Abstract
The nucleoside antibiotic sangivamycin (4-amino-7-(β-D-ribofuranosyl)pyrrolo[2,3-d]pyrimidine-5-carboxamide, (1) is an effective inhibitor of protein kinase A (PKA) and protein kinase C (PKC) but, upon its phosphorylation in intact cells, it gains the ability to affect other targets as well. To retain its selectivity for the protein kinases, a series of nonphosphorylatable sangivamycin derivatives was prepared by replacing the 5′-hydroxyl group with other functions including N3, F, SO2NH2, NO2, and NH2, These derivatives were more potent inhibitors of PKA and PKC than were the phosphorylatable compounds, although the latter were more potent inhibitors of leukemic cell growth.