close

Вход

Забыли?

вход по аккаунту

?

Explosion during the Oxidation of Tetralin with Hydrogen Peroxide in Acetone (Comments).

код для вставкиСкачать
Addition of NaHCO3 to an aqueous solution of (4u) precipitates the red quinonoid diazo compound (5u) [diazo
band at 2220 cm-I] in 63
yield. In contrast to the diazodicyanomethylene compound prepared by Hortzlcr, (5tr) can
be recrystallized from methanol by addition of ether and
gives good results for its elemental analysis even after 24 h.
On heating, it decomposes slowly without melting. The
diazo compound (Sb) is much less stable than (5u). I t is not
precipitated by N a H C 0 3 but can be extracted from its
aqueous solution with methylene chloride or ethyl acetate.
It decomposes within a few minutes and has, therefore, not
yet been isolated in the solid form. If hydrogen chloride is
passed into a fresh extract of (5b) in methylene chloride,
(46) is reformed. Compound (56) also couples with 9naphthol t o give an azo dye.
<:
Oxidation with alkaline peroxide at 30°C of the aldehyde
prepared from (26) led to 6-bromo-l -phenyl-4-azaflavazole3-carboxylic acid (2c), yellow prisms, m.p. 268-270°C froin
dioxan.
Received, October 12th. 1964
[Z 8431668 IE]
German version: Angew. Chem. 76. 954 (1964)
~~
.
[I] Regarding the nomenclature, cf. H . Ohle and C. A . Melkonian, Chem. Ber. 74, 280 (1941).
121 Cf. G. Henseke and K . Dittrich, Chem. Ber. Y2, 1550 (1959).
Reversibility of the Dissociation of Glutamate
Dehydrogenase from Beef Liver into Its
Polypeptide Chains [ l ]
[Z 842/667 IE]
Received, October 12th, 1964
German version: Angew. Chem. 76, 954 (1964)
By Dr. H . Sund
[I] H . D. Hartiler, J . Amer. chem. SOC.86, 2174 (1964).
[2] H. G. Garg, J. Indian chem. SOC.38, 343 (1961).
[3] F. M . Beringer, P . S. Forgione, and M . D.Yudis, Tetrahedron
8 , 49 (1960).
Chemisches Laboratorium
der Universitat Freiburg/Breisgau (Germany)
Azaflavazole Derivatives
~
New Heterocycles
By Prof. Dr. G. Henseke and Dip1.-Chem. D. Lehmann
Institut fur Organische Chemie der
Bergakademie Freiberg/Sachsen (Germany)
We have obtained azaflavazoles by three different routes.
2,3-Diamino-5-bromopyridinecondenses with l-phenyl-3methyl-4,5-dioxopyrazoline in water slightly acidified with
acetic acid to give the anil ( I ) , m. p. 218-220 'C (decornp.),
as red brown crystals from aqueous acetic acid. When heated
briefly in 1 N NaOH, the latter affords an 80 yield of 6bromo-3-methyl-l-phenyl-4-azal=iavazole
(20) [ I I as yellow
prisms, m. p. 223-224 " C from ethanol.
k
(1)
(Za), R = CH3, (2c), R = CO,H
HP 7
(2b), R = -C-C-CHZOH
I
OH
The reaction of 2,3-diamino-5-bromopyridine
with dehydroL-ascorbic acid and phenylhydrazine [2] at 25 "C leads to
20 % of the azaquinoxaline (3.) as red prisms, m.p. 281 to
283 "C (decomp.) from methanol; when (3.) is heated with
0.01 N NaOH, it is transformed quantitatively into 6bromo-3-[~-threu-I ,2,3-trihydroxypropyI]-1 -phenyl-4-araflavazole (Zb), yellow needles, m.p. 214-216 OC (decomp.)
from ethanol.
CGHS-NH
I H
N O H
Dehydrogenative cyclization with phenylhydrazine of 7bromo-5-azaquinoxaline-2-carboxaldehydephenylhydrazone
(36) in water weakly acidified with mineral acid gives a 50 7(:
yield of 5-bromo-1-phenyl-7-azaflavazole(4) as yellow
prisms, m.p. 247-248 " C from ethanol.
I n its native, associated state, glutamate dehydrogenase from
beef liver is a prolate particle with a particle weight of
2x 106. If it is considered as an ellipsoid of revolution, then its
major and minor axes are about 930 and 70 A long, respectively [2]. This particle is in a reversible, spontaneously
attained equilibrium with subunits having particle weights of
I .: 106, 0 . 5 ~
106, and 0.25~
106, all of which exhibit enzymatic
activity. Further cleavage into the polypeptide chains occurs
in the presence of urea or long-chain alkyl sulfates or at p H
values above 10 or below 4; this change is accompanied by
loss of the native chain conformation and the enzymatic
activity, and so far has been found t o be always irreversible
