Study of ring cleavage in quaternary ammonium salts of 1,3-diazaadamantane

A series of quaternary ammonium salts of 5,7-dimethyl-1,3-diazaadamantan-6-one bearing aryl and alkyl substituents was synthesized. On treatment with aqueous KOH, these compounds undergo ring cleavage to give 3,7-diazabicyclo[3.3.1]nonane derivatives. The product structure was confirmed by 1H and 13C NMR and IR spectroscopy.