Mass spectra of trimethylsilyl derivatives of naturally occurring flavonoid aglycones and chalcones

Electron impact mass spectra of the trimethylsilyl derivatives of a series of flavonoid aglycones and chalcones are reported. The spectra show prominent ions arising from fragmentation of the trimethylsilyl (TMS) groups. Inter‐actions between adjacent TMS groups, and between TMS groups in the 3‐ or 5‐position (6′‐position for the chalcones) and the C‐ring carbonyl, yield structurally significant ions. Few fragments associated with the retro‐Diels‐Alder cleavage of the C‐ring characteristic of the underivatized compounds, are observed. The TMS derivatives thus provide complementary information for the identification of flavonoid aglycones and chalcones in biological systems.