Steric effects in the mass spectra of aporphine alkaloids
Abstract
The mass spectra of aporphine alkaloids oxygenated at the 1- and 11-positions show marked differences from the spectra of other aporphines. These differences are attributed to the steric hindrance to coplanarity of the biphenyl ring system caused by the 1- and 11-substituents, and this factor may be of use in structural studies.