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Highly Selective Method (highly + selective_method)
Selected AbstractsChemInform Abstract: Malononitrile-Catalyzed and Highly Selective Method for the Synthesis of 2-((E)-1,3-Diarylallylidene)malononitriles in Ionic Liquid.CHEMINFORM, Issue 5 2010Xiang-Shan Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] A Mild, Catalytic, and Highly Selective Method for the Oxidation of ,,,-Enones to 1,4-Enediones.CHEMINFORM, Issue 28 2003Jin-Quan Yu Abstract For Abstract see ChemInform Abstract in Full Text. [source] An efficient and highly selective method for the synthesis of cryptotackiene derivatives catalyzed by iodineJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2010Xiang-Shan Wang A mild, efficient and highly selective approach to the synthesis of cryptotackiene derivatives via three-component reactions of 3-amino-9-ethylcarbazole and aromatic aldehydes with electron-rich alkenes, such as 2,3-dihydrofuran, or 3,4-dihydro-2H -pyran catalyzed by iodine in THF is reported. It is worth to note that only trans -products were obtained with high selectivity in good to high yields, which confirmed by X-ray diffraction analysis. J. Heterocyclic Chem., (2010). [source] Analysis of S -adenosylmethionine and related sulfur metabolites in bacterial isolates of Pseudomonas aeruginosa (BAA-47) by liquid chromatography/electrospray ionization coupled to a hybrid linear quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 21 2009Tommaso R. I. Cataldi A comprehensive and highly selective method for detecting in bacterial supernatants a modified sulfur nucleoside, S -adenosyl-L-methionine (SAM), and its metabolites, i.e., S -adenosylhomocysteine (SAH), adenosine (Ado), 5,-deoxy-5,-methylthioadenosine (MTA), adenine (Ade), S -adenosyl-methioninamine (dcSAM), homocysteine (Hcy) and methionine (Met), was developed. The method is based on reversed-phase liquid chromatography with positive electrospray ionization (ESI+) coupled to a hybrid linear quadrupole ion trap (LTQ) and 7-T Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). A gradient elution was employed with a binary solvent of 0.05,M ammonium formate at pH 4 and acetonitrile. The assay involves a simultaneous cleanup of cell-free bacterial broths by solid-phase extraction and trace enrichment of metabolites with a 50-fold concentration factor by using immobilized phenylboronic and anion-exchange cartridges. While the quantitative determination of SAM was performed using stable-isotope-labeled SAM-d3 as an internal standard, in the case of Met and Ade, Met- 13C and Ade- 15N2 were employed as isotope-labeled internal standards, respectively. This method enabled the identification of SAM and its metabolites in cell-free culture of Pseudomonasaeruginosa grown in Davis minimal broth (formulation without sulphur organic compounds), with routine sub-ppm mass accuracies (,0.27,±,0.68,ppm). The resulting contents of SCSS -SAM, SS -dcSAM, MTA, Ado and Met in the free-cell supernatant of P. aeruginosa was 56.4,±,2.1,nM, 32.2,±,2.2,nM, 0.91,±,0.10,nM, 19.6,±,1.2,nM and 1.93,±,0.02,µM (mean,±,SD, n,=,4 extractions), respectively. We report also the baseline separation (Rs ,1.5) of both diastereoisomeric forms of SAM (SCSS and SCRS) and dcSAM (SS and RS), which can be very useful to establish the relationship between the biologically active versus the inactive species, SCSS/SCRS and SS/RS of SAM and dcSAM, respectively. An additional confirmation of SAM-related metabolites was accomplished by a systematic study of their MS/MS spectra. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||