Cesium carbonate → 5-Benzyloxy-1-isopropyl-1H-indole-2-carboxylic acid ethyl ester

Participants

Reaction Steps

To a mixture of 5-benzyloxyindole-2-carboxylic acid ethyl ester (30 g, 1.0 eq.) and cesium carbonate (58. g, 1.75 eq.) in acetonitrile (200 mL), was added isopropylmethane sulfonate (24.8 g, 1.75 eq.). The reaction mixture was refluxed for 18 h and then concentrated in vacuo. The residue was partitioned between water and methyl-tert-butylether. The aqueous layer was extracted with methyl-tert-butylether and the combined organic layers were washed with brine, dried over sodium sulfate, filtered and dried in vacuo. then purified on silica eluting with dichloromethane/methanol 98:2 v:v. The crude material was purified by crystallization in ethanol and dried in vacuo to yield 31 g (90%) of the desired product as an off-white oil. MS (m/e): 338.4 (MH+, 100%).

Provenance & Evidence