A 2M solution of trimethylaluminium in toluene (0.413 mL, 0.83 mmol), was added drop-wise to a suspension of methyl 4-(1-ethylpiperidin-4-yl)benzoate (0.082 g, 0.33 mmol) and 5-[2-(3,5-dimethoxyphenyl)ethyl]-2H-pyrazol-3-amine (0.082 g, 0.33 mmol) in toluene (2 mL) at room temperature. The solution was then heated at 60° C. for 18 h. The reaction mixture was cooled, quenched with methanol (2 ml) and 2N hydrochloric acid (1 ml). The reaction mixture was purified by ion exchange chromatography, using a SCX column. The desired product was eluted from the column using 7M NH3/MeOH and fractions were evaporated to dryness. The crude product was purified by preparative HPLC, using decreasingly polar mixtures of water (containing 1% NH3) and MeCN as eluents. Fractions containing the desired compound were evaporated to dryness to afford the title compound (0.058 g, 38.0%) as a white solid.
