Beckmann rearrangement of adamantanone oxime as a route to ditopic and tritopic secondarily substituted adamantane derivatives

The reaction in mixtures of adamantanone with hydroxylamine hydrochloride was studied in hydrochloric, hydrobromic, and hydroiodic acid solutions. In hydrochloric and hydroiodic acids, mixtures of isomers of 4-chloroadamantan-2-one and 4-iodoadamantan-2-one, respectively, are formed, whereas in hydrobromic acid in the presence of excess hydroxylamine hydrochloride, three stereoisomers of 4,8-dibromoadamantan-2-one appear. All the stereoisomeric haloketones were isolated by elution adsorption chromatography on silica gel or by crystalization. For the pure substances, their infrared, mass, and NMR spectra were measured.