[NH2:1][C:2]1[CH:7]=[CH:6][C:5]([N+:8]([O-:10])=[O:9])=[CH:4][N:3]=1.[Cl:11][CH2:12][C:13](Cl)=[O:14]>C1COCC1>[Cl:11][CH2:12][C:13]([NH:1][C:2]1[CH:7]=[CH:6][C:5]([N+:8]([O-:10])=[O:9])=[CH:4][N:3]=1)=[O:14]2-Amino-5-nitropyridine (19) (4.0 g, 28.8 mmol) was dissolved in THF (300 mL). TEA (12.0 mL, 86.1 mmol) was added and the stirred mixture cooled to 0° C. Chloroacetyl chloride (7.0 mL, 87.9 mmol) was added dropwise. The stirred solution was allowed to warm to rt then stirred at this temperature for 1 hour. The mixture was heated at reflux for 1 hour. The solvent was evaporated in vacuo and the residue partitioned between DCM (100 mL) and saturated aqueous sodium bicarbonate solution (50 mL). The layers were separated and the organic phase washed with saturated brine solution (50 mL), then separated, dried over MgSO4, filtered and concentrated in vacuo. Approximately half the crude product was purified by column chromatography (Biotage SP1) eluting with isohexane→30% EtOAc-isohexane, combining the crude material with this purified product. The combined material was triturated with EtOAc-isohexane to provide the title compound as a brown solid (3.6 g, 58%); Rf: 0.45 (3:1 isohexane-EtOAc).
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