Syntheses of Terpenes by the Condensation of Aliphatic Compounds

Part II. Self-Condensation of Mesityloxide and Structures of Isomeric Isoxylitones

Abstract

Treatment of mesityloxide with basic condensing agents resulted in formation of isoxylitones-A, B, C and D and isophorone. These compounds were purely isolated and assigned their structures from spectroscopic and chemical evidences. Isoxylitone-A and isoxylitone-B were conformers of 1-acetyl-2, 4, 6, 6-tetramethyl-1, 3-cyclohexadiene separat-ed by the rotational barrier of acetyl group and interconversional barrier of cyclohexadiene ring. Isoxylitone-C was 4-isopropenyl-1, 5, 5-trimethyl-1-cyclohexen-3-one. Isoxylitone-D was 5, 5-dimethy1-3-(1-isobutenyl)-2-cyclohexen-l-one.