The photochemistry of phosphorus compounds. Part X. Photolysis of disodium α-D-glucose 6-phosphate in aqueous solution under nitrogen or oxygen
The reactions of disodium α-D-glucose 6-phosphate in aqueous solution upon irradiation at 254 nm in the presence of either nitrogen or oxygen were investigated, using g.l.c.–mass spectrometry, paper chromatography, paper electrophoresis, colorimetric tests, and kinetic methods for identification of products. The main photolysis products were 6-phosphogluconate, arabinose 5-phosphate, phosphoglycerate, phosphoglycolate, carbon dioxide, and orthophosphate. Glucose was not formed. Under oxygenative conditions only, an acid-labile phosphate ester was also formed, possibly a triose phosphate. The photolysis of glucose 6-phosphate caused the appearance of an u.v. absorbing band at 275 nm, presumably due to production of an αβ-unsaturated carbonyl compound. This band was formed in high yield by irradiation under nitrogen, but was weak in oxygenated solutions. The photolysis of trisodium 6-phosphogluconate was shown to yield an arabinose phosphate, thus indicating that 6-phosphogluconate may be an intermediate in the photolytic conversion of glucose 6-phosphate into arabinose 5-phosphate.