Br[C:2]1(Br)[C:10]2[C:5](=[N:6][CH:7]=[CH:8][CH:9]=2)[NH:4][C:3]1=[O:11].N1C2C(=CC=CN=2)C(=O)C1=O.Cl.[F:25][CH2:26][CH2:27][O:28][NH2:29]>CS(C)=O>[F:25][CH2:26][CH2:27][O:28][N:29]=[C:2]1[C:10]2[C:5](=[N:6][CH:7]=[CH:8][CH:9]=2)[NH:4][C:3]1=[O:11]A solution of 3,3-dibromo 7-aza oxindole (300 mg, 1.03 mmol) in DMSO (25 mL) was heated at 95° C. under house vacuum for 6.5 hours. The solution containing the corresponding 7-aza isatin was cooled to room temperature, followed by the addition O-(2-fluoro-ethyl)-hydroxylamine hydrochloride (prepared as described by Ishikawa et al J. Antibiot., 2000, 53, 1071) (131 mg, 1.13 mmol). After stirring for 1 hour at room temperature the mixture was quenched with water and extracted with ethyl acetate (6×25 mL). The combined organic phases were washed with brine and dried over MgSO4. The solvent was removed in vacuo and the residue purified by flash column chromatography (gradient, 2% MeOH in methylene chloride to 3%) to give 1H-pyrrolo[2,3-b]pyridine-2,3-dione 3-[O-(2-fluoro-ethyl)-oxime] (200 mg, 93%) as an orange solid that was further purified by trituration from diethyl ether-DCM (1:1).
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