1-octadecyl-1H-benzimidazole synthesis

Yield:113501-98-7 87%

Reaction Conditions:

Stage #1: benzoimidazolewith sodium hydride in tetrahydrofuran at 0 - 20; for 0.75 h;
Stage #2: 1-Bromooctadecane in tetrahydrofuran at 0 - 70;

Steps:

1-octadecyl-1H-benzo[d]imidazole

Benzimidazole (5.0 g, 42 mmol) was dissolved in 250 mL of THE and cooled to 0° C. Sodium hydride (1.28 g, 51 mmol) was added slowly and the reaction allowed to warm to ambient temperature over 45 min. The reaction was cooled back to 0° C. and bromooctadecane (14.11 g, 42 mmol) was added. The solution was heated at 70° C. for 2 hours, then allowed to stir at ambient overnight. The reaction was slowly quenched with water, extracted with three portions of ethyl acetate, and the combined organic fractions washed with brine, dried (MgSO₄), filtered, and then concentrated under reduced pressure to give a white solid. The product was purified by silica gel chromatography, eluting with 0-10% acetone/isohexane, to give the solid in 87% yield. ¹H NMR (400 MHz, CDCl₃, δ): 0.24 (t, J=8.0 Hz, 3H), 0.63 (m, 30H), 1.26 (m, 2H), 3.54 (t, J=8.0 Hz, 2H), 6.67 (m, 2H), 6.77 (m, 1H), 7.19 (m, 1H), 7.25 (s, 1H).

References:

US2020/339517,2020,A1 Location in patent:Paragraph 0693