| abstract |
The present invention develops a preparation method that obtains aminoalcohol derivatives with high optical purity and can be synthesized in large quantities at low cost. For example, the compound represented by the general formula is recrystallized in the middle of the production steps thereof. In the formula, R 1 represents, for example, a trihalomethyl group, R 2 represents, for example, a hydrogen atom, R 3 represents, for example, a halogen atom, R 4 represents, for example, a lower alkyl group, X represents a sulfur atom, n represents an integer of 1 to 4, and W represents hydrogen chloride or hydrogen bromide. |