2015 Volume 26 Issue 6

A BODIPY analogue from the tautomerization of sodium 3-oxide BODIPY
Peng-Zhong Chen , Hai-Rong Zheng , Li-Ya Niu , Yu-Zhe Chen , Li-Zhu Wu , Chen-Ho Tung , Qing-Zheng Yang
2015, 26(6): 631-635  doi: 10.1016/j.cclet.2015.04.018
[Abstract](282) [FullText HTML] [PDF 3060KB](0)
The introduction of hydroxy group to the 3-or 5-position of 4,4-difluoro-4-bora-3a,4a-diazaindacene (BODIPY) results in unexpected tautomerization to BDPONa with interesting structural and photophysical properties. The core of BDPONa is an anion with sodium cation as counter-ion. BDPONa displays strong fluorescence in organic solvents.
Solubilization of organic compounds by arginine-derived polymers
Xuchen Huang , Yanbin Huang
2015, 26(6): 636-640  doi: 10.1016/j.cclet.2015.04.009
[Abstract](265) [FullText HTML] [PDF 2319KB](0)
Poor aqueous solubility of drugs is one of the major challenges in the pharmaceutical science. In this study, a guanidinium-containing polymer based on arginine was designed and synthesized, and was evaluated as a solubility enhancing additive for three model organic compounds (coumarin, pyrene and doxorubicin). At a guanidinium group concentration of 100 mmol/L, the polymer could significantly increase the solubility of pyrene and doxorubicin by 6-and 11-fold respectively, much more effective than arginine (2-and 3-fold, respectively). In contrast, its effect on the solubility of coumarin was less effective than arginine. The solubilizing effect may be explained by the enhanced interaction between the guanidinium group in the polymer and the aromatic compounds.
Heterometallic zinc uranium oxyfluorides incorporating imidazole ligands
Xiao-Xiao Liu , Yuan Wang , Wan-Guo Tian , Weiting Yang , Zhong-Ming Sun
2015, 26(6): 641-645  doi: 10.1016/j.cclet.2015.03.024
[Abstract](246) [FullText HTML] [PDF 2740KB](0)
Two heterometallic uranium oxyfluorides with hybrid networks were hydrothermally synthesized by incorporating two imidazoles, 1-(biphenyl-4-yl)-1H-imidazole (bpi) and 1,4-di(1H-imidazol-1-yl)benzene (dib), formulated as Zn(bpi)2(UO2)2(H2O)F6 (1) and Zn(dib)(UO2)F4·0.5H2O (2). Compound 1 consists of chains of edge-sharing UO2F5 and UO2F4(H2O) pentagonal bipyramids, which are linked by Zn(bpi)2 moieties to form the sheet structure with decorated bpi. While in compound 2, sheets of edgesharing dimers of UO2F5 pentagonal bipyramids and ZnF3N2 polyhedra are linked by dib, creating a pillared three-dimensional framework. The two compounds represent the few examples of heterometallic uranium oxyfluorides incorporating organic ligands. The syntheses, structure as well as the IR spectra, UV-vis spectra and luminescent properties of the bimetallic uranium oxyfluorides are studied.
Phosphine-promoted [3 + 2] cycloaddition between nonsubstituted MBH carbonates and trifluoromethyl ketones
Hong-Yu Duan , Juan Ma , Zhe-Zhe Yuan , Ri-Sheng Yao , Wei Tao , Fang Xu , Hua Xiao , Gang Zhao
2015, 26(6): 646-648  doi: 10.1016/j.cclet.2015.03.019
[Abstract](239) [FullText HTML] [PDF 491KB](0)
A phosphine-promoted [3 + 2] cycloaddition from readily accessible MBH (Morita-Baylis-Hillman) carbonate and aryl trifluoromethyl ketone is described. The use of methyl vinyl ketone-derived allylic carbonate rather than common acrylate-derived counterpart renders the reaction pathway exclusive for 5-endo process, which enables the expeditious preparation of a range of trifluoromethylated 2, 3-dihydrofuran in a chemospecific manner.
Bis-triarylamine with a cyclometalated diosmium bridge: A multi-stage redox-active system
Meng-Jia Sun , Hai-Jing Nie , Jian-Nian Yao , Yu-Wu Zhong
2015, 26(6): 649-652  doi: 10.1016/j.cclet.2015.03.032
[Abstract](236) [FullText HTML] [PDF 1302KB](0)
A tetra(pyrid-2-yl)-pyrazine-bridged cyclometalated diosmium complex 1(PF6)2 with two distal redoxactive organic amine substituents has been synthesized and characterized. This complex displays four consecutive and separated anodic redox waves at +0.24, +0.38, +0.64, and +0.71 V vs. Ag/AgCl. Upon stepwise oxidation, four-step absorption spectral changes in the visible to near-infrared region have been observed. The different redox states of 1 (12+ through 16+) can be distinguished by the significantly different absorption spectra in the visible and near-infrared region. DFT calculations of 13+ show that the spin is delocalized on both osmium-amine components.
