Abstract
Low energy 4-hydroxypyridine ions ( HP- 1) decarbonylate but also readily lose hydrogen ( iso)cyanide. Surprisingly, this reaction leads to a specific loss of the label from the OD-labelled isotopomer. Our tandem mass spectrometry experiments show that ionized vinylketene, CH 2 CHCH C O + ( 1), is the product ion. This ion is also generated by the decarbonylation of 4-cyclopentene-1,3-dione ions ( CP- 1) and a computational analysis using the CBS-QB3 model chemistry indicates that these seemingly unrelated ionic systems share similar dissociation mechanisms. In this study, a mechanism is presented for the decarbonylation of metastable ions CP- 1 that satisfies the energy requirement dictated by its appearance energy. Our computational analysis further shows that ions HP- 1 may isomerize into the ( iso)imino analogues of CP- 1, by consecutive H-shift, ring-opening and cyclization steps. The CP- 1 analogues serve as the immediate precursors for the specific loss of DNC (rather than DCN) from OD-labelled HP- 1 and also its decarbonylation into the vinyl( iso)ketenimine ions CH 2 CHCH N CH + ( 3) and CH 2 CHCH C NH + ( 4).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
