DL-leucine → HCID 22799790, compound

13.1g (0.10 mol) of DL-leucine was neutralized with 50 ml of 2N-NaOH solution and to the solution were simultaneously added dropwise 17.1g (0.10 mol) of 2-bromopropionylchloride and 50 ml of 2N-NaOH solution at room temperature over one hour while stirring and maintaining the reaction mixture in a slightly alkaline condition. After completion of the addition, the ice bath used was removed and the mixture was stirred at room temperature for 3 hours. Successively, to the mixture was added the filtrate which had been prepared by neutralizing 13.8g (0.10 mol) of thiobenzoic acid with 50 ml of 2N--KOH solution and filtering. The resulting mixture was stirred at room temperature overnight and then acidified with hydrochloric acid to form oil. After extraction of oil with ethyl acetate, the oil was purified by subjecting it to chromatography using a silica gel column to give 18.5g of N-(2-benzoylmercaptopropionyl)leusine as oil. 40 ml of concentrated aqueous ammonia was added to 6.0g of N-(2-benzoylmercaptopropionyl)leucine to allow the derivative of leucine to hydrolyze in a manner similar to that used in Example I to give 2.6g of N-(2-mercaptopropionyl)leucine, ##EQU10## (m.p. 77° - 84°C)

1. temperaturemaintaining the reaction mixture in a slightly alkaline condition
2. additionAfter completion of the addition
3. customthe ice bath used was removed
4. stirringthe mixture was stirred at room temperature for 3 hours
5. additionSuccessively, to the mixture was added the filtrate which
6. filtrationKOH solution and filtering
7. stirringThe resulting mixture was stirred at room temperature overnight
8. customto form oil
9. extractionAfter extraction of oil with ethyl acetate
10. customthe oil was purified
11. customto give 18.5g of N-(2-benzoylmercaptopropionyl)leusine as oil

ORD record

ord-1c84be990af643d797df5492195ebb3e

Source dataset

uspto-grants-1976_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US03971828