Fragmentation Mechanism of Trans-α-Aryl-β-enamino Esters

Electron impact-induced fragmentation mechanisms of trans-α-aryl-β-enamino esters were investigated using mass-analyzed ion kinetic energy (MIKE) spectrometry and high resolution accurate mass data. It was found that the main characteristic fragmentations of compounds studied were: an odd electron ion M⁺ - EtOH was formed by losing a neutral molecule of ethanol; and the skeletal rearrangements took place; and the ring opening reaction happened after losing a carbon monoxide; and the typical McLafferty rearrangement underwent in ester group. The cyclization reaction caused by losing neutral molecule of TsNH₂ due to the ortho-effects of substituted group of aromatic ring was also observed.