Two 2-(quinonylcarboxamino)benzoates from the lateral roots of Aconitum carmichaelii
Zhi-Bo Jiang , Xian-Hua Meng , Bing-Ya Jiang , Cheng-Gen Zhu , Qing-Lan Guo , Su-Juan Wang , Sheng Lin , Jian-Gong Shi
2015, 26(6): 653-656  doi: 10.1016/j.cclet.2015.04.011
[Abstract](243) [FullText HTML] [PDF 495KB](0)
Two new 2-(quinonylcarboxamino)benzoates, named aconicarmiquinamides A (1) and B (2), were isolated from an aqueous extract of the lateral roots of Aconitum carmichaelii. Their structures were determined by spectroscopic data analysis, and confirmed by comparison with synthetic methyl 3,6-bis(diethylamino)benzoqunonylcarboxylate (3).
pH responsive Janus polymeric nanosheets
Peng Zhou , Qian Wang , Cheng-Liang Zhang , Fu-Xin Liang , Xiao-Zhong Qu , Jiao-Li Li , Zhen-Zhong Yang
2015, 26(6): 657-661  doi: 10.1016/j.cclet.2015.04.006
[Abstract](251) [FullText HTML] [PDF 3230KB](0)
pH responsive polymeric Janus nanosheets with poly(maleic acid) moiety and crosslinked PS onto the corresponding sides have been synthesized by free radical polymerization. The Janus nanosheets can serve as solid emulsifier to stabilize an oil/water emulsion, whose stability is easily triggered by changing pH across pKa of the poly(maleic acid).
Bioactive conformation analysis of anthranilic diamide insecticides: DFT-based potential energy surface scanning and 3D-QSAR investigations
Dan-Ping Jiang , Cheng-Chun Zhu , Xu-Sheng Shao , Jia-Gao Cheng , Zhong Li
2015, 26(6): 662-666  doi: 10.1016/j.cclet.2015.04.010
[Abstract](216) [FullText HTML] [PDF 1727KB](0)
Anthranilic diamides are fasting growing class insecticides in modern crop protection for their high activity, low ecotoxicity, and broad insecticidal spectra. However, the bioactive conformations of anthranilic diamides are still unclear until now. In the present study, DFT-based potential energy surface scanning was used to detect the low energy conformations of chlorantraniliprole, then were used respectively in the structure alignment for a series of anthranilic diamide compounds followed by detailed CoMFA and CoMSIA analyses. Finally, the bioactive conformations of anthranilic diamide insecticides were revealed from a series of low energy conformations, which might provide some clues for future insecticide design.
Direct amination of pyrimidin-2-yl tosylates with aqueous ammonia under metal-free and mild conditions
Hai-Peng Gong , Yue Zhang , Yu-Xia Da , Zhang Zhang , Zheng-Jun Quan , Xi-Cun Wang
2015, 26(6): 667-671  doi: 10.1016/j.cclet.2015.01.034
[Abstract](250) [FullText HTML] [PDF 1069KB](0)
Ametal-free synthesis of pyrimidine functionalized primary amines via direct amination of pyrimidin-2-yl tosylate with aqueous ammonia has been developed under mild conditions. The desired products pyrimidin-2-amines can be generated in excellent yields in PEG-400, without any catalysts or other additives.
Synthesis and bioactivity of novel pyrazole oxime derivatives containing oxazole ring
Sen-Lin Wang , Yu-Jun Shi , Hai-Bing He , Yu Li , Yang Li , Hong Dai
2015, 26(6): 672-674  doi: 10.1016/j.cclet.2015.04.017
[Abstract](214) [FullText HTML] [PDF 451KB](0)
A series of novel pyrazole oxime derivatives containing oxazole ring were designed and synthesized. The title compounds were structurally confirmed by 1H NMR, 13C NMR spectra and elemental analyses. Preliminary bioassay results showed that some of the title compounds displayed promising fungicidal activity besides insecticidal and acaricidal activity. Particularly, compound 8c exhibited potent fungicidal activity against cucumber Pseudoperonospora cubensis beyond good insecticidal activity against Aphis craccivora and Nilaparvata lugens.
Novel hybrids from N-hydroxyarylamide and indole ring through click chemistry as histone deacetylase inhibitors with potent antitumor activities
Mao Cai , Jie Hu , Ji-Lai Tian , Huang Yan , Chen-Guo Zheng , Wan-Le Hu
2015, 26(6): 675-680  doi: 10.1016/j.cclet.2015.03.015
[Abstract](202) [FullText HTML] [PDF 1269KB](0)
Novel hybrid molecules 8a-8o were designed and synthesized by connecting indole ring with N-hydroxyarylamide through alkyl substituted triazole, and their in vitro biological activities were evaluated. It was discovered that most of target compounds showed promising anticancer activities, particularly for 8n, which had a significant HDACs inhibitory and antiproliferative activities comparable to or slightly stronger than SAHA against human carcinoma cells. Furthermore, compound 8n exhibited much better selectivity for HDAC1 over HDAC6 and HDAC8 than SAHA. In addition, compound 8n also could dose-dependently induce cancer cell cycling arrest at G0/G1 phase and promote the expression of the acetylation for histone H3 and tubulin in vitro. Therefore, our novel findings may provide a new framework for the design of new selective HDAC inhibitor for the treatment of cancer.
