Abstract: | The mass spectra of O-methyloximes of fifteen aliphatic aldehydes and ketones of various molecular weights and degrees of branching have been examined. All give molecular ions, and many of the fragmentations parallel those of aldoximes and ketoximes. The formation of some ions is better explained by the initial production of a novel substituted cyclopropene ion. O-Methyloximes of of the long-chain aldehydes and methyl ketones are readily distinguished by the masses of abundant products of McLafferty rearrangement at m/e 73 and 87, repectively. |