PURPOSE: To industrially and advantageously obtain the subject compound, important as a cancer related antigen, useful as a material for medicines, having expectorant action and anti-inflammatory action, by precipitating a sialic acid from a solution of the sialic acid in the presence of a specific acid.
CONSTITUTION: A solution containing sialic acid or its analog obtained by synthesizing N-acetylneuraminic acid by condensing N-acetylmannosamine with pyruvic acid in the presence of sialic aldolase is concentrated by using an evaporator. The concentrated solution is mixed with a 2-3C organic aid (e.g. acetic acid) to make its concentration ≥80% (V/V). The concentrated solution is dissolved in a water bath at 50°C while stirring to make the concentration of sialic acid or its analog ≥3% (W/V). The solution is allowed to stand at 4°C to precipitate white crystal of sialic acid or its analog. Then the crystal is filtered to purify a large amount of sialic acid or its analog inexpensively, simply and efficiently.
OCHI SHUJI
HORIE YOSHIAKI
TABATA SHINOBU
