Under argon atmosphere 600 μL (0.6 mmol) of 1N NaOH, 13.8 mg (0.12 mmol) L-proline, 7.6 mg (0.04 mmol) of CuI and 52 mg (0.8 mmol) of NaN3 were added to a solution of 163 mg (0.4 mmol) 4-(5-bromo-isoquinoline-6-yloxy)-piperidin-1-carboxylic acid tert-butyl ester (11) in 0.6 mL of water. The mixture was heated to 95° C. for 3 h in a microwave reactor (CEM Discovery). After cooling to room temperature water and ethyl acetate were added. The mixture was filtered through Celite, washed with ethyl acetate and concentrated. The crude product was purified by preparative HPLC to yield 42 mg of compound 18 (containing some 11 as impurity).
