4-methyl-3-{[5-(pyrrolidin-1-ylmethyl)pyridin-3-yl]ethynyl}benzoic acid (18 mmol) is dissolved in methylene chloride (100 mL). To this solution is added 3 equivalents of 4-methylmorpholine (NMM) followed by 1.05 equivalents of oxalyl chloride. After stirring at ambient temperature for 30 minutes, 0.8 equivalents of 3-(1H-imidazol-1-yl)-5-(trifluoromethyl)aniline (prepared as above) is added along with 5 mole % of DMAP. After initially stirring at ambient temperature, the mixture is brought to reflux and stirred overnight. After 16 h an additional 0.2 equivalents of the aniline is added, bringing the total charge to 1 equivalent. The mixture can then be stirred for an additional 2 h, quenched with water, and the layers separated. The aqueous layer can be extracted with methylene chloride (2×50 mL) and the combined extracts can be washed with water. The combined methylene chloride layers can then be evaporated and the residue dissolved in 100 mL of ethyl acetate (20 mL). After standing for 1 h, the product is allowed to crystallize. The mixture is cooled, e.g. to 0° C., filtered, and the solid product is washed with cold ethyl acetate.
