4.35 g (21 mmol) of ethyl 5-fluoro-1H-indole-2-carboxylate, 4.29 g (23.1 mmol) of 2-bromo-4,6-dimethylpyridine, 9.36 g (44.1 mmol) of tripotassium phosphate, 0.66 ml (4.2 mmol) of 1,2-dimethylaminocyclohexane, 0.2 g (1.05 mmol) of copper iodide and 21 ml of dry toluene are added to a pressure tube. The tube is closed and the reaction mixture is stirred at 110° C. for 5 days. After this time, the mixture is poured onto a solution of 100 ml of water and the pH of the medium is adjusted to pH 5 by additions of acetic acid. 100 ml of ethyl acetate are added. The organic phase is separated, washed successively with 50 ml of water and 50 ml of a saturated aqueous sodium chloride solution, then dried over sodium sulfate, filtered and then concentrated under reduced pressure. The residue is purified by preparative chromatography (eluent: dichloromethane/ethyl acetate). 5.56 g of expected product are obtained, which product is used as is in the continuation of the synthesis.
