Alkaloids of the Australian Rutaceae: Halfordia scleroxyla. III. Mass spectrometry of halfordinol and related oxazoles

Abstract

Comparative studies by mass spectrometry of halfordinol [2-(3-pyridy1)-5-(4-hydroxyphenyl)oxazole] and other derivatives of the new oxazole alkaloid N-methylhalfordinium chloride with model aryloxazoles confirmed the structure of the alkaloid. One of the main features of the decomposition of 2,5-diaryloxazole ions in the mass spectrometer involved a novel concerted elimination of HCN and CO. A mechanism has been proposed for this and other reactions of oxazole ions, including those of 4,5- and 2,4-diphenyl derivatives.