Electron-impact studies XCV–skeletal rearrangement fragments in the mass spectra of 3,5- diphenylisoxazole and 3,5- diphenylpyrazole

The ion [C₁₃H₉]⁺ (m/e 165) is produced from the molecular ion of 3,5-diphenylisoxazole by the process [M ? CO ? H₂CN·] and [M ? CO ? HCN ? H·] and from that of 3,5-diphenyl-pyrazole by the eliminations [M ? N₂H· ? C₂H₂]. These processes have been studied by ²H and ¹³C labelling. A correlation between photochemical, thermal and electron-impact decompostions is noted for 3,5-diphenylisoxazole.