Hydrochloric Acid → 1-N-Ethoxycarbonyl-4-(2-amino-4-fluorophenoxy)-4-ethynylpiperidine

Participants

Reaction Steps

To a stirred solution of 22.3 g of 1-ethoxycarbonyl-4-ethynyl-4-(4-fluoro-2-nitrophenoxy)piperidine in 535 methanol was added 37 ml of concentrated hydrochloric acid in 150 ml of water. To the stirred mixture was added 78.6 g of iron (reduced, electrolytic) in aliquots. The reaction temperature rose to 45°. The reaction mixture cooled to ambient temperature over 1.5 hr. The mixture was poured into water/ice/sodium carbonate solution, extracted with dichloromethane, washed with water and saturated sodium chloride solution and dried over anhydrous potassium carbonate. Filtration followed by evaporation of solvent provided 20.2 g of an oil. An aliquot of 10.0 g of the oil was dissolved in ether and filtered through 200 g of alumina and the filtrate was evaporated. The residue was dissolved in 10% methanol/dichloromethane, filtered through 200 g of silica gel, and the filtrate was evaporated to provide 8.6 g (84.7%) of product, as an oil.

Provenance & Evidence