Search

An open-air palladium-catalyzed O-glycosylation was developed using glycals and arylboronic acids with base additives at ambient conditions. The novel approach enabled facile access to various

A mild and highly efficient Ugi-3CR using a novel Cu-COOH@MOF-6 as the catalyst has been developed, which provides facile access to α-amino amides. The recycling test and XRD images showed that the catalytic system has good stability and recyclability.

A new methodology of stereoselective C-glycosylation has been developed with 3,4-O-carbonate glycals and boronic acids, catalyzed by 1,2-bis(phenylsulfinyl)ethane palladium(II) acetate under open-air conditions at room temperature. This mild method is simple in operation, wide in substrate range, and tolerant in alcoholic/phenolic hydroxyl and amino groups. High to excellent yields were observed for all substrates tested, with the driving force mainly contributed by decarboxylation. Meanwhile, the high 1,4-trans-selectivity was achieved by steric effects as proposed.

Direct N-glycosylation between glycals and amides/amines was achieved with exclusive stereoselectivity in moderate to high yields. Various amides, amines, and 3,4-O-carbonate-glycals were tolerated, and unique β-N-glycosides were obtained. The strategy was based on palladium-catalyzed decarboxylative allylation, and the high 1,4-cis-selectivity was proposed because of the hydrogen bonding effect. Notably, all the synthesized products were subjected to preliminary bioactivity studies, revealing that three compounds were cytotoxic to tumor cells and nontoxic to normal human cells.

The interaction mechanisms of a series of bisabolonalone hydrazone carboxamides as H+,K+-ATPase reversible inhibitors were studied by molecular docking, QM/MM calculation, and MM/GBSA binding free energy analysis methods. The correlation coefficient, R, between calculated ΔG bind (the binding free energy with H+,K+-ATPase homology model) and experimental pIC50 (negative logarithms of 50% inhibition concentration) of ligands is −0.9386. A suitable molecular volume of ligand is needed to dock into the whole binding pocket, which includes Gln127–Leu141 in the loop of TM1–TM2; Arg328–Ala335 in the loop of TM4; Tyr799–Thr815 in the loop of TM5–TM6; Trp899–Phe917 in the loop of TM7–TM8; Leu921–Tyr928 in the loop of TM8; and Asn986–Asn989 in the loop of TM9–TM10. By the decomposed energy comparisons of residues in binding sites, the naphthyl group substituting benzene ring in bisabolonalone hydrazone carboxamides could increase the hydrophobic interaction with Cys813, which is a very important binding site for enhancing the inhibition activity. In addition, Asp137 is another key residue binding with ligand through the hydrogen bond and electrostatic interactions. The results of this analysis could help in further rational design of novel H+,K+-ATPase reversible inhibitors.

An inexpensive and effective cobalt coordinated conjugated microporous polymer (Co-CMP-2) made up from cross-linked an ethanediamine-based salen ligand with 1,3,5-triethynylbenzene. Co-CMP-2 exhibited extremely high catalytic efficiency in the synthesis of cyclic carbonates from CO2 and epoxides, which is superior to that of previously reported Co-CMP. Co-CMP-2 achieved a TOF of 23300 h−1 for ethylene carbonate. Moreover, the catalyst can be reused more than 10 times without significant loss in activity.

Covalent triazine-based frameworks (CTFs) are important microporous materials with a wide range of applications. Here, we demonstrate an environmentally benign and economic synthetic pathway to CTFs. The monomers used for CTFs, aromatic nitriles, were obtained by cyanation using nontoxic potassium hexacyanoferrate (Ⅱ) in place of commonly used toxic cyanides. Then, the CTFs were synthesized by trimerization of the corresponding cyano monomers in molten zinc chloride. A series of CTFs was synthesized, and the highest Brunauer-Emmett-Teller surface area measured in this series was 2404 m 2 /g. Among the synthesized CTFs, CTF DCP exhibited excellent CO 2 adsorption properties, with a CO 2 uptake of 225 mg/g at 0℃.

A novel gold-catalyzed C-glycosylation has been developed to gain access to α,(Z)-selective C-vinyl glycosides, starting from readily available glycals and propargylic carboxylate. This reaction involves a tandem intermolecular gold-catalyzed 1,3-acyloxy migration/Ferrier rearrangement with the involvement of allenic ester as the glycosyl acceptor. A wide range of substrate scope with good to excellent yields was achieved with complete diastereoselectivity. Ministry of Education (MOE) National Research Foundation (NRF) Accepted version We thank the Ministry of Education (MOE 2013-T3-1-002), National Research Foundation (NRF2016NRF-NSFC002-005), Nanyang Technological University, Singapore (RG14/16), China Scholarship Council (No. 201508420062), and Youth Talent Development Foundation of China Three Gorges University for their financial support. Dr. Yongxin Li and Dr. Ganguly Rakesh in the division of chemistry and biological chemistry, Nanyang Technological University are also acknowl-edged for X-ray analysis.

Bisabolangelone is the main active ingredient of Angelica polymorpha, which has the good pharmacological activities such as anti-celialgia, anti-dysmenorrhea and anti-gastralgia. In this study, the neuroprotective effect of bisabolangelone against hydrogen peroxide (H2O2)-induced neurotoxicity in human neuroblastoma cells was studied. The binding capacity between bisabolangelone and calcium channel was calculated by molecular docking method, and calcium concentration was detected by the calcium fluorescent probe of Fura-2 AM. The results indicated that bisabolangelone had a good neuroprotective effect on nerve cells by interacting with calcium channels, mainly blocking the voltage-gated calcium channels, suppressing calcium releasing from the calcium store.

