Elucidating the mass spectrum of the retronecine alkaloid using DFT calculations. (15th August 2018)

• Record Type: Journal Article
• Authors: Modesto‐Costa, Lucas; Martinez, Sabrina T.; Pinto, Angelo C.; Vessecchi, Ricardo; Borges, Itamar
• Is Part Of: Journal of mass spectrometry. Volume 53:Number 10(2018)
• Page Start: 934
• Page End: 941
• Publication Date: 2018-08-15
• Subjects: computational chemistry -- energy profile -- fragmentation pathways -- mass spectrometry -- odd‐electron rule -- pyrrolizidine alkaloids -- retronecine; Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/jms.4253
• Languages: English
• ISSNs: 1076-5174

Abstract

Abstract: Pyrrolizidine alkaloids are natural molecules playing important roles in different biochemical processes in nature and in humans. In this work, the electron ionization mass spectrum of retronecine, an alkaloid molecule found in plants, was investigated computationally. Its mass spectrum can be characterized by three main fragment ions having the following m/z ratios : 111, 94, and 80. In order to rationalize the mass spectrum, minima and transition state geometries were computed using density functional theory. It was showed that the dissociation process includes an aromatization of the originally five‐membered ring of retronecine converted into a six‐membered ring compound. A fragmentation pathway mechanism involving dissociation activation barriers that are easily overcome by the initial ionization energy was found. From the computed quantum chemical geometric, atomic charges, and energetic parameters, the abundance of each ion in the mass spectrum of retronecine was discussed.