| 摘要 |
The present invention relates to a process for the resolution of mandelic acid derivative enantiomers from (racemic) mixtures by salt formation (see, for example, formula IIa) with chiral base cyclic amides, and racemisation of the unresolved enantiomer in the same process, wherein an additional racemising base may optionally be used, employing an acid:total base (i.e. cyclic amide and optional additional base) molar ratio of at least 1:1; provided that the cyclic amide base is present in a molar ratio of at least 0.75; and to the use of the resolved mandelic acid derivatives as intermediates suitable for large-scale manufacturing of, for example, pharmaceutical compounds; wherein R is selected from CHF2, H, C1-6 Alkyl, CH2F, CHCl2 and CClF2; and wherein n is 0, 1 or 2; R1 is H or C1-6 Alkyl and X is H, halo or C1-6 Alkyl. |
