Potassium Carbonate → 5,6-Dimethyl-1-(4-methyl-benzo[b]thiophen-3-ylmethyl)-1,3-dihydro-benzimidazol-2-one

Participants

Reaction Conditions

Reaction Steps

To a slurry of 5,6-Dimethyl-2-benzimidazolinone (0.2 g, 1.2 mmol) in DMA (2 mL) (poor solubility) were added K2CO3 (0.10 g, 0.74 mmol) and trimethyl-(4-methyl-benzo[b]thiophen-3-ylmethyl)-ammonium; iodide (0.21 g, 0.62 mmol). The heterogeneous reaction mixture was heated to 130° C. for 10 min. Since there was still un-reacted starting material left, NaH (15 mg, 0.38 mmol) was added to the reaction mixture and heated to 150° C. for 10 min. The reaction was complete. The reaction mixture was then diluted with ethyl acetate (some MeOH was added to solubilize the reaction mixture into the organic phase) and washed with water (×5). The organic phase was dried over Na2SO4 and concentrated. The resulting solid had poor solubility. To the solid, CH2Cl2 was added and the resulting solid was filtered. The filtered solid was identified as the desired product (with a minimal amount of excess 5,6-Dimethyl-2-benzimidazolinone). Therefore, this filtered solid was used for the next reaction. LCMS (ESMS): m/z 323.13 (M+H+).

Provenance & Evidence