Potassium Carbonate → 3-[3-(4-Methyl-benzo[b]thiophen-3-ylmethyl)-2-oxo-2,3-dihydro-benzimidazol-1-yl]-hexanoic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-(4-Methyl-benzo[b]thiophen-3-ylmethyl)-1,3-dihydro-benzimidazol-2-one (0.2 g, 0.68 mmol) in DMA (5 mL) were added ethyl trans-2-hexanoate (0.19 g, 1.4 mmol) and benzyltrimethyl ammonium hydroxide in MeOH (0.43 g, 1.0 mmol) (Benzyltrimethyl ammonium hydroxide in MeOH can be replaced with K2CO3 (2eq) as a base). The reaction mixture was heated to 60° C. for 20 h. The reaction mixture was diluted with ethyl acetate and washed with water (×4). The organic phase was dried over Na2SO4 and concentrated. The resulting residue was attempted to dissolve in a mixture of CH2Cl2 and MeOH to load to a prep TLC. However, some insoluble material was present. This insoluble solid was filtered, however, the structure of the filtered solid couldn't be characterized (no aliphatic region in NMR). The filtrate was concentrated and resulting residue was purified by silica gel prep TLC using 98:2 CH2Cl2:MeOH as an eluent to afford 0.2 g of the desired product (with methyl ester instead of ethyl ester) as an oil. LCMS (ESMS): m/z 423.46 (M+H+).

Provenance & Evidence