Abstract: Highly pure optically active threo-3-amino-1,2-epoxy compounds appropriate for materials for manufacturing drugs and a process for producing the same on an industrial scale. An optically active threo-3-amino-1,2-diol derivative is subjected in an organic solvent in the presence of a base to alkylsufonylation or arylsulfonylation to thereby give the corresponding optically active threo-3-amino-2-hydroxy-1-sulfonyloxy compound. Next, the resultant product is subjected to epoxidation in the presence of a base to give the corresponding optically active threo-3-amino-1,2-epoxy compound. The thus obtained epoxy compound is purified by using an organic solvent and water, thus giving a highly pure epoxy compound.

Abstract: Highly pure optically active threo-3-amino-1,2-epoxy compounds appropriate for materials for manufacturing drugs and a process for producing the same on an industrial scale. An optically active threo-3-amino-1,2-diol derivative is subjected in an organic solvent in the presence of a base to alkylsufonylation or arylsulfonylation to thereby give the corresponding optically active threo-3-amino-2-hydroxy-1-sulfonyloxy compound. Next, the resultant product is subjected to epoxidation in the presence of a base to give the corresponding optically active threo-3-amino-1,2-epoxy compound. The thus obtained epoxy compound is purified by using an organic solvent and water, thus giving a highly pure epoxy compound.

Abstract: Highly pure optically active threo-3-amino-1,2-epoxy compounds appropriate for materials for manufacturing drugs and a process for producing the same on an industrial scale. An optically active threo-3-amino-1,2-diol derivative is subjected in an organic solvent in the presence of a base to alkylsufonylation or arylsulfonylation to thereby give the corresponding optically active threo-3-amino-2-hydroxy-1-sulfonyloxy compound. Next, the resultant product is subjected to epoxidation in the presence of a base to give the corresponding optically active threo-3-amino-1,2-epoxy compound. The thus obtained epoxy compound is purified by using an organic solvent and water, thus giving a highly pure epoxy compound.

Abstract: An optically active cyanohydrin represented by the following general formula (1): ##STR1## wherein each of R1 and R2 is a hydrogen atom or an amino-protecting group, and the configurations relating to the carbon atoms at the *2-position and *3-position are as follows: in the case of the carbon atom at the *2-position being in R-configuration, the carbon atom at the *3-position is in S-configuration, and in the case of the carbon atom at the *2-position being in S-configuration, the carbon atom at the *3-position is in R-configuration, can be efficiently produced by crystallizing one of the optically active cyanohydrins while treating a mixture of cyanohydrin diastereomers in the presence of an amine and an organic solvent to change the configuration relating to the carbon atom at the 2-position and thereby cause isomerization.