Citric Acid → HCID 14336499, compound

Participants

Reaction Steps

0.749 g (3.00 mmol) of Boc-D-leucine monohydrate, 1.252 g (3.30 mmol) of L-valine benzyl ester p-toluenesulfonate and 0.811 g (6.00 mmol) of N-hydroxybenzotriazole were dissolved in 15 ml of dichloromethane. The resulting mixture was cooled with ice, and admixed with 0.504 ml (3.60 mmol) of triethylamine and 1.108 g (4.20 mmol) of 97% 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide perchlorate. The reaction mixture was stirred for 2 hours, and then further stirred at room temperature for 4 hours. After the completion of the reaction, 30 ml of water and 5 ml of a 1% aqueous citric acid solution were added to the reaction mixture. The crystals thus deposited were filtered off. The organic layer successively was washed with 20 ml of water, 20 ml of a saturated aqueous sodium hydrogen carbonate solution and 10 ml of water, dried over anhydrous sodium sulfate, and distilled to remove the solvent therefrom, whereby 1.390 g of crude Boc-D-leucyl-L-valine benzyl ester product were obtained as white crystals.

Provenance & Evidence