To a solution of 12 mg of 3-[5-(5-Chloro-thiophen-2-yl)-isoxazol-3-ylmethyl]-3H-imidazole-2,4-dicarboxylic acid 2-ethyl ester (ii) in DMF (0.5 mL) and DCM (0.5 mL) was added successively 1-Hydroxy-7-azabenzotriazole (5 mg), N-Ethyl-N′-(3-dimethylaminopropyl)carbodiimide hydrochloride (7 mg) and diisopropyl ethylamine (26 μL). The mixture was stirred for 15 min at RT. 7 mg of 1-Isopropyl-piperidin-4-ylamine (dihydrochloride) were added and stirring was continued at RT. After 2 h the mixture was concentrated in vacuo and the residue was purified by preparative HPLC (C18 reverse phase column, elution with a H2O/MeCN gradient with 0.1% TFA). The fractions containing the product were evaporated to provide 8.5 mg of the title compound as its trifluoroacetate salt. Yield: 8.5 mg; MS (ESI+): m/e=505, chloro pattern.
