[NH2:1][C:2]1[C:3](Br)=[CH:4][C:5]2[O:10][CH2:9][C:8](=[O:11])[N:7]([CH3:12])[C:6]=2[CH:13]=1.[CH2:15](B(CC)CC)[CH3:16].C(Cl)Cl.C([O-])([O-])=O.[Cs+].[Cs+]>CN(C=O)C>[NH2:1][C:2]1[C:3]([CH2:15][CH3:16])=[CH:4][C:5]2[O:10][CH2:9][C:8](=[O:11])[N:7]([CH3:12])[C:6]=2[CH:13]=1A mixture of 6-amino-7-bromo-4-methyl-4H-benzo[1,4]oxazin-3-one (0.21 g, 0.82 mmol), triethylborane (2.47 ml of 1.0 M solution in hexane, 5.56 mmol), PdCl2dppf.CH2Cl2 (0.067 g, 0.082 mmol) and Cs2CO3 0.81 g, 2.46 mmol) in DMF (6 ml) was heated at 50° C. under argon for 18 hours. The mixture was partitioned between EtOAc and water. The EtOAc layed was dried (MgSO4), filtered, concentrated under reduced pressure and purified with prep-plate TLC (hexanes:EtOAc 1:1) to give 0.095 g of 6-amino-7-ethyl-4-methyl-4H-benzo[1,4]oxazin-3-one as a tan solid, 63%.
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