Abstract
Bubbling the dried air through the solution of all-trans β-carotene (I) in n-hexane, acetone or chloroform (irradiated with Xe-lamp or in dark), followed by column chromatography revealed the formation of the complicated mixture of oxidation products. They were identified and determined as all-trans and cis compounds of zeaxanthin, cryptoflavin, retro-dehydrocarotene, cryptoxanthin, I-5,8-monoepoxide (mutatochrome), I and I-5,6-monoepoxide in order of decreasing adsorption on the column. The yield of mutatochrome was amounted to 20% (15% of all-trans and 5% of cis) when I was air-oxidized in acetone solution in the presence of 3.4 NH_2SO_4. The efficacy of adding an acid for the formation of some epoxycarotenes was also observed in the liquid phase autoxidation of I. Abnormal formation of 3,4- and 3,4,3', 4'-dehydro-I and oxidation mechanism were also discussed.