Electro-oxidation of paracetamol in the presence of malononitrile: Application for green, efficient, none-catalyst, simple and one-pot electro-synthesis of new paracetamols
Alireza Asghari , Mohsen Ameri , Ali Akbar Ziarati , Sepideh Radmannia , Ali Amoozadeh , Behruz Barfi , Leila Boutorabi
2015, 26(6): 681-684  doi: 10.1016/j.cclet.2015.03.036
[Abstract](281) [FullText HTML] [PDF 696KB](0)
Electrochemical oxidation of paracetamol has been studied in the presence of malononitrile as a nucleophile in a phosphate buffer solution (0.15 mol/L, pH 7), using cyclic voltammetric techniques. The results indicated that the N-acetyl-p-benzoquinone-imine derived from paracetamol participates in a 1,4-Michael-type addition reaction with the malononitrile to form the corresponding paracetamol derivatives (6a, 7a). The present study has led to the development of a simple, green, non-catalyst and one-pot electrochemical method with high atom economy under mild conditions.
Synthesis and crystal structure of Ni, Cu complexes of 5-methyl-10,10,15,15,20,20-hexaethylcalix[4]pyrrole mono-Schiff bases
Juan-Juan Sun , Ying Han , Jing Sun , Chao-Guo Yan
2015, 26(6): 685-689  doi: 10.1016/j.cclet.2015.03.028
[Abstract](240) [FullText HTML] [PDF 647KB](0)
The functionalized calix[4]pyrrole meso-substituted Schiff bases were conveniently prepared by fourstep synthetic route. Furthermore, the nickel and copper complexes of calix[4]pyrrolemeso-substituted Schiff base with 1:2 stoichiometry were obtained. The crystal structures of the calix[4]pyrroles and their metal complexes were determined by X-ray diffraction.
Synthesis and spectroscopic characterization of novel 2-amino-4,5,6,7-tetrahydro-3H-cyclopenta[d]pyrimidine and pyrimido[1,2-a]pyrimidine derivatives
Mohamed S.A. El-Gaby , Jehan A. Micky , Nadia M. Saleh , Yousry A. Ammar , Heba S.A. Mohamed
2015, 26(6): 690-694  doi: 10.1016/j.cclet.2015.04.003
[Abstract](209) [FullText HTML] [PDF 477KB](0)
2-Aminocyclopenta[d]pyrimidines 3a-c were achieved via a one-pot, three-component reactions of cyclopentanone 1, aromatic aldehyde and guanidine hydrochloride (1:2:1 molar ratio). Also, cyclization of 2,5-bis-(arylmethylidene)cyclopentanones 2 with guanidine hydrochloride (1:1 molar ratio) in methanol in the presence of sodiummethoxide afforded cyclopenta-[d]pyrimidines 3. Compound 3a has been shown to be a useful building block for the synthesis of some novel pyrimido[1,2-a]pyrimidines 5, 7 and 12. The structures of the newly synthesized compounds were confirmed on the basis of analytical and spectral data.
Synthesis of PEGylated hyaluronic acid for loading dichloro(1,2-diaminocyclohexane)platinum(II) (DACHPt) in nanoparticles for cancer treatment
Xiu-Quan Quan , Lin Kang , Xue-Zhe Yin , Zhe-Hu Jin , Zhong-Gao Gao
2015, 26(6): 695-699  doi: 10.1016/j.cclet.2015.04.024
[Abstract](283) [FullText HTML] [PDF 1414KB](0)
Dichloro(1,2-diaminocyclohexane)platinum(II) (DACHPt), a cisplatin (CDDP) analog, has shown lower toxicity than CDDP and no cross-resistance with CDDP in many CDDP-resistant cancers. PEGylated hyaluronan (mPEG-HA) is an mPEG conjugated with hyaluronan biodegradable polymer which is a naturally occurring biopolymer in the interstitium, is primarily cleared by the lymphatic system. mPEGhyaluronan-DACHPt (PEG-HA-Pt) conjugate could circulate long-term in the bloodstream and increase DACHPt concentration in the tumor site and decrease systemic toxicity. mPEG-HA conjugates with the range of 1%-5% substitution were synthesized, and the structures were confirmed by 1H NMR and IR. The particle size of DACHPt incorporated with mPEG-HA was about 86 nm and the loading content and efficiency were about 19% (w/w) and 86%, respectively. The synthesized mPEG-HA with different PEG substitution degrees presented non toxicity, and the cell viability of DACHPt loaded in mPEG-HA nanoparticles increased with increasing doses of DACHPt. DACHPt release from nanoparticles slightly decreased with increasing PEG substitution degree from 1% to 5% at 37 ℃, pH 7.4 PBS solution. The DACHPt loaded inmPEG-HA nanoparticles significantly inhibited the growth of A549 xenografts in nude mice when compared to the DACHPt loaded in HA nanoparticles and the control group after 4 weeks treatment (p < 0.01 compared with control). The body weight change curve shows that the mice weight loss was less than 5% by treating with both DACHPt loaded in mPEG-HA and HA nanoparticles. In conclusion, a novel DACHPt loaded mPEG-HA delivery system was developed with sustained release and increased platinum concentration in the tumor.
