Acetic Acid → Methyl 4-{[(4-tert-butylcyclohexyl)amino]methyl}benzoate

Participants

Reaction Steps

To a solution of methyl-4-formylbenzoate (73 mmol, 12 g) in 200 mL of MeOH was added 4-tert-butylcyclohexylamine (74 mmol, 13.2 mL) via syringe. The reaction mixture was heated to reflux for 0.75 h, then was cooled in an ice bath. The resulting precipitate was filtered and the filter cake was washed with 2×20 mL of cold MeOH. The solid was dried under reduced pressure, then suspended in 224 mL of MeOH. HOAc (652 mmol, 37.4 mL) was added to the solution, followed by NaBH3CN (42.7 mmol, 2.68 g) in several portions. The reaction mixture was stirred at ambient temperature for 1.5 b, then concentrated under reduced pressure to ca. 25% of the initial volume. 400 mL of EtOAc was added to the solution and the mixture was washed with 3×200 mL of 5% NaHCO3 followed by brine. The organic phase was dried over MgSO4 and concentrated under reduced pressure. The residue was purified by flash chromatography on silica eluting with 1:1 EtOAc/hexanes to afford the trans isomer as a white solid. 1H NMR (500 MHz, CDCl3): δ 8.00 (d, 2H), 7.40 (d, 2H), 3.92 (s, 3H), 3.88 (s, 2H), 2.40 (m, 1H), 2.01 (m, 2H), 1.79 (m, 2H), 0.95-1.15 (overlapping m, 5H), 0.85 (s, 9H).

Provenance & Evidence