Pivaloyl chloride → N-[2-tert-butyl-1-(cyclohexylmethyl)-1H-benzimidazol-5-yl]acetamide

Participants

Reaction Steps

Following the same procedure of Example 6, a mixture of N-{3-amino-4-[(cyclohexylmethyl)amino]phenyl}acetamide (1.57 g, 6.0 mmol) (for preparation see in Example 6, step D) and DMAP (0.15 g, 1.2 mmol) in dichloromethane (70 mL) was treated with trimethylacetyl choride (0.83 g, 6.6 mmol) at −10° C. After evaporation of the solvent, the residue was dissolved in 1,2-dichloroethane (40 mL) and then divided into eight Teflon-capped test tubes. The vessels were irradiated by microwave for 2 h at 170° C. After purification by MPLC (EtOAc as eluent on silica gel), the desired title compound was obtained as a white solid (1.42 g, 72%). 1H NMR (400 MHz, CD3OD): δ 1.24 (m, 5H), 1.64 (m, 2H), 1.67 (s, 9H), 1.70 (m, 1H), 1.77 (m, 2H), 2.12 (m, 1H), 2.18 (s, 3H), 4.45 (d, J=7.62 Hz, 2H), 7.50 (m, 1H), 7.84 (d, J=8.98 Hz, 1H), 8.43 (d, J=1.95 Hz, 1H). MS (ESI) (M+H)+: 328.3. Anal. Calcd for C20H29N3O+1.20 TFA+0.30H2O (469.71): C, 57.28; H, 6.61; N, 8.95. Found: C, 57.34; H. 6.67; N, 8.85.

Provenance & Evidence