Ethyl bromoacetate → ethyl 2-(1H-1,3-benzodiazol-2-ylsulfanyl)acetate

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Reaction Steps

To a stirred solution of 1H-benzo[d]imidazole-2(3H)-thione (20.0 g, 0.13 mol, 1.0 eq.) in anhydrous ethanol (500 mL) at room temperature, was added potassium carbonate (9.25 g, 0.07 mol, 0.5 eq.) and ethyl bromoacetate (26.7 g, 0.16 mmol, 1.2 eq.). The reaction was heated to reflux and stirred at that temperature for 6 hours. The solvent was removed in vacuo and water (200 mL) was added. The aqueous phase was extracted with dichloromethane (3×100 mL), and the combined organic extracts were washed with water (200 mL) and brine (200 mL). The organic phase was dried over magnesium sulfate and concentrated in vacuo to give a colorless oil which solidified on standing. Purification by flash chromatography (CHCl3→10% MeOH:90% CHCl3) gave 4a as a white solid (11.7 g, 37%).

Provenance & Evidence