✦ LIBER ✦
A novel donor for stereoselective α-sialylation; efficient synthesis of an α(2–8)-linked bis-sialic acid unit
✍ Scribed by Nafizal Hossain; Göran Magnusson
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- French
- Weight
- 252 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
The novel sialyl donor methyl [ethyl 5-(N,N-diacetyl)-4,7,8,9-tetra-O-acetyl-2-thio-3thiophenyl-2,3,5-trideoxy-D-erythro-o,-L-gluco-2-nonulopyranosid]onate (2) was synthesized by Nacetylation of the corresponding 5-acetamido compound 1. a-Sialylation of mono-and disaccharide aglycons, having one or two unprotected hydroxyl groups, furnished the corresponding di-and trisaccharides in high yield and with virtually complete regio-and stereoselectivity. As one example, a Neu5Ac~(2--)8)Neu5Ac derivative was thus obtained in 44% yield; the corresponding 13 anomer was not observed.