Synthesis and SARs of indole-based alpha-amino acids as potent HIV-1 non-nucleoside reverse transcriptase inhibitors

A series of non-nucleoside reverse transcriptase inhibitors derived from indole-based a-amino acids were designed and synthesized. Their inhibitory activities were detected by a TZM-bl cell assay on HIV virus type HIV-1(IIIB). The comprehensive understanding of the SAR was obtained by utilizing the variation of the substituents of the indole-based alpha-amino acids. From the screened compounds, the novel inhibitors 19 and 29 were identified to be highly potent candidates with EC50 values of 0.060 mu M and 0.045 mu M respectively (CC50 values of 109.545 mu M and 49.295 mu M and SI values of 1825.8 and 1095.4). In most cases, the variation of substituents at different positions had a significant effect on the potency of activities. The results also indicate that the indole-based alpha-amino acids as efficient NNRTIs displayed comparable anti-HIV-1 activities to the reference drug NVP. We hope the identification of these indole-based amino acids as efficient NNRTIs of RT could stimulate researchers to develop more diversified anti-HIV drugs.