Mass Spectrometry of Chromen-2-ones (Coumarins) and of Furo- and Pyrano-chromenones

Mass-spectrometric results for the coumarins, furocoumarins, and pyranocoumarins are summarised. The characteristic elimination of carbonyl groups characteristic of coumarin itself can be traced also in the spectra of substituted (halogenated, hydroxylated, methoxylated, carbonylated, O- and C-alkylated, and O- and C-acylated) coumarins, but the nature of the substituent has a decisive influence on the way in which derivatives break down, and in many cases elimination of carbonyl groups takes place only after partial or complete elimination of the substituent. With bicoumarins elimination of carbonyl groups is observed in the later stages of decomposition or not at all. The regularities reported for coumarins are found also with furo- and pyrano-coumarins. Differences in the spectra of positional isomers are usually apparent only in differences in the peak intensities of the characteristic ions.
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