Structural variations onN-acetylneuraminic acid, 16. A convenient approach to 3-deoxy-D-glycero-D-galacto-nonulosonic acid (KDN), 5-azido-5-deoxy-KDN and 5-deoxy-KDN, and their 4-methylumbelliferyl 2α-glycosides

✍ Scribed by Schreiner, Erwin ;Zbiral, Erich

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 685 KB
• Volume: 1990
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.1990199001107

✦ Synopsis

Abstract

The reaction of peracetylated N‐acetylneuraminic acid methyl ester 1 with nitrosyl acetate affords a mixture of anti/syn‐N‐nitroso derivatives 2a and 2a′, which can be transformed with sodium trifluoroethanolate into the 5‐diazo compound 3. The reaction of 3 with tetrabutylammonium acetate/acetic acid yields methyl 2,4,5,7,8,9‐hexa‐O‐acetyl‐3‐deoxy‐D‐clycero‐β‐D‐galacto‐2‐nonulopyranosidonate (KDN) (4a). On the other hand, 5‐azido‐5‐deoxy‐KDN (5a) is formed by treating 3 with hydrazoic acid in toluene. Heating of 2a/2a′ in toluene furnishes a mixture of the peracetylated deaminated furanoid sialic acid derivative 10 with probably changed configuration at C‐5 and C‐6 and the deaminated 5,6‐ and 4,5‐didehydrosialic acid derivatives 6 and 7. Catalytic hydrogenation of 6 and 7 yields the 5‐deoxy‐KDN derivative 9a and ‐ after hydrogen‐olysis of the 4‐acetoxy group ‐ a minor amount of compound 8. The compounds 4a, 5a, and 9a have been converted into the free deaminated sialic acids 4e, 5e, and 9e via the 4‐me‐thylumbelliferyl 2α‐glycosides 4c, d, 5c, d, and 9c, d.