Triethylamine → (R)-alpha-[(2-Benzyloxycarbonylamino-2-methyl-1-oxopropyl)amino]benzenebutanoic acid allyl ester

Participants

Reaction Steps

The amine obtained in Step B of this Example (300 mg; 1.37 mmol) triethylamine (380 ml; 2.73 mmol) and N-carbobenzyloxy-2-methylalanine (278 mg; 1.37 mmol) were dissolved in dry methylene chloride (3 ml) and BOP (605 mg; 1.37 mmol) was added. The reaction mixture was stirred at room temperature for 2 h and the resultant homogenous yellow solution quenched by addition of brine. The two phase system was extracted with methylene chloride (2×25 ml) and the combined methylene chloride layers dried over powdered anhydrous magnesium sulfate. Filtration of the methylene chloride solution to remove the spent drying agent followed by evaporation of solvent afforded an oil which was purified by column chromatography on silica gel using a solvent mixture of ethyl acetate and hexanes (1:1 v/v) as eluant. The desired product (419 mg; 69.7%) was isolated as a white amorphous solid. FAB-MS:- calculated for C25 H30N2O5 438.2; found 439.3 (M+1).

Provenance & Evidence