Synthesis of colloid silica coated with ceria nano-particles with the assistance of PVP
Lei Yu , Wei-Li Liu , Ze-Fang Zhang , Zhi-Tang Song
2015, 26(6): 700-704  doi: 10.1016/j.cclet.2015.01.039
[Abstract](264) [FullText HTML] [PDF 1182KB](0)
In this paper, a facile synthesis of 100 nm commercial colloid silica coated with nano-ceria core-shell composite particles by the precipitation method using ammonium cerium nitrate and urea as a precipitator with polyvinylpyrrolidone (PVP) as an assistant was briefly introduced. The results showed that the colloid silica was surrounded by nano-ceria uniformly forming the core-shell composite particles. The synthesis process was further discussed and optimized. It was found that the type and quantity of surfactant played a key role in the process. PVP connected the surface of colloid silica and that of the ceria precursor.
Recognizing parallel-stranded G-quadruplex by cyanine dye dimer based on dual-site binding mode
Li-Jia Yu , Wei Gai , Qian-Fan Yang , Jun-Feng Xiang , Hong-Xia Sun , Qian Li , Li-Xia Wang , Ai-Jiao Guan , Ya-Lin Tang
2015, 26(6): 705-708  doi: 10.1016/j.cclet.2015.02.002
[Abstract](254) [FullText HTML] [PDF 455KB](0)
G-quadruplexes (G4s) play important roles in biological systems, such as telomere maintenance, replication, and transcription. Based on the DNA sequence, loop geometry, and the local environments, G4s can be classified into different conformations. It is important to detect different types of G4s to monitor the diseases related with G4s. Most ligands bind to G4s based on end-stacking modes, while rare ligands bind to G4s through groove binding modes. We have found that a cyanine dye DMSB interacts with parallel G4 by end-stacking and groove simultaneous binding mode. In this article, we found that DMSB could simply discriminate parallel G4s from other DNA motifs by using UV-vis spectrum. These results give some clues to develop high specificity G4 probes.
Characterization and reactivity of γ-Al2O3 supported Pd-Ni bimetallic nanocatalysts for selective hydrogenation of cyclopentadiene
Yi-Si Feng , Jian Hao , Wei-Wei Liu , Yun-Jin Yao , Yue Cheng , Hua-Jian Xu
2015, 26(6): 709-713  doi: 10.1016/j.cclet.2015.03.006
[Abstract](212) [FullText HTML] [PDF 2378KB](0)
Several γ-Al2O3 supported Pd-Ni bimetallic nanocatalysts (Pd-Ni (x:y)/Al2O3; where x and y represent the mass ratio of Pd and Ni, respectively) were prepared by the impregnation method and used for selective hydrogenation of cyclopentadiene to cyclopentene. The Pd-Ni/Al2O3 samples were confirmed to generate Pd-Ni bimetallic nanoparticles by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The catalytic activity was assessed in view of the effects of different mass ratios of Pd and Ni, temperature, pressure, etc. Among all the samples, the Pd-Ni (1:1)/Al2O3 (PN-1:1) catalyst showed extremely high catalytic ability. The conversion of cyclopentadiene and selectivity for cyclopentene can be simultaneously more than 90%.
A comparative study of liquid and solid inner contact roxatidine acetate ion-selective electrode membranes
Mohamed K. Abd El-Rahman , Hala E. Zaazaa , Samah S. Abbas , Badr El-Zeany , Zeinab A. EL-Sherif , Dalia A. EL-Haddad
2015, 26(6): 714-720  doi: 10.1016/j.cclet.2015.03.010
[Abstract](232) [FullText HTML] [PDF 1929KB](0)
A comparative study was conducted using two designs of a roxatidine acetate (ROX)-selective electrode; a conventional liquid inner contact called electrode A and a graphite-coated solid contact called electrode B. The fabrication of electrodes was based on roxatidine-tetraphenylborate (ROX-TPB) as an ion-association complex in a PVC matrix using different plasticizers. Electrode A has a linear dynamic range of 2.2×10-5 mol/L to 1.0×10-2 mol/L, with a Nernstian slope of 54.7 mV/decade and a detection limit of 1.4×10-6 mol/L. Electrode B shows linearity over the concentration range of 1.0×10-6 mol/L to 1.0×10-2 mol/L, with a Nernstian slope of 51.2 mV/decade and a limit of detection of 1.1×10-7 mol/L which is remarkably improved as a result of diminishing ion fluxes in this solid contact, ion-selective electrode. The proposed sensors display useful analytical characteristics for the determination of ROX in bulk powder and its pharmaceutical formulation. The present electrodes show clear discrimination of ROX from several inorganic, organic ions, sugars, some common drug excipients and the degradation product (3-[3-(1-piperidinyl methyl) phenoxy] propyl amine) of ROX. Furthermore, the proposed electrodes were utilized for the determination of ROX in human plasma, where electrode B covers drug Cmax which indicated its applicability to pharmacokinetic, bioavailability and bioequivalent studies. The results obtained by the proposed electrodes were statistically analyzed and compared with those obtained by a reported HPLC method. No significant difference for either accuracy or precision was observed.
