Odorless Isocyanide Chemistry: One-Pot Synthesis of Heterocycles via the Passerini and Postmodification Tandem Reaction Based on the in Situ Capture of Isocyanides.

This paper reports the tandem reaction strategy of the Passerini/Staudinger/aza-Wittig reaction based on the in situ capture of isocyanides. According to this strategy, isocyanides are synthesized in situ and immediately work as the substrate for the Passerini reaction and postmodification tandem reaction in one pot. In addition, two types of new compounds, 5-oxo-3,5-dihydrobenzo[ e][1,4]oxazepines and 6-oxo-5,6-dihydro-2 H-1,4-oxazines, were synthesized using the tandem reaction strategy that includes five-step transformations in one pot.

Design, synthesis and biological evaluation of bisabolangelone oxime derivatives as potassium-competitive acid blockers (P-CABs).

With the aim of searching novel P-CABs, seven bisabolangelone oxime derivatives were designed, synthesized, characterized and evaluated the H(+),K(+)-ATPase inhibitory activities guided by computer aided drug design methods. The binding free energy calculations were in good agreement with the experiment results with the correlation coefficient R of -0.9104 between ΔGbind and pIC50 of ligands. Compound 5 exhibited the best inhibitory activity (pIC50=6.36) and most favorable binding free energy (ΔGbind=-47.67 kcal/mol) than other derivatives. The binding sites of these compounds were found to be the hydrophobic substituted groups with the Cys813 residue by the decomposed binding free energy analysis.

Computational insights into the interaction mechanism of triazolyl substituted tetrahydrobenzofuran derivatives with H(+),K(+)-ATPase at different pH.

The interaction mechanism of triazolyl substituted tetrahydrobenzofuran derivatives (compound 1 (N, N-Dipropyl-1-(2-phenyl-4,5,6,7-tetrahydrobenzofuran-4-yl)-1H-1,2,3-triazole-4-methanamine) and 2 (1-(2-Phenyl-4,5,6,7-tetrahydrobenzofuran-4-yl)-4-(morpholin-4-ylmethyl)-1H-1,2,3-triazole)) with H(+),K(+)-ATPase at different pH were studied by induced-fit docking, QM/MM optimization and MM/GBSA binding free energy calculations of two forms (neutral and protonated form) of compounds. The inhibition activity of compound 1 is measured and almost unchanged at different pH, while the activity of compound 2 increases significantly with pH value decreased. This phenomenon could be explained by their protonated form percentages and the calculated binding free energies of protonated and neutral mixture of compounds at different pH. The binding free energy of protonated form is higher than that of neutral form of compound, and the protonated form could be a powerful inhibitor of H(+),K(+)-ATPase. By the decomposed energy comparisons of residues in binding sites, Asp137 should be the key binding site to protonated form of compound because of the hydrogen bond and electrostatic interactions. These calculation results could help for further rational design of novel H(+),K(+)-ATPase inhibitors.

Synthesis and cytotoxic activities of 2-substituted (25R)-spirostan-1,4,6-triene-3-ones via ring-opening/elimination and 'click' strategy.

To develop more effective antitumor steroidal drugs, we synthesized a library including twenty-two novel cytotoxic 2-alkyloxyl substituted (25R)-spirostan-1,4,6-triene-3-ones and corresponding 1,2,3-triazoles through an abnormal monoepoxide ring-opening/elimination and 'click' reactions. After the cytotoxic evaluations against HepG2, Caski and HeLa cell lines, three steroidal triazoles 5b, 5f and 5m in this library were found to possess potent anti-proliferative effects against Caski cells with the half-inhibitory concentrations (IC50) of 9.4-11.8 µM. The high-efficient and straightforward process was attractive feature for facile preparation of anti-tumor steroidal triazoles.

Efficient fixation of CO2 by a zinc-coordinated conjugated microporous polymer.

Zinc-coordinated conjugated microporous polymers (Zn-CMPs), prepared by linking salen zinc and 1,3,5-triethynylbenzene, exhibit extraordinary activities (turnover frequencies of up to 11600 h(-1) ), broad substrate scope, and group tolerance for the synthesis of functional organic carbonates by coupling epoxides with CO2 at 120 °C and 3.0 MPa without the use of additional solvents. The catalytic activity of Zn-CMP is comparable to those of homogeneous catalysts and superior to those of other heterogeneous catalysts. This catalyst could be reused more than ten times without a significant decrease in performance.

3-Acyl-5-hydroxybenzofuran derivatives as potential anti-estrogen breast cancer agents: a combined experimental and theoretical investigation.

