257624-17-2Relevant articles and documents
Process for making 4,4′-diketo-carotenoids
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, (2008/06/13)
A process for the manufacture of a symmetrical, terminally ring-substituted polyenes by reacting a polyene di(O,O-dialkyl acetal) with a cyclic dienol ether in the presence of a Lewis or Br?nsted acid, hydrolyzing the condensation product resulting therefrom and cleaving off alcohol under basic or acidic conditions from the polyene derivative produced at this stage. The novel cyclic dienol ethers, as well as, novel intermediates resulting from the condensation and additional intermediates in this process form further aspects of the invention. The final products are primarily carotenoids, which find corresponding use, e.g., as colorings and pigments for foodstuffs, animal products, etc.
