In small portions, just sufficient to maintain the blue color,
5.0 g. (0.22 gram atom) of clean, metallic sodium is added with vigorous stirring. After dissolution is complete (Note
3), a solution of
23.4 g. (0.20 mole) of indole (Note
4) in
50 ml. of anhydrous ether is added slowly and then, after an additional 10 minutes, a solution of
31.2 g. (0.22 mole) of methyl iodide in an equal volume of anhydrous
ether is added dropwise. Stirring is continued for a further 15 minutes. The
ammonia is allowed to evaporate (Note
5), 100 ml. of water is added, followed by
100 ml. of ether. The
ether layer is separated, the aqueous phase extracted with an additional
20 ml. of ether, and the combined
ether extracts washed with three 15 ml.-portions of water (Note
6) and dried over
anhydrous sodium sulfate. The solvent is removed at atmospheric pressure, and the crude oil (
n18.5°D 1.6078) is purified by distillation under reduced pressure.
1-Methylindole is obtained as a colorless oil, b.p.
133°/26 mm.,
n18.5°D 1.6082. In several runs the yield is
22.3–24.9 g. (
85–95%).