Tributylphosphine → Ethyl 5-[4-(methylsulfonyl)phenoxy]-7-(tetrahydro-2H-pyran-4-yloxy)-1H-indole-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of ethyl 7-hydroxy-5-[4-(methylsulfonyl)phenoxy]-1H-indole-2-carboxylate (2.0 g), tetrahydro-2H-pyran-4-ol (2.02 mL), 1,1′-(azodicarbonyl)dipiperidine (5.3 g), tributylphosphine (5.3 mL), and tetrahydrofuran(60 mL) was stirred at 70° C. for 6 hr. To the reaction solution were added tetrahydro-2H-pyran-4-ol (1.02 mL), 1,1′-(azodicarbonyl)dipiperidine (2.5 g) and tributylphosphine (2.5 mL) and the mixture was stirred at 70° C. for 14 hr. The reaction solution was concentrated under reduced pressure to a half volume and the precipitated solid was filtered off. The filtrate was concentrated under reduced pressure, and the residue was subjected to silica gel column chromatography (volume ratio, ethyl acetate:hexane=5:95 to 50:50), and then basic silica gel column chromatography (volume ratio, methanol:ethyl acetate:hexane=0:2:98 to 20:80:0) to give the title compound (5.33 g) as a yellow oily crude product.

Provenance & Evidence