Journal of Lipid Research, Vol. 19, 250-259, February 1978
Copyright © 1978 by Lipid Research, Inc.

Total synthesis of stereospecific sphingosine and ceramide

Yukihiro Shoyama , Hikaru Okabe , Yasuo Kishimoto , and Catherine Costello

John F. Kennedy Institute and Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205; Eunice Kennedy Shriver Center, Waltham, MA 20154, and Department of Neurology, Massachusetts General Hospital, Boston, MA 02114; and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139

A small-scale synthesis of the four sphingosine stereoisomers (d-erythro, l-erythro, d-threo, and l-threo) and lignoceroyl d- and l-erythro-sphingosines, which is suitable for synthesis of tritium-labeled compounds, is described. Ethyl dl-erythro-2-acetamino-3-hydroxy-4t-octadecenoate was esterified with l(+)-acetylmandeloyl chloride and the two diastereomers obtained were separated from each other by thin-layer or column chromatography. Each diastereomer was subjected to ethanolysis to obtain ethyl d- or l-erythro-2-amino-3-hydroxy-4t-octadecenoate which was then reduced with LiAlH₄ or NaBH₄ to yield d- or l-erythro-sphingosine. d-erythro-[1-³H]Sphingosine with high specific activity was prepared by using LiAl³H₄ in the last step. d- and l-threo-sphingosines were synthesized from ethyl dl-threo-2-acetamino-3-hydroxy-4t-octadecenoate by using a similar procedure.

Ceramide (lignoceroyl sphingosine) was prepared either by acylating sphingosine or by the following new method. Ethyl dl-erythro-2-amino-3-hydroxy-4t-octadecenoate was converted to the N-lignoceroyl derivative and esterified with l(+)-acetylmandeloyl chloride. The two diastereomers obtained were separated and each isomer was treated with a catalytic amount of sodium ethoxide. One of the products, ethyl d-erythro-2-lignoceroylamino-3-hydroxy-4t- octadecenoate, was reduced with NaBH₄ to yield ceramide. N-palmitoyl dl-erythro-sphingosine was also prepared using an identical procedure. N-lignoceroyl d-erythro-[1-³H]sphingosine was prepared by NaB³H₄ reduction of the corresponding amide ester. A doubly labeled ceramide, [1-¹⁴C]lignoceroyl [1-³H]sphingosine, containing high specific activity, was prepared by mixing the above N-lignoceroyl d-erythro-[1-³H]sphingosine and N-[1-¹⁴C]lignoceroyl d-erythro-sphingosine. The conversion of the doubly labeled ceramide to 3-keto derivative is also described.

Supplementary key words Resolution of ethyl d- and l-erythro-2-acetamino-3-[l(+)-acetylmandeloyloxy]- 4t-octadecenoate • resolution of d- and l-erythro-2-lignoceroylamino-3-[l(+)- acetylmandeloyloxy]-4t-octadecenoate • [1-³H]sphingosine • N-acyl [1-³H]sphingosine • doubly labeled ceramide • NaBH₄ reduction of ethyl 2-acylamino-3-hydroxy-4t-octadecenoate • doubly labeled 3-ketoceramide

Submitted on May 18, 1977
Accepted on September 20, 1977

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