4-Amino-5-chloro-2-methoxybenzoic acid (I) was coupled to 4-(aminomethyl)-1-[2-(methylsulfonylamino)ethyl]piperidine (II) employing 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride and 1-hydroxybenzotriazole. The resulting compound was then treated with oxalic acid to provide the corresponding oxalate salt.