Acetic Acid → BOC-Leu-Ser-Thr-OBzl

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

52.5 g of H-Ser-Thr-OBzl.TFA are dissolved in 145 ml of dimethylformamide and mixed at 0° C. with a solution of 48.0 g of BOC-Leu-ONP. 21 ml of triethylamine and 0.75 ml of glacial acetic acid are then added. The reaction mixture is stirred for 3 hours at 0° C. and overnight at room temperature. After adding 2.1 liters of ethyl acetate the solution is extracted by shaking twice with water, twice with 0.1 N hydrochloric acid, twice with 10% strength sodium chloride solution, eight times with 20% strength potassium carbonate solution, twice with 10% strength sodium chloride solution and once with 30% strength sodium chloride solution. After drying over sodium sulphate the solution is concentrated to about 1.4 liters. The protected tripeptide of melting point 114°-116° C. crystallises overnight in the refrigerator; [α]D -14° (c = 2 in dimethylformamide); Rf2 = 0.25 (on silica gel).

Herkunft & Nachweise