Hydrochloric Acid → Z-Lys(Boc)-Lys(Boc)-Pro-NH2

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Reaction Steps

A solution of compound XIII (1.25 g, 2 mmoles) in dimethylformaide (8 ml) is chilled to -40° C to -50° C in a Dry-ice-acetone bath and 3.66M hydrogen chloride in dioxane (1.37 ml) is added. To this is then added dropwise isoamyl nitrite (0.29 ml, 2.2 mmoles) and the mixture is stirred at -10° C to -20° for 10 minutes. The mixture is again chilled to -40° C to -50° C and an ice-cold solution of XIV (0.30 g, 2 mmoles) and triethylamine (1.1 ml, 7.7 mmoles) in dimethylformamide (10 ml) is introduced. The temperature is allowed to rise to 0° C, at which the mixture is stirred for 3 hours. After the pH have been adjusted to about 8 with an additional quantity of triethylamine (0.27 ml, 2 mmoles) the reaction mixture is kept at 4° C for 2 days. The solvent is removed by evaporation in vacuo at a bath temperature of 40° C. The resulting residue is dissolved in ethyl acetate and the solution is washed with ice-cold M hydrochloric acid and M sodium bicarbonate, dried over magnesium sulfate and evaporated in vacuo. Repeated precipiration of the residue obtained above yields the desired tripeptide XV; yield 1.29 g (91%), mp. 85°-90° C, [α]D22 - 40.5°±0.4° (c 2.0, methanol).

Provenance & Evidence