Synthesis And Activity Evaluation Of Diaryl Amides

Hedgehog(Hh) signaling pathway is an indispensable biological pathway. It Mainly contains Hh Protein, Patched protein, Smoothened protein and Gli transcription factors. Abnormal expression of any part of this pathway can lead to tumor formation. So some measures targeting Hh pathway can be used to treat cancer. SMO receptor is considered to be the most promising drug target. The first SMO receptor inhibitor vismodegib (GDC-0449) has been approved at the end of 2012 by the FDA, which belongs to the diaryl amide compounds. It indicates that further study and structural optimization deserved to be done about diaryl amides to find the better effect of SMO receptor inhibitors.First,11 diaryl amides (B1-B11) were designed and synthesized based on the structure activity relationship studies of GDC-0449, and docked into the SMO protein using Discovery Studio software for in silico evaluation. The result shows that 11 compounds can interact with SMO protein through the amino acid residues and hydrophobic bond.Second,11 compounds (B1-B11) have been synthesized using 2-chloro-5-nitro benzoic acid, o-Phenylenediamine,2-Chloro-phenyl ethanone and so on. All the structures of compounds are verified by NMR and MS to be correct. During the synthetic process, the synthetic conditions for several important intermediates have been optimized, and better yields are obtained.Then, MTT method are used to evaluate the in vitro anti-tumor activity, and p-NPP method are used to evaluate inhibitory activity against Hh signaling pathway of 11 compounds. In the in vitro evaluation of antiproliferative actvity, the compounds show no or weak cytotoxicity against tumor cells. At the same time, the compounds B1, B2, B5, B6, A5 and A6 containing benzimidazole ring structure exhibied strong inhibitory activity against Hh signaling pathway. Compound B2 exhibits more active activity than GDC-0449.At last, we used the standard addition method combined with HPLC to investigate the solubility of target compounds. The results show that solubility of benzimidazole compounds are lower than other structures. However, the solubility can be increased significantly by the methylation of the N atoms in the imidazole ring.