Acetic Acid → trans-(4-Cyclopentylamino-tetrahydro-pyran-3-yl)-carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

trans-(4-Amino-tetrahydro-pyran-3-yl)-carbamic acid tert-butyl ester (intermediate G, 1.0 g, 4.63 mmol) was dissolved in 90 mL methanol. Acetic acid (1.4 g, 23 mmol) and cyclopentanone (1.18 g, 14 mmol) were added and the reaction mixture was stirred at 45° C. overnight. Sodium cyanoborohydride (612 mg, 9.7 mmol) was added and stirring was continued at 45° C. for 2 h. The mixture was extracted with 2N sodium carbonate solution and ethyl acetate. The combined organic phases were dried on sodium sulfate, filtered and evaporated. Purification of the residue by flash chromatography on silica gel (dichloromethane/methanol/ammonia 100:0:0→90:10:1) yielded the title compound as a yellow solid (815 mg, 62%), MS: m/e=229.4 [(M-butene)+].

Provenance & Evidence