Crystal Structure Of A Photolysis Product Of Vitamin B-6: A Pyridodihydrofuran-Condensed Skeleton Compound Of Pyridoxal 5'-Phosphate

An aqueous solution dissolving pyridoxal 5'-phosphate (PLP) was exposed to sun-light at room temperature to yield a photolysis product, 4b,9b-dihydro-4b,9b-dihydroxy-1,6-dimethyl-4,9-bis(phosphonooxymethyl) {pyrido[3',4':2,3]furo[4,5-b])pyrido[4,3-d]furan (1), whose structure was crystallographically determined. The product 1 was found to be a novel C(sp(3)) C(sp(3)) side-sharing pyridodihydrofuran-condensed skeleton compound with the two pyridodihydrofuran planes taking a 'V-shape'-like molecular configuration. Hydrogen bonding patterns of molecules of 1 in the crystal lattice are analyzed by the graph set approach. The most probable mechanism for the formation of 1 is described. (C) 2017 Published by Elsevier B.V.