THE STRUCTURE OF SPHINGOSINE

Abstract

Levene and West?have suggested that sphingosine is l-amino-2,3-dihydroxyheptadecene-4.Klenk and Diebold, as a result of later studies, revised this formula to 1,2-dihydroxy-3-aminooctadecene-4.The data of the latter authors establish conclusively that sphingosine has a Cl8 chain, a double bond between carbon atoms 4 and 5, and an amino and two hydroxyl groups on carbon atoms 1, 2, and 3.However, their evidence for the relative positions of the substituents is open to question.Therefore, as an initial step in a study of the biochemistry of the cerebrosides, we are making a further investigation of this problem.Sphingosine sulfate2 was benzoylated in aqueous alkali in the presence of ether.The crude N-benzoylsphingosine thus obtained was reduced catalytically with platinum oxide to N-benzoyldihydrosphingosine.The latter compound was converted in excellent yield to tribenzoyldihydrosphingosine (m.p. 144-146") by benzoylation in pyridine.Tribenzoyldihydrosphingosine was hydrolyzed to N-benzoyldihydrosphingosine with hot alcoholic alkali.The N-benzoyl derivative was not obtained in a crystalline form.Its purity was established, however, by analyses and reconversion to tribenzoyldihydrosphingosine in 90 per cent yield.N-Benzoyldihydrosphingosine was not oxidized by periodic acid under a variety of conditions.Since periodic acid is a specific and powerful oxidizing agent for 1,2-glycols, this result argues strongly against both of the structures proposed for sphingosine, since each of these contains a 1,2-glycol group.N-Benzoyldihydrosphingosine was readily converted into a cyclic acetal by the action of benzaldehyde and zinc chloride.This reaction is characteristic of