Recent progress in commercial retinoids and carotenoids

Abstract

Among the retinoids vitamin A has an exceptional position both by volume and in its field of application. The competing technical syntheses are discussed. The other retinoids namely (all E)- and (13 Z)-Retinoic acid and Etretinate are used as topical and systemic agents in dermatology. Commercial synthetic carotenoids are mainly used as pigmenters for food in vivo; examples are egg yolk - and broiler pigmentation with B-apo-8' ‘-carotenoic acid ethylester and pigmentation of farm-raised salmon with astaxanthin. Another field of application is direct coloration of food, e.g. of margarine with β-carotene. Presently β-carotene is booming as a substitute for vitamin A without teratogenic potential and as a biological antioxidant. Two strategies compete in manufacture of these carotenoids - synthesis of β-apo-8' ‘-carotenoids and 3-carotene starting from vitamin A and its precursors followed by the stepwise oxidation of β-carotene to canthaxanthin and astaxanthin - conversion of oxo-isophorone to C15-phosphonium salts of different oxidation pattern in the β-ionone-ring followed by Wittig condensation with C10-dialdehyde. © 1991 1UPAC