Ammonia → 1-Benzylindole

Participants

Reaction Steps

To a stirred mixture of sodium amide (prepared from 19.6 g, 0.85 mole of sodium and a few mg of Fe(NO3)3 -9H2O) and 800 mL of liquid NH3 (a dry ice condenser was used) was added a solution of 100 g (0.85 mole) of indole in 250 mL of dry ether during 15 minutes. The mixture was stirred for 30 minutes and then a solution of 107.8 g (0.85 mole) of benzyl chloride in 100 mL of dry ether was added during 30 minutes. The ammonia was allowed to evaporate overnight. The sides of the flask were washed down with MeOH and then 500 mL of H2O was added. The mixture was extracted with ether (2×500 mL). The combined ether extracts were washed with 250 mL of H2O and dried over MgSO4. The solvent was evaporated. The residue was distilled at 2 mm: fr 1, b.p. 172°- 183°, fr II, b.p. 183°-186°, 5 g; fr III, b.p. 186°-187°, 10.9 g; fr IV, b.p. 187°-191°, 121.8 g; fr V, b.p. 191°-197°, 13.9 g. Fractions III-V solidified upon standing several hours. Fraction IV had m.p. 42°-43°. Fraction III was crystallized from aqueous MeOH giving 9.9 g of colorless needles, m.p. 42.5°-43.5°. Fraction V was crystallized from aqueous MeOH giving 11.6 g of colorless needles, m.p. 43°-45.5°. The total yield was 143.3 g (81.5%).

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