In order to probe the effect of C-2(S)-substituted groups in the antibacterial activity, a series of novel C-2(S) substituted pleuromutilin analogs of SB-225586 were synthesized and evaluated for their in vitro antibacterial activity. The results of antibacterial acticities indicated that C-2(S)-substituted pleuromutilin derivatives retained appreciable antibacterial activity, and the 2-fluorination compounds 6a and 6b are more potent than the corresponding 2-hydroxylation analogues7a and 7b.
2,5-Disubstituted tetrahydrofurans were obtained from lactones and organozinc halides in moderate to high yield in the presence of Lewis acids.
A novel thermoregulated phosphine ligand Ph2P(CH2CH2O)nCH3 ( n = 22 ) was synthesized and used for the Rh-catalyzed hydroformylation of mixed C11~12 olefins in aqueous/organic biphasic system. Under the optimized conditions, pressure = 5 MPa (H2:CO = 1:1 ), phosphine / Rh = 13 ( molar ratio ), reaction time = 6 h and temperature =130 oC, the conversion of C11~12 olefins and the yield of aldehyde are 99 % and 94%, respectively. The catalyst retained in aqueous phase can be easily separated from the product-containing organic phase by simple phase separation and the catalytic activity remains almost constant after four consecutive cycles.
The first successful lithium bromide mediated solvent free condensation of arylenediamine and esters to obtain 2-substituted benzimidazole and imidazopyridine in good to excellent yields is described.
In this article, an efficient, simple and environmentally friendly approach to the synthesis of diacetals (diketals) pentaerythritol using SO3H-functionalized ionic liquids (ILs) as catalysts was reported. The ILs show high catalytic activity and reusability with good to excellent yields of the desired products. Hammett method has been used to determine the acidity order of these ionic liquids and the results are consistent with the catalytic activities observed in acetalization reaction. Maximum product yield 93% were observed on using [PSPy]OTf as catalyst and it can be reused at least 8 times without obvious activity loss.
Direct measurement of dipole potential in biological membranes has been impossible and 3-hydroxyflavones (3HFs) have allowed detection of changes in dipole potential in biological systems. In the present study, sixteen derivatives of 3HF with aliphatic hydrocarbon chains of different lengths at 4′-position and 6-position were synthesized. The basic fluorescence properties of 3HFs are maintained in all the probes in terms of strong blue shift in maximum fluorescence emission wavelength and >100 fold increase in quantum yield in organic solvents and in dioleoylphosphatidylcholine (DOPC) small unilamellar vesicles (SUV) in comparison to in aqueous Hepes buffer (15 mmol/L, pH 7.4). More importantly, the ability of the new compounds to report dipole potential changes in biological systems are also maintained, since all the new probes showed spectrum properties that are similar to yet different from that of F4N1, which potentially may allow more sensitive measurement of the dipole potential change in membranes.
This paper gives a brief report of the preparation of hexadecane microcapsule with polyurea-melamine formaldehyde resin shell materials (HMPM). The sealing performance and thermal stability of HMPM was enhanced much more effectively than that of microcapsule with polyurea shell material (HPM). The results of microscopical imaging analysis system, DSC, TG, and laser particle analyzer were briefly introduced.
The first three component and regioselective synthesis of pyridazinones and phthalazinones from arenes, anhydrides and ArNHNH2 in the presence of efficient recyclable heterogeneous catalyst, montmorillonite-KSF, in high yield and short reaction time is reported.
In this study, 6-chloro-4-hydroxy-2-quinolone and 6-flouro-4-hydroxy-2-quinolone were synthesized from corresponding dianilides. These compounds were coupled with some diazotized aromatic amines to give the corresponding azo disperse dyes. The structures of the quinolone derivatives and new azo dyes were confirmed by UV-vis, FT-IR, 1H NMR and elemental analysis.
Boric acid efficiently catalysed the one-pot reaction of alkyl or aryl aldehydes with 2-naphthol to afford the corresponding 14-alkyl- or aryl-14H-dibenzo[a,j]xanthenes in good yields under solvent-free conditions.
A simple and efficient procedure for the synthesis of 2-arylquinazolin-4(3H)-ones has been developed through cyclocondensation of 2-aminobenzamide with aromatic aldehydes using tetrabutylammonium bromide (TBAB) as novel neutral ionic liquid catalyst in the presence of copper (II) chloride (CuCl2) as oxidizing agent under solvent-free conditions at 100 oC. In the absence of CuCl2 and under a nitrogen atmosphere, the unoxidized intermediates, 2-aryl-2,3-dihydroquinazolin-4(1H)-ones, were isolated. Treatment of these intermediates with CuCl2 in TBAB media gave the oxidized products 2-arylquinazolin-4(3H)-ones. On the other hand, cyclocondensation of 2-aminobenzamide with aromatic aldehydes in TBAB under microwave irradiation directly gave 2-arylquinazolin-4(3H)-ones.
