Imidazole → 4-(t-Butyldimethylsilyloxy)indole

Reaction equation

[OH:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[CH:5][NH:6]2.N1C=CN=C1.[Si:16](Cl)([C:19]([CH3:22])([CH3:21])[CH3:20])([CH3:18])[CH3:17]>ClCCl>[Si:16]([O:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[CH:4]=[CH:5][NH:6]2)([C:19]([CH3:22])([CH3:21])[CH3:20])([CH3:18])[CH3:17]

Participants

Procedure

A solution of 4-hydroxyindole (13.31 g, 75 mmol) in dry dichloromethane (400 mL) was treated with imidazole (8.17 g, 120 mmol) and t-butyldimethylsilyl chloride (18.09 g, 120 mmol) and the mixture was stirred at room temperature under nitrogen overnight. The precipitated white solid was filtered off and washed with dichloromethane and the combined filtrates were washed successively with 0.5 M aq. hydrochloric acid, 0.5 M aq. sodium hydroxide and brine, dried and evaporated to give 9 as white crystals (21.03 g, 85%), mp 80-81° C. (from hexanes); 1H NMR (500 MHz) δ 8.06 (br s, 1H), 7.08 (dd, J=3.1, 2.4 Hz, 1H), 6.99-7.05 (m, 2H), 6.58-6.59 (m, 1H), 6.52 (dd, J=7, 1.5 Hz, 1H, 1.06 (s, 9H), 0.23 (s, 6H). Anal. Calcd. for C14H21NOSi: C, 67.97; H, 8.56; N, 5.66. Found: C, 67.60; H, 8.80; N, 5.57.