Triphenylphosphine → 6-Bromo-5-(1-isopropyl-piperidin-4-yloxy)-1H-indole-2-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a suspension of 5.7 g (20.0 mmol) 6-bromo-5-hydroxy-1H-indole-2-carboxylic acid ethyl ester in 120 mL tetrahydrofuran, 3.44 g (24.0 mmol) isopropyl-piperidin-4-ol and 6.30 g (24.0 mmol) triphenylphosphine were added. The suspension was cooled to 0° C. and 5.53 g (24.0 mmol) di-tert-butyl azodicarboxylate was added. The ice bath was removed and the reaction mixture was stirred for 18 h at room temperature. The volatile components were removed and the residue was chromatographed on silica gel with dichloromethane:methanol:ammonia (9:1:0.1 v/v) as eluant to afford 6.2 g (76%) of the compound as a light-yellow foam.

Provenance & Evidence