Synthesis and structural and conformational study of 3,7-dimethyl-3,7-diazabicyclo[3.3.1]nonan-9-one oxime and its tautomer imine N-oxide

In an attempt to synthesize the 3,7-dimethyl-3,7-diazabicyclo[3.3.1]nonan-9-one oxime hydrochloride, the corresponding tautomer imine N-oxide hydrochloride (I·HCl) was obtained, as deduced from X-ray and IR data. By neutralization of I·HCl, the corresponding oxime (II) was obtained and characterized by IR data. From the 1H and 13C NMR spectra of I·HCl and II, a twin-chair conformation for the bicyclic system, more flattened in II, was deduced. This conformation has also been shown by X-ray data for I·HCl. © 1994.