Stereoselective synthesis and antiproliferative activity of allo-gibberic acid-based 1,3-aminoalcohol regioisomers.

A new library of allo-gibberic acid-based aminoalcohol regioisomers was synthesised stereoselectively starting from commercially available gibberellic acid, which yields allo-gibberic acid under mild acidic conditions. The successful formation of hydroxymethyl ketone derivative 5, by acid-mediated rearrangement of previously prepared epoxide, paved the way to obtain the desired 1,3-aminoalcohols through Schiff base formation. To obtain the desired regioisomers, the primary alcohol functionality of 5 was subjected to mesylation, then replaced with either primary amine or sodium azide. The formed azide derivative was subjected to either CuAAC reaction to obtain 1,2,3-triazoles or underwent Pd-catalysed hydrogenolysis to obtain primary aminoalcohol, which was further transformed into 1,3-aminoalcohols by reductive alkylation. All prepared aminoalcohols were identified in a satisfactory manner using modern spectroscopic techniques and assessed for their antiproliferative activity against a panel of human cancer cell lines. The antiproliferative effects of the prepared compounds were assayed by in vitro MTT method against a panel of human cancer cell lines (HeLa, SiHa, A2780, MCF-7 and MDA-MB-231). A significant difference was observed in the antiproliferative activity between the regioisomers. Some compounds exerted outstanding activities against the malignant cells with limited action on fibroblasts, indicating considerable cancer selectivity.

Stereoselective Synthesis and Application of Gibberellic Acid-Derived Aminodiols.

A series of gibberellic acid-based aminodiols was designed and synthesized from commercially available gibberellic acid. Exposure of gibberellic acid to hydrochloric acid under reflux conditions resulted in aromatization followed by rearrangement to form allo-gibberic acid. The key intermediate, ethyl allo-gibberate, was prepared according to literature methods. Epoxidation of key intermediate and subsequent ring-opening of the corresponding epoxide with different nucleophiles resulted in N-substituted aminodiols. The regioselective ring closure of N-benzyl-substituted aminodiol with formaldehyde was also investigated. All aminodiol derivatives were well characterized using modern spectroscopic techniques and evaluated for their antiproliferative activity against a panel of human cancer cell lines. In addition, structure-activity relationships were examined by assessing substituent effects on the aminodiol systems. The results indicated that aminodiols containing aromatic rings on their nitrogen substituents displayed significant cytotoxic effects. Among these agents, N-naphthylmethyl-substituted aminodiols were found to be the most potent candidates in this series. One of these molecules exhibited a modest cancer selectivity determined by non-cancerous fibroblast cells. A docking study was also made to exploit the observed results.

New 1,3,4-thiadiazoles derivatives: synthesis, antiproliferative activity, molecular docking and molecular dynamics.

Aim: A series of 1,3,4-thiadiazole himachalene hybrids were prepared from the treatment of a himachalen-4-one thiosemicarbazone derivative with N-aryl-C-ethoxycarbonyl-nitrilimines and diarylnitrilimines via a 1,3-dipolar cycloaddition reaction. Materials & methods: The structures were confirmed by NMR, IR and high-resolution mass spectroscopy (HRMS). Results & conclusion: The newly synthesized hybrid compounds were tested for their in vitro antitumor activities against a panel of cancer cell lines including fibrosarcoma (HT-1080), lung carcinoma (A-549) and breast carcinoma (MCF-7 and MDA-MB-231). Among the tested products, 4a showed excellent activity against the HT-1080 and MCF-7 cell lines with IC50 values of 11.18 ± 0.69 and 12.38 ± 0.63 µm, comparable to that of the reference drug. Docking results confirmed that the active inhibitors were well accumulated in the mushroom tyrosinase active site. Flow cytometry analysis indicated that hybrid 4a induced apoptosis and cell cycle arrest in the G0/G1 phase. Molecular modeling studies affirmed the intercalative binding of compound 4a in the active site.

Design, synthesis, evaluation of new 3-acetylisoxazolines and their hybrid analogous as anticancer agents: In vitro and in silico analysis.

3-Acetylisoxazolines were synthesized by the reaction of natural (R)-limonene and (R)-carvone with acetone in the presence of iron (III) nitrate. The reaction showed to be highly peri- and regioselective. Next, using a 1,3-dipolar cycloaddition reaction, the mono-3-acylisoxazolines derived from these monoterpenes were evaluated for their reactivity with nitrilimines. Only the enone of carvone-isoxazoline was regioselectively reactive, providing a new fused isoxazoline-carvone-pyrazolines. The structure of all the newly synthesized mono-cycloadducts (3 & 5) and bis-cycloadducts (4 & 7a-c) were fully identified based on their HRMS and NMR spectral data. They have also been screened for their cytotoxic activity against four human cancer cell lines: fibrosarcoma (HT-1080), lung carcinoma (A-549), and breast (MCF-7 and MDA-MB-231) cell lines. The obtained results showed that compound 4 was a potent cytotoxic agent against all selected cells. The possible mechanism of apoptosis induction by compound 4 was investigated using Annexin-V binding assay, caspase-3/7 activity and analysis cell cycle progression. The compound 4 induced the early apoptosis of both MCF-7 and MDA-MB-231 through caspase-3/7 activation, and the compound 4 have elicited S and G2/M phase arrest in MCF-7and MDA-MB-231 cancer cells, respectively. For further target investigations, a molecular docking study was employed and it showed that compound 4 has an inhibitory activity against Pim-1 protein kinase. Molecular dynamics study showed that compound 4/Pim-1 complex was stable during the simulation run at different time intervals. In-Silico ADMET predicted that compound 4 has good pharmacokinetic properties with high estimated oral bioavailability.