Org. Synth. 1953, 33, 93
Submitted by E. Campaigne, R. C. Bourgeois, and W. C. McCarthy1
Checked by Charles C. Price and E. A. Dudley.
Hexamethylenetetramine (77 g., 0.55 mole) is dissolved in 200 ml. of chloroform, and 88 g. (0.5 mole) of 3-thenyl bromide (p.921) is added as rapidly as possible with shaking (Note 1). A reflux condenser is attached, and the mixture is refluxed over a steam bath for 30 minutes. After being cooled, the mixture of chloroform and crystalline product (Note 2) is poured into 250 ml. of water and stirred until all the salt dissolves. The chloroform layer is separated and washed twice with 125-ml. portions of water, and the combined water extracts are steam-distilled. When the distillate comes over clear (about 1 l. of distillate is usually collected), it is acidified with a little hydrochloric acid (Note 3) and extracted with three 100-ml. portions of ether. After drying over Drierite, the ether is evaporated, and the residue is distilled. 3-Thenaldehyde is collected at 72–78°/12 mm. or 195–199°/744 mm., nD20 = 1.5860 (Note 4). The yield is 30–40 g. (54–72%).
The reaction mixture refluxes spontaneously, and it is necessary to be cautious in adding the reagents to prevent the chloroform
from boiling over.
The crystalline hexamine salt may be isolated and recrystallized at this step. It softens at 120° and melts with decomposition at 150°.
The Sommelet procedure2
yields a mixture of aldehyde and amines. Acidification removes the amines from the ether
The checkers obtained the product, b.p. 80–81°/14 mm.
has previously been prepared by Steinkopf and Schmitt3
from 3-thienylmagnesium iodide
and ethyl orthoformate
in low yield. The first application of the method described here was reported by Campaigne and LeSuer.4 3-Thenaldehyde
also has been obtained from 3-thenoic acid
by the Sonn-Müller procedure5
and from 3-bromothiophene
by treatment with butyllithium
This preparation is referenced from:
Chemical Abstracts Nomenclature (Collective Index Number);
hydrochloric acid (7647-01-0)
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