Parallel Solution-Phase Synthesis of Targeted Tyrphostin Libraries with Anticancer Activity

Abstract

The combination of semi-automation, an elegant synthesis, and parallel solution-phase synthesis approaches has allowed the development of five targeted, symmetrical tyrphostin compound libraries. These libraries on average are comprised of 12 compounds. Notwithstanding this, low micromolar potent growth inhibitors against HT29 (colorectal carcinoma) and G401 (renal carcinoma) cell lines were discovered. Additionally, significant SAR data was obtained. We noted that the most potent growth inhibitory activity was consistently observed for those analogues that possessed a 2-chlorophenyl (for 10: GI_{50 HT29} 5.5 ± 0.4 μM, GI_{50 G401} 2.6 ± 0.4 μM; for 23: GI_{50 HT29} 2.4 ± 0.2 μM, GI_{50 G401} 1.9 ± 1 μM; for 34: GI_{50 HT29} 8.8 ± 3.1 μM, GI_{50 G401} 6.2 ± 2.9 μM; for 46: GI_{50 HT29} 5.2 ± 0.9 μM, GI_{50 G401} 3.7 ± 0.6 μM; for 57: GI_{50 HT29} 4.6 ± 0.8 μM, GI_{50 G401} 2.1 ± 0.2 μM), a 3-chlorophenyl (for 11: GI_{50 HT29} 3.8 ± 0.7 μM, GI_{50 G401} 1.7 ± 0.7 μM; for 48: GI_{50 HT29} 5.9 ± 0.1 μM, GI_{50 G401} 3.4 ± 0.6 μM; for 58: GI_{50 HT29} 4.8 ± 0.9 μM, GI_{50 G401} 3.4 ± 0.2 μM), or a 3-methoxyphenyl substituent (for 13: GI_{50 HT29} 7.4 ± 3.8 μM, GI_{50 G401} 2.8 ± 0.5 μM; for 26: GI_{50 HT29} 4.5 ± 0.5 μM, GI_{50 G401} 4.9 ± 1 μM; for 37: GI_{50 HT29} 3.7 ± 0.2 μM, GI_{50 G401} 1.6 ± 0.2 μM; for 49: GI_{50 HT29} 3.7 ± 0.4 μM, GI_{50 G401} 3.4 ± 0.2 μM; for 60: GI_{50 HT29} 4.1 ± 0.6 μM, GI_{50 G401} 1.8 ± 0.3 μM). Finally, we noted that increasing the distance between the terminal aromatic rings had only a minimal effect on the 2-, 3-chlorophenyl, and 3-methoxyphenyl analogues, but did have a favourable effect on OH, COOH, and multiply substituted analogues.