ELECTRON-IMPACT-INDUCED FRAGMENTATION OF CYCLIC 2-DIAZO-1,3-DIKETONES

The electron-impact-induced fragmentation (the mass spectra, 15-70 eV) of cyclic 2-diazo-1,3-diketones (2-diazo-1 ,3-cyklohexadione, la; 2-d iazo-4,4-dimetyl-1,3-cyklohexandione, Ib; 2-diazo-5,5-dimetyl-1,3-cykl ohexandione, Ic; 2-diazo-4,6-dioxa-5,5-dimetyl-1,3-cyklohexandione, Id ; 2-diazo-5-fenyl-1,3-cyklohexandione, le) was studied. For all invest igated diazocompounds fragmentational schemes were proposed. All cycli c diazo-1,3-diketones show molecular ion with 0.7-86.4 % of relative a bundance and Wolff rearrangement (without Id). A typical fragments are [M](+), [M-N-2](+), [M-N-2-CO](+), [M-N-2-CO-CH2](+) and [M-N-2-CO-CH 3](+).