Hydrochloric Acid → 1,3-Bis(4-tert-butylbenzyl)-1,3-dihydrobenzimidazol-2-one

Participants

Reaction Conditions

Reaction Steps

To a solution of benzimidazolinone (1.5 g, 11.2 mmol) in abs. DMF (25 mL) there were added 4-tert-butylbenzyl bromide (1.8 mL, 9.8 mmol), potassium carbonate (2.76 g, 20 mmol), and a catalytic amount of potassium iodide under a blanket of argon. The reaction mixture was heated to 75° C. over a period of 2 h. Following cooling, the reaction mixture was poured into a solution of H2O (200 mL) and 2N hydrochloric acid solution in H2O (10 mL). The resulting mixture was extracted with EtOAc (5×40 mL), the combined organic phases were washed with sat. NaCl solution (2×30 mL), dried over Na2SO4, and the solvent was removed in vacuo. The residue was taken up in chloroform (50 mL), and the resulting solid matter was isolated by filtration. The filtrate was concentrated in vacuo. The residue was purified by means of column chromatography (SiO2, cyclohexane/EtOAc 2:1), and there were obtained 1,3-bis(4-tert-butylbenzyl)-1,3-dihydrobenzimidazol-2-one (O) (0.9 g, mp: 164-168° C.) and the desired product 1-(4-tert-butylbenzyl)-1,3-dihydrobenzimidazol-2-one (N) (615 mg, 22% of theory, mp: 179-180° C.) as the more polar substance.

Provenance & Evidence