SYNTHESIS OF CAROTENOID GLYCOSYLESTERS AND OTHER CAROTENOIDS

The naturally occurring crocetin di(β-D-glucosyl)ester can be synthesised from crocetin diimidazolide or crocetin di-(l,2,4-triazolide) and [β-D-glucose in pyridine in presence of a base. The application of this new method to other carboxylic acids '-apo-β-carotene-8'-oic acid, vitamin A acid, benzoic acid and stearic acid) and carbohydrates (galactose, lactose) shows that this new method, using unprotected carbohydrates and azo-lides proceeds with a high degree of regiose1ectivity and ste-reoselectivity and is of general importance. The synthesis of the three chiral C30-apocarotenoids β-citrau-rin, β-citraurol and β-citraurinene, isolated from orange peel, was carried out with (3R)-3-hydroxy-β-ionone as starting ma-terial. Furthermore, C 30 -apocarotenoids with one methyl group shifted by one carbon atom (= diapocarotenoids) were prepared as model compounds. According to the scheme C10 + C20 + C 10, starting with trans-citral via geraniol epoxide, the corresponding C15 -epoxy Wittig salt and crocetin dialdehyde 1,2-epoxy-lycopene, 1,2, 1 ’,2’-di - epoxy-lycopene and a 1,2-epoxy-C30 -apocarotina1 were synthesised. © 1979, Walter de Gruyter. All rights reserved.