I[C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[N:8]=[CH:7][CH:6]=[N:5]2.[CH2:12]([O:14][C:15](=[O:22])[CH2:16][C:17]([O:19][CH2:20][CH3:21])=[O:18])[CH3:13].C1(C2C=CC=CC=2)C(O)=CC=CC=1.C(=O)([O-])[O-].[Cs+].[Cs+]>C1COCC1.[Cu](I)I.O>[CH2:12]([O:14][C:15](=[O:22])[CH:16]([C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[N:8]=[CH:7][CH:6]=[N:5]2)[C:17]([O:19][CH2:20][CH3:21])=[O:18])[CH3:13]
A solution of 6-iodo-quinoxaline (0.323 g, 1.26 mmol), malonic acid diethyl ester (0.404 g, 2.52 mmol), copper iodide (0.012 g, 0.063 mmol), biphenyl-2-ol (0.021 g, 0.126 mmol) and cesium carbonate (0.616 g, 1.89 mmol) in THF (5 mL) was heated to 70° C. in a sealed tube for 24 hours. The solution was then cooled to room temperature, water was added and the crude product was extracted from ethyl acetate. The product was purified via silica gel column chromatography in hexane:ethyl acetate (1:1) to give 2-quinoxalin-6-yl-malonic acid diethyl ester. 2-quinoxalin-6-yl -malonic acid diethyl ester (0.066 g, 0.229 mmol) was added to a solution of sodium hydroxide [2N] (0.229 mL) in methanol (2 mL) and stirred for several hours at room temperature. The reaction was then evaporated in vacuo, 1N HCl was added and the product was extracted with ethyl acetate to give 0.030 g (70%) of quinoxalin-6-yl-acetic acid. 1H NMR (400 MHz, DMSO-d6) δ 12.6 (bs, 1H), 8.93 (dd, 2H, J=2.0, 6.0 Hz), 8.05 (d, 1H, 8.8 Hz), 7.99 (m, 1H), 7.79 (dd, 1H, J=2.0, 8.8 Hz), 3.89 (s, 2H).
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