Cesium carbonate → 5-(5-Benzenesulfonyloxy-2-chlorobenzyloxy)-1-[(2-thiophen-3-yl)ethyl]-1h-indole-2-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-hydroxy-1-[(2-thiophen-3-yl)ethyl]-1H-indole-2-carboxylic acid ethyl ester (0.42 g, 1.33 mmol) in dry DMF (10 mL) was added Cs2CO3 (0.65 g, 1.99 mmol). After stirring at 60° C. for 30 min, benzenesulfonic acid 3-bromomethyl-4-chlorophenyl ester (0.48 g, 1.33 mmol), from Example 1(b) above, was added. The reaction was kept stirring at 60° C. for 18 h. The reaction mixture was cooled and partitioned between EtOAc and water. The organic layer was washed with brine, dried (Na2SO4) and concentrated in vacua. Purification by flash column chromatography (silica gel, EtOAc/hexanes) afforded the partially purified product which was used directly in the next step without further purification (see Examples 1(h) and 2(c)).

Provenance & Evidence