General procedure for the synthesis of 4-bromo-2-(N-morpholinyl)benzaldehyde from 4-bromo-2-fluorobenzaldehyde and morpholine: To a solution of 4-bromo-2-fluorobenzaldehyde (1.0 eq.) and K2CO3 (1.15 eq.) in DMF (1.0 M) was added morpholine (1.15 eq.). The reaction mixture was heated to reflux and maintained for 2 hours until TLC monitoring showed complete conversion of the feedstock to the target product. Upon completion of the reaction, the mixture was cooled to room temperature and allowed to stand overnight. The following day, the reaction mixture was diluted with EtOAc and water with vigorous stirring. The organic layer was separated, washed sequentially with water and brine, dried over anhydrous MgSO4 and filtered, and the filtrate was concentrated under reduced pressure. The residue was purified by fast column chromatography (eluent: 0-50% EtOAc/heptane gradient) to afford the target compound 4-bromo-2-(N-morpholino)benzaldehyde as a light yellow solid in 90% isolated yield.LCMS analysis showed [M+H]+ m/z = 271.8 and retention time (Rt) = 1.33 min.
