Synthesis of 4-Oxo and 4-Hydroxyimino-4-Deoxy-Kdn2En Derivatives

ABSTRACT 2,6-Anhydro-3-deoxy-D-manno-non-2-en-4-ulosonic acid (4-oxo-Kdn2en, 2) was synthesized from methyl 2,6-anhydro-3-deoxy-D-glycero-D-galacto-non-2-enonate (Kdn-2en methyl ester, 7) by the oxidation with manganese dioxide in dry acetone in good yield. 4-Hydroxyimino-Kdn2en derivatives (3), and 4-carbethoxymethylene-Kdn2en derivatives (4) were synthesized from the peracetylated methyl ester of 4-oxo-Kdn2en by oximation and Wittig reaction in good yield, respectively.