Mass Spectra of Dodecadienic Compounds with a Conjugated Double Bond, Lepidopterous Sex Pheromones

抄録

All geometrical isomers of 5, 7-, 6, 8-, 7, 9-, 8, 10- and 9, 11-dodecadien-1-ols, and their acetates and aldehyde derivatives were analyzed by electron impact mass spectrometry. The abundance of molecular ion (M⁺) was observed in every spectrum, and the relative intensity of M⁺ tended to be strong if the compound possessed an (E)-double bond(s). In addition to M⁺, [M -H²O] ⁺ (alcohols) and [M -CH₃CO₂H]⁺ (acetates), every dienic compound showed typical series of C_nH_2n-2⁺∼C_nH^2n-5+ with abundance maxima around C₄, C₅, C₆ or C₇. Each double bond positional isomer characteristically yielded different ion peaks in the series, which were useful for its distinction from other isomers. These results indicate that the chemical structure of a natural pheromone of Lepidoptera is easily deduced successfully by GC-MS analysis if it is a conjugated dienic pheromone.