Electron Impact and Ammonia Chemical Ionization Mass Spectra of n-Azabicycloalkan-(n+1)-ones (m=3-6, n=6-9)

Article abstract of DOI:10.1002/oms.1210210202

Electron impact induced fragmentation of the title compounds obeys a route where the lactam moiety, OCNH, is cleaved first, with the accompanying formation of a cycloalkene ion.This can be verified by low-resolution, high-resolution, B/E and B²/E spectra as well as by collisional activation spectra of, for example, the ions m/z 82 and 67 from 7-azaabicyclo<4.2.0>octan-8-one and from cyclohexene.The only, and fairly weak, fragment ions including O and N are ⁺, kH_2k-2N>⁺ (k=5-8) and ⁺.The ammonia chemical ionization spectra are also characteristic for all four lactams and show the same dominant ions in all cases, namely ⁺, ^+. and <2M+1>^+..