Sodium Hydroxide → 3,4-Dihydroisoquinoline

Participants

Reaction Steps

Polyphosphoric acid (25 g) and phosphorus pentoxide (5.4 g, 38.0 mmol) were heated to 180° C. over the course of one hour in an oil bath under an argon atmosphere. N-Phenylethylformamide (146) (4.3 g, 28.8 mmol) was then added at 160° C., and the mixture was stirred for 1.5 hours at constant temperature. The mixture was then allowed to cool to room temperature, and water (40 ml) was added. The mixture was subsequently adjusted to pH 10 by careful addition of saturated aqueous NaOH solution. The mixture was then extracted with ether (500 ml), and the organic phase was separated off and dried using NaOH. Evaporation gave a brown oil (2.81 g, 21.4 mmol, 74%).

Provenance & Evidence