The mass spectral fragmentations of eight substituted pyrimido[6,1-a]isoquinolin-2-ones and four pyrimido[6,1-a]isuquinoline-2,4-diones under electron ionization were examined by metastable ion analysis, a collision-induced dissociation technique and exact mass measurements. The major fragmentation pathways began as radical site-initiated cleavage, and ionization of the nitrogen atom in the isoquinoline ring seemed to prevail. Only the isoquinolinediones gave fragments resulting from ionization of the phenyl ring. Substituents on N3 and C4 had larger effects on the peak intensities than substituents on C6. The major fragmentation pathway was different from that for the related oxazino[4,3-a]isoquinolines studied earlier.
|Number of pages||5|
|Journal||Rapid Communications in Mass Spectrometry|
|Publication status||Published - Jan 1 1997|
ASJC Scopus subject areas
- Analytical Chemistry
- Organic Chemistry