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Structural variations ofN-acetylneuraminic acid, 14. Synthesis of the β-methyl ketosides of 4-oxo-, 7-oxo-, and 8-oxo-N-acetylneuraminic acid and the corresponding 7,7- and 8,8-dimethoxy derivatives their behaviour towards CMP-sialate synthase

1990; Wiley; Volume: 1990; Issue: 1 Linguagem: Inglês

10.1002/jlac.199019900112

0170-2041

Michael Hartmann, Rudolf Christian, Erich Zbiral,

Biochemical and Molecular Research

Abstract The 4‐, 7‐, and 8‐ oxo ‐sialic acid β‐methyl ketosides 7, 10a , and 11a were obtained by transformation of easily available derivatives of N ‐acetylneuraminic acid ( 1a ). The carbonyl migration from C‐7 to C‐8 can be carried out under well‐defined conditions with formation of the ketone 11b . Starting from 7‐ and 8‐ketones 17 and 20 the corresponding dimethyl acetals are prepared. The 4‐ketone 7 behaves as a moderate competitive inhibitor of CMP‐sialate synthase [EC 2.7.7.43], whereas the 8‐ketone 11a , the 8,8‐dimethyl acetal 19 , and the 7,7‐dimethyl acetal 23 prove not to be inhibitors of this enzyme. The 7‐ketone 10a was not tested because of instability under test conditions at pH 8.5.