Total synthesis of an immunosuppressive glycolipid, (2S,3S,4R)-1-O- (alpha-d-galactosyl)-2- tetracosanoylamino-1,3,4-nonanetriol.
ABSTRACT [reaction: see text] A practical and efficient total synthesis of (2S,3S,4R)-1-O-(alpha-d-galactosyl)-2-tetracosanoylamino-1,3,4-nonanetriol, OCH 1b, a potential therapeutic candidate for Th1-mediated autoimmune diseases, is described. The synthesis incorporates direct alkylation onto epoxide 5 and stereospecific halide ion catalyzed alpha-glycosidation reaction. A key intermediate 10 was obtained in only eight steps and 37% overall yield from commercially available d-arabitol 2, and the total synthesis of 1b was accomplished in 12 steps and 19% overall yield. This method will enable the synthesis of a variety of phytosphingolipids, especially that with the shorter sphingosine side chain than 1a, in a highly stereoselective manner.
- Journal of chemical engineering of Japan 01/2009; 42(7):508-511. · 0.61 Impact Factor
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ABSTRACT: The stereocontrolled synthesis of β-galactosyl-5-aza-sphinganines was accomplished with high efficiency by a novel and convergent strategy. The truncated β-galactosphinganine 5 was easily acylated with different long chains. Moreover, the simple conversion of thiazole to formyl enabled 5-aza-alkylchains to be introduced via an amino-reduction reaction. The overall yield for the synthesis of β-galacto-5-aza-sphinganines 9 and 13 was about 30–35% starting from 5. Preliminary results concerning the β-transgalactosylation of a truncated sphinganine catalyzed by galactosidases are also presented and discussed.Tetrahedron 07/2011; 67(29):5176-5183. · 2.82 Impact Factor
- Helvetica Chimica Acta 05/2009; 92(5). · 1.39 Impact Factor