D-2,4-dihydroxy-3,3-dimethylbutyronitrile, its production and use and process for production of D-pantolactone, D-2,4-dihydroxy-3,3-dimethylbutyramide and D-pantothenic acid

摘要

2.1. D-(-)-Pantolactone is an important intermediate in the synthesis of D-(+)-pantothenic acid or D-panthenol and can be obtained from the racemic compound by elaborate racemate resolution methods in the form of pantoic acid salts with chiral auxiliary bases and subsequent resolution of the pairs of salts with subsequent cyclisation of the pantoic acid. Since this synthesis is very elaborate, the object of the present invention is to provide a more suitable intermediate for pantolactone synthesis, which is to be obtainable straightforwardly and at low cost. 2.2. Such an intermediate is D-2,4-dihydroxy-3,3-dimethylbutyronitrile in an optical purity (D:L) of at least 80:20. D-(-)-pantolactone can be prepared in high yields by hydrolysis of the nitrile with concentrated acids. The nitrile is obtainable by reaction of hydroxypivalaldehyde with hydrogen cyanide in the presence of relatively large amounts of a D-oxynitrilase. 2.3. Preparation of D-(-)-pantolactone and D-(+)-pantothenic acid.