Conformational Analysis of SubstitutedN-Nitroso-trans-decahydroquinolin-4-ones

Abstract

1H and 13C NMR resonance assignments and conformational assignments were carried out for four N-nitroso-2-phenyl-trans-decahydroquinolin-4-ones. In addition to conventional 1D NMR methods, 2D shift-correlated NMR techniques (1H–1H COSY, 1H–1H NOESY and 1H–13C HETCOR) were used for the signal assignments. At room temperature the title compounds exist in two isomeric forms. The preferred conformations of both the isomers of nitrosamines were determined by a comparison of the spectral data with those for the parent amines, and with the aid of substituent parameters. Molecular strain in nitrosamines is minimized by partial escape of the piperidine moiety into non-chair conformation. © 1997 by John Wiley & Sons, Ltd.