Synthesen in der Carotinoid‐Reihe. 2. Mitteilung. Über den Aufbau der Ringkomponenten

Abstract
Starting from β‐ionone, 2,6,6‐trimethyl‐cyclohexanone‐(1) and 2,6,6‐trimethyl‐cyclohexene‐(2)‐one‐(1), intermediates for carotenoids are synthesized. New methods for chain‐lengthening and rearrangement of double bonds are developed. 16 different ring compounds are characterised by their phenyl semicarbazones.