A series of new 6,7-disubstituted-4-(benzothiazol-6-ylamino)quinoline-3-carbonitrile derivatives (12a-l) were synthesized. The cytotoxicity of 12 new compounds was evaluated in AGS, HepG2 and HT-29 cell lines. The results showed that compounds 12g, 12h, 12i, 12k and 12l displayed more potent cytotoxic activities than Bosutinib, compound 12l exhibited the most potent antitumor activity among the tested compounds.
A high-purity benzoxazine (Boz-BOA) containing benzoxazole structure was successfully synthesized by three-step synthetic method using 2-(4-aminophenyl)-1H-benzoxazole-5-amine (BOA) and ortho-hydroxybenzaldehyde. The structure of Boz-BOA was confirmed by FTIR and 1H NMR spectra. The DSC was utilized to probe the curing behavior of Boz-BOA and exhibited a narrow melting peak and curing exothermic peak.
Herein we report an efficient organocatalyst for the multicomponent Hantzsch reaction at mild condition. The product easily isolated by simple filtration and catalyst can be recovered.
Hydroxymethylation of 6,8-O-dimethyl emodin was easily achieved in good yields by the modified Marschalk reaction. The influence of the amount of solvent, base and formaldehyde toward the hydroxymethylation was discussed. The results showed that a relatively dilute reaction solution facilitated the generation of the desired 2-hydromethyl product, while the thick reaction solution benefited the generation of the methylated quinizarins.
Two new cage compounds, 4-trinitroethyl-10-nitro-2,6,8,12-tetraacetylhexaazaisowurtzitane (3) and 4-trinitroethyl-2,6,8,10,12-pentanitrohexaazaisowurtzitane (4), containing trinitromethyl group were synthesized by a novel method, and their structures were confirmed by IR, 1H NMR, MS and single crystal X-ray. DSC result shows that compound 4 has surprising thermal stability and could be a potential energetic compound.
In this paper, a series of optically active MeO-BIPHEP-type ligands, (S)-6,6´-dimethoxy-2,2´-bis(di-p- alkoxyphenylphosphine)-1,1´-biphenyl were synthesized and used to prepare the ruthenium complex. The effects of para-substituted were observed, the results showed that the ruthenium catalysts [diphosphine RuCl2 diamine] containing both t-Bu- and i-Pr substitutions have better activities and enantioselectivities than the non-substituted ruthenium catalysts in the asymmetric hydrogenation of acetophenone.
Two new furostanol glycoside, 26-O-β-D-glucopyranosyl-(25S)-5α-furost-3β,22α,26-triol-3-O-β-D- rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-galactopyranoside (1) and 26-O-β-D-glucopyranosyl- (25S)-5α-furost-20(22)-en-2α,3β,26–triol-3-O-β-D-glucopyranosyl-(1→2)-O-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside (2) were isolated from the fruits of Tribulus terrestris L.. The structures of two new furostanol saponins were elucidated by spectroscopic methods.
A new benzophenone C-glucoside, 3'-C-[4-O-(5-hydroxyferuloyl)-β-D-glucopyranosyl]-2',4',6'-trihydroxy-3,4-dimethoxy benzophenone, named telephenone D, was isolated from the whole plants of Polygala telephioides, and its structure was determined by analysis of spectroscopic data.
A new ent-labdane diterpenoid lactone was isolated from Andrographis paniculata. Its structure was identified on the basis of spectral data including 2D NMR.
A new sesquiterpene, (Z)-7-acetoxy-methyl-11-methyl-3-methylenedodeca-1,6,10-triene (AMDT) was isolated and identified from the methanol extract of the hairy root culture of Artemisia annua. The structure of AMDT was determined based on the analysis of spectroscopic data, notably of the 2D NMR spectra. This new compound showed cytotoxicity against human tumor cell lines 95-D and HeLa with IC50 values of 27.08 μmol/L and 20.12 μmol/L, respectively.
A new flavonoidic glycoside, tricin-4′-O-β-L-arabinoside (1) was isolated from the leaves of Alstonia macrophylla along with two known flavonoids, vitexin and myricetin-3′-rhamnoside-3-O-galactoside. Their structures were established by chemical and spectral evidences. The known compounds were reported for the first time from this plant. Moreover compound 1 was tested for antifungal and antibacterial avtivities.
