反应详情

To a solution of 1-(tert-butoxycarbonyl)-4-(methoxymethyl)-piperidine-4-carboxylic acid from step B (718 mg, 2.63 mmol), pyridine (0.84 mL, 10.52 mmol), and DMF (catalytic, 3 drops) in CH2Cl2 (13 mL) was added dropwise oxalyl chloride (0.25 mL, 2.89 mmol, caution: exothermic). After gas evolution subsided, the reaction was stirred at ambient temperature for 30 minutes. 3-Aminophenyl dimethylcarbamate (475 mg, 2.63 mmol) was added in one portion to this solution and stirred for another 30 minutes. The reaction was quenched with saturated aqueous NH4Cl, and the aqueous layer was extracted with ethyl acetate (3×50 mL). The combined organic layers were washed with brine, dried over MgSO4, filtered, and concentrated under vacuum. Silica gel chromatography (50% ethyl acetate:hexanes) afforded the title compound (1.03 g, 90% yield for two steps). MS (ES+) [M+NH4]+=453.3

1. stirringstirred for another 30 minutes
2. customThe reaction was quenched with saturated aqueous NH4Cl
3. extractionthe aqueous layer was extracted with ethyl acetate (3×50 mL)
4. washThe combined organic layers were washed with brine
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated under vacuum