To a suspension of 6-bromo-3-(hydroxymethyl)-3,4-dihydro-1,8-naphthyridin-2(1H)-one (10 mg, 0.039 mmol; which may be prepared as described in Step 2) in DMF (200 μL) and proprionitrile (200 μL) under Argon were added DIPEA (8 μL, 0.047 mmol), 1-acryloyl-4-[(4-fluorophenoxy)methyl]piperidine (14 mg, 0.053 mmol; which may be prepared as described in Step 1), tri(o-tolyl)phosphine (2 mg, 0.008 mmol) and palladium acetate (1 mg, 0.004 mmol). The mixture was stirred at 100° C. for 2 days, then was allowed to come back to room temperature, filtered through Celite pad. The residue obtained after concentration of the filtrate was purified by preparative TLC (eluent: DCM/MeOH 9/1) to give the title compound as a white solid (1 mg, 6%).
