Heng-Shan Wang

Samarium(III)-catalyzed C(sp3)-H bond activation: synthesis of indolizines via C-C and C-N coupling between 2-alkylazaarenes and propargylic alcohols.

A new rare earth metal and samarium-catalyzed C(sp(3))-H bond activation is reported in which 2-alkylazaarenes and propargylic alcohols were converted to indolizines. This process operates under mild conditions and solvent-free conditions. A broad scope of coupling partners has been established, and a likely mechanism has also been suggested.

Synthesis and antitumor activities of novel thiourea α-aminophosphonates from dehydroabietic acid.

A series of novel thiourea α-aminophosphonate derivatives containing DHA structure was designed and synthesized as antitumor agents. Their inhibitory activities against the NCI-H460 (lung), A549 (lung adenocarcinoma), HepG2 (liver) and SKOV3 (ovarian) human cancer cell lines were estimated using MTT assay in vitro. The screening results revealed that many compounds exhibited moderate to high levels of antitumor activities against the tested cancer cell lines and that most demonstrated more potent inhibitory activities compared with the commercial anticancer drug 5-fluorouracil. The mechanism of compound 5f was preliminarily investigated by acridine orange/ethidium bromide staining, Hoechst 33258 staining, JC-1 mitochondrial membrane potential staining, TUNEL assay, DNA ladder assay and flow cytometry, which indicated that the compound can induce cell apoptosis in A549 cells.

Synthesis, Cytotoxic Activity, and DNA Binding Properties of Copper (II) Complexes with Hesperetin, Naringenin, and Apigenin

Complexes of copper (II) with hesperetin, naringenin, and apigenin of general composition [CuL2(H2O)2] ⋅ nH2O (1–3) have been synthesized and characterized by elemental analysis, UV-Vis, FT-IR, ESI-MS, and TG-DTG thermal analysis. The free ligands and the metal complexes have been tested in vitro against human cancer cell lines hepatocellular carcinoma (HepG-2), gastric carcinomas (SGC-7901), and cervical carcinoma (HeLa). Complexes 1 and 3 were found to exhibit growth inhibition of SGC-7901 and HepG2 cell lines with respect to the free ligands; the inhibitory rate of complex 1 is 43.2% and 43.8%, while complex 3 is 46% and 36%, respectively. The interactions of complex 1 and its ligand Hsp with calf thymus DNA were investigated by UV-Vis, fluorescence, and CD spectra. Both complex 1 and Hsp were found to bind DNA in intercalation modes, and the binding affinity of complex 1 was stronger than that of free ligand.

Synthesis and antitumor activities of novel α-aminophosphonates dehydroabietic acid derivatives

A series of novel α-aminophosphonate derivatives containing DHA structure were designed and synthesized as antitumor agents. In vitro antitumor activities of these compounds against the NCI-H460 (human lung cancer cell), A549 (human lung adenocarcinoma cell), HepG2 (human liver cancer cell) and SKOV3 (human ovarian cancer cell) human cancer cell lines were evaluated and compared with commercial anticancer drug 5-fluorouracil (5-FU), employing standard MTT assay. The pharmacological screening results revealed that many compounds exhibited moderate to high levels of antitumor activities against the tested cancer cell lines and that most demonstrated more potent inhibitory activities compared with the commercial anticancer drug 5-FU. The action mechanism of representative compound 7c was preliminarily investigated by acridine orange/ethidium bromide staining, Hoechst 33258 staining, JC-1 mitochondrial membrane potential staining and flow cytometry, which indicated that the compound can induce cell apoptosis in NCI-H460 cells. Cell cycle analysis showed that compound 7c mainly arrested NCI-H460 cells in G1 stage.

Design, synthesis, and biological evaluation of novel quinazolinyl-diaryl urea derivatives as potential anticancer agents.

Through a structure-based molecular hybridization approach, a series of novel quinazolinyl-diaryl urea derivatives were designed, synthesized, and screened for their in vitro antiproliferative activities against three cancer cell lines (HepG2, MGC-803, and A549). Six compounds (7 g, 7 m, 7 o, 8 e, 8 g, and 8 m) showed stronger activity against a certain cell line compared with the positive reference drugs sorafenib and gefitinib. Among the six compounds, 8 g exhibited the strongest activity. In particular, compound 8 g induced A549 apoptosis, arrested cell cycle at the G0/G1 phase, elevated intracellular reactive oxygen species level, and decreased mitochondrial membrane potential. This compound can also effectively regulate the expression of apoptosis- and cell cycle-related proteins, and influence the Raf/MEK/ERK pathway. Molecular docking and structure-activity relationship analyses revealed that it can bind well to the active site of the receptor c-Raf, which was consistent with the biological data. Therefore, compound 8 g may be a potent antitumor agent, representing a promising lead for further optimization.

Synthesis and antitumor activities of novel α-aminophosphonate derivatives containing an alizarin moiety.

