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91.
Size controlled synthesis of ornithine‐based polypeptides by ring‐opening polymerization of α‐(amino acid)‐N‐carboxyanhydrides 下载免费PDF全文
92.
93.
Synthesis of 5‐substituted 1H‐tetrazoles using a recyclable heterogeneous nanonickel ferrite catalyst 下载免费PDF全文
An efficient method was developed for the [2 + 3] cycloaddition of sodium azide with nitriles to afford 5‐substituted 1H‐tetrazoles using nanonickel ferrite (NiFe2O4) as an effective heterogeneous catalyst in dimethylformamide. The main advantages of this method are high yields, simple methodology and easy work‐up. The catalyst can be recovered and reused for several cycles with predictable activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
94.
New dicarboxylate-functionalized pillared materials with a general formula of λ-ZrPO4(OH)1-x(OOC(CH2)nCOO)x/2(dmso) (n=6, 8 and 10) have been prepared by post-synthesis modification of the inorganic layers of λ-zirconium phosphate (λ-ZrP), where the superficial Chloride monovalent anionic ligands of λ-layer are partially exchanged with the divalent anionic ligands of a series of long-chain aliphatic dicarboxylic acids, namely octanedioic acid, decanedioic acid and dodecanedioic acid. The synthesized materials are characterized by X-ray diffractometry, FT-IR spectrophotometry, elemental and thermogravimetric analyses. The X-ray diffraction patterns show that the obtained solid phases are pure. Furthermore, the interlayer distance of λ-ZrP systematically increases from 1.02 to 1.59 nm as a result of the incorporation of the mentioned acids inside the interlayer gallery. 相似文献
95.
96.
Li‐Na Wang Zhen‐Xun Zhou Dr. Xiao‐Na Li Dr. Tong‐Mei Ma Prof. Sheng‐Gui He 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(18):6957-6961
In addition to generation of a methyl radical, formation of a formaldehyde molecule was observed in the thermal reaction of methane with AuNbO3+ heteronuclear oxide cluster cations. The clusters were prepared by laser ablation and mass‐selected to react with CH4 in an ion‐trap reactor under thermal collision conditions. The reaction was studied by mass spectrometry and DFT calculations. The latter indicated that the gold atom promotes formaldehyde formation through transformation of an Au?O bond into an Au?Nb bond during the reaction. 相似文献
97.
Jia-Kuo Liu Wei Gu Xiao-Rui Cheng Jun-Ping Cheng Wen-Xia Zhou Ai-Hua Nie 《中国化学快报》2015,26(10):1327-1330
Based on the lead compound 1 reported in literature, a series of novel BACE1 inhibitors were designed and synthesized, among which compound 11 exhibited a 14-fold improvement in potency over the lead compound 1. This represents a good lead for the discovery of more promising BACE1 inhibitors for the potential treatment of AD. 相似文献
98.
Development and validation of a reversed‐phase HPLC method for CYP1A2 phenotyping by use of a caffeine metabolite ratio in saliva 下载免费PDF全文
Elias Begas Evangelos Kouvaras Andreas K. Tsakalof Maria Bounitsi Eftihia Konstadinos Asprodini 《Biomedical chromatography : BMC》2015,29(11):1657-1663
CYP1A2 is important for metabolizing various clinically used drugs. Phenotyping of CYP1A2 may prove helpful for drug individualization therapy. Several HPLC methods have been developed for quantification of caffeine metabolites in plasma and urine. Aim of the present study was to develop a valid and simple HPLC method for evaluating CYP1A2 activity during exposure in xenobiotics by the use of human saliva. Caffeine and paraxanthine were isolated from saliva by liquid‐liquid extraction (chlorophorm/isopropanol 85/15v/v). Extracts were analyzed by reversed‐phase HPLC on a C18 column with mobile phase 0.1% acetic acid/methanol/acetonitrile (80/20/2 v/v) and detected at 273nm. Caffeine and paraxanthine elution times were <13min with no interferences from impurities or caffeine metabolites. Detector response was linear (0.10–8.00µg/ml, R2>0.99), recovery was >93% and bias <4.47%. Intra‐ and inter‐day precision was <5.14% (n=6). The limit of quantitation was 0.10µg/ml and the limit of detection was 0.018±0.002µg/mL for paraxanthine and 0.032±0.002µg/ml for caffeine. Paraxanthine/caffeine ratio of 34 healthy volunteers was significantly higher in smokers (p<0.001). Saliva paraxanthine/caffeine ratios and urine metabolite ratios were highly correlated (r=0.85, p<0.001). The method can be used for the monitoring of CYP1A2 activity in clinical practice and in studies relevant to exposure to environmental and pharmacological xenobiotics. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
99.
Silver(I)‐Catalyzed Enantioselective [3+2]‐Cycloaddition Reaction of α‐Silylimines: A Facile Route to Quaternary‐Carbon‐Rich Scaffolds 下载免费PDF全文
Dr. Naredla Kesava‐Reddy Christopher Golz Prof. Dr. Carsten Strohmann Dr. Kamal Kumar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18373-18377
A silver‐catalyzed highly enantioselective 1,3‐dipolar cycloaddition reaction of α‐silylimines with pyrone‐based trisubstituted olefins was developed affording bi‐ and tricyclic α‐quaternary‐carbon‐rich pyrano‐pyrrolidines in excellent yields. The tricyclic benzopyrone adducts thus obtained were efficiently transformed into highly complex tetracyclic scaffolds supporting four consecutive stereogenic centers with three quaternary carbons. 相似文献
100.
A sensitive and efficient method for trace analysis of some phenolic compounds using simultaneous derivatization and air‐assisted liquid–liquid microextraction from human urine and plasma samples followed by gas chromatography–nitrogen phosphorous detection 下载免费PDF全文
Mir Ali Farajzadeh Mohammad Reza Afshar Mogaddam Ali Akbar Alizadeh Nabil 《Biomedical chromatography : BMC》2015,29(12):1921-1931
In present study, a simultaneous derivatization and air‐assisted liquid–liquid microextraction method combined with gas chromatography–nitrogen phosphorous detection has been developed for the determination of some phenolic compounds in biological samples. The analytes are derivatized and extracted simultaneously by a fast reaction with 1‐flouro‐2,4‐dinitrobenzene under mild conditions. Under optimal conditions low limits of detection in the range of 0.05–0.34 ng mL?1 are achievable. The obtained extraction recoveries are between 84 and 97% and the relative standard deviations are less than 7.2% for intraday (n = 6) and interday (n = 4) precisions. The proposed method was demonstrated to be a simple and efficient method for the analysis of phenols in biological samples. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献