[NH2:1][C:2]1[CH:7]=[C:6]([N+:8]([O-:10])=[O:9])[CH:5]=[CH:4][C:3]=1[OH:11].Br[C:13]([CH3:20])([CH3:19])[C:14](OCC)=[O:15].C([O-])([O-])=O.[K+].[K+]>CN(C=O)C.O.CCOC(C)=O>[CH3:19][C:13]1([CH3:20])[O:11][C:3]2[CH:4]=[CH:5][C:6]([N+:8]([O-:10])=[O:9])=[CH:7][C:2]=2[NH:1][C:14]1=[O:15]2-Amino-4-nitrophenol (5 g), ethyl 2-bromo-2-methylpropanoate (5.77 mL, 1.2 eq.), and K2CO3 (6.7 g, 1.5 eq.) were suspended in DMF (50 ml). The reaction mixture was heated at 70° C. overnight. The mixture was then diluted with water (200 mL) and EtOAc (150 mL). The EtOAc layer was washed with water (2×150 mL) and evaporated. The residue was purified by Combiflash chromatography (EtOAc in hexanes=10-100%) to give 2,2-dimethyl-6-nitro-2H-benzo[b][1,4]oxazin-3(4H)-one (3.45 g).
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