Methanol → t-Butyl [5-chloro-2-(2-oxopyrrolidin-1-yl)benzyl]carbamate

Participants

Reaction Steps

(Step 2) To a solution (227 ml) of 5-chloro-2-(2-oxopyrrolidin-1-yl)benzonitrile obtained in Step 1 (5.0 g) and nickel chloride 6 hydrate (0.54 g) in methanol was gradually added sodium tetrahydroborate (4.29 g) at 0° C., and the mixture was stirred for 10 min. Water (50 ml) was slowly added to quench the reaction. The solvent was evaporated under reduced pressure. The residue was extracted with ethyl acetate and water, and the aqueous layer was extracted with ethyl acetate three times. The organic layers were combined, washed with saturated brine, dried over sodium sulfate, and filtered. The solvent was evaporated under reduced pressure. The residue was dissolved in methylene chloride (150 ml), a solution of di-t-butyl dicarbonate (5.15 ml) in methylene chloride (40 ml) was added to this solution, and triethylamine (7.82 ml) was added at room temperature. The reaction mixture was stirred at room temperature for 2 hr, and quenched with 5% hydrochloric acid (10 ml) and water (50 ml). The organic layer was washed with water and saturated brine, dried over sodium sulfate, and filtered. The solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate:hexane=1:10→1:5) to give t-butyl [5-chloro-2-(2-oxopyrrolidin-1-yl)benzyl]carbamate (2.70 g).

Provenance & Evidence