Ethylene chlorohydrin




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Catalyzed Asymmetric 2-chloroethanol Synthesis

Time:2015/11/12 3:25:26

2-chloroethanol formation from unsaturated fatty acids reacted with hypochlorous acid.

Stimulated neutrophils produce hypochlorous acid (HOCl) via the myeloperoxidase-catalyzed reaction of hydrogen peroxide with chloride. The reactions of HOCl with oleic, linoleic, and arachidonic acids both as free fatty acids or bound in phosphatidylcholine have been studied. The products were identified by gas chromatography-mass spectrometry of the methylated and trimethylsilylated derivatives. Oleic acid was converted to the two 9,10-2-chloroethanol isomers in near stoichiometric yield. Linoleic acid, at low HOCl:fatty acid ratios, yielded predominantly a mixture of the four possible mono2-chloroethanol isomers. Bis2-chloroethanols were also formed, in increasing amounts at higher HOCl concentrations. Arachidonic acid gave a complex mixture of mono- and bis2-chloroethanols, the relative proportions depending on the amount of HOCl added. Linoleic acid appears to be slightly more reactive than oleic acid with HOCl. Reactions of oleic and linoleic acids with myeloperoxidase, hydrogen peroxide, and chloride gave 2-chloroethanol products identical to those with HOCl. Lipid 2-chloroethanols have received little attention as products of reactions of neutrophil oxidants. They are more polar than the parent fatty acids, and if formed in cell membranes could cause disruption to membrane structure. Since cellular targets for HOCl appear to be membrane constituents, 2-chloroethanol formation from unsaturated lipids could be significant in neutrophil-mediated cytotoxicity.

A New Palladium(II)-Catalyzed Asymmetric 2-chloroethanol Synthesis

A new approach is reported for secondary-ion time-of-flight mass spectrometry (TOF-SIMS) sample preparation. The method involves the use of halide additives or halide modification of silver substrate surfaces to promote analyte cationization and protonation. The enhancement of signal intensity has been demonstrated for neutral organic lipophilic and hydrophilic compounds including various small peptides and nucleosides. Improvement factors range from 2-30 for cationized species to 20-2000 for protonated species. However, the new sample preparation does not affect the signal intensities of preformed ionic species. The sample preparation approach is applicable to a wide variety of neutral compounds and should find broad use for organic analysis by TOF-SIMS. (C) 1998 John Wiley & Sons, Ltd.