Iodine → 2-(1-Phenylindol-3-yl)-2-thioisourea hydroiodide

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Reaction Steps

N-Phenylindole (28.95 g; 0.15M) and thiourea (11.4 g; 0.15M) were dissolved in a mixture of methanol (140 ml) and ethanol (100 ml) by rapid stirring at 20°. To this solution was added in four portions a solution of potassium iodide (52.5 g; 0.3M) and iodine (38.1 g; 0.15M) in water (60 ml) over 10 minutes. The solution was then stirred at 20° for 17 hours. The resulting heavy yellow precipitate of the crude product was filtered off, washed successively with isopropanol (3×200 ml), water (3×200 ml), isopropanol (3×200 ml) and ether (2×200 ml), and then dried at 60° to give the title compound, weight 46.2 g (78.0% yield). An analytical sample was prepared by crystallisation from a 1:1 mixture of methanol and ethanol. This gave colourless rhombohedral crystals of the title compound, m.p. 264°-6°.

Provenance & Evidence