Mass spectrometry of β-keto aldehydes: Novel hydroxyl transfer reactions

The mass spectral fragmentation of 2,3-diaryl-3-oxo-1-propanals has been investigated by low electron energy, metastable defocusing and shift techniques. The o-nitro group strongly interacts with α-cleavage reactions of the carbonyl group. The cyclization/elimination processes, accompanied by oxygen and hydroxyl transfer in the mass spectra of o-nitro-β-keto aldehydes, are preceded by hydrogen abstraction by the nitro group.