2-Bromo-3-oxobutyric acid tert-butyl ester → (R)-4-(5-tert-butoxycarbonyl-4-methyl-thiazol-2-yl)-1-(4-trifluoromethoxy-benzenesulfonyl)-piperazine-2-carboxylic acid benzyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of the compound (2.12 g) obtained in Step 4 and 2-bromo-3-oxobutyric acid tert-butyl ester (2.0 g) in acetonitrile (20 ml) was stirred at 80° C. for 30 min. The reaction mixture was concentrated under reduced pressure, and the residue was partitioned by adding ethyl acetate and saturated aqueous sodium carbonate solution. The organic layer was washed successively with saturated aqueous sodium carbonate solution and saturated brine, dried over anhydrous sodium sulfate, filtrated, and concentrated under reduced pressure. The residue was purified by column chromatography (ethyl acetate:n-hexane=1:2) to give the title compound (1.82 g).

Provenance & Evidence