Reaction #7286

Reaction equation

2-(trimethylsilyl)ethoxymethyl chloride

benzimidazole

N,N-diisopropylethylamine

DMF

→

1-(2-trimethylsilylethoxymethyl)-benzimidazole

Yield 76.0%

1-[[2-(trimethylsilyl)ethoxy]methyl]-benzimidazole-2-carboxaldehyde

Yield 76.0%

Conditions

Workup

1. 1
   OtherPurification of the crude brown oil through a plug of silica gel (CH2Cl2/MeOH, 19:1)

Procedure

To a stirred solution of benzimidazole (2.00 g, 16.9 mmol) in anhydrous DMF (25 mL) was added N,N-diisopropylethylamine (7.3 mL, 42.2 mmol) followed by 2-(trimethylsilyl)ethoxymethyl chloride (3.3 mL, 18.6 mmol) and the resultant solution was heated to 80□ C. for 4 hours. Purification of the crude brown oil through a plug of silica gel (CH2Cl2/MeOH, 19:1) provided the 1-(2-trimethylsilylethoxymethyl)-benzimidazole (3.19 g, 76%) as an orange oil. 1H NMR (CDCl3) −0.05 (s, 9H), 0.90 (t, 2H, J=9 Hz), 3.51 (t, 2H, J=9 Hz), 5.55 (s, 2H), 7.32–7.37 (m, 2H), 7.55 (br d, 1H, J=6 Hz), 7.83 (br d, 1H, J=6 Hz), 7.98 (s, 1H).

Source