Dicyclohexylcarbodiimide → HCID 22825549, compound

Participants

Reaction Steps

N-t-butyloxycarbonyl-O-benzyl-L-serine (4.43 g, 15 m mols) and D-isoglutamine benzyl ester (3.54 g, 15 m mols) were dissolved in acetonitrile (100 ml), and under ice-cooling, N,N'-dicyclohexylcarbodiimide (3.50 g, 17 m mols) was added. The mixture was stirred under ice-cooling for 3 hours and, then, at room temperature for 15 hours. The precipitate was filtered off, the solvent was distilled off and the residue was dissolved in ethyl acetate (100 ml). The solution was washed with 1 N-hydrochloric acid, 5% aqueous sodium hydrogen carbonate and water in the order mentioned and dried over anhydrous sodium sulfate. The solvent was distilled off and the residue was crystallized from ethyl acetate-petroleum ether. By the above procedure there was obtained 3.40 g of N-t-butyloxycarbonyl-O-benzyl-L-seryl-D-isoglutamine benzyl ester. m.p. 65°-66° C.; [α]D23 +5.7° (c=0.5, ethanol); Rf1 -0.73.

Provenance & Evidence