Abstract The mass spectra of methyl kojate (2-hydroxymethyl-5-methoxy-4H-pyran-4-one), two deuterated analogues and 14 related 3 (5)-methoxy-4-pyrones have been studied. These compounds fragment according to a common mechanism, initiated by primary rearrangement of the molecular ion (s). Guidelines which indicate the presence of 3 (5)- methoxy-4-pyrones and allow structural determinations to be made from their mass ...
