Diisopropylethylamine → HCID 118080494, compound

Participants

Reaction Conditions

Reaction Steps

A 250-mL round-bottom flask was charged with 3,3-difluorocyclobutan-1-ol (2.41 g, 22.3 mmol), 1,2-dichloroethane (50 mL), N,N-diisopropylethyl amine (3.5 mL, 20 mmol) and triphosgene (1.33 g, 4.48 mmol). The resulting solution stirred 30 minutes at 50° C., and then a solution of (S)-1-(6-bromo-2-methyl-3,4-dihydroquinoxaline-1(2H)-yl)ethan-1-one (600 mg, 2.23 mmol) and N,N-diisopropylethyl amine (3.5 mL, 20 mmol) in 1,2-dichloroethane (30 mL) was added. The resulting solution stirred overnight at 50° C. After cooling to room temperature, the reaction mixture was concentrated under vacuum. The residue was dissolved in ethyl acetate (50 mL), washed with saturated sodium carbonate solution (2×50 mL), dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified via column chromatography on silica gel (eluting with 2:3, ethyl acetate/petroleum ether) to afford 3,3-difluorocyclobutyl (S)-4-acetyl-7-bromo-3-methyl-3,4-dihydroquinoxaline-1(2H)-carboxylate (800 mg, 89%) as a brown solid. MS (ESI, pos. ion) m/z 404, 405 [M+1]+.

Provenance & Evidence