Org. Synth. 1950, 30, 75
[1,3-Butadiene, 1-phenyl-, trans-]
Submitted by Oliver Grummitt and Ernest I. Becker1
Checked by Charles C. Price and T. L. Patton.
In a 1-l. three-necked flask equipped with a mercury-sealed stirrer, a reflux condenser protected with a calcium chloride drying tube, a separatory funnel, a nitrogen inlet tube, and a thermometer is placed 0.515 mole of methylmagnesium bromide in 250–350 ml. of ether (a 1.5–2.0N solution). The mixture is cooled to a temperature below 10° by means of an ice-water bath, the stirrer is started, and a solution of 66.1 g. (0.50 mole) of cinnamaldehyde (Note 1) in 60 ml. of absolute ether is added, the rate of addition being controlled so that the temperature is kept below 10°. Throughout the addition, which takes about 1 hour, a slow stream of dry nitrogen is passed through the flask (Note 2).
The flask is detached from the condenser and stirrer, and its contents are transferred to a 500-ml. separatory funnel
. The apparatus is then reassembled, without the nitrogen inlet tube or the drying tube, and 175 ml. of 30% sulfuric acid
(by weight) is placed in the flask. Without cooling, but with efficient stirring with a Hershberg Nichrome wire stirrer
at 1500–1700 r.p.m. (Note 3)
the ethereal solution of the cinnamaldehyde-methylmagnesium bromide
adduct is added rapidly to the acid. The time for this addition (5–7 minutes) is limited by the efficiency of the condenser. Heat then is applied to maintain gentle reflux until the total
time elapsed from the initiation of hydrolysis is 20 minutes. The contents of the flask are immediately
transferred to a 1-l. separatory funnel
, the lower aqueous layer is discarded, and the ether
layer is washed successively with 50 ml. of water, a mixture of 50 ml. of 5% aqueous sodium hydroxide
and 50 ml. of saturated ammonium chloride
solution, and 50 ml. of water. Before each of the washings the air in the separatory funnel is displaced with nitrogen
. When the second wash solution is added, 0.3 g. of phenyl-β-naphthylamine
is dissolved in the ether
layer. The washed solution is dried with 20 g. of anhydrous sodium sulfate
for 30 minutes and then with 15 g. of anhydrous potassium carbonate
for 12 hours.
The ethereal solution is filtered and concentrated by distillation from a steam bath
to a residual volume of 80–100 ml. Some water separates at this time, and the mixture is cooled and then dried with about 15 g. of anhydrous potassium carbonate
. The concentrated solution is filtered into a 125-ml. modified Claisen flask3
and distilled under reduced pressure in a nitrogen
atmosphere into a receiver
containing 0.3 g. of phenyl-β-naphthylamine
. In this manner 52–54 g.
) of crude trans-1-phenyl-1,3-butadiene
is obtained, b.p. 81–85°/10–11 mm.
1.606–1.608, which may contain some methylstyrylcarbinol
and water. This material is dried with 5 g. of anhydrous potassium carbonate
, filtered, and distilled as before. The yield of trans-1-phenyl-1,3-butadiene
is 47–49 g.
), b.p. 78–81°/8 mm.
1.607–1.608. This product is satisfactory for most purposes (Note 4)
and (Note 5)
Cinnamaldehyde obtained from the Eastman Kodak Company
was purified by washing a solution in an equal volume of ether
with aqueous sodium carbonate
and then with water, dried, and distilled under nitrogen
; b.p. 101–102°/2–3 mm.
The procedure may be altered at this point so that trans-methylstyrylcarbinol
is obtained. It is necessary, however, to observe the precaution that all apparatus coming in contact with the trans-methylstyrylcarbinol
be free from traces of acid.
The solution is stirred for 30 minutes after the addition is complete. Then 125 ml. of a saturated solution of ammonium chloride (about 28%), which has been neutralized to litmus with concentrated ammonium hydroxide, is added dropwise, the temperature being held at 5–10°. This addition takes from 1 to 1.5 hours. After decanting the ether layer, breaking up the precipitate and extracting it with two 60-ml. portions of absolute ether, and adding the extracts to the main solution, the solution is distilled from a steam bath until the residual volume is about 100 ml. The solution is transferred to a Claisen flask, and the residual ether is removed by evacuation with a water pump. After the discard of a small fore-run, the product is collected at 93–94°/1.5 mm.; yield, 65–67 g. (88–90%).
