Phase-transfer-catalyzed synthesis of aryl α-ketosides of N-acetylneuraminic acid. A 2-methylfluoran-6-yl glycoside of N-acetylneuraminic acid, 2-methyl-6-(5-acetamido-3,5-dideoxy-α-d-glycero-d-galacto-nonulopyranosyl-onic acid)xanthene-9-spiro-1′-isobenzofuran-3′-one, a new substrate for neuraminidase assay

✍ Scribed by Jörg Rothermel; Hans Faillard

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 884 KB
• Volume: 196
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(90)84104-3

✦ Synopsis

Glycosidation of N-acetylneuraminic acid by phase-transfer catalysis in chloroform-aqueous alkali gave several known and some new aryl cY-ketosides in a short reaction time and in good yields. The 4-methylumbelliferyl cu-ketoside, the standard substrate for neuraminidase, was prepared in a yield of up to 70%. New NeuSAc ketosides were prepared with fluorescein and the fluorescein analog, 2methyl-6-hydroxyfluoran

(2-methyl-6-hydroxyxanthen&9-spiro-l'-isobenzofuran-3'-one) as aglycons, the latter being synthesized from 2-(2-hydroxy-5methylbenzoyl) benzoic acid and 3-fluorophenol. The a configuration was ascertained by 400-MHz 'H-n.m.r. spectroscopy and by cleavage of the ketosides with neuraminidases from Vibrio cholerae and Clostridium perfringens. The enzymic hydrolysis of the 2-methylfluorand-yl ketoside gave K, values of 82 PM (V. cholerae) and 96 PM (C. perfringenes).