Farnesylation of Ras and other proteins is required for their membrane attachment and normal function. Here we report on the synthesis of α-cyanocinnamide derivatives, a new family of farnesyltransferase inhibitors. These compounds are nonpeptidic and do not contain sulfhydryl groups. The most potent compound is a pure competitive inhibitor with respect to the Ras protein and mixed competitive with respect to farnesyl diphosphate. ...