C-1 position. Optionally, a starting material comprising D-(+)-allose or D-(+)-altrose can undergo a decarboxylation reaction 35 to produce an intermediate comprising D-(−)-ribose (aldehyde) that can subsequently undergo an oxidation reaction 37 to produce the desired reactant 40 comprising D-ribonic acid. Similarly, a starting material comprising D-(+)-glucose or D-(+)-mannose can undergo a decarboxylation reaction 85 to produce an intermediate comprising D-(−)-arabinose (aldehyde) that can subsequently undergo an oxidation reaction 87 to produce the desired reactant 90 comprising D-arabinonic acid. U.S. Pat. No. 4,515,667 describes a process for the photochemical decarboxylation of an alpha-hydroxy carboxylic acid to the corresponding alcohol which process comprises irradiating a mixture of a solution of an alpha-hydroxy carboxylic acid and a metal titanate.