1,2-Dichloroethane → 1,1-dimethylethyl (3R)-3-(cyclopentyl methyl)-4-{5-[(dimethylamino)carbonyl]-4,5-dihydro-1H-pyrazol-1-yl}-4-oxobutanoate

Participants

Reaction Steps

To a solution of 1-{(2R)-2-(cyclopentylmethyl)-4-[(1,1-dimethylethyl)oxy]-4-oxobutanoyl}-4,5-dihydro-1H-pyrazole-5-carboxylic acid (353 mg, 1.0 mmol), Hunig's base (0.35 ml, 2.0 mmol), EDC (231 mg, 1.2 mmol) and aza-HOBt (136 mg, 1.0 mmol) in dichloromethane (DCM) (10 ml) was added N-methylmethanamine (1.0 ml, 2.0 mmol), which was in THF. The reaction mixture was stirred at room temperature overnight. The mixture was then washed with water (5 mL), NaHCO3 solution (5 mL×3), and concentrated to provide the crude product which was purified by Combiflash automated silica gel chromatography (0-50% EtOAc in hex) to afford 1,1-dimethylethyl (3R)-3-(cyclopentyl methyl)-4-{5-[(dimethylamino)carbonyl]-4,5-dihydro-1H-pyrazol-1-yl}-4-oxobutanoate (315 mg, 0.83 mmol, 83% yield) as a yellow solid. MS: 380 ([M+H]+).

Provenance & Evidence