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Chemistry100%

Selected Abstracts

Influence of technological parameters on the epoxidation of 1-butene-3-ol over titanium silicalite TS-2 catalyst

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2009
Agnieszka Wróblewska
Abstract BACKGROUND: The influence of technological parameters on the epoxidation of 1-butene-3-ol (1B3O) over titanium silicalite TS-2 catalyst has been investigated. Epoxidations were carried out using 30%(w/w) hydrogen peroxide at atmospheric pressure. The major product from the epoxidation of B3O was 1,2-epoxybutane-3-ol, with many potential applications. RESULTS: The influence of temperature (20,60 °C), 1B3O/H2O2 molar ratio (1:1,5:1), methanol concentration (5,90%(w/w)), TS-2 catalyst concentration (0.1,6.0%(w/w)) and reaction time (0.5,5.0 h) have been studied. CONCLUSION: The epoxidation process is most effective if conducted at a temperature of 20 °C, 1B3O/H2O2 molar ratio 1:1, methanol concentration (used as the solvent) 80%(w/w), catalyst concentration 5%(w/w) and reaction time 5 h. Copyright © 2009 Society of Chemical Industry [source]

Synthesis of 6-acrylamido-4-(2-[18F]fluoroanilino)quinazoline: a prospective irreversible EGFR binding probe

JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 2 2005
Neil Vasdev
Abstract Acrylamido-quinazolines substituted at the 6-position bind irreversibly to the intracellular ATP binding domain of the epidermal growth factor receptor (EGFR). A general route was developed for preparing 6-substituted-4-anilinoquinazolines from [18F]fluoroanilines for evaluation as EGFR targeting agents with PET. By a cyclization reaction, 2-[18F]fluoroaniline was reacted with N, -(2-cyano-4-nitrophenyl)- N,N -dimethylimidoformamide to produce 6-nitro-4-(2-[18F]fluoroanilino)quinazoline in 27.5% decay-corrected radiochemical yield. Acid mediated tin chloride reduction of the nitro group was achieved in 5 min (80% conversion) and subsequent acylation with acrylic acid gave 6-acrylamido-4-(2-[18F]fluoroanilino)quinazoline in 8.5% decay-corrected radiochemical yield, from starting fluoride, in less than 2 h. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Quantitative determination of ,,, -dimethylacrylshikonin (DASK) in rat whole blood by liquid chromatography,tandem mass spectrometry with pre-column derivation and its pharmacokinetic application

BIOMEDICAL CHROMATOGRAPHY, Issue 4 2009
Huifang Tian
Abstract A sensitive and selective liquid chromatography,tandem mass spectrometric (LC-MS/MS) method was developed and validated for the determination of ,,, -dimethylacrylshikonin (DASK) in rat whole blood. DASK was pretreated using pre-column derivatization with 2-mercaptoethanol followed by liquid,liquid extraction with cyclohexane. Detection was performed on Thermo Finnigan TSQ Quantum triple quadrupole mass spectrometer by selected reaction monitoring mode via electrospray ionization source. The linear range for the determination of DASK spiked in rat whole blood (0.25 mL) was 3,3000 ng/mL. The accuracy was within 9%. Intra- and inter-day precisions were no more than 16.1 and 13.3%, respectively. The validated LC-MS/MS method was successfully applied to the preliminary pharmacokinetic study in rats. After DASK administration (60 mg/kg, p.o.) in rats, pharmacokinetic parameters were obtained, where the area under the drug concentration,time curve was 2393.7 ± 224.4 ng h/mL and the elimination half-life was 27.6 ± 5.3 h. Copyright © 2008 John Wiley & Sons, Ltd. [source]

A sensitive method for determination of salvianolic acid A in rat plasma using liquid chromatography/tandem mass spectrometry

BIOMEDICAL CHROMATOGRAPHY, Issue 7 2008
Lixia Pei
Abstract Salvianolic acid A (SAA), a major effective constituent of Salvia miltiorrhizas, is widely used in traditional Chinese medicine. A sensitive rapid analytical method was established and validated for SAA in rat plasma, which was further applied to assess the pharmacokinetics of SAA in rats receiving a single oral dose of SAA. The method used liquid chromatography tandem mass spectrometry in multiple reaction monitoring mode with chloramphenicol as the internal standard. A simple liquid,liquid extraction based on ethyl acetate was employed. The combination of a simple sample cleanup and short chromatographic run time (3 min) increased the throughput of the method substantially. The method was validated over the range 1.4,1000 ng/mL with a correlation coefficient >0.99. The lower limit of quantification was 1.4 ng/mL for SAA in plasma. Intra- and inter-day accuracies for SAA were 95,113 and 98,107%, and the inter-day precision was less than 12%. This method is more sensitive and faster than previous methods. After a single oral dose of 100 mg/kg of SAA, the mean peak plasma concentration (Cmax) of SAA was 318 ng/mL at 0.5 h, the area under the plasma concentration,time curve (AUC0,12 h) was 698 ± 129 ng·h/mL, and the elimination half-life (T1/2) was 3.29 h. Copyright © 2008 John Wiley & Sons, Ltd. [source]