Design, synthesis, characterization, cytotoxic and structure activity relationships of novel Ru(II) complexes
Sreekanth Thota , Srujana Vallala , Rajeshwar Yerra , Eliezer J. Barreiro
2015, 26(6): 721-726  doi: 10.1016/j.cclet.2015.03.011
[Abstract](225) [FullText HTML] [PDF 2084KB](0)
Platinum containing compounds have shown antineoplastic potential, but their clinical applications have been limited by high toxicity. Ruthenium containing complexes have long been known to be well suited for biological applications, and have long been utilized as replacements to popular platinum based-drugs. Here, we report a novel series of ruthenium(II) arene compounds bearing thiosemicarbazone and isonicotinylhydrazone ligands with potent anticancer activity their structure activity relationships and apoptosis was studied. The cytotoxic activity of the new ruthenium(II) arene compounds has been evaluated in several cell lines (Molt 4/C8, L1210, CEM, HL60 and BEL7402). Among them, ten complexes were found to be excellent in vitro growth inhibitory activity against various cell lines with IC50 in the sub-micromolar range.
Synthesis of a novel naphthyl-based self-catalyzed phthalonitrile polymer
Feng-Hua Zhao , Ruo-Jin Liu , Xiao-Yan Yu , , Cheng-Chun Tang , Xiong-Wei Qua , Qing-Xin Zhang
2015, 26(6): 727-729  doi: 10.1016/j.cclet.2015.03.025
[Abstract](251) [FullText HTML] [PDF 1073KB](0)
A novel naphthyl-based self-catalyzed phthalonitrile monomer was prepared via nucleophilic displacement reaction. The structure was characterized by Fourier infrared spectrum (FT-IR) and nuclear magnetic resonance (1H NMR). The polymerization mechanism was explored. Thermal properties were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), which demonstrated self-promoted behavior and excellent heat resistance.
Mechanism and reactivity of rhodium-catalyzed intermolecular [5 + 1] cycloaddition of 3-acyloxy-1,4-enyne (ACE) and CO: A computational study
Xiao-Na Ke , Casi M. Schienebeck , Chen-Chen Zhou , Xiu-Fang Xu , Wei-Ping Tang
2015, 26(6): 730-734  doi: 10.1016/j.cclet.2015.03.016
[Abstract](231) [FullText HTML] [PDF 1937KB](0)
The first theoretical study on the mechanism of [RhCl(CO)2]2-catalyzed [5 + 1] cycloadditions of 3-acyloxy-1,4-enyne (ACE) and CO has been performed using density functional theory (DFT) calculations. The effect of ester on reactivity of this reaction has been investigated. The computational results have revealed that the preferred catalytic cycle involves the sequential steps of 1,2-acyloxy migration, CO insertion, reductive elimination to form ketene intermediate, 6π-electroncyclization, and aromatization to afford the resorcinol product. The 1,2-acyloxy migration is found to be the rate-determining step of the catalytic cycle. The electron-rich p-dimethylaminobenzoate substrate promotes 1,2-acyloxy migration and significantly increases the reactivity by stabilizing the positive charge building up in the oxocyclic transition state.
A convenient synthesis of 2-aminocyclohex-1-ene-1-carboxylic esters by FeCl3/SiO2 nanoparticles as robust and efficient catalyst
Sima Kalhor , Javad Safaei-Ghomi
2015, 26(6): 735-738  doi: 10.1016/j.cclet.2015.01.035
[Abstract](233) [FullText HTML] [PDF 1003KB](0)
A simple and green method has been developed for the synthesis of 2-aminocyclohex-1-ene-1-carboxylic esters through a one-pot three-component condensation reaction of primary amines, ethyl acetoacetate and chalcones using FeCl3/SiO2 nanoparticles in ethanol. This method has several advantages such as high to excellent product yields in short time, using an inexpensive and reusable catalyst and available starting material.
Propylphosphonic anhydride (T3P®) catalyzed one-pot synthesis of α-aminonitriles
Sirigireddy Sudharsan Reddy , Bhoomireddy Rajendra Prasad Reddy , Peddiahgari Vasu Govardhana Reddy
2015, 26(6): 739-743  doi: 10.1016/j.cclet.2015.03.021
[Abstract](239) [FullText HTML] [PDF 479KB](0)
The Strecker reaction was performed via a one-pot three component condensation of hetero aromatic/aromatic aldehydes, secondary amines and trimetylsilyl cyanide in the presence of propylphosphonic anhydride (T3P®) to accomplish the corresponding α-aminonitriles. The main advantages of this method are very short reaction time and excellent yields.
C2-symmetric BINOL-squaramide as efficient organocatalyst for the enantioselective α-amination of 1,3-dicarbonyl compounds with dialkyl azodicarboxylates
Shi Tang , Zhi-yong Wang , Bin Liu , Chun-E. Dong
2015, 26(6): 744-748  doi: 10.1016/j.cclet.2015.03.033
[Abstract](232) [FullText HTML] [PDF 539KB](0)
The asymmetric α-amination of 1,3-dicarbonyl compounds with dialkyl azodicarboxylates has been achieved by C2-symmetric BINOL-squaramide bearing multiple hydrogen bond donors to provide the desired products in excellent yields and enantioselectivities (up to 99% yield and 98% ee).
