2-Butyl-benzofuran-3-carbonyl chloride (2.22 g, 9.36 mmol), prepared in step 2 of Example 4, in 40 mL of anhydrous THF was added under nitrogen dropwise over 20 minutes to a mixture of the HBr salt of 4′-amino-biphenyl-4-ol (3.26 g, 12.3 mmol), prepared in the previous step, and triethylamine (3.42 mL, 24.5 mmol) in 100 mL of anhydrous THF at ice bath temperature. After the addition the reaction was stirred at room temperature for 20 h. The reaction was filtered and the filtrate concentrated under reduced pressure to give a solid. Purification of the solid on 1 Kg of silica gel (230-400 mesh) using 30% ethyl acetate-hexane as the eluent gave 2-butyl-N-(4′-hydroxy[1,1′-biphenyl]-4-yl)-1-benzofuran-3-carboxamide (2.27 g, 48%) as an off-white solid, mp 181-183° C.; MS (APCI) m/z 386 [M+H]+. Elemental Analysis for C25H23NO3: Calc'd: C, 77.90; H, 6.01; N, 3.63; Found: C, 77.48; H, 5.86; N, 3.56.
