title: Ring contraction reactions of 2,3-dihydro-4H-1,3-oxazin-4-ones under electrospray ionization conditions.
abstract: The mass spectral behavior of 2,3-dihydro-4H-1,3-oxazin-4-ones has been investigated using electrospray ionization multi-stage mass spectrometry (ESI-MS(n)). All compounds showed a predominant retro-Diels-Alder (RDA) fragmentation pathway, and a novel ring contraction reaction by loss of isocynates was also found. The fragmentation mechanisms proposed for 4H-1,3-oxazin-4-ones are supported by ESI-MS/MS/MS spectra.
authors.affiliation: Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Ministry of Education, Department of Chemistry, School of Life Science and Engineering, Tsinghua University, Beijing 100084, China. mayuan@mail.tsinghua.edu.cn
authors.forename: Yuan
authors.initials: Y
authors.lastname: Ma
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.forename: Yufen
authors.initials: Y
authors.lastname: Zhao