Diisopropylamine → 3-Phenyl-2-t-butylcarboxymethylpropionic acid, ethyl ester

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Reaction Conditions

Reaction Steps

[4S-[4α, 7α(R*), 12bβ]]-7-[(1-Oxo-2-carboxymethyl-3-phenylpropyl)amino]-1,2,3,4,6,7,8,12b-octahydro-6-oxopyrido[2,1-a][2]benzazepine-4-carboxylic acid Dissolve diisopropylamine (3.5 mL, 25 mmol) in tetrahydrofuran (30 mL). Add n-butyllithium (14 mL of a 1.6M solution in hexane, 22.4 mmol). Stir for 15 minutes and cool to -78° C. Add, by dropwise addition, ethyl dihydrocinnamate (3.5 mL, 20 mmol) and stir for 30 minutes. Add t-butyl bromoacetate (4.0 mL, 25 mmol) and gradually warm to room temperature overnight. Quench the solution with ammonium chloride solution (10 mL) and partition between water (25 mL) and ethyl ether (50 mL). Separate the organic phase, dry (MgSO4) and evaporate the solvent in vacuo. Purify by silica gel chromatography (5% ethyl acetate/hexane) to give 3-phenyl-2-t-butylcarboxymethylpropionic acid, ethyl ester as a pale yellow oil (2.68 g, 46%).

Provenance & Evidence