Unusual reactivity of N-tert-butylimines under FVT conditions

Abstract Thermal reactions of N - tert -butyl-( E )-crotonaldimine ( 1a ) and 1,4-di-( tert -butyl)-1,4-diazabuta-1,3-dien (glyoxal-bis- N - tert -butylimine) ( 1b ) under FVT conditions have been studied. It has been found that at 800 °C compound 1a yielded pyrrole and crotononitrile, presumably via homolytic t -Bu–N bond cleavage and formation of the iminyl radical. In the reaction of 1b at 800 °C, 2-methylimidazole ( 4b ) has been obtained unexpectedly as the major product. The mechanism of these reactions has been proposed. Furthermore, combined FVT and UV-photoelectron spectroscopy have been applied for direct generation and in situ characterization of compounds 1a and 1b under thermal activation conditions.