Electron ionization mass spectra of phosphorus‐containing heterocycles. III. 1,3,4,2‐Oxadiazaphosphinane 2‐oxides

Abstract

The 1,3,4,2-oxadiazaphosphinane 2-oxides differ not only in the relative configuration of the P atom (R* or S*), but also in many other ways such as the ring size, ring fusion, P substitution and bridgehead N atom whose effects on their fragmentations have been studied. Some fragmentations resembled those of 3,1,2-oxazaphosphinane 2-oxides and 1,3,2-diazaphosphinane-2-oxides, but new routes were also found, initiated by ionization at the bridgehead N atom. The relative abundances of the molecular ions and some fragment ions allowed the differentiation of cis-trans epimers. Compounds with n = 2 and R=N(CH(2)CH(2)Cl)(2), and linearly or angularly isoquinoline-fused isomers in most cases, gave more numerous ions with lower relative abundances than the other compounds in this series. Only the isoquinoline derivatives provided fragments resulting from ionization of the aromatic part of the molecule.

Electron Ionization Mass Spectra of Organophosphorus Compounds. Part III: Mass Spectrometric Fragmentation of Diethyl Spiro[Pyrimidino[5,3′][1,2]Oxazole] Phosphonate, Diethyl (Oxazolo[5,4-D]Pyrimidine-4,6-Dione)Phosphonate, and Diethyl (Pyrimidino[4,5-B][1,4]Oxazine)Phosphonate Derivatives

“…[5][6][7][8][9][10] Mass spectrometry (MS) was applied to the characterization of this class of compounds using analysis of metastable ions by the collision induced dissociation technique and exact mass measurements. [11][12][13][14][15] The mass spectral fragmentation patterns under ionization of phosphorus containing isolated or fused heterocycles were studied in detail. However, to our knowledge, there is no mass spectral fragmentation studies for spiro-and fused phosphorus compounds.…”