Process for preparing (S) and (R)—2-[4-(4-chlorobenzhydryl)piperazin-1-yl]-ethoxyacetamide
The present invention relates to a process for preparing (S)-2-[4-(4-chlorobenzhydryl)piperazin-1-yl]-ethoxyacetamide and (R)-2-[4-(4-chlorobenzhydryl)piperazin-1-yl]-ethoxyacetamide by separation of a racemic mixture using multiple column chromatography.
1. Process for preparing (S)—2-[4-(4-chlorobenzhydryl)piperazin-1-yl]-ethoxyacetamide and (R)—2-[4-(4-chlorobenzhydryl)piperazin-1-yl]-ethoxyacetamide, by enantiomeric resolution of racemic 2-[4-(4-chlorobenzhydryl)piperazin-1-yl]-ethoxyacetamide using simulated mobile bed chromatography.
2. Process according to claim 1 , wherein at least three columns filled with chiral stationary phase are used.
3. Process according to claim 2 , wherein the chiral stationary phase is chosen from phases based on silica gel supporting polymeric compounds.
4. Process according to claim 2 , wherein the chiral stationary phase is a phase based on silica gel supporting an ester or a carbamate of cellulose or of amylose.
5. Process according to claim 1 , wherein the simulated moving bed chromatographic system uses at least one column packed with an optical resolution packing material, said packing material consisting of silica gel supporting amylose tris(3,5-dimethylphenylcarbamate) or a chemically modified form thereof.
6. Process according to claim 5 , wherein the average particle diameter of the packing material is 1 to 300 μm.
7. Process according to claim 6 wherein the particles of the packing material are porous.
8. Process according to claim 7 , wherein the pore diameter of the particles is 10 Å–5000 Å.
9. Process according to claim 5 , wherein the amylose tris(3,5-dimethylphenylcarbamate) or chemically modified form thereof is 1 to 99% weight percent of the silica gel support.
10. Process according to claim 1 , wherein it is performed at a temperature of 5–50° C.
11. Process according to claim 1 , wherein it uses a simulated mobile bed system comprising eight columns.
12. Process according to claim 1 , wherein the simulated mobile bed system uses an eluent selected from methanol, or a mixture of n-heptane and n-propanol.
13. Process according to claim 3 , wherein the polymeric compounds are selected from polysaccharide derivatives, polyacrylic derivatives and polyamide derivatives.