Synthesis and mass spectra of 4-mono- and 4,4-disubstituted 5,6-tetramethylenetetrahydro-1,3-oxazine-2-thiones

The syntheses and mass spectra of 5,6-tetramethylenetetrahydro-1,3-oxazine-2-thione and its 4-mono- and 4,4-disubstituted analogs are reported. The primary decay processes under electron impact are loss of the 1,3-oxazine ring, formation of hydrocarbon ions, and rearrangement of the [M−C6H9]+ ion.