Synthesis and Antitumor Activity of Sorafenib Analogs Containing a Tetrazole Moiety

Design, synthesis, in vitro and in silico evaluation of indole-based tetrazole derivatives as putative anti-breast cancer agents

A series of new indole-tetrazole derivatives were designed and synthesized to develop potential anti-breast cancer agents. The compounds exhibited in vitro anti-proliferative activity against ER-α positive T-47D (IC50 = 3.82-24.43 μM), MCF-7 (IC50 = 3.08-22.65 μM), and ER-α negative MDA-MB-231 (IC50 = 7.69-19.4 μM) human breast cancer cell lines. Compounds 5d and 5f displayed significant anti-proliferative activity compared to bazedoxifene (IC50 = 14.23 ± 0.68 μM), with IC50 values of 10.00 ± 0.59 and 3.83 ± 0.74 μM, respectively, against the ER-α dominant T-47D cell line. Also, both compounds showed non-significant cytotoxicity against normal cells HEK-293. Further, the ER-α binding affinity of 5d and 5f was assessed through a fluorescence polarization-based competitive binding assay, where 5d and 5f have shown significant binding with IC50 = 5.826 and 110.6 nM, respectively, as compared to the standard drug bazedoxifene (IC50 = 339.2 nM). Western blot analysis confirmed that compound 5d reduced ER-α protein expression in T-47D cells, hindering its transactivation and signalling pathways. Additionally, a molecular docking study suggests that compounds 5d and 5f bind in such a fashion that induces conformational changes in the protein, culminating in their antagonistic effect. Pharmacokinetic profiles showed that the compounds possessed drug-like properties. Furthermore, molecular dynamics simulation studies establish the dynamic stability and conformational behaviour of the ER-α protein and ligand complex of both compounds. Additionally, 5d and 5f ensure biological feasibility as per their DFT analysis through HOMO-LUMO energy gap analysis. In conclusion, compounds 5d and 5f, exhibiting significant ER-α antagonistic activity, can act as potential lead compounds for anti-breast cancer therapies.

Synthesis of sorafenib analogues incorporating a 1,2,3-triazole ring and cytotoxicity towards hepatocellular carcinoma cell lines

A series of 1,2,3-triazole-containing Sorafenib analogues, in which the aryl urea moiety of Sorafenib (1) was replaced with a 1,2,3-triazole ring linking a substituted phenoxy fragment, were prepared successfully via Huisgen 1,3-dipolar cycloaddition and nucleophilic aromatic substitution. The studies of cytotoxicity towards human hepatocellular carcinoma (HCC) cell lines, HepG2 and Huh7, indicated that p-tert-butylphenoxy analogue 2m showed significant inhibitory activity against Huh7 with IC₅₀ = 5.67 ± 0.57 µM. More importantly, 2m showed low cytotoxicity against human embryonal lung fibroblast cell line, MRC-5, with IC₅₀ > 100 µM, suggesting its highly selective cytotoxic activity (SI > 17.6) towards Huh7 which is much superior to that of Sorafenib (SI = 6.73). The molecular docking studies revealed that the analogue 2m bound B-RAF near the binding position of Sorafenib, while it interacted VEGFR2 efficiently at the same binding position of Sorafenib. However, 2m exhibited moderate inhibitory activity toward B-RAF, implying that its anti-Huh7 effect might not strictly relate to inhibition of B-RAF. Wound healing and BrdU cell proliferation assays confirmed anti-cell migration and anti-cell proliferative activities towards Huh7. With its inhibitory efficiency and high safety profile, 2m has been identified as a promising candidate for the treatment of HCC.

Tetrazoles as anticancer agents: A review on synthetic strategies, mechanism of action and SAR studies

Cancer is a leading cause of death worldwide. Even after the availability of numerous drugs and treatments in the market, scientists and researchers are focusing on new therapies because of their resistance and toxicity issues. The newly synthesized drug candidates are able to demonstrate in vitro activity but are unable to reach clinical trials due to their rapid metabolism and low bioavailability. Therefore there is an imperative requisite to expand novel anticancer negotiators with tremendous activity as well as in vivo efficacy. Tetrazole is a promising pharmacophore which is metabolically more stable and acts as a bioisosteric analogue for many functional groups. Tetrazole fragment is often castoff with other pharmacophores in the expansion of novel anticancer drugs. This is the first systematic review that emphasizes on contemporary strategies used for the inclusion of tetrazole moiety, mechanistic targets along with comprehensive structural activity relationship studies to provide perspective into the rational design of high-efficiency tetrazole-based anticancer drug candidates.

Facile synthesis of 1,5-disubstituted tetrazoles by reacting a ruthenium acetylide complex with trimethylsilyl azide

Treatment of [Ru]-C[triple bond, length as m-dash]CPh (1, [Ru] = (η⁵-C₅H₅)(dppe)Ru, dppe = Ph₂PCH₂CH₂PPh₂) with trimethylsilyl azide afforded the cationic nitrile complex {[Ru]NCCH₂Ph}[N₃] (2) and the further cycloaddition of 2 with trimethylsilyl azide at 60 °C afforded the N(2)-bound tetrazolato complex [Ru]N₄CCH₂Ph (3). The regiospecific alkylation of 3 gave a series of cationic N(2)-bound N(4)-alkylated-5-benzyl tetrazolato complexes {[Ru]N₄(CH₂R)CCH₂Ph}[Br] (4a, R = C₆F₅; 4b, R = Ph; 4c, R = 4-CN-C₆H₄; 4d, R = 2,6-F₂-C₆H₃; 4e, R = 6-CH₂Br-C₅NH₃) and the subsequent cleavage of the Ru-N bond of 4a-4e gave N(1)-alkylated-5-benzyl tetrazoles N₄(CH₂R)CCH₂Ph (5a-5e) in good to excellent yields and [Ru]-Br, which, on reacting with phenylacetylene, resulted in the formation of 1 thus forming a reaction cycle. The structures of 2, 3, 4a, 4c and 5a were confirmed by single-crystal X-ray diffraction analysis.