A solution of 5-chlorothiophene-2-carboxylic acid (120 mg, 0.72 mmol) in methylene chloride and DMF (0.005 mL) was treated with oxalyl chloride (0.105 mL, 1.20 mmol). After 0.25 h, the mixture was concentrated and the residue was dissolved in chloroform. This solution was added dropwise to a solution of N2-[1-(4-pyridyl)piperidin-4-ylmethyl]-2,3-pyridinediamine (170 mg, 0.6 mmol) in pyridine and chloroform. The reaction mixture was then purified using a procedure similar to that described in Example 2, Part D, yielding 160 mg (58%) of the title compound as a hydrochloride salt.
