Ethanol → Pipecolic acid, (-)-

Temperature

80 °C

To a mixture of about 600 mL of 95% ethanol and 200 mL water at 80° C. was added about 40 g of DL-pipecolic acid followed by the addition of 49 g of D-tartaric acid. The reaction mixture was stirred at 80° C. for about an hour to get a clear solution. The solution was allowed to stand at about 25° C. for about 48 hrs and the solid precipitated was filtered. The filtrate was reduced to 260 mL by evaporation and allowed to stand at about 25° C. for 24 h. At the end of that period, more solid had precipitated out and was removed by filtration The filtrate was evaporated to dryness and the residue was dissolved in 1 L water. The water solution recovered was then treated with Amberlite Ion-Exchange resin IR-120 H+ form (Hydrous form) to remove the tartaric acid followed by 10% NH4OH solution treatment of the resin to give L-pipecolic acid of optical purity of about 85-90%. After drying 22 g of a solid was obtained.

1. customto get a clear solution
2. customthe solid precipitated
3. filtrationwas filtered
4. customThe filtrate was reduced to 260 mL by evaporation
5. waitto stand at about 25° C. for 24 h
6. customAt the end of that period, more solid had precipitated out and
7. customwas removed by filtration The filtrate
8. customwas evaporated to dryness
9. dissolutionthe residue was dissolved in 1 L water
10. customThe water solution recovered
11. additionwas then treated with Amberlite Ion-Exchange resin
12. customH+ form (Hydrous form) to remove the tartaric acid

ORD record

ord-abe8527c093b408cac0f2f688410c93a

Source dataset

uspto-grants-2010_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07683175B2