Org. Synth. 1942, 22, 63
DOI: 10.15227/orgsyn.022.0063
2-HYDROXY-1-NAPHTHALDEHYDE
[1-Naphthaldehyde, 2-hydroxy-]
Submitted by Alfred Russell and Luther B. Lockhart.
Checked by W. E. Bachmann and Charles E. Maxwell.
1. Procedure
In a 2-l. three-necked round-bottomed flask (Note 1) fitted with a 40-in. reflux condenser, a mercury-sealed stirrer, and a dropping funnel are placed 100 g. (0.69 mole) of β-naphthol and 300 g. of 95% ethanol. The stirrer is started, and a solution of 200 g. (5 moles) of sodium hydroxide in 415 g. of water is rapidly added.
The resulting solution is heated to 70–80° on a steam bath, and the dropwise addition of chloroform is started. After the reaction begins (Note 2), further heating is unnecessary. A total of 131 g. (1.1 moles) of chloroform is added at such a rate that gentle refluxing is maintained (Note 3). Near the end of the addition the sodium salt of the phenolic aldehyde separates. Stirring is continued for 1 hour after all the chloroform has been added.
The ethanol and excess chloroform are removed by distillation from a steam bath. Hydrochloric acid (sp. gr. 1.18) is added dropwise to the residue, with good stirring, until the contents of the flask are acid to Congo red paper (Note 4). The dark oil that separates is mixed with a considerable amount of sodium chloride. Sufficient water to dissolve the salt is added, and the oil is separated and washed several times with hot water. By distillation of the oil under reduced pressure there is obtained 87.5–93.7 g. of a slightly colored distillate which boils at 163–166° at 8 mm. (Note 5) and which solidifies on cooling. Recrystallization of the solid from 75 ml. of ethanol yields 45.2–57.5 g. (38–48%) of pure 2-hydroxy-1-naphthaldehyde, melting at 79–80°.
2. Notes
1.
The submitters employed a
5-l. flask for a run four times this size. They obtained the same percentage yield of product.
2.
The beginning of the reaction is indicated by the formation of a deep blue color.
3.
The
chloroform is added over a period of 1 to 1.5 hours.
4.
About
175 ml. of hydrochloric acid is required to neutralize the excess
sodium hydroxide and to liberate the
phenolic aldehyde from its sodium salt.
5.
The boiling range of the aldehyde is
177–180°/20 mm. The lower pressure is preferable to avoid decomposition. The checkers found a boiling point of
139–142°/4 mm. The color of the distillate varies in different runs; it may be green, pink, or amber.
3. Discussion
2-Hydroxy-1-naphthaldehyde has been prepared from
β-naphthol,
zinc chloride, and
hydrogen cyanide;
1 from
β-naphthol,
zinc cyanide, and anhydrous
hydrogen chloride;
2 from
β-naphthol,
chloroform, and
sodium hydroxide (Reimer-Tiemann reaction);
3,4 from
β-naphthol and
hexamethylene tetramine in
glycerin-boric acid, followed by hydrolysis;
5 and by hydrolysis of
2-hydroxynaphthaldehyde anil,
6 prepared in turn from
2-hydroxydithionaphthoic acid.
7.
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
sodium salt of the phenolic aldehyde
2-hydroxynaphthaldehyde anil
ethanol (64-17-5)
hydrogen chloride,
hydrochloric acid (7647-01-0)
sodium hydroxide (1310-73-2)
chloroform (67-66-3)
sodium chloride (7647-14-5)
hydrogen cyanide (74-90-8)
β-naphthol (135-19-3)
zinc chloride (7646-85-7)
phenolic aldehyde (90-02-8)
hexamethylene tetramine (100-97-0)
2-Hydroxy-1-naphthaldehyde,
1-Naphthaldehyde, 2-hydroxy- (708-06-5)
glycerin-boric acid
2-hydroxydithionaphthoic acid
zinc cyanide (557-21-1)
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