Organic Syntheses, CV 4, 690
Submitted by S. J. Angyal, J. R. Tetaz, and J. G. Wilson
1.
Checked by R. S. Schreiber and Paul E. Marlatt.
1. Procedure
Precautions should be taken to avoid contact with
1-chloromethylnaphthalene, which is a lachrymator and a vesicant, and with the aldehyde, which seems to possess the same properties to a lesser degree.
In a
1-l. flask fitted with a reflux condenser are placed
106 g. (0.6 mole) of 1-chloromethylnaphthalene2 (Note
1),
168 g. (1.2 moles) of hexamethylenetetramine,
250 ml. of glacial acetic acid, and 250 ml. of water. This mixture is heated under reflux for 2 hours. In about 15 minutes the solution becomes homogeneous, and then an oil starts to separate. After the reflux period,
200 ml. of concentrated hydrochloric acid is added and refluxing is continued for an additional 15 minutes (Note
2). After cooling, the mixture is extracted with
300 ml. of ether; the
ether layer is washed three times with 100-ml. portions of water, then with
100 ml. of 10% sodium carbonate solution (Note
3), and again with 100 ml. of water. The
ether extract is dried with about
15 g. of anhydrous sodium sulfate and filtered, and the
ether is removed by distillation. The residual liquid is distilled under reduced pressure, the distillate being collected at
105–107°/0.2 mm. or
160–162°/18 mm. (Note
4). The yield of colorless
1-naphthaldehyde freezing between 0.0° and 2.5° (Note
5) is
70–77 g. (
75–82%).
2. Notes
1. The
chloromethylnaphthalene used melted at
24–26°. Material with a lower melting point can be used, but the yield is correspondingly smaller; e.g., a sample having a melting point of
15–18° gave a
73% yield of slightly impure
1-naphthaldehyde.
In this variation of the preparation, it is best to use a
wide-bore tube as a condenser to remove the unreacted
naphthalene. After the
naphthalene has been distilled, the wide-bore tube is replaced with an
ordinary condenser and the
naphthaldehyde is distilled in the usual manner.
2. The various amines and aldehydes present combine to form Schiff's bases. If these are not hydrolyzed by a strong acid, they will contaminate the final product.
5. The melting point of
1-naphthaldehyde given by Stephen
3 (
33–34°) is apparently incorrect. A sample that was purified through the bisulfite addition compound and redistilled had a freezing point of 2.5°.
In no instance could the checkers obtain a completely colorless product even though it was redistilled several times with ordinary laboratory distilling apparatus.
3. Discussion
1-Naphthaldehyde has been made from
α-naphthonitrile by reduction with
stannous chloride,
3,15,16 sodium triethoxyaluminohydride,
17 lithium triethoxyaluminohydride,
18 or
diisobutylaluminum hydride;
19 from
naphthalene by the action of
aluminum chloride,
hydrogen cyanide, and
hydrochloric acid,
20 by treatment with
dichloromethyl methyl ether in the presence of
stannic chloride,
21 and by the reaction with
carbon monoxide in the presence of
boron trifluoride and
hydrogen fluoride;
22 from
α-naphthoyl chloride by reduction with
lithium tri-tert-butoxyaluminohydride;
23 from
α-naphthoic acid N,N-dimethylamide by reduction with
lithium diethoxyaluminohydride;
24 from the
1,3-diphenyltetrahydroimidazole derivative of 1-naphthaldehyde by hydrolysis;
25 from the reaction of
α-naphthylmethylpyridinium bromide with
p-nitrosodimethylaniline and hydrolysis of the resulting nitrone;
26 by the decomposition of
1-(benzenesulfonhydrazidocarbonyl) naphthalene with
sodium carbonate;
27 and by the oxidation of
α-methylnaphthalene with
selenium dioxide.
28
This preparation is referenced from:
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