| 摘要 |
Mineral acid addition or alkali metal salts of a -amino-b -hydroxy butyric acid are made by reacting, preferably above 130 DEG C., a -hydroxy-proprionaldehyde or a -acetoxypropionaldehyde with hydrogen cyanide, or an alkali metal cyanide and ammonia or an ammonium salt and hydrolysing the aminonitrile produced with mineral acid or alkali metal hydroxide. The free acid may be produced by neutralizing or preferably by treating the alkali metal salt with a weak acid cation exchange resin, or the mineral acid salt with a strong acidic cation exchange resin, eluting the adsorbed product with ammonium hydroxide and concentrating the eluate to dryness respectively. The description includes a study of the variations of reaction parameters on threonine yields and examples using a -aciloxy as well as a -hydroxy propionaldehyde as starting materials. Specifications 863,248 and 980,239 are referred to.
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