[CH3:1][C:2]1[CH:3]=[C:4]([OH:11])[CH:5]=[CH:6][C:7]=1[N+:8]([O-:10])=[O:9].Br[CH2:13][C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15].C(=O)([O-])[O-].[K+].[K+].O>CN(C=O)C>[C:17]([O:16][C:14](=[O:15])[CH2:13][O:11][C:4]1[CH:5]=[CH:6][C:7]([N+:8]([O-:10])=[O:9])=[C:2]([CH3:1])[CH:3]=1)([CH3:20])([CH3:19])[CH3:18]A mixture of 1.53 g (10 mmol) of 3-methyl-4-nitrophenol, 1.95 g (10 mmol) of t-butyl bromoacetate and 2.76 g (20 mmol) of potassium carbonate in 10 mL of DMF are stirred at RT for 2 h. Water is added and the mixture is extracted with EtOAc and the organic phase is washed with water and brine, and dried over anhydrous Na2SO4. The solvent is removed under reduced pressure and the residual oil is filtered through a pad of silica gel using CH2Cl2 as the eluant to give (3-methyl-4-nitrophenoxy)-acetic acid t-butyl ester as an oil: 1H-NMR (CDCl3) δ 8.08 (d, J=9.56, 1H), 6.82-6.75 (m, 2H), 4.58 (s, 2H), 2.63 (s, 3H), 1.49 (s, 9H); Anal. Calcd for C13H17NO5 C, 58.42; H, 6.41; N, 5.24; Found C, 58.04; H, 6.51; N, 5.09.
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