Diisopropylethylamine → tert-Butyl methylcarbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-1-{(S)-2-[(S)-2-(tert-butoxycarbonyl-methyl-amino)-propionylamino]-2-phenyl-acetyl}-2,3-dihydro-1H-indole-2-carboxylic acid (50 mg, 104 μmol, Eq: 1) and (5-fluoro-2-methylphenyl)methanamine (28.9 mg, 208 μmol, Eq: 2) in DCM (3 mL) cooled to 0° C. was added 2,4,6-tripropyl-1,3,5,2,4,6-trioxatriphosphorinane-2,4,6-trioxide (50% weight solution in EtOAc, volume added: 150 μL, Eq: 2) and diisopropylethylamine (54 μL, Eq: 3). The reaction mixture was stirred at 0° C. for 20 min and then at 23° C. for 1 h. The reaction was quenched with saturated aqueous NaHCO3 to pH=8. The two phases were separated and aqueous phase was re-extracted with DCM. The organic layers were combined and concentrated in vacuo. The mixture was purified by flash chromatography (silica gel, 0% to 70% EtOAc in hexanes) to give ((S)-1-{(S)-2-[(S)-2-(5-fluoro-2-methyl-benzylcarbamoyl)-2,3-dihydro-indol-1-yl]-2-oxo-1-phenyl-ethylcarbamoyl})-ethyl)-methyl-carbamic acid tert-butyl ester as a white powder (49 mg), m/z=603 (M+H).

Provenance & Evidence