| abstract |
PURPOSE: To prepare optically active mandelic acid at low cost in high purity, by reacting (±)-mandelic acid with optically active α-phenyl-ethylamine at an amount about half of the conventionally used amount, thereby improving the optical purity of the scarcely soluble salt of both compounds. n CONSTITUTION: An optically active mandelic acid is prepared by reacting 1 equivalent of (±)-mandelic acid (A) with 0.25W0.75 equivalent of optically active α- phenylethylamine (B). By the use of less than equivalent of (+)- or (-)-B, excess A is retained in the solution in such a form that it has higher solubility than that of the easily soluble salt [(+)-A.(+)-B or (-)-A.(-)-B], whereby the optical purity of the desired hardly soluble salt [(+)-A.(-)-B or (-)-A.(+)-B] is increased. Addition of NaOH, etc. to the reaction system forms soluble mandelic acid salt, and further improves the effect. n COPYRIGHT: (C)1980,JPO&Japio |