Acetonitrile (1212 μL) and 0.5M sodium carbonate solution (0.36 mL, 1.5 eq) were added to tert-butyl 4-(2-amino-5-bromopyridin-4-ylamino)piperidine-1-carboxylate (45 mg, 0.121 mmol), 4-methoxyphenylboronic acid (27.6 mg, 0.182 mmol), and tetrakis(triphenylphosphine) palladium(0) (7.00 mg, 6.06 μmol) in a microwave vial (0.5 mL). The capped vial was heated to 150° C. by microwave irradiation for 20 min. After cooling the solution was diluted with MeOH and purified by ion exchange on SCX-II acidic resin (2 g) column, eluting with MeOH then 2M ammonia in MeOH. The basic fractions were combined and concentrated. The crude product was dissolved in dichloromethane and loaded onto a Biotage SNAP silica column (10 g) which was eluted with a gradient of MeOH/NH3 (99/1) in dichloromethane to give tert-butyl 4-(2-amino-5-(4-methoxyphenyl)pyridin-4-ylamino)piperidine-1-carboxylate (19 mg, 0.048 mmol, 39%) as a colourless foam.
