Dichloromethane → N-((3S,4R)-1-ethyl-3-fluoropiperidin-4-yl)benzamide

Participants

Reaction Conditions

Reaction Steps

A 50 L autoclave was purged with nitrogen. N-(1-ethyl-3-fluoro-1,2,5,6-tetrahydro-pyridin-4-yl)benzamide (6.00 kg, 24.16 mol) was dissolved in methanol (19 L) and dichloromethane (1 L) and transferred to the inert autoclave. After four high vacuum—nitrogen fill cycles the prepared catalyst solution (6.5 L) was added to the autoclave. The reaction was pressurized with hydrogen gas to 20 bar and left to stand at 1000 rpm for 20 h at room temperature, was heated to 40° C. for 7 h, and then cooled to 25° C. Following a nitrogen purge the contents of autoclave were transferred into a 60 L reactor with methanol (2.0 L). Deloxan THPII (2.4 kg, 40 mass %) was added, and stirred at 500 rpm for 3 days at room temperature. The suspension was filtered over Arbocel (0.7 kg) applying high vacuum, the filter cake was washed with methanol (5.0 L), and solvent evaporated at 20 mbar and 45° C. Obtained 6.58 kg of N-((3S,4R)-1-ethyl-3-fluoropiperidin-4-yl)benzamide which was used without further purification. 1H NMR (400 MHz, MeOD) δ 7.83 (2H, t, J=9.1 Hz), 7.53 (1H, t, J=7.3 Hz), 7.45 (2H, t, J=7.6 Hz), 4.84 (1H, d, J=49.28 Hz), 4.25-3.91 (1H, m), 3.37-3.22 (2H, m), 3.10-2.95 (1H, m), 2.60-2.39 (2H, m), 2.32-2.02 (3H, m), 1.79 (1H, d, J=12.3 Hz), 1.11 (3H, t, J=7.2 Hz).

Provenance & Evidence