Upon cooling at 0–10° the trans-methylstyrylcarbinol forms a mass of white crystals melting at 30–34°. These may be purified by crystallization from petroleum ether (b.p. 30–35°) -methylene chloride (6:1). For each 30 g. of the carbinol, 350 ml. of the solvent mixture is used. The solution is cooled to −75° to −80° in Dry Ice and kept at that temperature for about 3 hours. The solution is filtered quickly by suction through a chilled funnel, washed with the cold solvent mixture, and dried in a vacuum desiccator. The yield of pure trans-methylstyrylcarbinol is 28.5 g., m.p. 33.5–34.5°; n35D 1.5598; d354 0.9995.
The stirring must be vigorous in order to mix the ether
and aqueous layers. This is absolutely essential for the production of reasonable yields. Slower stirring necessitates a longer time for the hydrolysis with consequent longer contact time between the 1-phenyl-1,3-butadiene
and the sulfuric acid
, which results in extensive polymerization of the product and corresponding decrease in yield.
was obtained by distillation of the twice-distilled product under nitrogen
through a 12-plate column
of the total reflux-variable takeoff type2
after adding 0.5% of phenyl-β-naphthylamine. The packed section of the column was an 18-in. section of Pyrex tubing (10 mm. o.d.) filled with 4-mm. single-turn glass helices. Insulation was provided by means of a vacuum jacket, and heat losses were compensated by resistance wire wound on the jacket.
About 50% of the sample taken was collected, b.p. 86°/11 mm.; n25D 1.6086–1.6090; d254 0.9235–0.9239.
Present evidence indicates that 1-phenyl-1,3-butadiene4
prepared by this method is the trans
has been prepared by the decarboxylation of allocinnamylideneacetic acid6
and of cinnamylidenemalonic acid
the dehydration of methylstyrylcarbinol
from the Grignard addition of methylmagnesium halide to cinnamaldehyde
the rearrangement and dehydration of the alcohol intermediate formed by the Grignard addition of phenylmagnesium bromide to crotonaldehyde
the formation of methylstyrylcarbinol
, its conversion to methylstyrylcarbinyl chloride
, and dehydrohalogenation;10
a modified Wurtz reaction in which benzyl chloride
is coupled with allyl chloride
by means of sodium in liquid ammonia
the condensation of styrene
and dehydration of the intermediate in the presence of sulfuric acid
in acetic acid
and by the dehydrochlorination of 4-chloro-1-phenyl-2-butene
(prepared by the condensation of butadiene
with benzenediazonium chloride
describes the preparation of 1-phenyl-1,3-butadiene
by pyrolysis of 1-phenyl-1,3-butyleneglycol diacetate
. The present method is a modification of the procedure of von der Heide.8
has been prepared by several methods: the hydrolysis of the addition product formed from methylmagnesium halide and cinnamaldehyde
in a variety of ways;10,14
hydrolysis of the addition compound formed from styrylmagnesium bromide
hydrolysis and hydrogenation of the product formed in the Grignard reaction of phenylethynylmagnesium bromide
the addition of hypobromous acid
followed by reduction with sodium amalgam in acetic acid
the allylic rearrangement of 1-phenyl-1-acetoxy-3-butene
followed by saponification;17
and the reduction of benzalacetone
by means of aluminum isopropoxide
The method employed here is essentially that of Kenyon, Partridge, and Phillips.14
Chemical Abstracts Nomenclature (Collective Index Number);
potassium carbonate (584-08-7)
sulfuric acid (7664-93-9)
acetic acid (64-19-7)
ammonium chloride (12125-02-9)
sodium hydroxide (1310-73-2)
sodium carbonate (497-19-8)
sodium sulfate (7757-82-6)
allyl chloride (107-05-1)
benzyl chloride (100-44-7)
hypobromous acid (13517-11-8)
ammonium hydroxide (1336-21-6)
methylene chloride (75-09-2)
methylmagnesium bromide (75-16-1)
cinnamylidenemalonic acid (4472-92-8)
1,3-Butadiene, 1-phenyl-, trans- (16939-57-4)
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