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Bromination in Liquid Bromine.

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Since training periods of up to five to seven weeks are
required in order to get well trained donors other training procedures have been tried. It has been found that
fish spontaneously prefer certain tastes, whereas other
chemical compounds are strongly disliked. Quinine or
acetic acid, both spontaneously disliked, have been used
as the conditioning stimuIus after the fishes were trained
to react positive to either of these stimuli. Even when
glucose is offered as a competing spontaneously preferred
stimulus, the fish had learned after five days to react positive to either quinine or acetic acid. Brain extract prepared
from either kind of donor made the recipients go specifically for the taste offered as the conditioning stimulus
during the training period. It was shown that the acquired
information is strictly related to the stimulus used during
the training procedure. The memory for taste training
lasts for about one week, whereas fishes that have learned
the same tasks by active training can remember this task
up to three months. Evidence is presented that "double
transfers" are possible, i.e the donor fish can been trained
to react positive to a color as well as to a taste stimulus.
J . H . Levan (Chicago, USA) reported on investigations
with mice, which prefer a 1% saccharine solution to water
if both are offered simultaneously. When after a certain
observation period the animals are treated with x-ray or
gamma radiation, they reverse their drinking habit : now
water is strongly preferred to the simultaneously offered
saccharine solution. This aversion towards saccharine could
be induced in non-irradiated animals by the injection of
brain extracts prepared from irradiated donors. Such a
transfer effect was not observed after injection of extract
prepared from blood but positive transfer has been seen
with extracts prepared from liver and spleen tissues of
trained donors. This latter observation raised an interesting discussion about the possible distribution of memory
transfer factors over the whole body.
nitrile with hydrogen sulfide and ammonia. A larger number of trimethylsilyl-substituted mono-, di-, tri-, and tetracarboxylic acids were used for the synthesis of anthraquinone vat dyes. Trimethylsilyl-substituted anilidocyanuric
chlorides were used for the preparation of triazinylaminoanthraquinone vat dyes.
Acid anthraquinone dyes were synthesized by condensation of bromaminic acid with aromatic aminosilanes.
Trimethylsilyl-substituted aromatic amines react with
leucoquinizarin to give anthraquinone dispersion dyes.
Comparison with tert-butyl substituted dyes revealed a
distinct superiority of the trimethyl substitution as regards
afinity, and stability toward light and chlorine. All the
dyes and intermediates investigated showed the typical
bands at 750, 835, 1250cm-' for -Si(CH,), and at 1095
R spectra.
and 1120cm-' for -Si(C,H,),
in their I
Lecture at Erlangen on January 15,1971 [VB 274 IE]
German version: Angew. Chem. 83,258 (1971)
Brornination in Liquid Bromine
By Hermanri Stetter and Erhard Pesper"]
The bromination of adamantane in liquid bromine has
already been shown to proceed via an ionic mechanism
that leads to a stepwise selective bromination of the
tertiary hydrogen atoms. It has also been shown that
defined bromination products can be obtained, sometimes in hi9h yields, on brornination of aliphatic hydrocarbons with adjacent tertiary carbon atoms and in
the case of tetraalkylated ethylenes. The reactions carried
out may be summarized as follows:
[VB 272 IE]
German version: Angew. Chem. 83,257 (1971)
BrI-12C,
/X
c=c,
or
B~H~C'
Y
Trimethylsilyl- and Triphenylsilyl-Substituted Dyes
By Heinrich H ~ p f f " ~
TrimethylsiIyl- and triphenylsilyl-substituted aron,
compounds are now readily accessible via the Wurtz-Fittig
synthesis. Permanganate oxidation of 3- and 4-trimethylsilyl-o-xylene leads to the previously unknown trimethylsilylphthalic acids which have been used for the synthesis
of phthaleins, phthalocyanines, and quinophthalones. Introduction of the trimethylsilyl group causes a slight
deepening in color, a noticeable increase in the solubility
in organic solvents, and in certain cases, much better
light-fastness. The advantage of such properties is particularly evident in the coloration of plastics and in "solvent
dyeing".
~
Trimethylsilylindigo could only be obtained from the
corresponding o-nitrobenzaldehyde by condensation with
acetone in alkaline solution according to the method of
A . t'. Baeyer. 6,6'-Bis(trimethylsilyl)dithioxo-P,P'-isoindigo was prepared by reaction of trimethylsilylphthalodi[*] Prof. Dr. H. Hopff
Technisches Laboratorium der ETH
CH-8006 Zurich, Universitatsstrasse 6 (Switzerland)
280
(1)
(2)
(3)
(4)
R'
R"
X
Y
CH,
C,H,
n-C,H,
C,H,
CH,
CH,
CH,
C,H,
CH,Br
CHBr-CH,Br
CHBr-CHBr-CH,
CHBr-CH,Br
CH,Br
CH,Br
CH,Br
CHBr-CH,Br
In studies of the reactivity of the bromination product
tetrakis(bromomethy1)ethylene ( I ) in the nitrile syn[*] Prof. Dr. H. Stetter and Dr. E. Tresper
lnstitut fur Organische Chemie der Technischen Hochschule
51 Aachen, ProLPirlet-Strasse 1 (Germany)
Angew. Chem. internat. Edit. Vol. I0 (1971) / No. 4
thesis, the reaction with cuprous cyanide took the following interesting course:
mechanism of the isomerization reaction is as yet unknown, but it most probably involves the participation of
metal-olefin x complexes as active intermediates.
