Mass fragmentation pattern of 3-[2 '-(4 ''-methoxyphenyl) ethyl]isocoumarin, 3-benzylisocoumarin and their 3,4-dihydro-derivatives under electron ionization mass spectrometric studies

Electron ionization mass spectra of 3-[2'-(4 "-methoxy-phenyl)ethyl]isocoum arin (1), 3-benzylisocoumarin (2), (dl)-3-[2'-(4 "-methoxy-phenyl)ethyl]-3, 4-dihydroisocomarin (3) and (dl)-3-benzyl-3,4-dihydroisocoumarin (4) are di scussed. The elimination of neutral fragments or radicals afforded differen t cations and radical cations by ring contraction and alpha-cleavage. The m ass fragmentation patterns are designed with the help of LREIMS and HREIMS peak matching of molecular ion peaks exhibited by EIMS are also given.