Imidazole → HCID 86708513, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of benzyl 7-oxa-3-azabicyclo[4.1.0]heptane-3-carboxylate (0.7 g, 3.00 mmol) and methanamine (3.75 mL, 30.0 mmol) in ethanol (5 mL) was heated in a sealed reaction pressure vessel at 70° C. overnight. The reaction mixture was cooled to room temperature and concentrated to dryness. The residue was dissolved in dichloromethane (5.00 mL), triethylamine (0.502 mL, 3.60 mmol) and di-tert-butyl dicarbonate (0.766 mL, 3.30 mmol) were added and the reaction mixture was stirred at room temperature for 4 h. The reaction mixture was washed with water and brine, dried over magnesium sulfate and concentrated to give colorless oil. The above oil was dissolved in DMF (5.00 mL), imidazole (0.409 g, 6.00 mmol) and tert-butyldimethylchlorosilane (0.678 g, 4.50 mmol) was added. The mixture was stirred at room temperature overnight. Water was added and the reaction mixture was extracted with ethyl acetate (3×), the organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo, the crude product was purified by flash chromatography on silica gel using an automated ISCO system (80 g gold column, eluting with 5-30% ethyl acetate/hexanes) to give (+/−)-(3R,4R)-benzyl 3-((tert-butoxycarbonyl)(methyl)amino)-4-((tert-butyldimethylsilyl)oxy)piperidine-1-carboxylate (Isomer A, 0.697 g) and (+/−)-(3R,4R)-benzyl 4-((tert-butoxycarbonyl)(methyl)amino)-3-((tert-butyldimethylsilyl)oxy)piperidine-1-carboxylate (Isomer B, 0.556 g). The structures were confirmed by NMR studies (1H-1D, 13C-1D, COSY, NOESY, dept-1H-13C-HSQC, 1H-13C-HMBC).

Provenance & Evidence