Mass spectral characteristics of some 3,5-disubstituted 4-isoxazolecarboxylic acids

Authors

  • Milka Maksimović,

    Corresponding author
    1. Department of Chemistry, Faculty of Science, University of Sarajevo, Vojvode Putnika 43, 71000 Sarajevo, Yugoslavia
    • Department of Chemistry, Faculty of Science, University of Sarajevo, Vojvode Putnika 43, 71000 Sarajevo, Yugoslavia
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  • Ana Nikolin,

    1. Department of Chemistry, Faculty of Science, University of Sarajevo, Vojvode Putnika 43, 71000 Sarajevo, Yugoslavia
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  • Branko Nikolin

    1. Faculty of Pharmacy, University of Sarajevo, Moše Pijade 6, 71000 Sarajevo, Yugoslavia
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Abstract

Mass spectrometry has been applied for the structural study of some new unsymmetrically 3,5-disubstituted 4-isoxazolecarboxylic acids prepared by a modification of the general procedure of Quilico and Fusco. The new glucoside, 3-[2-(β-D-glucopyranosiloxy)-5-chlorophenyl]-5-methyl-4-isoxazolecarboxylic acid (1) and 3-(2-hydroxy-3,5-dichlrophenyl)-5-methyl-4-isoxazolecarboxylic acid (2) have been prepared starting from the glucoside helicin, 2-(β-D-glucopyranosiloxy) benzaldehyde or the corresponding aglucon, the salicylaldehyde, respectively. Fragmentation patterns of 2 and its analogue 3-(2-hydroxy-5-chlorophenyl)-5-methyl-4-isoxazolecarboxylic acid (3), obtained by the cleavage of the glycosidic linkage of 1 are discussed. The principal fragmentation routes of these compounds are formulated to occur via azirine intermediates.

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