Analytical chemistry of synthetic routes to psychoactive tryptamines. Part III. Characterisation of the Speeter and Anthony route to N,N-dialkylated tryptamines using CI-IT-MS-MS.

Twelve symmetrically and 13 asymmetrically N,N-disubstituted glyoxalylamide precursors and their corresponding tryptamine derivatives have been characterised by gas chromatography low-pressure chemical ionisation ion trap tandem mass spectrometry (CI-IT-MS-MS) with internal (in situ) ionisation using methanol as the chemical ionisation reagent. Mass spectral differences and similarities between the investigated compounds are discussed and put into context with previous investigations. In tryptamines the formation of [CH2=N+R2R3] iminium ions after beta-cleavage appears to be the dominating process. Dissociation of the protonated molecule into [3-vinylindole]+ for example, appears to be a minor pathway when compared with electrospray triple quadrupole tandem mass spectrometry (ESI-TQ-MS-MS) where this ion transition was found to be of distinctive importance. CI-IT-MS-MS is also found to enable the differentiation between most isomeric derivatives studied.