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To a solution of 3 (1.37 g, 2.75 mmol) in EtOAc (50 mL) was added stannous chloride dihydrate (2.5 g, 11.08 mmol). The resulting mixture was refluxed for 1 hour under N2. The reaction mixture was poured into a saturated NaHCO3 solution (50 mL) and extracted with EtOAc (150 mL). The organic layer was washed with aqueous NaHCO3 solution (3×30 mL), dried over MgSO4, filtered, and then concentrated in vacuo. MPLC purification (Hex/EtOAc 4:1) of the residue gave the desired intermediate ethyl (2-bromo-5-(3-amino-4-(phenylethynyl)benzoyl)-thiophen-3-yl)acetate as a yellow foam (1.28 g, 100%). To a 100 mL flask containing freshly distilled toluene (20 mL) were added ethyl (2-bromo-5-(3-amino-4-(phenylethynyl)benzoyl)thiophen-3-yl)acetate (1.28 g, 2.70 mmol) and indium tribromide (500 mg, 1.41 mmol) under N2. The resulting mixture was refluxed for 12 hours. The solvent was removed in vacuo. MPLC purification (Hex:EtOAc/4:1) of the residue gave 4 as a yellow amorphous solid (454 mg, 56%). 1H NMR (400 MHz, CDCl3) δ 8.88 (s, 1H), 8.02 (s, 1H), 7.74 (d, J=7.6 Hz, 2H), 7.70-7.64 (m, 2H), 7.56 (s, 1H), 7.49 (t, J=7.6 Hz, 2H), 7.40 (t, J=7.6 Hz, 1H), 6.90 (s, 1H), 4.19 (q, J=7.2 Hz, 2H), 3.66 (s, 2H), and 1.27 (t, J=7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 187.62, 170.13, 144.16, 142.47, 136.69, 135.86, 135.05, 133.38, 131.84, 130.69, 129.31, 128.77, 128.70, 125.92, 121.81, 120.27, 113.73, 100.08, 61.67, 35.43, and 14.44.

1. temperatureThe resulting mixture was refluxed for 12 hours
2. customThe solvent was removed in vacuo
3. customMPLC purification (Hex:EtOAc/4:1) of the residue