Triphenylphosphine → 5-(1-isopropyl-pyrrolidin-3-yloxy)-1H-indole-2-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a cold (0° C.) mixture of 5-hydroxy-1H-indole-2-carboxylic acid ethyl ester (10 g, 1.0 eq.), 1-isopropyl-piperidin-4-ol (intermediate 1, step 1, 7.32 g, 1.05 eq.) and triphenylphosphine (15.3 g, 1.2 eq.) in tetrahydrofuran (280 ml) was slowly added a solution of diisopropylazodicarboxylate (11.8 g, 1.2 eq.) in tetrahydrofuran (20 mL). The mixture was stirred 30 min at 0° C. and overnight at room temperature, was concentrated in vacuo, dissolved in methyltertiobutylether (310 mL), washed with sodium hydroxide aqueous solution (0.5N), brine, dried over Na2SO4, filtered and evaporated. The residue was purified on silica eluting with dichloromethane/methanol/ammoniac. One fraction was isolated and dried in vacuo, to yield 7.0 g (43%) of the desired product as white solid. MS (m/e): 331.5 (MH+, 100%)

Provenance & Evidence