DL-alanine → N-Butyrylalanine

Temperature

0 °C

22.27 g (250 mmol) of D,L-alanine and 55.66 g (550 mmol) of triethylamine are dissolved in 250 ml of dichloromethane, and the solution is cooled to 0° C. 59.75 g (550 mmol) of trimethylsilyl chloride are added dropwise, and the solution is stirred at room temperature for 1 hour and at 40° C. for one hour. After cooling to −10° C., 26.64 g (250 mmol) of butyryl chloride are added dropwise, and the resulting mixture is stirred at −10° C. for 2 hours and at room temperature for one hour. With ice-cooling, 125 ml of water are added dropwise, and the reaction mixture is stirred at room temperature for 15 minutes. The aqueous phase is evaporated to dryness, the residue is triturated with acetone and the mother liquor is filtered off with suction. Following removal of the solvent, the residue is chromatographed. The resulting product is dissolved in 3N aqueous sodium hydroxide solution, and the resulting solution is evaporated to dryness. The residue is taken up in conc. HCl and again evaporated to dryness. The residue is triturated with acetone, the precipitated solid is filtered off with suction and the solvent is removed under reduced pressure. This gives 28.2 g (71%) of a viscous oil which crystallizes after some time.

1. temperatureAfter cooling to −10° C.
2. stirringthe resulting mixture is stirred at −10° C. for 2 hours and at room temperature for one hour
3. temperatureWith ice-cooling
4. stirringthe reaction mixture is stirred at room temperature for 15 minutes
5. customThe aqueous phase is evaporated to dryness
6. customthe residue is triturated with acetone
7. filtrationthe mother liquor is filtered off with suction
8. customremoval of the solvent
9. customthe residue is chromatographed
10. dissolutionThe resulting product is dissolved in 3N aqueous sodium hydroxide solution
11. customthe resulting solution is evaporated to dryness
12. customagain evaporated to dryness
13. customThe residue is triturated with acetone
14. filtrationthe precipitated solid is filtered off with suction
15. customthe solvent is removed under reduced pressure
16. customThis gives 28.2 g (71%) of a viscous oil which crystallizes after some time

ORD record

ord-31e1d85d8b2c4f0e93d8ab303bc7e3a9

Source dataset

uspto-grants-2005_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06878708B2