Methyl transfer: the mass spectra of reserpine derivatives
Abstract
The mass spectrum of methyl 18β-(4-hydroxy-3-methoxycinnamoyloxy)-11,17α-dimethoxy-3β,20α-yohimban-16β-carboxylate (3)[methyl O-(4-hydroxy-3-methoxycinnamoyl)reserpate] shows that the ester methyl group is transferred intermolecularly to the basic nitrogen of the yohimban system; this was confirmed by studies on the [2H]methyl ester (8), the ethyl ester homologue (4), and the quaternary salt of (3).