Triethyl 2-phosphonopropionate → 3-[2-(ethoxycarbonyl)prop-1-enyl]-N-(3-pyridyl)indole

Participants

Reaction Steps

A solution of lithium diisopropylamide (from 1.4 ml of diisopropylamine and 6.3 ml of 1.6M n-butyllithium in hexane) in 25 ml of dry tetrahydrofuran under nitrogen is cooled to -70° and 2.14 ml of triethyl 2-phosphonopropionate is added dropwise. The reaction mixture is stirred for 20 minutes at -70° and 2.0 g of N-(3-pyridyl)indole-3-carboxaldehyde is added. The reaction is allowed to warm to room temperature for 14 hours. The solvent is evaporated and the residue is partitioned between 20 ml of half saturated ammonium chloride solution and 30 ml of methylene chloride. The organic phase is separated, dried over sodium sulfate and evaporated to a solid which is recrystallized from methanol to yield 3-[2-(ethoxycarbonyl)prop-1-enyl]-N-(3-pyridyl)indole, m.p. 97°-99°.

Provenance & Evidence