1H and 13C NMR spectra, isomers, and imine-enamine tautomers of N-(1,2,5-trimethyl-4-piperidylidene)aniline

The product of condensing 1,2,5-trimethylpiperidin-4-one with aniline has been investigated by NMR spectroscopy. Three isomers of N-(1,2,5-trimethyl-4-piperidylidene)aniline have been identified differing in the configuration of the methyl groups at C2 and C5 of the piperidine ring and the Z,E isomerism about the C=N bond. Traces of the enamine tautomeric form of the imine were also detected. {Mathematical expression}, {Mathematical expression}, and {Mathematical expression} spin-spin couplings were used to determine the structural configuration of the isomers. © 1990 Plenum Publishing Corporation.