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Corresponding Acetates (corresponding + acetate)
Selected AbstractsA validated gas chromatographic method for the evaluation of enzymatic enantioselectivity in kinetic resolution applicationsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6 2005Ykelien L. Boersma Abstract An enantioselective gas chromatography (GC) method has been developed and validated for determination of the enantiomers of citronellol in kinetic resolution experiments. S -(,)-,-Citronellol is a precursor of rose oxide. After solid-phase extraction (SPE) with ethyl acetate, the enantiomers of R -(+)-,-citronellol and S -(,)-,-citronellol and their corresponding acetate- and butyrate esters were separated through enantioselective GC respectively. The method was validated and found to be reproducible, specific, accurate, and precise. Analyte recoveries and detection limits were also determined. The applicability of this method was shown in a kinetic resolution experiment using lipase A of Bacillus subtilis. [source] A multicriteria ranking of organotin(IV) compounds with fungicidal propertiesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 10 2003Godwin A. Ayoko Abstract The application of multicriteria decision-making methods to the results of in vitro antifungal properties of organotin compounds of the type PhxSnXz (x = 2 or 3; X = O2CC6H4OH, O2CC6H4OCOCH3, Cl or O2CCH3; z = 1 or 2) and of free 2-hydroxybenzoic and 2-acetoxybenzoic acids against Aspergillus niger, Aspergillus flavus, Candida albicans, Penicillium citrinum, Trichophyton rubrum and Trichophyton violaceum have been described. Ranking information necessary to select one toxicant in preference to others and to assess the properties influencing the preference has been obtained. Patterns in the multivariate analyses suggest that cationic and anionic moieties of the toxicant play some roles in their fungicidal activities. The triphenyltin compounds were generally more active than their diphenyltin analogues, but the acetoxybenzoates were more active than the corresponding hydroxybenzoates, acetates or chlorides. Thus, triphenyltin acetoxybenzoate is up to 7.5 times as active as the corresponding acetate, which is commercially marketed as a fungicide. The results of the analyses have been discussed in the light of the mechanism of antifungal activity of organotin compounds and the potential of multivariate data analysis techniques to facilitate the screening and ranking of antifungal agents. Copyright © 2003 John Wiley & Sons, Ltd. [source] Synthesis and Biological Evaluation of Apicularen A AnaloguesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2005Andreas F. Petri Abstract Reactions between amide anions and propanal derivatives containing benzolactone components at their 3-positions produced hemiaminals, which were dehydrated via the corresponding acetates to provide the apicularen A analogues 21, 29, 34, 38, and 41. Of these, 21 and 29 contain the intact enamide side chain of apicularen A but have modifications in the macrolactone core. On the other hand, compounds 34, 38, and 41 are characterized by the natural core structure but are modified in the enamide part. Biological studies showed that 21 and 29 are quite active but that the other three analogues show only minor activities. The 11-deoxy analogue 21 turned out to be the most active compound against a mdr cell line. It can be concluded that the macrolactone part of apicularen A will tolerate modifications to some degree, whereas the enamide part is rather sensitive towards structural modifications. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Synthesis of Chiral 2-Phospha[3]ferrocenophanes and their Behaviour as Organocatalysts in [3+2],Cyclization ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Arnaud Voituriez Abstract Planar chiral 2-phospha[3]ferrocenophanes have been prepared via a stereoselective three-step synthesis. The key step is the lithiation of the 1,1,-disubstituted ferrocene 11 bearing (S)-2-(methoxymethyl)pyrrolidines as the chiral ortho -directing groups. The diastereoselectivity of these reactions has been mastered by an appropriate choice of the metallating agent, so as to afford a suitable access to C2 -symmetrical, tetrasubstituted ferrocenes. These compounds have been converted into the enantiomerically pure 2-phospha[3]-ferrocenophanes 16, via the corresponding acetates and their reactions with primary phosphines. Phosphines 16 have been used as nucleophilic catalysts in model cyclization reactions. Unlike 2-phospha[3]-ferrocenophanes with stereogenic ,-carbons, the planar chiral derivatives 16 proved to be suitable catalysts for these processes. Thus, for instance, phosphine 16c successfully promotes the enantioselective [3+2],annulations of allenes and enones into functionalized cyclopentenes (ees up to 96%). Among others, spirocyclic derivatives have been obtained in good yields and ees in the range 77,85%. The robustness of this catalyst has been demonstrated by recycling experiments. [source] A method for the identification of the double-bond position of isomeric linear tetradecenols and related compounds based on mass spectra of dimethyl disulfide derivativesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 1 2002Gu Yuan A simple method is presented for calculation of the double-bond position in linear tetradecenols based on mass spectral data of dimethyl disulfide derivatives. In this approach, the m/z ratios of the molecular ion and of one (or both) of the two most abundant fragment ions were utilized to calculate the double-bond position, without the requirement to identify both fragment ions resulting from carbon-carbon cleavage across what was originally the double bond. The approach was tested with mass spectra of dimethyl disulfide derivatives of 12 isomeric tetradecenols, and the double-bond position in each isomer was successfully identified by this method. The method was shown to work also for the corresponding acetates. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||