4-Methylmorpholine → 2-((2R)-2-tert-Butoxycarbonylamino-3-(2-naphthyl)propionylamino)-3-oxo-3-phenylpropionic acid methylester

Participants

Reaction Conditions

Reaction Steps

(2R)-2-tert-Butoxycarbonylamino-3-(2-naphthyl)propionic acid (5.49 g; 17.42 mmol) was dissolved in dry tetrahydrofuran (200 ml) and N-methylmorpholine (1.92 ml; 17.42 mmol) was added. The reaction mixture was cooled to -20° C. and stirred 15 min. Isobutyl chloroformate (2.27 ml; 17.42 mmol) was dissolved in dry tetrahydrofuran (3 ml) and added dropwise to the reaction mixture at -20° C. N-methylmorpholine (1.92 ml; 17.42 mmol) and 2-amino-3-oxo-3-phenylpropionic acid methylester (4.0 g; 17.42 mmol) were added and and the mixture was stirred 30 min at -20° C. The reaction mixture was heated to room temperature and the solvent was removed in vacuo. The residue was dissolved in methylene chloride (200 ml), washed with water (200 ml) and dried (magnesium sulfate). The solvent was removed in vacuo and the residue was chromatographed on silica (5×45 cm) using heptane/ethyl acetate/methylene chloride (2:1:1) as eluent to afford 6.19 g of a diastereomeric mixture of 2-((2R)-2-tert-butoxycarbonylamino-3-(2-naphthyl)propionylamino)-3-oxo-3-phenylpropionic acid methylester.

Provenance & Evidence