Compounds with Bridgehead Nitrogen

Article abstract of DOI:10.1002/mrc.1270200411

The position of conformational equilibra in 1,5-,1,6- and 1,8-dimethylperhydro-oxazolo<3,4-a>pyridines were determined by 1H NMR spectroscopy.The cis-(H-5,H-8a)-1,5-dimethylperhydro-oxazolo<3,4-a>pyridines adopted the trans fused conformation, as did the two isomers of cis-(H-1,H-8a)-1,6-dimethyl-perhydro-oxazolo<3,4-a>pyridine.In contrast, r-1,t-6,t-8a-1,6-dimethyl-perhydro-oxazolo<3,4-a>pyridine preferred the cis-fused conformation.Three of the 1,8-dimehylperhdro-oxazolo<3,4-a>pyridines adopted the trans-fused conformations (with distortion of the system in the case of the r-1,c-8,c-8a derivative) and the r-1,c-8,c-8a-1,8-dimethyl derivative adopted the cis-fused conformation.