Trifluoroacetic acid → HCID 117697925, compound

Participants

Reaction Steps

Step II and III: a mixture of tert-butyl 7-(2-ethoxy-2-oxo-ethyl)-6-oxo-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate 125b (654 mg, 2.0 mmol), trifluoroacetic acid (1.0 mL) and dichloromethane (2.0 mL) was stirred at room temperature for one hour. The reaction mixture was concentrated. The residue was dissolved in dimethylformamide (5.0 mL), followed by adding potassium carbonate (700 mg, 5.0 mmol) and N,N-diisopropylethylamine (0.3 mL). The result mixture was warmed to 40° C., then added dropwise benzyl chloroformate (311 μL, 2.2 mmol) in dimethylformamide (1.0 mL). The resulting mixture was stirred for another two hours. The reaction was quenched by adding ice-water, extracted with PE: EA=5:1 (30 mL) three times. The combined organic phases were dried over Na2SO4, and concentrated. The residue was purified by silica gel column to give benzyl 7-(2-ethoxy-2-oxo-ethyl)-6-oxo-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate 125d (650 mg, yield: 90%).

Provenance & Evidence