title: Characterization of artefacts produced by treatment of organic acids with diazomethane.
abstract: When alpha, beta-unsaturated acids and alpha-keto acids react with diazomethane not only are the corresponding methylates produced, but also diazomethane is added to the C = C double bond or to the oxo group. The gas chromatographic and mass spectral behaviour of these undesired products and some further artefacts produced in the hot inlet lines of a gas chromatograph are described. The mass spectra and retention indices allowed the structural assignment of several "unknown" compounds found previously in the methylated acid fraction of urine. A detailed analysis of the reaction of alpha-oxo acids with diazomethane revealed that, besides the already known oxirane methyl esters, homologous esters are also produced by an insertion reaction.
mesh_terms: D001826:Body Fluids / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D003521:Cyclopropanes / Q000032:analysis; D003978:Diazomethane; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007651:Keto Acids / Q000652:urine; D011720:Pyrazoles / Q000032:analysis; D012997:Solvents
chemical_list: D003521:Cyclopropanes; D007651:Keto Acids; D011720:Pyrazoles; D012997:Solvents; D003978:Diazomethane; C030797:cyclopropane