A series of novel α-aminophosphonate derivatives containing an alizarin moiety (6-7) was designed and synthesized as antitumor agents. MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) assay results indicated that most compounds exhibited moderate to high inhibitory activity against KB, NCI-H460, HepG 2, A549, MGC-803, Hct-116, CNE and Hela tumor cell lines. The action mechanism of representative compounds 7h, 7j and 7n were investigated by fluorescence staining assays, flow cytometric analysis and real-time polymerase chain reaction (PCR) assays, which indicated that these compounds induced apoptosis and involved G1 phase arrest by increasing the production of intracellular Ca(2+) and reactive oxygen species (ROS) and affecting associated enzymes and genes. The results demonstrated that these compounds may induce apoptosis through a mitochondrion-dependent pathway.

Combretastatin A-4 Analogue: A Dual-Targeting and Tubulin Inhibitor Containing Antitumor Pt(IV) Moiety with a Unique Mode of Action.

Three new Pt(IV) complexes comprising a combretastatin A-4 analogue were designed and synthesized. The resulting antitumor Pt(IV) complexes could significantly improve the antiproliferative activity and overcome the drug resistance of cisplatin in vitro. Interestingly, these novel compounds not only can carry the DNA binding Pt(II) warhead into the cancer cells but also have a small molecule fragment that can inhibit tubulin polymerization. Among them, complex 13, which was attached to an inhibitor of tubulin at one axial position of Pt(IV) octahedral coordination sphere, could effectively enter cancer cells, arrest the cell cycle in HepG-2 cancer cells at G2/M phases, and induce activation of caspases triggering apoptotic signaling via the mitochondrial-dependent apoptosis pathways. Moreover, complex 13 has the ability to effectively inhibit the tumor growth in the HepG-2 xenograft model without causing significant loss of animal body weight in comparison with cisplatin.

Palladium-catalyzed synthesis of benzoxazoles by the cleavage reaction of carbon–carbon triple bonds with o-aminophenol

A novel and mild procedure for efficient synthesis of benzoxazoles by the cleavage reaction of carbon–carbon triple bonds with o-aminophenol in the presence of a catalytic amount of palladium chloride has been successfully developed, which provides rapid and efficient access to benzoxazoles.

Novel Coumarin-Containing Aminophosphonatesas Antitumor Agent: Synthesis, Cytotoxicity, DNA-Binding and Apoptosis Evaluation.

A series of novel coumarin-containing α-aminophosphonates were synthesized and evaluated for their antitumor activities against Human colorectal (HCT-116), human nasopharyngeal carcinoma (human KB) and human lung adenocarcinoma (MGC-803) cell lines in vitro. Compared with 7-hydroxy-4-methylcoumarin (4-MU), most of the derivatives showed an improved antitumor activity. Compound 8j (diethyl 1-(3-(4-methyl-2-oxo-2H-chromen-7-yloxy) propanamido)-1-phenylethyl-Phosphonate), with IC50 value of 8.68 μM against HCT-116 cell lines, was about 12 fold than that of unsubstituted parent compound. The mechanism investigation proved that 8c, 8d, 8f and 8j were achieved through the induction of cell apoptosis by G1 cell-cycle arrest. In addition, the further mechanisms of compound 8j-induced apoptosis in HCT-116 cells demonstrated that compound 8j induced the activations of caspase-9 and caspase-3 for causing cell apoptosis, and altered anti- and pro-apoptotic proteins. DNA-binding experiments suggested that some derivatives bind to DNA through intercalation. The results seem to imply the presence of an important synergistic effect between coumarin and aminophosphonate, which could contribute to the strong chelating properties of aminophosphonate moiety.

Antiviral Matrine-Type Alkaloids from the Rhizomes of Sophora tonkinensis.

Three new matrine-type alkaloids, (+)-5α-hydroxyoxysophocarpine (1), (-)-12β-hydroxyoxysophocarpine (2), and (+)-5α-hydroxylemannine (3), along with 14 known analogues, (-)-sophocarpine (4), (-)-5α-hydroxysophocarpine (5), (-)-9α-hydroxysophocarpine (6), (+)-12α-hydroxysophocarpine (7), (-)-12β-hydroxysophocarpine (8), (+)-oxysophocarpine (9), (+)-matrine (10), (+)-sophoranol (11), (+)-9α-hydroxymatrine (12), (-)-14β-hydroxymatrine (13), (+)-oxymatrine (14), (+)-5α-hydroxyoxymatrine (15), (-)-14β-hydroxyoxymatrine (16), and (+)-sophoramine (17), were isolated from the rhizomes of Sophora tonkinensis. Their structures were elucidated via spectrometric data analyses, and the absolute configurations were established by single-crystal X-ray diffraction and ECD data. Alkaloids 2, 6, 11, and 13 exhibited antiviral activity against the Coxsackie virus B3 (CVB3), with IC50 values of 26.62-252.18 μM, and alkaloids 7, 8, and 17 inhibited influenza virus A/Hanfang/359/95 (H3N2) replication with IC50 values of 63.07-242.46 μM.