High resolution mass spectrometry in molecular studies. Part XVII. Evidence for ring contractions in molecular ions: The fragmentation of N-acetylmorpholine

✍ Scribed by J. M. Tesarek; W. J. Richter; A. L. Burlingame

• Publisher: John Wiley and Sons
• Year: 1968
• Tongue: English
• Weight: 612 KB
• Volume: 1
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210010113

✦ Synopsis

In comparing N-acetylmorpholine to closely relatcd systcnis, two niajor difkrences in fragmentation are observed. M-15 and M-43 fragmcnts, although quitc conimon to such systems, are unusual with respect to their genesis. Formation of the M-15 fragment by loss of C-3 instead of the anticipitated loss of C-2 or C-8 is evident from shifts in the spectra of deuterated analogs. The M-43 species arises from total loss of the N-acyl substituent rather than the usual two-step loss of ketene plus a ring hydrogen. These data are presented in support of mechanistic rationale involving radical induced ring contraction to a common intermediate molecular ion. Techniques of high resolution mass spectrometry and isotope labeling have been employed to substantiate certain mechanistic details.

* Financial support was provided by the National Aeronautics and Space Administration, Grants NsG 101 and NGR 05-003-134.