[Br:1][C:2]1[CH:11]=[C:10]2[C:5]([C:6](=O)[CH:7]=[CH:8][NH:9]2)=[N:4][CH:3]=1.CN(C=O)C.C(Cl)(=O)C([Cl:21])=O.C(=O)(O)[O-].[Na+]>>[Br:1][C:2]1[CH:3]=[N:4][C:5]2[C:10]([CH:11]=1)=[N:9][CH:8]=[CH:7][C:6]=2[Cl:21]7-bromo-1,5-naphthyridin-4(1H)-one (23.8 g, 105.8 mmol), acetonitriel (192 mL, 105.8 mmol), and DMF (2.05 mL, 26.5 mmol) were placed in a 3-necked round bottom flask set up with a reflux condenser. Argon bubbled through. Reaction mixture brought to reflux (˜95° C.). Oxalyl chloride (28.7 ml, 328.1 mmol) was added dropwise via addition funnel over 40 minutes and reaction allowed to stir at this temperature for 16 hrs. Reaction mixture cooled to 0° C. and basified to pH ˜8 with aqueous sodium bicarbonate solution. Product extracted with DCM (500 mL) three times. Organic layers combined, dried over sodium sulfate and concentrated to afford brown solid. This was purified by ISCO silica gel chromatography to afford 3-bromo-8-chloro-1,5-naphthyridine (3.6 g, 14% yield) as fluffy tan solid.
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