Lecture at Aachen on January 22,1971 [VB 275 IE]
German version : Angew. Chem. 83, 296 (1971)
I
[l]S . Wurwel and H.-P. Hemmerich, Tetrahedron Lett. 1970, 3185
Substituted o-Benzoquinones"'
A series of characteristic reactions was undertaken with
the nitriles (6) and (7).
Lecture at Aachen on January 22, 1971 [VB 276 IE]
German version : Angew. Chem. 83,296 (1971)
By Franz Dallacker, Zoltan Damd, and Gernot Lohnert"]
We have synthesized low molecular secondary plant substances by treating the compounds (la)-(lc), which are
readily prepared by reaction of alkyl halides with 2,3-dimethoxy-5,6-methylenedioxyphenyllithium,
with dilute nitric acid. Resonance stabilized 4,5-methylenedioxy-o-benzoquinones ( 2 a ) - ( 2 c ) are formed in good yields.
r
R
R
Photochemical cis-trans Isomerization of
n-Octenes in the Presence of Organoaluminum
Compounds
By Sieyfried Warwel, Heinz-Peter Hemmerich, and Friedrich
Asinger[*]
Pure cis-trans isomerization of an olefin can be effected by
reversible radical addition at the olefinic double bond or
via a photochemical route using UV light or y-radiation;
in the latter cases the presence of photosensitizers such as
benzene or benzophenone is usually necessary.
We have now found that n-octenes containing an internal
double bond also undergo cis-trans isomerization when
subjected to irradiation with UV light or y-rays if molar
amounts of an organoaluminum compound (HAlR,['I or
AlR,) are present. This cis-trans isomerization, which under otherwise similar reaction conditions is not observed
in the absence of the organometallic compound, proceeds
without any shift of the CC double bond in the olefin molecule and leads, irrespective of the configuration of the olefin
used, almost to the thermodynamically stable equilibrium
mixture of the configurational isomers. Thus, e. g., y-irradiation (60Co source, dose: 4.3 x lo6 rad) of cis-n-4-octene
for 37 h in presence of tri-n-butylaluminum (molar ratio
1 :4) at 22°C leads to an n-4-octene which consists of only
17.8% cis-, but 82.2% trans-n-octene. On irradiation of
trans-n-4-octene the product of the isomerization reaction
contained cis and trans'isomers in the ratio 18.1:81.9.
Not only Al(n-C,H,),,
but also HAl(i-C,H&,
Al(i-C4H9)3, and Al(n-C,H,,), effect a pure cis-trans
isomerization ; the extent of isomerization differs in each
case, Al(n-C8H, 7)3 being considerably less effective than
the other compounds.
The configurational isomerization is noticeably hindered
if the organometal compound is complexed by electron
donors. Triethylamine, tetrahydrofuran, and di-n-butyl
sulfide hinder the isomerization almost completely. The
[*I
Dr. S . Warwel, Dip1.-Chem. H.-P. Hemmerich, and Prof. Dr. F.
Asinger
Institut fur Technische Chemie und Petrolchemie der Technischen
Hochschule
51 Aachen, Alte Maastrichter Str. 2
Angew. Chem. internat. Edit. 1 Vol. 10 (1971) / No. 4
~
~
R
Rr
H,C-(CHd,o
( b ) H,C-(CH,),,
(c) H,C-(CH,),,
(0)
I
43
H
49-50
H
H,C 49-50
72
69
65
110-111
1-1
;07
;;
74
The ditoluene-di-o-quinone derivative (3) (dec. pt. 256 "C)
can be prepared in 72% yield by the same method.
0
CH3
c H3
131
i41
When aqueous potassium hydroxide solutions of the quinones (2a)-(2c) and ( 3 ) (if necessary with addition of a
few milliliters of ethanol) are acidified with hydrochloric
acid, the natural substances embelin (Sa), rapanon ( 5 b ) ,
oosporein ( 4 ) , and the dehydromaesaquinone (5c) are
precipitated in high yields.
R'
Lecture at Aachen on January 22,1971 [VB 277 IE]
German version: Angew. Chem. 83,297 (1971)
[*] Prof. Dr. F. Dallacker, Dr. Z. Damo, and Dip1.-Chem. G. Lohnert
Institut fur Organische Chemie der Technischen Hochschule
51 Aachen. Prof.-Pirle-Str. I
[I]Derivativesof Methylenedioxybenzene, Part 29.-Part 28: F . Dallacker, Monatsh. Chem. 100, 742 (1969).
28 1
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