Dicyclohexylcarbodiimide → Boc-Gly-Lys(Z)-OBzl

Participants

Reaction Conditions

Reaction Steps

To a solution of 20.35 g of H-Lys(Z)-OBzl.HCl (manufactured by Kokusan Kagaku) in 35 ml of dimethylformamide (called DMF hereinbelow), after neutralized by addition under cooling with ice of 7 ml of triethylamine, were added 8.76 g of Boc-Gly-OH (manufactured by Kokusan Kagaku), 7.43 g of HOBt (manufactured by Kokusan Kagaku) and 11.35 g of DCC (manufactured by Kokusan Kagaku). The mixture was stirred for 3 hours and at 4° C. for additional 16 hours. Dicyclohexylurea by-product was removed by filtration followed by addition of 300 ml of ethyl acetate. The resulting mixture was washed successively with saturated aqueous sodium chloride, 8% by weight aqueous sodium carbonate, saturated aqueous sodium chloride, 8% by weight aqueous citric acid and saturated aqueous sodium chloride. From the ethyl acetate layer, after dried over anhydrous sodium sulfate, was removed the solvent, and the residue was again dissolved in a small amount of ethyl acetate. From the solution after filtered, the solvent was completely distilled off to give 21.1 g (80% yield) of Boc-Gly-Lys(Z)-OBzl as an oily substance.

Provenance & Evidence