[Cl:1][C:2]1[N:3]=[CH:4][CH:5]=[C:6]2[C:11]=1[N:10]=[CH:9][C:8]([O:12]C)=[CH:7]2.B(Br)(Br)Br.ClCCl>ClCCCl>[Cl:1][C:2]1[N:3]=[CH:4][CH:5]=[C:6]2[C:11]=1[N:10]=[CH:9][C:8]([OH:12])=[CH:7]2To a 75 mL pressure vessel were charged with 8-chloro-3-methoxy-1,7-naphthyridine (0.8 g, 4.11 mmol) and DCE (10 ml). To this was added boron tribromide, 1.0M in dichloromethane (20.55 ml, 20.55 mmol) slowly. The brown heterogeneous mixture was stirred at RT and then was heated to 60° C. in oil bath and stirred for 3 h. It was cooled to 0° C. by ice bath and quenched with sat. Na2CO3 very slowly. Organic solvents were reduced, and 100 ml EtOH was added to the resulting residue. The white precipitate was filtered out. The filtrate was concentrated to yield 8-chloro-1,7-naphthyridin-3-ol as crude product which was used for next step directly. MS m/z: 181.2 [M+H].
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