cis-4,4,6-Trimethylbicyclo[3.1.1]heptan-2-one in the synthesis of nitrogen-containing bicyclic compounds

cis-4,4,6-Trimethylbicyclo[3.1.1]heptan-2-one (verbanone) in mannich condensation with paraformaldehyde and dimethylamine ads an aminomethyl fragment at the most sterically accessible carbon C-3 to form an equatorial isomer. The latter treated with sulfuric acid in acetonitrile affords a mixture of two 2-azalactams, 4-(dimethylaminomethyl)-5,7,7-trimethyl-2-azabicyclo[4.1.1]octan-3-one and its deamination product 4-methylene-5,5,7-trimethyl-2-azabicyclo[4.1.1]octan-3-one in 9:1 ratio. Z-isomer of amino oxime prepared by oximation of 3-(dimethylaminomethyl)verbanone under similar conditions affords a mixture of two 3-azalactams, 4-(dimethylaminomethyl)-5,7,7-trimethyl-3- azabicyclo[4.1.1]octan-2-one and its deamination product in 5:3 ratio. Mannich bases prepared from verbanone and its oxime were converted into the respective iodomethylates. Deamination of the latter results in a single product, alpha,beta -unsaturated ketone 3-methyleneverbanone.