Synthesen in der Carotinoid‐Reihe. 15. Mitteilung Synthesen in der β‐Carotinal‐ und β‐Carotinal‐Reihe

To study the oxidative degradation of p‐carotene to vitamin A in the animal body, a number of possible intermediates have been prepared. Starting with 15,15′‐dehydro‐β‐apo‐12′‐carotenal(C25) vinylogous series of polyene aldehydes and acetates with 25 to 40 carbon atoms have been synthesized by successive enol ether condensations. The synthetic β‐apo‐8′‐carotenal(C30) and β‐apo‐8′‐carotenal(C30) were identical with the permanganate oxidation product of β‐carotene and its corresponding alcohol isolated by KARRER.