Acetic Acid → 1-(2,6-Difluorobenzyl)-2-(2-Fluoro-4-Methoxylphenyl)-4-Aminobenzimidazole

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Reaction Steps

To 1-(2,6-difluorobenzyl)-2-(2-fluoro-4-methoxylphenyl)-4-nitrobenzimidazole (Example 50) (2.00 g, 4.98 mmol) dissolved in acetic acid (20 mL) was added SnCl2x2H2O (9.02 g) dissolved in concentrated HCl (8 mL). After stirring for 30 min at room temperature, the mixture was concentrated. The residue was diluted with CH2Cl2 and washed with NaHCO3 (sat. aq.) and NaCl (sat. aq.). The combined washings were dried (Na2SO4), filtered, and evaporated. The crude product was recrystallized from methanol to give 3.26 g of white crystals, (8.78 mmol, 70% yield). M.p. 200-202° C. 1H-NMR (200 MHz, CD2Cl2) δ 7.45 (m, 1H, H4′), 7.22 (m, 1H, H4″), 7.05 (dd, J=7.8, 7.6 Hz, 1H, H6), 6.85-6.72 (m, 5H, H3″,5″), 6.50 (dd, J=7.7, 1.0 Hz, 1H, H5), 5.21 (d, J=5.4 Hz, 2H, CH2PhF2 (rotamers)), 4.34 (br, 2H, NH2), 3.72 (s, 3H, OCH3).

Provenance & Evidence