Benzal chloride → Ethyl 1-(p-chlorobenzyl)-5-chloro-3-thiophenylindole-2-carboxylate

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Reaction Steps

To a cold (-78°), stirred solution containing 664 mg of ethyl 5-chloro-3-thiophenylindole-2-carboxylate from Preparation 5 in 3.5 mL of dry tetrahydrofuran, under argon, was added 3.5 mL of a 0.62 M solution of potassium hexamethylsilamide in toluene. The reaction mixture was stirred at -78° for 1 h and at 0° for 1 h then recooled to -78°. 0.75 mL of g chlorobenzyl chloride, 1.0 mL of hexamethylphosphoric triamide and 20 mg of tetra-n-butylammonium bromide were then added. The resultant mixture was allowed to warm to room temperature and stirred for 18 h. Saturated aqueous ammonium chloride and ether were added. The ether layer was separated, washed with water, 10% aqueous cupric sulfate, water and brine and dried over MgSO4.

Provenance & Evidence