Acetic Acid → 6-[1-(3-Ethoxy-4-hydroxy-benzyl)-piperidin-4-ylamino]-4-trifluoromethyl-nicotinic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 6-(piperidin-4-ylamino)-4-trifluoromethyl-nicotinic acid methyl ester dihydrochloride (56.42 mg, 0.15 mmol, 1.0 equiv; intermediate B7) in ethanol (2 mL), acetic acid (72.1 mg, 1.2 mmol, 8.0 equiv) and N-ethyl diisopropylamine (77.6 mg, 0.6 mmol, 4.0 equiv) was added 3-ethoxy-4-hydroxy-benzaldehyde (30.0 mg, 0.18 mmol, 1.2 equiv; commercially available) and the mixture stirred at 55° C. After 1 h, sodium cyanoborohydride (47.1 mg, 0.75 mmol, 5.0 equiv), dissolved in ethanol (0.5 mL), was added and the mixture stirred at 55° C. over night. A solution of 10 M NaOH (0.5 mL) was added and the reaction mixture heated by microwave irradiation to 100° C. for 15 min. Removal of the solvent under reduced pressure and purification by preparative HPLC on reversed phase eluting with a gradient of acetonitrile/water provided 4.3 mg (7%) of the title compound. MS (ISP): 440.3 [M+H]+.

Provenance & Evidence