Synthesis of mammalian dolichols from plant polyprenols

Abstract

Mixture of a long chain betulaprenol-type polyprenol ( ω- t 2- c n -OH) and/or its acetate were isolated from the leaves of Gymnospermae plant. Especially in Ginkgo biloba, Cedrus deodara and some other plants, the number ( n) of cis units was 11–19, predominantly 14, 15, 16, which is very similar to that of mammalian dolichols ( ω- t 2- c n -OH). Mammalian dolichols were synthesized from the polyprenyl acetates isolated from Ginkgo biloba by the Grignard coupling reaction with the optically active C 5-unit. The establishment of this synthetic process enabled us to have many other derivatives and analogues of mammalian dolichols. [1- 14C]Dolichols were also synthesized by the similar Grignard reaction using the optically active C 4-unit followed by one carbon homologation reaction with K 14CN. Investigations on the biological function of mammalian dolichols have been performed using these synthetic materials.