P(Cl)(Cl)([Cl:3])=O.[NH:6]1[C:10]2=[N:11][CH:12]=[CH:13][CH:14]=[C:9]2[C:8]([C:15](=O)[CH3:16])=[CH:7]1.C[C:19]([O-:21])=O.[Na+]>CN(C=O)C>[Cl:3]/[C:15](/[C:8]1[C:9]2[C:10](=[N:11][CH:12]=[CH:13][CH:14]=2)[NH:6][CH:7]=1)=[CH:16]/[CH:19]=[O:21]Phosphorous oxychloride (3.7 mL, 40 mmol) was added dropwise to DMF (6.2 mL, 80 mmol) at 0° C. The reaction mixture was let warm to room temperature and stirred for 15 minutes. 1-(1H-Pyrrolo[2,3-b]pyridin-3-yl)-ethanone was added in DMF (20 mL) and the reaction heated to 60° C. for 4 hours, cooled to 0° C. and 150 mL of saturated NaOAc solution added. The reaction mixture was heated briefly to 50° C. and then extracted with EtOAc. The organic layer was washed with brine, dried over sodium sulfate and concentrated to an oil which contains impure product. Upon standing a solid precipitated from the aqueous layer to give 0.9 g of a brown solid, 4.3 mmol, 22% yield.
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