10009-20-8

383-63-1

657-27-2

10009-20-8

1. Sodium ethanolate solution was prepared by dissolving sodium metal (4.6 g, 0.2 mol) in 200 mL of anhydrous ethanol. 2. L-lysine hydrochloride (18.25 g, 0.1 mol) was slowly added to the above solution under stirring conditions. 3. The reaction mixture was stirred continuously for 1 hour, followed by filtration to remove the insoluble precipitate. 4. The filtrate was cooled in an ice bath and ethyl trifluoroacetate (21.3 g, 0.15 mol) was added slowly and dropwise with vigorous stirring. 5. The reaction mixture was gradually warmed to room temperature and stirring was continued for 2 hours. 6. Acetic acid (6 g, 0.1 mol) was added to neutralize the reaction system and the resulting precipitate was subsequently collected by filtration. 7. The precipitate was washed sequentially with ethanol and acetone and dried to give the target product trifluoroacetyl lysine. 8. Yield: 15 g (62% yield). 9. MALDI-TOF mass spectrometry (positive ion mode): m/z 242.455 ([M+H]+, relative abundance 67%).