67509-73-3

Upstream product

• 10464-96-7 15,15'-didehydro-8'-apo-β-caroten-8'-al 
• 1107-26-2 trans-β-apo-8'-carotenal 
• 103400-22-2 15,15'-didehydro-10'-apo-β-caroten-10'-al-diethylacetal 

Downstream Products

• 1107-26-2 trans-β-apo-8'-carotenal 

Relevant academic research and scientific papers

Selected cis/trans isomers of carotenoids formed by bulk electrolysis and iron(III) chloride oxidation

Bulk electrolysis and chemical oxidation with FeCl3 of all-trans canthaxanthin (I) and 8′-apo-β-caroten-8′-al (II) gave primarily the 9- and 13-cis-isomers, which were separated by HPLC and identified by 1H NMR spectroscopy. Optical absorption measurements showed that the 15-cis, 9,13-di-cis isomers of I are also formed by these methods. In the case of the unsymmetrical compound II, additional isomers were formed. The cis isomers account for about 40-60% of products formed. Formation of the isomers is believed to occur by rotation about certain bonds in the cation radicals or dications, which are formed in the oxidation processes. The neutral cis species are then formed by an electron exchange reaction of the cis-cation radicals with neutral all-trans carotenoids in solution. The electrochemical and iron(III) chloride oxidation induced isomerization are shown to be efficient and improved methods for forming selected carotenoid isomers.

Simultaneous Electrochemical and Electron Paramagnetic Resonance Studies of Carotenoid Cation Radicals and Dications

Comproportionation equilibrium constants have been determined from simultaneous electrochemical and EPR measurements for the carotenoid cation radicals (CAR.+) and dications (CAR2+) of β-carotene (I), β-apo-8'-carotenal (II), and canthaxanthin (III).K(I)com = 2.4x10-2, Kcom(II) = 1.8x10-2, Kcom(III) = 2.1x103.These indicated that, upon oxidation of III, 96percent CAR.+ would be formed while 99.7percent CAR2+ would be formed for I and II if the oxidation potential was 100 mV anodic of the first observed voltammetric wave.This explains the reason for the strong EPR spectrum observed for III and the weak EPR spectra observed for I and II.Rotating disk experiments confirm that oxidation of carotenoids occurs by an EE rather than by a ECE mechanism and are highly quasireversible systems.The second oxidation peak in the CV spectrum of II has been shown not to be due to a dication analogous to the CV of III but to a radical apparently from the oxidation of a decay product of the dication from II.