Hydrochloric Acid → 3-(Benzyloxycarbonylamino) propionyl-L-histidine

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Reaction Conditions

Reaction Steps

A 0.5 L round-bottom flask is loaded with 22.6 g of 3-aminopropionyl-histidine, 150 ml of water and 30 ml of acetone. The solution is adjusted to pH 13.00 with 30% sodium hydroxide, then cooled to 0-5° C., at which temperature 18.7 g of benzyl chloroformate are dropwise added in about 1 h, keeping pH at 12-13 with sodium hydroxide. Afterwards, the mixture is stirred for 15 h at 20-25° C., acidified to pH 2.0-2.5 with 37% hydrochloric acid, then concentrated under vacuum, at 50° C. maximum, carrying out repeated evaporations with isopropanol to a white solid residue. 40 g of a residue are obtained.

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