Diisopropylethylamine → HCID 131714300, compound

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Reaction Steps

A solution of N2 -ethyl-N-(3-phenylpropyl)-D-alaninamide (2.71 g.), N-benzyloxycarbonyl-O-benzyl-L-tyrosine pentafluorophenyl ester (5.71 g.) and diisopropylethylamine (1.29 g.) in tetrahydrofuran (65 ml.) was stirred overnight at room temperature. Dimethylformamide (10 ml.) and more N-benzyloxycarbonyl-O-benzyl-L-tyrosine pentafluorophenyl ester (5.71 g.) were added, stirring was continued over the weekend, and the mixture was concentrated. A solution of the residual syrup in ethyl acetate was washed with water, dilute hydrochloric acid, aqueous sodium chloride, aqueous sodium hydroxide (1N, 20 ml.) and aqueous sodium chloride again, then dried and stripped of ethyl acetate. High pressure liquid chromatography of the residue (9.2 g.) on silica gel (350 g.) using hexane-ethyl acetate (55:45) as the eluant (200 ml./min.) afforded in the fractions having a k' value range of 2.5-4.5 (N-benzyloxycarbonyl-O-benzyl-L-tyrosyl)-N2 -ethyl-N-(3-phenylpropyl)-D-alaninamide as a syrup which crystallized (2.291 g.).

Provenance & Evidence