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0 °C

N1-Trityl-N-(4-methoxyphenyl)benzimidazol-5-amine (990 mg; 2 mmol; 1 eq.) was dissolved in THF (5 ml), cooled to 0° C. and treated with lithiumbis(trimethylsilyl)amide 1M in THF (2.4 ml; 2.4 mmol; 1.2 eq.). Phenylethylbromide (0.330 ml; 2.4 mmol; 2.4 eq.) was added and the mixture was stirred at room temperature for 24 h. The mixture was diluted with water and extracted with ethyl acetate (3×25 ml). The combined organic layers were dried over Na2SO4 and evaporated. The residue was dissolved in MeOH (5 ml) and treated with TFA (1 ml). After heating to reflux for 1 h the mixture was poured into saturated NaHCO3-solution and extracted with ethyl acetate (3×25 ml). The combined organic layers were dried over Na2SO4 and evaporated. The residue was purified by flash chromatography on silica using a CHCl3/MeOH gradient. Yield: 0.058 g (8.1%); MS m/z: 358.1 [M+H]+; 1H-NMR (500 MHz, DMSO d6): δ 2.85 (t, 2H, 3J=7.9 Hz); 3.57 (t, 2H, 3J=7.9 Hz); 3.69 (s, 3H); 4.44 (s, 2H); 6.77-6.79 (m, 2H); 6.83-6.86 (m, 2H); 7.14-7.16 (m, 2H); 7.18-7.21 (m, 1H); 7.23-7.25 (m, 2H); 7.28-7.30 (m, 2H); 7.38-7.39 (m, 1H); 7.92 (s, 1H); 11.92 (br s, 1H); HPLC (METHOD [A]): rt 16.74 min (96.3%)

1. extractionextracted with ethyl acetate (3×25 ml)
2. dry with materialThe combined organic layers were dried over Na2SO4
3. customevaporated
4. dissolutionThe residue was dissolved in MeOH (5 ml)
5. additiontreated with TFA (1 ml)
6. temperatureAfter heating
7. temperatureto reflux for 1 h the mixture
8. additionwas poured into saturated NaHCO3-solution
9. extractionextracted with ethyl acetate (3×25 ml)
10. dry with materialThe combined organic layers were dried over Na2SO4
11. customevaporated
12. customThe residue was purified by flash chromatography on silica using a CHCl3/MeOH gradient
13. customrt 16.74 min (96.3%)