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Organic syntheses - Roger A.

Roger A. Organic syntheses - Chapman, 1936. - 110 p.
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dicarbethoxypyrrole, obtained from ethyl diacetosuccinate and ammonia.2
1 Paal, Ber. 18, 2254 (1885).
2 Knorr, ibid, 18, 299, 1565 (1885).
C6H5CH2C02H + C6H5CH=CHCHO------------------>
CeH5CH==CHCH=CHC6Hs + co2 + H20
Submitted by A. B. Corson.
Checked by C. R. Nollek and J. F. Carson.
1. Procedure
In a i-l. round-bottomed flask equipped with a reflux condenser and
protected by a calcium chloride tube are placed 150 g. (x.i moles) of
phenylacetic acid (Org. Syn. Coll. Vol. 1, 427),
147 g. (1.1 moles) of freshly distilled cinnamic aldehyde, 122 g. of
litharge, and 155 cc. of acetic anhydride. The mixture is boiled for five
hours (Note r), poured while still hot into a beaker, and allowed to
stand overnight. The semi-solid contents are stirred to a mush, filtered
with suction in a large Buchner funnel, and pressed dry. The solid is
washed on the funnel with two 35-cc. portions of ethyl alcohol, stirring
the material thoroughly before applying suction. The cake is transferred
to a beaker, stirred to a mush with 50 cc. of alcohol, and again filtered
with suction. The material is washed with another 50-cc. portion of
alcohol in the same manner (Note 2). The product, which is light yellow
to tan in color, weighs 62-67 g- (27-29 per cent of the theoretical
amount) (Note 3) and melts at 149.5-153-5°.
For purification the material is dissolved in 300 cc. of hot benzene,
the solution boiled three minutes with 5 g. of decolorizing carbon, and
filtered hot, with gentle suction, through a warm Buchner funnel. The
benzene filtrate is treated with
500 cc. of hot ethyl alcohol, heated to boiling, and then cooled to io°
in an ice bath, with shaking. After filtering the crystals with suction
and pressing thoroughly, 50 cc. of ethyl alcohol is allowed to soak into
the cake and suction applied again. The recrystallized product weighs 52-
57 g. (23-25 per cent of the theoretical amount) (Note 4) and melts at
152.5-153.50. This product is the trans-trans form of the diene.
2. Notes
1. During the first half hour, the flask should be heated gently
and shaken several times to facilitate solution of the lead oxide.
2. Thorough washing is essential.
3. About 8 g. of crude hydrocarbon can be recovered from the
original mother liquor, but the recovery is tedious and is not
4. An additional quantity of about 5.5 g. can be obtained by
evaporating the mother liquor to 25 cc. and allowing to crystallize.
3. Methods of Preparation
The only method of preparative interest is the condensation of
phenylacetic add and cinnamic aldehyde.1 The aboye procedure follows the
method of Kuhn and Winterstein.2 Bistyryl has been obtained also from
styrylmagnesium bromide and cupric chloride.3
1 Thiele and Schleussner, Ann. 306,198 (1899).
•Kuhn and Winterstein, Helv. Chim. Acta 11,103 (1928).
•Sakellarios and Kyiimis, Ber. 67, 325 (1924); see also, Gilman and
Parker, J. Am. Chem. Soc. 46, 2827 (1924), Gilman and Pickens, ibid. 47,
2410 (1925).
2XCH2CHOHCH2X + Ca(OH)2 ->
2CH2-CH-CH2X + CaX2 + 2H2O
Submitted by Geza Braun.
Checked by W. W. Hartman and G. L. Boomer.
1. Procedure
(E) EpicUorohydrin.-In a 5-I. round-bottomed flask, 1350 g. (988 cc.,
X0.5 moles) of glycerol a,o-dicblorohydrin (Org. Syn. Coll. Vol. 1, 286),
840 g. (10 moles) of technical, finely powdered calcium hydroxide (88 per
cent), and 840 cc. of water (20°) are shaken vigorously for fifteen
minutes (Note 1). The mixture forms a thick paste at the beginning, but
the epichlorohydrin soon separates from the calcium salts as a mobile
liquid. The flask is fitted with a rubber stopper carrying a wide
delivery tube, and the mixture is distilled from a water bath, at first
under 40-50 mm. pressure. The pressure is then lowered to 10 mm. and the
temperature raised gradually to 95-100° (Note 2). The receiver must be
cooled effectively in an ice-salt mixture to - 50 or below, to insure a
maximum yield. The distillate is transferred to a separatory funnel, the
aqueous (upper) layer returned to the reaction flask, and the
distillation repeated. A third distillation in a similar manner gives a
small additional amount of epichlorohydrin (Note 3). The lower layers
from the successive distillations are combined and distilled through a
fractionating column, under reduced pressure. The epichlorohydrin
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