Mannich Condensation of 3,3,5-Trimethylcyclohexanone and Its Oxime

Abstract

Mannich condensation of 3,3,5-trimethylcyclohexanone with paraformaldehyde and dimethylamine or benzylamine hydrochloride involves both activated methylene group in the initial ketone to give compounds with equatorial aminomethyl substituent. The major isomer is that formed by addition at the less sterically hindered carbon atom. Likewise, Mannich condensation of the E and Z isomers of 3,3,5-trimethylcyclohexanone oxime react at both methylene groups, and the addition of aminomethyl fragment occurs preferentially at that methylene group which is located more closely to the oxime hydroxy group.