Two new indole alkaloids, evodiagenine 1 and dievodiamine 2 were isolated from the fruits of Evodia rutaecarpa (Juss.) Benth. The structure of compounds 1 and 2 were elucidated by comprehensive spectroscopic analysis and compound 1 was confirmed by X-ray crystallographic analysis.
A new triterpenoid 3, 4, 6-trihydroxy-2-oxo-1(10), 3, 5, 7-tetraen-23, 24-nor-D: A-friedooleana-29-oic acid, as well as twelve known terpenes were isolated from the roots of Tripterygium wilfordii. Its structure was established on the basis of spectroscopic methods.
A new cerebroside, 1-O-(β-D-glucopyranosyloxy)-(2S,3R,4E,8Z)-2-[(2´R)-2´-hydroxylignoceranoylamino]-4,8- tetradecene-3-diol was isolated from the 60% EtOH extract of traditional Chinese medical plant Cyperus rotundus L.. Its structure was determined on basis of spectroscopic data. This new compound showed anti-proliferation effect on vascular smooth muscle cells (VSMCs).
Two new ent-kaurane diterpenoids, taihangexcisoidesin C (1) and it’s acetonide, taihangexcisoidesin D (2) were isolated from the leaves of Isodon excisoides. Their structures were determined by 1D and 2D spectroscopic analysis.
A novel eremophilane dimer, named fischelactone (1), was isolated from the roots of Ligularia fischeri. Complete structural elucidation of this compound was performed by HRESIMS, IR, 1D NMR and 2D NMR (1H-1H COSY, HMBC, HMQC and NOESY) data.
Alkali soluble associative latex thickeners modified with hydrophobic long chain alkyl groups were prepared using common acrylics and varying amount of a functional monomer, ethoxylated behenyl methacrylate (BEM), through emulsion polymerization. It was found that the size of the emulsion particle became larger with addition of BEM. The light transmittance of the thickener latex sharply increased with pH varied from 6 to 7. The associative latex thickener manifested a higher viscosity when solids in the latex thickeners were kept at 0.5 wt% or higher, and the optimal amount of BEM was found to be around 2.5 wt%, or 0.16 mol%. Effective thickening was achieved in a styrene-acrylic copolymer latex.
A new polymer, polyzirconoxanesal (PZS), is synthesized from the reaction of zirconium oxychloride octahydrate (ZrOCl2•8H2O) with acetylacetone (Hacac) and salicyl alcohol (SA) by one-pot protocol. The polymer is soluble in common organic solvents, such as ethanol, methanol, acetone, tetrahydrofuran and chloroform, and exhibits rheology with viscosity of 100~300mpa•s at 25°C. These properties are suitable for uses in fabrication of ceramic matrix fiber composites. Pyrolysis of this polymer at 1300°C in argon provides nanosized ZrC with spherical morphology and size of 20~100nm.
Europium (Ⅲ) -doped YF3 is prepared by a hydrothermal process at 200 °C. X-ray diffraction (XRD) pattern identifies the formation of YF3 phase without detectable impurity. Environment scanning electron microscopy (ESEM) image shows the even size distribution of the samples with cubic morphology. The excitation and emission spectra of the rare earth ions doped YF3 is investigated by fluorescence spectrophotometer. The excitation spectrum for 591 nm emission has several excitation bands at 320，365，386, 397 and 467，and the main peak value was 397 nm. Typical Eu3+ emission peaks at 591 nm（5D0→7F1） and 612 nm（5D0→7F2） are observed when excited by 397 nm, and the strongest emission is 591 nm, demonstrating that the rare earth ions occupy the centrosymmetrical sites in YF3.
Poly (N-vinyl-2-pyrrolidone) (PVP) –stabilized ruthenium nanorods with high aspect ratio by refluxing ruhenium(Ⅲ) chloride in n-propanol have been successfully prepared by means of a facile and rapid microwave heating for the first time. The structure and morphology of the obtained products were characterized by transmission electron microscopy (TEM), select area electron diffraction (SAED), ultraviolet-visible spectrophotometry (UV-vis), X-ray photoelectron spectroscopy (XPS) and Fourier transform spectroscopy (FT-IR). XPS analysis reveals that the nanorods were in the metallic state. TEM images showed that ruthenium nanorods had an obvious one-dimensional structure with the aspect ratio ranged from 5-40 nm and length up to 600 nm. SAED patterns indicated that the nanorods were single-crystalline with a hexagonal structure.