Preparation of 9‐fluoro‐9‐deoxy‐<i>N</i>‐[2‐¹⁴C]acetylneuraminic acid

Abstract

9‐Fluoro‐9‐deoxy‐ N ‐[2‐ 14 C]acetylneuraminic acid has been prepared from 6‐fluoro‐6‐deoxy‐ N ‐acetylmannosamine and [2‐ 14 C]pyruvic acid for the first time, using Clostridium perfringens N ‐acetylneuraminate pyruvate‐lyase (EC 4.1.3.3). The fluoro sugar was activated by CMP‐ N ‐acetylneuraminic acid synthase and CTP to yield CMP‐9‐fluoro‐9‐deoxy‐ N ‐[2‐ 14 C]acetylneuraminic acid. Both products were obtained in good yield (60 and 30%, respectively). The radioactive sugar in its activated form is glycosidically attached to asialo‐α 1 ‐acid glycoprotein by sialyltransferase and can be removed by the action of Vibrio cholerae sialidase. The reaction rates of the enzymes studied are lower with the 9‐fluoro derivatives than with the N ‐acetylneuraminic acid substrates.