Potassium Carbonate → 2-[(1H-indol-4-yl)-ethenyl]-phenol

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Reaction Steps

Under an inert atmosphere, 31 g of ortho hydroxybenzyltriphenyl-phosphonium bromide were suspensed in 350 ml of tetrahydrofuran and then over a period of one hour, 86 ml of a 1.6 M solution of butyllithium in hexane were added. The mixture stood for 30 minutes with stirring and then over 30 minutes, a solution of 5 g of 4-formyl-indole in 150 ml of tetrahydrofuran was added. The mixture was stirred for 24 hours and then was diluted with 500 ml of water. Potassium carbonate was added to saturation, and the mixture was extracted with ethyl acetate. The fractions with Rf=0.20 were isolated by chromatography on silica (eluent: methylene chloride) and the crystals obtained were triturated in methylene chloride, then filtered and dried under reduced pressure to obtain 7.4 g of 2-[(1H-indol-4-yl)-ethenyl]-phenol melting at 140° C., and after recrystallization from methylene chloride at 142° C.

Provenance & Evidence