PEGylated WS2 nanosheets for X-ray computed tomography imaging and photothermal therapy
Xiao-Zhen Cui , Zhi-Guo Zhou , Yan Yang , Jie Wei , Jun Wang , Ming-Wei Wang , Hong Yang , Ying-Jian Zhang , Shi-Ping Yang
2015, 26(6): 749-754  doi: 10.1016/j.cclet.2015.03.034
[Abstract](231) [FullText HTML] [PDF 4160KB](0)
WS2 nanosheets were prepared by the solvent-thermal method in the presence of n-butyl lithium, then the exfoliation under the condition of ultrasound. The formed WS2 nanosheets were conjugated with thiol-modified polyethylene glycol (PEG-SH) to improve the biocompatibility. The nanosheets (WS2-PEG) were able to inhibit the growth of a model HeLa cancer cell line in vitro due to the high photothermal conversion efficiency of 35% irradiated by an 808 nm laser (1 W/cm2). As a proof of concept, WS2-PEG nanosheets with the better X-ray attenuation property than the clinical computed tomography (CT) contrast agent (Iohexol) could be performed for CT imaging of the lymph vessel.
Synthesis and antitumor activity of α-aminophosphonate derivatives containing thieno[2,3-d]pyrimidines
Yan-Chun Guo , Jing Li , Jiao-Li Ma , Zhi-Ran Yu , Hai-Wei Wang , Wen-Juan Zhu , Xin-Cheng Liao , Yu-Fen Zhao
2015, 26(6): 755-758  doi: 10.1016/j.cclet.2015.03.026
[Abstract](283) [FullText HTML] [PDF 623KB](0)
Two series of thieno[2,3-d]pyrimidine derivatives were designed and synthesized, in which bioactive α-aminophosphonate subunits were introduced at the N3 position through an N-N bond connection. The in vitro cytotoxic activity of the novel compounds was tested against human esophageal carcinoma cells (EC109), human hepatocarcinoma cells (HepG2), human gastric carcinoma cells (MGC-803), respectively, by the MTT method. The evaluation results revealed that compounds 6mb, 6mf, 6mg, 6nd and 6nh exerted the most potent inhibition against HepG2, MGC-803 and EC109 cells, respectively. In particular, compound 6mg presented excellent inhibitory effect against HepG2 (91.2%) and MGC-803 (94.4%) cells.
Novel NO-releasing derivatives of betulinic acid with antitumor activity
Jin-Hong Liu , Zi-Fei Zhu , Jia Tang , Ai-Qin Jiang , Liu-Fang Hu , Li Chen
2015, 26(6): 759-762  doi: 10.1016/j.cclet.2015.04.002
[Abstract](203) [FullText HTML] [PDF 471KB](0)
Thirteen novel NO-releasing derivatives of betulinic acid (BA) bearing two types of NO-donors (nitrates and furoxans) were synthesized and evaluated for their antitumor activity. The results showed that furoxan-based derivatives exhibited higher antitumor activity than nitrate-based derivatives, with compounds 11a and 11b displaying promising potency against B16 cell lines and HepG2 cell lines (IC50 < 1 μmol/L). Wesupposed that NO-releasing amount of these derivatives which can be detected by Griess method may contribute more to their antitumor activity. As a result, furoxan-based derivatives released larger amount of NO than that of nitrate-based derivatives, which partially explained the higher anti-tumor activity of the former.
Design, synthesis and biological evaluation of LpxC inhibitors with novel hydrophilic terminus
Shi Ding , Wen-Ke Wang , Qiao Cao , Wen-Jing Chu , Le-Fu Lan , Wen-Hao Hu , Yu-She Yang
2015, 26(6): 763-767  doi: 10.1016/j.cclet.2015.03.029
[Abstract](236) [FullText HTML] [PDF 1306KB](0)
In order to develop novel LpxC inhibitors with good activities and metabolic stability, two series of compounds with hydrophilic terminus have been synthesized and their in vitro antibacterial activities against Escherichial coli and Pseudomonas aeruginosa were evaluated. Especially, compounds 22b and c exhibited comparable antibacterial activities to CHIR-090 and better metabolic stability than CHIR-090 and LPC-011 in liver microsomes (rat andmouse), which indicated the terminal methylsulfone may be a preferred structure in the design of LpxC inhibitors and worthy of further investigations.
Formation of six-coordinated silicon in calcium phosphosilicate xerogels assisted by polyols at low temperature and pressure
Ai-Ling Li , Yan-Ping Ma , Dong Qiu
2015, 26(6): 768-772  doi: 10.1016/j.cclet.2015.03.004
[Abstract](205) [FullText HTML] [PDF 640KB](0)
Silicon is usually found to be four-coordinated when neighbored with oxygen. Six-coordinated silicon is only seen in samples at very specific composition or made at high temperature/pressure. In this study, we managed to synthesize calciumphosphosilicate xerogels containing six-coordinated silicon with the help of polyols by sol-gel method, without the need of treatment at high temperature or high pressure. Both phosphorus precursors and polyols were found to be essential for the formation of six-coordinated silicon species; in the absence of either species, only normal four-coordinated silicon was observed under otherwise identical conditions. Samples containing six-coordinated silicon sites were found to release silicon species faster than those without six-coordinated silicon sites upon dissolved in water, suggesting that six-coordinated silicon species have higher reactivity toward hydrolysis.
