1.59 g (4.40 mmol) of 5-bromo-4-chloro-1-(2-trimethylsilanyl-ethoxymethyl)-1H-pyrrolo[2,3-b]pyridine, 1.482 g (5.35 mmol) of 3-(ethoxycarbonyl)pyridine-5-boronic acid pinacol ester and 181 mg (0.22 mmol) of (1,1′-bis(diphenylphosphino)ferrocenepalladium(II)-dichloride dichloromethane adduct were dissolved in a mixture of 7 mL of acetonitrile, 7 mL of toluene and 8 mL of a saturated aqueous solution of sodium bicarbonate. The resulting mixture was heated to 110° C. in a closed vial for 15 h. The resulting mixture was distributed between dichloromethane and water. The aqueous phase was separated and extracted three times with dichloromethane and the once with ethyl acetate. The ethyl acetate phase was washed with brine and combined with the other organic phases, dried over sodium sulfate and evaporated. The resulting crude was purified by flash chromatography on silica gel using a gradient of ethyl acetate in hexanes to afford 1.0703 g (2.48 mmol, 56%) of 5-[4-chloro-1-(2-trimethylsilanyl-ethoxymethyl)-1H-pyrrolo[2,3-b]pyridin-5-yl]-nicotinic acid ethyl ester as a pale yellow oil. 1H-NMR [500 MHz, d6-DMSO] δ: 9.15 (d, 1H), 8.97 (d, 1H), 8.41 (m, 1H), 8.40 (m, 1H), 7.89 (d, 1H), 5.69 (s, 2H), 4.38 (q, 2H), 3.55 (t, 2H), 1.35 (t, 3H), 0.84 (t, 2H), −0.08 (s, 9H); MS [MH+] m/z: 432+434.
