Cyclisation of 2-methyl-2-(4-methyl-3-oxopentyl)cyclohexanone

Abstract

A Mannich condensation on dimethyl isopropyl ketone gave a mixture of 1-diethylamino-4-methylpentan-3-one, 1-diethylamino-2,2-dimethylbutan-3-one, and an undentified compound, which were separated by gas–liquid chromatography. 1-Diethylamino-4-methylpentan-3-one was condensed with 2-methylcyclohexanone to give 2-methyl-2-(4-methyl-3-oxopentyl)cyclohexanone, cyclisation of which in alkali gave 1,1,10-trimethyl-Δ⁸-2-octalone in small yield.