反应详情

Dibenzoyl-L-tartaric acid salt of 4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine was prepared by reacting 4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine (1.0 mole) with Dibezoyl-L-tartaric acid monohydrate (1.18 molar equivalent) in IPA-methanol at 25-70° C. till solid mass precipitated out. The salt was filtered and washed with IPA; an enantiomerically enriched desired isomer was obtained. The salt was taken into ethyl acetate. It was basified with aq. NaHCO3. Ethyl acetate layer was separated and washed with water and brine solution. Ethyl acetate extract was collected and dried over anhydrous sodium sulfate. Ethyl acetate was distilled out to obtain a mixture of (2R) and (2S)-4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine (% Purity by HPLC-98%; % Chiral purity by HPLC of R-isomer 70%).

1. customat 25-70° C.
2. customprecipitated out
3. filtrationThe salt was filtered
4. washwashed with IPA
5. customwas obtained
6. customEthyl acetate layer was separated
7. washwashed with water and brine solution
8. extractionEthyl acetate extract
9. customwas collected
10. dry with materialdried over anhydrous sodium sulfate
11. distillationEthyl acetate was distilled out
12. customto obtain