Dicyclohexylcarbodiimide → HCID 20096977, compound

Participants

Reaction Steps

1,3-Dicyclohexylcarbodiimide (DCC; 0.81 g, 3.92 mmol) was added in one portion to a rapidly-stirred mixture of 4-[[[(2,6-dimethylphenyl)amino]carbonyl]methyl]-1-piperazineacetic acid (1.0 g, 3.27 mmol), 2-hydroxy-1,2-di-(4-ethylphenyl)ethanone (IX; 0.88 g, 3.27 mmol) and dimethylaminopyridine (DMAP: 40 mg) in anhydrous dimethylformamide (25 mL). After 2 hours at ambient temperature, an additional equivalent of DCC and DMAP were added. The mixture was stirred further for 22 hours at room temperature before it was heated to 70° C. for 6 hours. Upon cooling, the mixture was diluted with ethyl acetate, washed with saturated sodium bicarbonate solution and brine, dried and concentrated. Purification of the residue by flash chromatography on silica gel (gradient elution with 50% ethyl acetate in hexanes followed by ethyl acetate) afforded 0.50 g of the benzoin ester product (VI) as an off-white solid. The ester was used in subsequent reactions without additional purification.

Provenance & Evidence