AbstractObservation of the nmr spectra of several Δ3‐ and Δ4‐tetrahydropyridines hydrochlorides provides a useful method for the structural determination of this type of compound. The Δ3‐ Isomers exist as one predominant epimer only whereas the Δ4‐isomers exist as a mixture of the two possible epimers. The respective assignments are discussed in view of the criteria previously applied in the study of this type