N-carboxamide-substituted 7-deazaguanine-7carboxamides and their ribofiuanosyl compounds have been synthesized as echiguanine derivatives, and evaluated for inhibition of phosphatidylinositol (PI) 4-kinase. The ethylamide derivative and the corresponding ribofuranosyl compound inhibited PI Ckinase with IC5o values of 0.02 and 2.4 pg/ml, respectively. The latter was suggested to also inhibit the enzyme in cultured human epidennoid carcinoma cells. 0 1997 Elsevier Science Ltd.