Ethanolamine → (e)-3-(5-Bromo-2-methoxy-phenyl)-n-{2-[4-(4-fluoro-benzyl)-4-hydroxy-piperidin-1-yl]-ethyl}-acrylamide

Participants

Reaction Conditions

Reaction Steps

To a suspension of 2-(formyl-3-methoxyphenoxy)ethyl polystyrene (AMEBA) resin (ex Novabiochem) (1.5 g, 1.05 mmol) in a mixture of trimethylorthoformate/dichloromethane (15 ml, 1:1 v/v) is added 2-amino ethanol (0.317 ml, 5.25 mmol), sodium triacetoxyborohydride (1.113 g, 5.25 mmol) followed by methanol (2 ml) and the mixture shaken for 8 hours at 20° C., then filtered. The resin is washed with methanol, dichloromethane and THF. The dried resin is suspended in THF/acetonitrile (40 ml, 9:1 v/v) and treated with triphenylphosphine (2.75 g, 10.5 mmol), imidazole (0.715 g, 10.5 mmol) and iodine (2.66 g, 10.5 mmol). The suspension obtained is, shaken for 6 hours at 20° C., then filtered. The resin is washed with THF followed by DMF and dried under vacuum. To the freshly prepared resin (1.0 g, 0.7 mmol) suspended in DMF (3 ml) is added 4-(4-fluoro-benzyl)-piperidin-4-ol acetate (0.399 g, 1.4 mmol) and diisopropylethylamine (0.36 g, 2.8 mmol). The mixture is heated at 50° C. for 16 hours and then filtered. The resin is washed with DMF. To the washed resin (0.5 g, 0.35 mmol ) suspended in DMF (3 ml) is added a solution of (E)-3-(5-bromo-2-methoxy-phenyl)-acrylic acid (0.27 g, 1.05 mmol), 2-(1H-benzotriazol-1-yl)-1,1,3,3,-tetramethyluronium tetrafluoroborate (0.34 g, 1.05 mmol), diisopropylethylamine (0.29 g, 1.05 mmol) in DMF (2 ml) and the mixture is shaken at 20° C. for 4 hours, then washed with DMF, methanol and dichloromethane after which it is treated with trifluoroacetic acid/dichloromethane (6 ml, 1:1 v/v) at 20° C. for 1 hour to remove the product from the resin. The resulting mixture is filtered and the filtrate evaporated under vacuum to give the crude product which is purified by preparative HPLC to afford (E)-3-(5-Bromo-2-methoxy-phenyl)-N-{2-[4-(4-fluoro-benzyl)-4-hydroxy-piperidin-1-yl]-ethyl}-acrylamide, as the trifluoroacetate salt, [MH]+ 490.9, 492.8

Provenance & Evidence