3-(2-bromoethoxy)prop-1-yne

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-Chlorobenzimidazole (30.0 g) and 2-bromoethyl propargyl ether (41.0 g) are dissolved in N,N-dimethylformamide (300 ml), and thereto is added a 25% aqueous sodium hydroxide (40.0 g), and the mixture is stirred at 60° C. for 4 hours. Water (700 ml) is added to the reaction mixture, and the mixture is extracted with ethyl acetate. The extract is washed with water, dried over anhydrous magnesium sulfate and then concentrated. The resulting residue is distilled under reduced pressure to give 2-chloro-1-[2-(propargyloxy)ethyl]benzimidazole (24.5 g) as a colorless oily substance, b.p. 158°-160° C./1.2 mmHg. the mixture is extracted with ethyl acetate The extract is washed with water dried over anhydrous magnesium sulfate concentrated The resulting residue is distilled under reduced pressure