The electron impact mass spectral fragmentation pathways for a series of 1,
3-di- and 1,2,3-trisubstituted imidazolidines were investigated. The data s
how remarkable differences depending on the location and identity of substi
tuents. The atypical 1,2,2,3-tetrasubstituted imidazolidine, 2-cyano-1-meth
yl-3-(p-nitrophenyl)-2-phenylimidazolidine, was also investigated.