Atom transfer radical polymerization of methyl acrylate, methyl methacrylate and styrene in the presence of trolamine as a highly effective promoter
Qiao Xu , Yi-Feng Zhu , Zhao Yuan , Hua-Dong Tang
2015, 26(6): 773-778  doi: 10.1016/j.cclet.2015.03.012
[Abstract](227) [FullText HTML] [PDF 565KB](0)
Transition metal-mediated atom transfer radical polymerization (ATRP) is a "living"/controlled radical polymerization. Recently, there has been widely increasing interest in reducing the high costs of catalyst separation and post-polymerization purification in ATRP. In this work, trolamine was found to significantly enhance the catalytical performance of CuBr/N,N,N',N'-tetrakis(2-pyridylmethyl) ethylenediamine (CuBr/TPEN) and CuBr/tris[2-(dimethylamino) ethylamine] (CuBr/Me6TREN). With the addition of 25-fold molar amount of trolamine relative to CuBr, the catalyst loadings of CuBr/TPEN and CuBr/Me6TREN were dramatically reduced from a catalyst-to-initiator ratio of 1 to 0.01 and 0.05, respectively. The polymerizations of methyl acrylate, methyl methacrylate and styrene still showed first-order kinetics in the presence of trolamine and produced poly(methyl acrylate), poly(methyl methacrylate) and polystyrene with molecular weights close to theoretical values and low polydispersities. These results indicate that trolamine is a highly effective and versatile promoter for ATRP and is promising for potential industrial application.
A new oxidovanadium(IV) Schiff base complex containing asymmetric tetradentate ONN'O' Schiff base ligand: Synthesis, characterization, crystal structure determination, thermal study and catalytic activity
Gholamhossein Grivani , Abbase Ghavami , Válav Eigner , Michal Dušek , Aliakbar Dehno Khalaji
2015, 26(6): 779-784  doi: 10.1016/j.cclet.2015.03.014
[Abstract](211) [FullText HTML] [PDF 2643KB](0)
After synthesis of an asymmetric tetradentate ONN'O' Schiff base ligand (H2L) followed by reaction of the synthesized H2L with an equimolar mixture of methanolic solutions of the VO(acac)2, a new oxidovanadium(IV) Schiff base complex (VOL) was synthesized. The Schiff base ligand and its complex were characterized by FT-IR and UV-vis spectra and C, H, N analysis. The crystal structure of VOL was also determined by single crystal X-ray analysis. The VOL complex crystallizes in monoclinic space group Cc. The Schiff base ligand acts as a tetradentate ligand through its two iminic nitrogens and two phenolic and acetylacetonate oxygens. Thermogravimetric analysis of the VOL showed that it decomposes in two steps and converts to mixed vanadium oxides at 477℃. In addition, thermal decomposition of the VOL complex in air at 660℃ leads to formation of V2O5 nanoparticles with the average size estimated from XRD 49 nm. The catalytic activity of the VOL complex was investigated in the epoxidation reaction and different reaction parameters were optimized. The results showed that the cyclic alkenes were efficiently converted to the corresponding epoxides, whereas the VOL did not appreciably convert the linear alkenes.
Naphthylethyne based liquid crystals with high birefringence and characteristics of selective reflection
Yu-Zhen Zhao , Dong Wang , Ze-Min He , Gang Chen , Lan-Ying Zhang , Hai-Quan Zhang , Huai Yang
2015, 26(6): 785-789  doi: 10.1016/j.cclet.2015.03.023
[Abstract](200) [FullText HTML] [PDF 576KB](0)
A series of high birefringence liquid crystalline molecules with cyano, isothiocyanato and trifluoromethyl terminal compounds based on naphthylethyne core was successfully synthesized and characterized. The molecular structures of the intermediates and resulting compounds were confirmed by Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), mass spectrometry (MS), and elemental analysis (EA). Their thermal stability, transition temperatures, and phase sequences were investigated by simultaneous thermal analyzer polarized (STA), optical microscopy (POM) and differential scanning calorimetry (DSC). The birefringence was measured by using an Abbe refractometer. In addition, the selective reflection characteristics with naphthylethyne compounds were also studied.
A highly efficient way to recycle inactive stereoisomers of Bedaquiline into two previous intermediates via base-catalyzed Csp3-Csp3 bond cleavage
De-Long Kong , Ye Huang , Lai-Yang Ren , Wen-Hua Feng
2015, 26(6): 790-792  doi: 10.1016/j.cclet.2015.04.013
[Abstract](420) [FullText HTML] [PDF 460KB](0)
Bedaquiline is a new medicine for pulmonary multi-drug resistant tuberculosis (MDR-TB), which is a pure enantiomer with two chiral centers. The current industrial preparation process requires the separation of active Bedaquiline from a mixture of four isomers. Obviously, direct dispose of the other three undesired stereoisomers will cause significant waste and increase the unnecessary cost of production. Here, we developed an efficient, facile and scalable process for recycling the inactive stereoisomers of Bedaquiline. All these inactive stereoisomers could be recycled by their conversion to two important intermediates in the Bedaquiline synthesis via a base-catalyzed Csp3-Csp3 bond cleavage of a benzyl alcohol intermediate. And the precise conditions and mechanism of the base-catalyzed cleavage reaction were discussed.
