The fragmentation of organic molecules under electron‐IMPACT—II. The mass spectra of tetronic acid and some of its derivatives

The mass spectra of tetronic acid and of a number of its derivatives are recorded and discussed. Where necessary, the composition of the fragment ions has been checked by high resolution mass measurements. Fragmentation of the molecular ion is explained in terms of the rupture of a bond attached to C‐4, and the predominant routes for many of the compounds can be explained on the basis of two schemes, the first involving preliminary ketonisation of the molecular ion, followed by elimination of carbon monoxide, the second involving rupture of the C‐4R3 bond prior to elimination of carbon monoxide. Special structural features, however, provide alternative routes.