Sulfuric acid-promoted rearrangement of 3-(<Emphasis Type="Italic">N</Emphasis>-acylamino)-substituted caran-4-one oximes

The rearrangement of 3-(N-acylamino)-substituted caran-4-one oximes in the presence of sulfuric acid affords 2-oxa-4-azabicyclo3.3.1]non-3-en-6-one derivatives. 3-Aminocaran-4-one oximes, in which the amino group contains such substituents as acetyl, propionyl, chloroacetyl, 1-adamantylcarbonyl, benzoyl, 2-thienylcarbonyl, or anilinocarbonyl, undergo this reaction. N-Acyl derivatives of higher fatty (heptanoic and nonadecanoic) acids do not undergo this reaction. The reaction with D₂SO₄ leads to the replacement of all hydrogen atoms of the isopropyl group by deuterium. The mechanism of this rearrangement is proposed. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1837–1844, August, 2005.