Organic Syntheses, CV 5, 621
HYDROXYMETHYLFERROCENE
Submitted by Daniel Lednicer, T. Arthur Mashburn, Jr., and Charles R. Hauser
1.
Checked by B. C. McKusick, H. F. Mower, and G. N. Sausen.
1. Procedure
Caution! This preparation should be conducted in a
hood because
trimethylamine is evolved.
A solution of
10.0 g. (0.25 mole) of sodium hydroxide in 250 ml. of water is prepared in a
1-l. round-bottomed flask equipped with a
reflux condenser and a
mechanical stirrer.
Twenty-five grams (0.065 mole) of N,N-dimethylaminomethylferrocene methiodide2 is added to the solution. The resulting suspension is heated to reflux temperature with stirring. At this point the solid is in solution. Within 5 minutes oil starts to separate from the solution and
trimethylamine starts to come off. At the end of 3.5 hours, at which time the evolution of the amine has virtually ceased, the reaction mixture is allowed to cool to room temperature. The oil generally crystallizes during the cooling. The mixture is stirred with
150 ml. of ether until the oil or solid is all dissolved in the
ether. The
ether layer is separated in a
separatory funnel and the aqueous layer is extracted with two additional
150-ml. portions of ether. The combined
ether extracts are washed once with water and dried over
sodium sulfate.
The oil that remains when the solvent is removed from the extract crystallizes when cooled to room temperature. This orange solid is recrystallized from
150 ml. of hexane (Note
1) to yield
9.5–12.5 g. (
68–89%) of
hydroxymethylferrocene, m.p.
74–76°. One more recrystallization from the same solvent affords
8.2–11.0 g. (
59–79%) (Note
2) of good-quality alcohol as golden needles, m.p.
76–78° (Note
3).
2. Notes
1.
Eastman Kodak Company practical grade hexane is suitable.
2. The yield of this reaction is directly dependent on the purity of the quaternary salt employed. If the salt is prepared from redistilled
N,N-dimethylaminomethylferrocene, the yield of alcohol may be as high as
90%.
3
3. The pure alcohol melts at
81–82°.
3. Discussion
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