Photophysical and photochemical properties of C-linked ribosides of pyridin-2-one

Absorption and emission properties as well as photochemical behavior of C-r ibosides bearing pyridone as the aglycone, namely 5-(beta-D-ribofuranosyl)- pyridin-2-one (1) and 3-(beta-D-ribofuranosyl)-pyridin-2-one (2) and pyrido ne-uridine bichromophoric compound (6) have been investigated. Photocyclois omerization of the pyridone ring leading to diastereomeric Dewar type photo products is the major photochemical pathway both in C-nucleosides 1,2 and t he bichromophoric compound 6. In the case of the photocycloisomerization of 1 diastereomeric excess of 26% was determined by HPLC. (C) 2000 Elsevier S cience S.A. All rights reserved.