1.5 ml of saturated aqueous sodium carbonate solution, 40 mg (0.18 mmol) of 6-ethoxy-2-naphthaleneboronic acid and 14 mg (0.01 mmol) of tetrakis(triphenylphosphine)palladium are added to 50 mg (0.12 mmol) of the compound of Example 5A in 3 ml of dioxane. The mixture is stirred at 80° C. overnight and, after addition of 50 ml of ethyl acetate, extracted three times with 50 ml of water. The organic phase is dried over magnesium sulfate and freed of solvent under reduced pressure. The residue is purified by preparative HPLC (eluent: acetonitrile/water with 0.1% formic acid, gradient 10:90→95:5). 26 mg (44% of theory) of product are obtained.
