Vergleichende Untersuchung von Reaktivitäten und Ionenstrukturen beim monomolekularen Abbau isomerer Hydroxyzimtsäuremethylester unter Elektronenbeschuss

Abstract

Comparative investigation of reactivities and ion structures upon electron impact induced degradations of the isomeric hydroxy cinnamic acid methyl estersBy analysis of energy release data in metastable peaks it is shown that m‐ and p‐hydroxy cinnamic acid methylesters retain specific structural features upon degradation under electron impact, although their spectra are very similar and the shapes of the metastable peaks due to the initial methoxy cleavage are identical. A pronounced charge radical localization in the molecular ion is indicated. The o‐isomer is found to yield a coumarin type structure by elimination of methanol, whose further degradation by decarbonylation involves at least three different mechanisms. The resulting ion structures are different from benzofuran.