We first report the application of 3-acyl-5-hydroxybenzofurans as a scaffold to develop potential drugs for breast cancer. Seven novel derivative compounds were synthesized by using a microwave-assisted synthesis method. Those compounds exhibited different antiproliferation against human breast cancer MCF-7 cells, with the best activity of IC50=43.08µM for compound 1. A Quantum Mechanics Polarized Ligand Docking (QPLD) study was carried out to investigate the binding interactions between these compounds and estrogen receptor alpha (ERα). The simulation results showed that the trend of receptor-ligand binding interactions was same as that of their antiproliferative activities. A detailed analysis indicated that compound 1 possesses the highest Van der Waals and hydrogen bond interactions compared to the other six compounds and better inhibitors are achievable by enhancing the hydrogen bond interactions. Based on these results, we addressed that 3-acyl-5-hydroxybenzofuran is an attractive scaffold for designing drugs against breast cancer.

Tupisteroide A-C, three new polyhydroxylated steroidal constituents from the roots of Tupistra chinensis.

Three new steroidal compounds with polyhydroxy groups, tupisteroide A-C (1-3), were obtained from the roots of Tupistra chinensis, together with one known compound (4) that was isolated from this plant for the first time. The structures of tupisteroide A-C were determined on the basis of one- and two-dimensional NMR spectroscopy, including (1) H-(1) H Correlation Spectroscopy, Heteronuclear Multiple Bond Correlation, and Heteronuclear Single Quantum Coherence experiments. The isolated compounds were evaluated for their cytotoxic activities against A549, HepG2, and CaSki cancer cell lines in vitro. Among them, compounds 1, 2, and 4 did not show significant inhibitory activity, but compound 3 showed cytotoxicity against A549 cancer cell lines with IC(50) values of 25.0 µM.

Five new furostanol saponins from the rhizomes of Tupistra chinensis.

Five new furostanol saponins (1-5), together with three known compounds (6-8) were obtained from the n-butanol soluble fraction of ethanol extract from Tupistra chinensis. Their structures were determined on the basis of chemical methods and spectral data. The isolated compounds were tested in vitro for their cytotoxic activities against the A549, HepG 2 and Caski cancer cell lines. Among them, compounds 6, 7, and 8 showed cytotoxicity against A549 cancer cell lines with IC(50) values of 6.6, 6.7 and 29.1 µM, respectively.

[Design, synthesis and activity of a new type of influenza virus N1 neuraminidase inhibitors].

In this study, the "150-cavity", next to the H5N1 influenza virus neuraminidase activity site, has been used as the target to design and synthesize a structural analogue of chlorogenic acid, N-caffeoyl-GABA, using the flexible docking simulation. The docking study showed that the N-caffeoyl-GABA could be inserted into the "150-cavity" and combined with the Arg156 side chain by hydrogen bond. The best binding free energy of H5N1 NA-N-caffeoyl-GABA complex was -7.70 kcal mol(-1), equivalent that of the NA-oseltamivir. At the same time, using the H5N1 pseudotyping virus-based NA inhibitors screening model, we determined the inhibitory effect of oseltamivir, chlorogenic acid and N-caffeoyl-GABA on the NA. Compared with chlorogenic acid, N-caffeoyl-GABA significantly enhanced the inhibitory effect on NA, but less than oseltamivir. This study showed that the "150-cavity" could possibly be used as a new neuraminidase inhibitors target, and provided a path for the development of new neuraminidase inhibitors.

Efficient regioselective synthesis of indole N-carboximidamides and N-carboximidoates by a sequential Aza-Wittig/Ag(I)-catalyzed cyclization.

An efficient Ag(I)-catalyzed regioselective cyclization of (2-alkynylphenyl)guanidine or (2-alkynylphenyl)isourea to indole N-carboximidamides or N-carboximidoates has been developed. The approach has the advantages of high regioselectivity, mild reaction conditions, easily accessible starting materials, and good yields.

Efficient synthesis and biological evaluation of 1,2,9-trisubstituted 1,9-dihydro-6H-purin-6-ones.

The carbodiimides 4, obtained from aza-Wittig reactions of iminophosphorane 3 with aromatic isocyanates, reacted with amines in the presence of a catalytic amount of RO(-)Na(+) to give the 1,2,9-trisubstituted 1,9-dihydro-6H-purin-6-ones 6 in good yields. Compound 6 exhibited cytotoxicity against various cancer cells. For example, compounds 6b showed the best inhibition activities against KB, HepG2 and OVCAR3 with IC(50) 9.5, 20.4 and 10.0 microM.