2M Oxalyl chloride solution in dichloromethane (0.115 ml) and DMF (0.005 ml) were added to a suspension of 3-[2-(tert-butoxycarbonyl-pyridin-4-yl-amino)-ethoxy]-5-chloro-benzoic acid (0.060 g) in anhydrous dichloromethane (5 ml). The reaction was stirred at room temperature for 1.5 h then [2-(2,2-dimethyl-[1,3]dioxolan-4-ylmethoxy)-ethyl]-(4-fluoro-phenyl)-amine (0.078 g) as a solution in dichloromethane (0.5 ml), DMAP (0.002 g) and DIPEA (0.080 ml) were added. The reaction mixture was stirred at room temperature for 16 h. The reaction mixture was diluted with further dichloromethane and extracted with saturated aqueous sodium bicarbonate. The aqueous layer was removed and the organic phase washed with water and dried with brine and over sodium sulphate and concentrated under reduced pressure. The residue was purified by flash column chromatography, eluting with ethyl acetate:petroleum ether (1:1, 2:1 and 4:1 v/v), to give the title compound as a colourless gum (0.037 g).
