Photochemistq of the nucleoside transport inhibitor 6-[(4-nitrobenzyl) thio]-BGB- Dribofuranosyl) p~ e (NBMPR, 1) yielded products from the initial homolytic cleavage of the benzyl-sulfur bond. Photoreduction of the nitro group also occurred to a minor extent. The quantum yield for the disappearance of 1 wa8-0.04. Several photoproducts and secondary photoproducts were identified and confirmed by synthesis. Irradiation of 6-(benzylthio)-g-( ...