Mannich-type three component condensation of α-substituted caran-4-one oximes with formaldehyde and secondary amines

Under the conditions of the Mannich reaction, 3-substituted oximes of caran-4-one undergo aminomethylation at the α-carbon atom to oxime. The reaction takes place successfully only in a mixture of methanol and acetic acid to produce α-aminomethyl derivatives in 25–83% yields. The secondary or tertiary amino group at the α’-position is eliminated under the reaction conditions to form derivatives of α,β-unsaturated oxime, while sulfur-containing substituents remain unchanged.