2M Oxalyl chloride solution in dichloromethane (0.080 ml) and DMF (0.001 ml) were added to a suspension of 3-[2-(tert-butoxycarbonyl-pyridin-4-yl-amino)-ethoxy]-5-chloro-benzoic acid (0.050 g) in anhydrous dichloromethane (1 ml). The reaction was stirred at room temperature for 2 h then a solution of N-ethyl-2-fluoroaniline (0.029 g) DMAP (0.001 g) and DIPEA (0.070 ml) were added. The reaction mixture was stirred at room temperature for 16 h and then triflouroacetic acid (1 ml) was added. The solvent was removed in vacuo, the residue was subjected to preparative hplc and the required fraction dried by repetitive addition of acetonitrile and concentration under reduced pressure to give the title compound (0.020 g) as a colourless gum.
