To date, a variety of methodologies have been intensively investigated for the processes of synthesizing optically active β-hydroxyethylamine compounds, in particular, optically active β-hydroxyethylamine compounds having a desired steric configuration, or their equivalents (i.e. oxazolidinone derivatives of the β-hydroxyethylamine compounds). A process of converting optically active β-hydroxyethylamine compounds into their enantiomers or diastereomers may be mentioned as one of the methodologies [JP-A-09/169,744; JP-A-55/145650; Adv.Carbohydr. Chem.Biochem., vol. 22, p. 109 (1967)].
As one example of the production by this methodology, a process of converting N-alkoxycarbonyl-ethylamine compounds having a leaving group at the β-position, which are obtained by converting a hydroxyl group of optically active β-hydroxyethylamine compounds into a leaving group, into oxazolidinone derivatives of β-hydroxyethylamine compounds having an inverted steric configuration at the β-position carbon is known [Adv.Carbohydr.Chem.Biochem., vol. 22, p. 139 (1967)].
If the oxazolidinone derivatives of β-hydroxyethylamine compounds obtained by this process are contacted with a base, without isolation and purification up to a pure or almost pure form from the operational and/or economical viewpoint in the industrial production, for example, if the derivatives are supplied to a further derivatization under basic conditions, however, there arise problems such as the secondary production of impurities as a side reaction and the decrease of the yield. More particularly, for example, if the derivatives are derivatized into β-hydroxyethylamine compounds by contacting with water under basic conditions, impurities are apt to be produced secondarily and the yield tends to decrease. Accordingly, there is a strong need for establishment of a production process of oxazolidinone derivatives of β-hydroxyethylamine compounds suitable for contact with a base, which process is economically advantageous and is suitable for an industrial production.
In view of the above circumstances, the object of the present invention was to provide a process for preparing oxazolidinone derivatives of β-hydroxyethylamine compounds which is economically advantageous and is suitable for an industrial production, and thereby, to provide a process for preparing β-hydroxyethylamine compounds in a high quality and a high yield which is economically advantageous and is suitable for an industrial production.