Trifluoroacetic acid → Benzyl [(cis-4-aminocyclohexyl)methyl]carbamate

関与物質

反応手順

To a stirred slurry of (4-aminomethyl-cyclohexyl)-carbamic acid tert-butyl ester (500 mg, 2.19 mmol) and N,N-diisopropylethylamine (382 μL, 2.63 mmol) in DCM (8 mL) at 0° C. under N2 was added benzylchloroformate (311 μL, 2.41 mmol) dropwise via syringe. After 30 min the reaction was allowed to warm to room temperature and stirred for a further 2 h before diluting with DCM (50 mL). The solution was washed successively with 1 N HCl, sat. NaHCO3 and brine before drying over Na2SO4. Residual chloroformate was removed by chromatography using a 12 g ISCO combi-flash cartridge (silica gel, 90:10 to 50:50 hexane/EtOAc) to afford the di-protected intermediate which was treated directly with DCM (2 mL) and TFA (2 mL). After 1 h the volatiles were removed in vacuo and the residue partitioned between sat. NaHCO3 and EtOAc. Concentration of the organic layer in vacuo afforded (4-amino-cyclohexylmethyl)-carbamic acid benzyl ester (517 mg, 90%) as a white solid.

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