Photochemistry of glycosyl azides-II: Investigation of the dual behavior: formation of a reversible intermediate and chain-degradation

The photochemistry of glycosyl azides has been studied. Some of the azides, for example, β-d-glucopyranosyl or α-d-mannopyranosyl azide, were found to afford in good yield, on irradiation with UV light, the corresponding next-lower aldose. In other cases, for example, β-maltosyl or β-d-ribofuranosyl azide, there was observed the formation of an intermediate which, on standing in the dark, reverts back to starting material. A rationalization of the two types of behavior is suggested.