THE THERMAL REVERSIBILITY OF THE MICHAEL REACTION: II. NITROKETONES AND RELATED COMPOUNDS

In continuation of the study of the thermal reversibility of Michael adducts, 13 γ-nitroketones were examined in the mass spectrometer, using the inlet heated at 230°. The presence of furans was indicated, arising from the intact molecule. Such remotely related substances would never have been envisaged had not the mass spectrum been available. In contrast to the behavior of delta ketonic nitriles (Part I) only normal retrogression was found. There were many secondary products resulting from extensive decomposition of the expected nitro addend. Not all the products can be isolated by classical procedures, but their presence is predictable, and can be shown by the use of the mass spectrometer. Nine simple nitro- and bromonitro-ethylenes, sensitive to heat alone, were unexpectedly stable in the heated inlet of the mass spectrometer, but did give rise to very small amounts of decomposition products. Phenyl- and 1-naphthyl-nitromethanes, which decomposed completely, gave comparable types of products. Most of these nitro compounds have previously been thermally treated by classical methods.