Acidic rearrangement of benzyl group in flavone benzyl ethers and its regioselectivity
Chong-Qing Wang , Xin Chen , Jun-Hang Jiang , Hui Tang , Kong-Kai Zhu , You-Jun Zhou , Can-Hui Zheng , Ju Zhu
2015, 26(6): 793-796  doi: 10.1016/j.cclet.2015.03.035
[Abstract](279) [FullText HTML] [PDF 1414KB](0)
The benzyl-substituted flavone compounds are rare in nature, while some of which have interesting biological activities. The total synthesis of benzyl-substituted flavone derivatives via the acidic rearrangement of benzyl groups in flavone benzyl ethers, and the complicated regioselectivity of the rearrangement were reported. The regioselectivity was proposed to be determined by the steric hindrance as well as the ease of electrophilic substitution reaction for benzyl cations at different positions of corresponding debenzylated flavone compounds.
Detection of parathion methyl using a surface plasmon resonance sensor combined with molecularly imprinted films
Yuan Tan , Israr Ahmad , Tian-Xin Wei
2015, 26(6): 797-800  doi: 10.1016/j.cclet.2015.04.001
[Abstract](213) [FullText HTML] [PDF 1052KB](0)
An ultra-sensitive and highly selective parathion methyl (PM) detection method by surface plasmon resonance (SPR) combined with molecularly imprinted films (MIF) was developed. The PM-imprinted film was prepared by thermo initiated polymerization on the bare Au surface of an SPR sensor chip. Template PM molecules were quickly removed by an organic solution of acetonitrile/acetic acid (9:1, v/v), causing a shift of 0.5° in SPR angle. In the concentrations range of 10-13-10-10 mol/L, the refractive index showed a gradual increase with higher concentrations of template PM and the changes of SPR angles were linear with the negative logarithm of PM concentrations. In the experiment, the minimum detectable concentration was 10-13 mol/L. The selectivity of the thin PM-imprinted film against diuron, tetrachlorvinphose and fenitrothion was examined, but no observable binding was detected. The results in the experiment suggested that the MIF had the advantages of high sensitivity and selectivity.
Design, synthesis and biological evaluation of sulfenimine cephalosporin sulfoxides as β-lactamase inhibitors
Kai Zhang , Huai-Wei Ding , Hao Ju , Qi Huang , Li-Juan Zhang , Hong-Rui Song , De-Cai Fu
2015, 26(6): 801-803  doi: 10.1016/j.cclet.2015.04.025
[Abstract](224) [FullText HTML] [PDF 444KB](0)
A series of sulfenimine cephalosporin sulfoxide derivatives (7a-v) were designed, synthesized and evaluated for their inhibitory activity against TEM-1 and cephalosporinase in cell-free systems. Some of the tested compounds showed enhanced inhibitory activity against class C β-lactamase cephalosporinase compared with the tazobactam. The most promising compounds 7c and 7n (IC50 = 7.6 and 8.6 μmol/L, respectively) were further investigated in combination with cefradine against a variety of clinical isolated β-lactamase-producing bacterial strains.
1H-15N HMBC spectra of C18-diterpenoid alkaloids
Qian Mei , Yao-Nan Wang , Ming Zhao , Xiao-Yu Liu , Shi-Qi Peng , Feng-Peng Wang
2015, 26(6): 804-806  doi: 10.1016/j.cclet.2015.04.028
[Abstract](321) [FullText HTML] [PDF 517KB](0)
The normally underused 1H-15N HMBC spectra of thirteen C18-diterpenoid alkaloids have been determined for the first time. As a result, the significant effects of the substituents of nitrogen atoms, the conformations of A ring, and protonation, on the nitrogen-15 chemical shifts are demonstrated.
Polypropylene non-woven supported fibronectin molecular imprinted calcium alginate/polyacrylamide hydrogel film for cell adhesion
Dun-Wan Zhu , Zhuo Chen , Kong-Yin Zhao , Bo-Hong Kan , Lan-Xia Liu , Xia Dong , Hai Wanga , Chao Zhang , Xi-Gang Leng , Lin-Hua Zhang
2015, 26(6): 807-810  doi: 10.1016/j.cclet.2015.04.033
[Abstract](243) [FullText HTML] [PDF 2017KB](0)
Fibronectin (FN) imprinted polypropylene (PP) non-woven supported calcium alginate/polyacrylamide hydrogel film (PP-s-CA/PAM MIP) was prepared using non-woven PP fiber as matrix, FN as template molecule, sodium alginate (SA) and acrylamide (AM) as functional monomers, via UV radiation-reduced polymerization. The PP-s-CA/PAM MIP exhibited an obvious improvement in terms of adsorption capacity for FN compared with non-imprinted polymer (NIP). The PP-s-CA/PAM MIP was successfully used for the culture of mouse fibroblast cells (L929) and the results showed that PP-s-CA/PAM MIP exhibited better cell adherence performance than the NIP did.
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