Non-thiol farnesyltransferase inhibitors: evaluation of different AA(X)-peptidomimetic substructures in combination with arylic cysteine replacements.

In the course of our studies on non-thiol farnesyltransferase inhibitors based on the 2, 5-diaminobenzophenone AAX-peptidomimetic substructure, we have developed the (4-nitrophenyl)butyryl (R(1)), the (2-naphthyl)acryloyl (R(2)), the 4-nitrocinnamoyl (R(3)), and the 5-(4-nitrophenyl)furylacryloyl (R(4)) groups as useful cysteine replacements. In this study, we combined these four groups with other AA(X)-peptidomimetic substructures (5-10: R = H) reported in the literature. The 5-(4-nitrophenyl)furylacryloyl moiety (R(4)) turned out to be the most useful non-thiol cysteine replacement yielding in all cases the most active inhibitors. By combination of this 5-(4-nitrophenyl) furylacryloyl moiety (R(4)) with the structurally simple AAX-peptidomimetics 4-aminobenzophenone (5) and 4-aminodiphenylsulfone (6) potent, readily accessible non-thiol farnesyltransferase inhibitors were obtained (IC(50) = 12 nMand 10 nM).