Org. Synth. 1967, 47, 76
DOI: 10.15227/orgsyn.047.0076
ISOPHTHALALDEHYDE
Submitted by J. H. Ackerman and A. R. Surrey
1.
Checked by Kenneth H. Brown, Wayland E. Noland, and William E. Parham.
1. Procedure
A solution of 272 g. (261 ml., 2.00 moles) of α,α'-diamino-m-xylene (Note 1), 1.00 kg. (7.1 moles) of hexamethylenetetramine, 480 ml. of concentrated hydrochloric acid, and 3.2 l. of 50% aqueous acetic acid in a 12-l. flask is stirred and heated at the reflux temperature for 2.5 hours. The hot amber reaction mixture is then poured into a large battery jar in a well-ventilated hood, and a solution prepared from 298 g. of sodium hydroxide and 3.85 l. of water is added slowly with stirring (Note 2). The mixture is covered and allowed to stand overnight at about 5°. The product, which separates as long needles, is collected, washed on a Buchner funnel with 100 ml. of cold water, and then dried to constant weight under vacuum (Note 3) over calcium chloride. There is obtained 158–166 g. (59–62%) of almost colorless needles of isophthalaldehyde, m.p. 88–90° (Note 4).
2. Notes
1.
α,α'-Diamino-m-xylene was obtained from California Chemical Company and Aldrich Chemical Company.
2.
The
sodium hydroxide solution is added to neutralize most of the
acetic acid present. Better yields are obtained using this neutralization procedure than by merely cooling the reaction mixture.
3.
The checkers observed that house vacuum removed only 50% of the water after 48 hours.
4.
One lot of
α,α'-diamino-m-xylene from Aldrich Chemical Company gave the
isophthalaldehyde as pale pink, long needles, m.p.
88–90°. When 12.0 g. of this material was recrystallized from 500 ml. of water, there was obtained
10.9 g. (
91%) of pale cream, long needles, m.p.
89–91°.
3. Discussion
The procedure described is a modification of the general procedure of Angyal
2 for the preparation of aldehydes from benzylamines by the Sommelet reaction.
Isophthalaldehyde has been prepared from
m-xylene by preparation of the tetrachloro derivative and hydrolysis,
3 from
isophthaloyl chloride by the Rosenmund reaction,
4 from
α,α'-dibromo-m-xylene by the Sommelet reaction,
5 and from
isophthaloyl chloride by reduction with
lithium tri-t-butoxyaluminumhydride.
64. Merits of the Preparation
Isophthalaldehyde is a valuable intermediate. Although the yields obtained by some of the other reported methods of preparation are better than the yield obtained here, the availability of starting material and the simplicity of reaction make this method attractive.
This appears to be the first reported case of the Sommelet reaction starting with a diamine.
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
calcium chloride (10043-52-4)
hydrochloric acid (7647-01-0)
acetic acid (64-19-7)
sodium hydroxide (1310-73-2)
hexamethylenetetramine (100-97-0)
Isophthalaldehyde (626-19-7)
isophthaloyl chloride (99-63-8)
lithium tri-t-butoxyaluminumhydride (17476-04-9)
m-xylene (108-38-3)
α,α'-diamino-m-xylene
α,α'-dibromo-m-xylene
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