Mass-spectrometric study of compounds of the cyclopropane series. 9. Behavior of esters under electron impact

1. The mass spectra of the cyclopropanecarboxylic acids and their methyl and ethyl esters exhibit rather strong intensity peaks of the molecular ions, the stability towards electron impact being greater for the methyl esters than for the acids, and the stability of the acids being greater than for the ethyl esters. 2. Fragmentation of the studied compounds is accompanied by formation of the characteristic ions [M-H]+, [M-CH3OH]+, [M-CH3]+, and [M-55]+, the effect of the cyclopropane ring on the dissociation of the molecular ions being most clearly evident for the methyl esters.