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Explosion during the Uncatalyzed Addition of Trichlorobromomethane to Ethylene.

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The infrared spectrum of compound (IIa) was identical with
that of another sample which we had obtained by a different
route [3].
The cleavage reaction outlined here is variable within wide
limits and has been elaborated further. Spectral data relating
to the now more accessible thioketones, and other properties,
will be described in detail elsewhere.
Received, March 9th. 1962
[Z 234161 IE]
[l] X th. Communication on Sulfur Heterocycles. - IX th. Communication: J. Jentzsch and R. Mayer, J. prakt. Chem., in press.
[2]J. Jentzsch, J. Fabian, and R . Muyer, Chem. Ber. in press.
[3] R. Mayer and P. Barthel, Chem. Ber. 93, 428 (1960); further
elaboration with confirmation of structure: G. Wenschuh, Ph. D.
Thesis, Technische Universitat Dresden (not yet completed).
1. The desthiolactone (I), prepared from lactaminic acid (Nacetylneuramhic acid) was deacetylated with Ba(OH)2 and
subsequently cleaved with NaI04. The resulting solution of
the lactone aldehyde (11) was reduced with NaBH4 to give
the triol (111) (total yield, 50 %).
2. L-(+)-Glutamic acid was converted to L-(-)-a-hydroxyglutaric acid with nitrous acid; the methyl ester (V) of its
lactone (IV) was hydrogenated by LiAlH4 to form (111) in
80 % yield.
3. Acetone- n-glyceraldehyde (VI) was converted by Wittig
synthesis to the a$-unsaturated dihydroxy ester (VII) in
75 % yield. From this, the laevo rotatory triol (111) was
obtained by catalytic hydrogenation, cleavage of the isopropylidene group with dilute acid, and subsequent reduction with LiAIH4. The trislphenylurethane) melts at
105-107 "C [a]","
= -18
(in pyridinej.
The revision of the sialic acid formula is in agreement with
the results of R. Kuhn and G. Baschang [4],who succeeded on
the one hand in converting an a,P-unsaturated lactone,
obtained from N-acetll- D-mannosamine and oxalacetic ester,
into lactaminic acid by H e attack, and on the other hand by
ozonolysis to 3-acetylamino-3-desoxy-~-manno-~-galaheptose [5] whose structure is well established.
Received, March 12th. 1962
[Z 235/65 IE]
[l] R. Kuhn and R . Brossmer, Angew. Chem. 69, 534 (1957).
[2]R. Kuhn and R . Brossmer, Liebigs Ann. Chem. 624, 137 (1959).
[3]Trio1 in CHsOH, plus an equal volume of saturated aqueous
NazB407 solution.
[4]Unpublished results.
[5]R. Kuhn and G. Baschang, Liebigs Ann. Chem. 636,164(1960).
Pentane-l,4,5-triol
from
lactaminic acid
L-plutamic acid
D-glieraldehyde
1
Explosion during the Uncatalyzed Addition of
Trichlorobromomethaneto Ethylene
ID in
Borate [3]
[a10in
CH3OH
I 1
-12.5"
-11.5"
-12.7O
f3.5"
+3.5
+4S0
By Dr. H. Elsner and Dr. S. Saure
Wissenschaftliches Laboratorium der Dynamit Nobel AG.,
Troisdorf (Germany)
CHO
H&-0,
VI
&H2OH
\l.-Ac
l'Pd'Hz
t
q
COzH
I
He
-I12.3. LiAlH4
i-0-1
CH2
HC-OIV
,CH3
I 1%CH3
H2C-0
v
&OnCHa
We have obtained proof through preparation of the R-(-)pemtane-1,4,5-triol (€11) by three methods:
218
In the laboratory preparation of l,l,l-trichloro-3-bromopropane according to the method of W. A. Skinner et al. [l],
the high-pressure autoclave exploded with great force in the
fourth run, following three incident-free experiments. The
circumstances under which the explosion occurred may stand
as a warning to chemists using this reaction, which has not
previously been considered dangerous.
The pressure vessel was designed for an operating temperature
of 350 "C and an operating pressure of 300 gauge-atm. (testpressure 420gauge-atm.). It had avolume of about900 ml., and
was provided with an electromagnetic stirrer, external resistance heating, a manometer, a thermometer connection, and
gas inlet and outlet valves. The values recommended in the
literature for the initial pressure (approximately 50 gaugeatm.) and for the reaction temperature (120'0, were
observed. The trichlorobromomethane was freshly distilled;
its purity had been confirmed by boiling point, refractive
index, and density measurements.
Our fourth run proceeded normally for about 1-1/2 hours,
that is, for more than one-third of the prescribed time (4
hours), when, suddenly, a strong explosion occurred, shattering the 12 mm. thick wall of the autoclave. The manometer
(with a scale maximum of 400 atm.) was also shattered. The
labofatory walls were covered with soot. As far as can
be determined, no failure of the ancillary equipment had
occurred.
A query directed to the authors of the method elicited the
response that they had never at any time observed an explosion during the course of this reaction.
It must be assumed that a previously unknown side reaction
suddenly occurred.
Received. March 14th. 1962
[Z23-5/61IE]
[ l l J. org. Chemistry 23, 1710 (1958).
Anzew. Chem. internnt. Edit.
1 Vol. 2 (1962)1 No. 4
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explosion, ethylene, additional, uncatalyzed, trichlorobromomethane
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