1,2-Dimethoxyethane → 2-(Benzofuran-2-yl)-4-fluorobenzonitrile

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Reaktionsschritte

A mixture of 2-bromo-4-fluorobenzonitrile (515 g, 25.65 mmol), benzofuran-2-ylboronic acid (5.0 g, 30.8 mmol), 1,2-dimethoxyethane (25 mL) and 2M Na2CO3 (40 mL) was heated to reflux before Pd2(dba)3 (100 mg) was added and heating was continued for 5 h. After cooling to r.t, EtOAc (20 mL) was added to dissolve the product. The mixture was filtered through celite, the organic layer was separated, dried (Na2SO4) and concentrated under reduced pressure. The residue was dissolved in minimum amount of CHCl3 and passed through Silica. Solvent was evaporated and the residue was first purified by crystallisation from a mixture CHCl3/PE (98/2). The filtrate was purified by Combiflash chromatography (40 g column, 13 g Silica, gradient of eluent from PE to PE/EtOac 9/1) to give the title compound as light yellow solid purified by rinsing with PE to give at the end a white solid (5.15 g). This solid had to be purified an ultimate time by drying under vacuum at 80° C. for O/N. Finally, pure expected compound was obtained as a off-white solid in 59% yield (3.6 g); mp 123-124° C.; 1H NMR (270 MHz, CDCl3) 87.13 (1H, td, J=2.5 and 7.3 Hz, ArH), 7.30 (1H, t, J=7.7 Hz, ArH), 7-40 (1H, t, J=77 Hz, ArH), 7.56 (1H, d, J=7.7 Hz, ArH), 7.69 (1H, d, J=73 Hz, ArH), 7.76-7.86 (3H, m, ArH); Anal. Calcd. for C15H8FNO: C, 75.94, H, 3.40, N, 5.90. Found: C, 75 70, H, 3.37, N, 5.97%.

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