Seeking a strategy for triggering the cryptic natural product biosynthesis to yield novel compounds in the plant-associated fungus Xylaria sp., the effect of culture conditions on metabolite production was investigated. A shift in the production of five known cytochalasin-type analogues 1–5 to six new α-pyrone derivatives, xylapyrones A–F (compounds 6–11), from a solid to a liquid medium was observed. These compounds were identified by analysis of 1D and 2D NMR and HRMS data. Compounds 1–3 showed moderate cytotoxicity against HepG2 and Caski cancer cell lines with IC50 values ranging from 25 to 63 μM and compounds 4–11 were found to be inactive, with IC50 values &gt, 100 μM.

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 degrees 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.

We reported a bifunctional material, Cr-salen implanted conjugated microporous polymer (Cr-CMP), which is able to capture excellent CO2 amounts and has a remarkable catalytic activity towards the cycloaddition reaction of CO2 to epoxides forming cyclic carbonates at mild conditions without additional solvents. This heterogeneous Cr-CMP catalyst has a superior catalytic activity to its related homogeneous catalyst and can be reused more than ten times without a significant decrease in catalytic activity.

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=43.08 mu m 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 (er alpha). 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. (c) 2013 elsevier ltd. all rights reserved.

A highly solid-emissive Boron–Fluorine scaffold with two conjugated alkyne groups ( BOPIM-S ) is facilely synthesized, which shows enhanced fluorescent intensity compared to the BOPIM dye without alkyne units. According to X-ray single crystal analysis, the terminal alkyne groups interact with atoms B, F, C and N on neighbouring molecules, producing a rigid rectangular structure, which helps to avoid energy loss via non-irradiative decay. Furthermore, BOPIM-S can undergo copper catalysed alkyne–azide-cycloaddition (CuAAC) chemistry with aromatic azides to produce conjugated molecules with high yields. According to absorption and fluorescent measurements, all these compounds synthesized by CuAAC emit large Stokes shift (over 100 nm) both in solution and in solid state. But the electronic environments of terminal aromatic rings slightly affect their photophysical properties.

Pharmacophore and three-dimensional quantitative structure–activity relationship (3D-QSAR) model of 106 aryl diphenolic azoles as estrogen receptor-β ligands were proposed. The best pharmacophore model, five-site model including two hydrogen bond donors and three aromatic rings, has been established. The biological activity values (pIC50) and classification (active or inactive) of compounds were predicted by 3D-QSAR model. The model correlation coefficient (R 2) is 0.9623. The classification accuracies in predicting for training, test, and total datasets are 97.5, 84.6, and 94.3 %, respectively. The 3D-QSAR model maps revealed that hydrogen bond donor, hydrophobic, and electron-withdrawing fields would be the essential factors for designing new ligands with higher biological activity. The results indicate that the combination of pharmacophore and 3D-QSAR analyses could be a powerful modeling tool for finding novel estrogen receptor-β ligands.

Two new thiazole and thiadiazole alkaloids, penicilliumthiamine A and B (2 and 3), were isolated from the culture broth of Penicillium oxalicum, a fungus found in Acrida cinerea. Their structures were elucidated mainly by spectroscopic analysis, total synthesis and X-ray crystallographic analysis. Biological evaluations indicated that compound 1, 3a and 3 exhibit potent cytotoxicity against different cancer cell lines through inhibiting the phosphorylation of AKT/PKB (Ser 473), one of important cancer drugs target.

The homology model of human gastric H+/K+-ATPase has been produced based on the template provided by pig gastric H+/K+-ATPase (PDB code: 3IXZ). After molecular mechanics optimization, induced-fit docking simulation between gastric H+/K+-ATPase and bisabolangelone that has significantly inhibition activity of H+/K+-ATPase was performed. The results of ligand docking showed that the binding pocket involves the amino acid residues Asp101, Asp102, Tyr105, Leu106, Val296, Phe297, Met299, Ala300, Tyr764, Tyr767, Leu774, Gly777, Cys778, Ile779, Gln889, Tyr893, and Ile952. The hydrogen bonds are formed between bisabolangelone and the amino acid residues Cys778, Gln889, and Tyr893.

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 mu M. The high-efficient and straightforward process was attractive feature for facile preparation of anti-tumor steroidal triazoles. (C) 2015 Elsevier Ltd. All rights reserved.

Three new furostanol saponins (1-3), including a polyhydroxyl saponin, were isolated from the rhizomes of Tupistra chinensis. The structures of these compounds were identified by NMR, MS spectral data and chemical methods.

Two new spirostanols and a new furostanol, reinocarnoside A (1), B (2) and C (3), were isolated from the roots of Reineckia carnea, together with two known compounds, (25S)-1β,3β,4β-trihydroxyspirostan-5β-yl-O-β-D-glucopyranoside (4), kitigenin-5β-O-β-D-glucopyranoside (5). The structures of three new compounds were elucidated by spectroscopic methods including 1-D NMR, 2-D NMR and MS spectrums, and their anticancer activities were evaluated by MTT method.