Heptafulvenes. IV. Mass Spectra of 8, 8-Dicyanoheptafulvene Derivatives

The mass spectra of 8, 8-dicyanoheptafulvene and its derivatives, which are considered to belong to a non-benzenoid aromatic compound, were measured. The high degree of aromaticity of 8, 8-dicyanoheptafulvenes was made clear by mass spectrometry. Low mass regions of dicyanoheptafulvene showed the elimination of hydrogen cyanide from parent ion and rearrangement to phenylpropiolonitrile ion. The mass spectra of methoxy dicyanoheptafulvenes showed fragmentation quite different from that of 8, 8-dicyanoheptafulvenes. The structures and fragmentation processes of dicyanoheptafulvenes were discussed.