Mass spectrometry of 'onium compounds. Part XIV. Methiodides of methyl pyridylacetates

Abstract

Methiodides of the three isomeric methyl pyridylacetates have been investigated by mass spectrometry. Thermal loss of hydrogen iodide with formation of the volatile anhydro-base was an important process for the 2- and 4-isomers. The 3-isomer underwent a redox process to give a volatile dihydropyridine whose structure was confirmed by separate synthesis of the 1,4-dihydro-derivative. Demethylation was shown by deuteriation to take place mainly from the ester group. Ionization potential values have been determined and used in structural deductions. The major electron-induced fragmentation pathways are discussed.