[2-71.
We have now succeeded in showing that this dissociation,
too, is in fact reversible. Incubation of glutamate dehydrogenase in the presence of mercaptoethanol at p H 2.0-2.2
leads to complete inactivation of the enzyme. Subsequent
dialysis against mercaptoethanol at p H 7.6 effects extensive
reactivation: specific activity [8] before denaturation with
acid: 6200 min-1, after denaturation: 10 min-1, after renaturation by dialysis at p H 7.6: 4500 min-1. These results
show that glutamate dehydrogenase from beef liver contains
in its amino-acid sequence the information required for the
chain conformation of the native, catalytically active enzyme protein.
Received, October 12th, 1964
[Z 841/669 IE]
German version: Angew. Chem. 76, 954 (1964)
[ I ] Reported at the Meeting of West-German Chemistry Lecturers in Freiburg/Breisgau, April 29th, 1964.
[2] H . Sund, Acta chem. Scand. 17, S 102 (1963) and unpublished
results.
[3] B. Jirgensons, J . Amer. chem. SOC.83, 3161 (1961).
[4] H . F. Fisher, L. L. McGregor. and D. G . Cross, Biochim.
biophysica Acta 65, 175 (1962).
[5] J . W o l f , J. biol. Chemistry 237, 230 (1962).
[6] C. Frieden, J.bioI.Chemistry237,2396 (1962); 238, 146 (1963).
[7] H . Sund in : Mechanismen enzymatischer Reaktionen (14th
Mosbacher Colloquium of the Gesellschaft fur Physiologische
Chemie). Springer-Verlag, Berlin-Gottingen-Heidelberg 1964,
p. 318.
[8] H. Sund and A. Akeson, Biochem. Z. 340, 421 (1964).
Explosion during the Oxidation of Tetralin with
Hydrogen Peroxide in Acetone (Comments)
By Prof. Dr. W. Treibs, Heidelberg (Germany)
H . Seidl recently reported [l] on a n explosion which occurred
during the preparation of tetralone from tetralin in acetone
using hydrogen peroxide.
Since publication of the original procedure [2], this method
has been used in numerous experiments for oxidizing open-
802
Angew. Chem. internut. Edit.
Vol. 3 (1964)
/ Nu. 12
chain and cyclic olefins and ketones, as well as terpenes and
sesquiterpenes without any accidents. Since the description
of the original procedure was rather terse,detailed instructions
are given here for the production of cc-tetralone.
One gram of vanadium pentoxide is placed in a beaker and a
total of 30 ml of 10 % hydrogen peroxide is added in portions.
Strong effervescence occurs and heat is liberated. The product
is a green-brown voluminous mass, which is dissolved in
100 ml of a 20:SO v/v mixture of 10 % H202 and acetone.
The solution is filtered and added to a solution of 500 g of
tetralin in 5 1 of acetone. The reaction mixture is stirred or
shaken and 30-40 % H202 is added in portions of 50 ml,
keeping the temperature at 30-40 ‘ C ; before each new
addition, the color of the mixture should be allowed to
change from yellow-red to green or brown-green. If the
mixture separates into two phases, enough acetone is added
to make the solution homogenous again. The oxidation is
complete when the color change occurs only slowly. A little
fresh tetralin is then added, and the whole is boiled for 1 h
under reflux. The solvent is then distilled off, and the residue
is separated in a separating funnel. The lower, aqueous
phase is extracted with ether, and the extract is added to the
upper, organic phase, which is then shaken with 100 ml of
2 N sodium hydroxide and washed thrice with 100 ml portions of distilled water. The ether is removed, and the residue
is fractionated in YUCUO on an oil bath.
The acetone used as solvent in the reaction is distilled beforehand from KMn04. Pure methanol can also be used as
solvent, but after dilution with H202 it has less dissolving
power than acetone. Minernl acids must not be preAent, not
even i n troces.
Received, October 15th, 1964
[Z 856/681 I E I
German version: Angew. Chem. 76, 990 (1964)
....
[I] H . Seidl, Angew. Chem. 76, 719 (1964); Angew. Chem.
internat. Edit. 3, 640 (1964).
[2] W. Treibs, Ber. dtsch. chem. Ges. 72, 7. I194 (1939); Angeu..
Chem. 52,698 (1939); Brennstoffchemie 20,358 (1939); W. Treibr,
G. Friritke, G. Leichsenrinx, and H . Roeder, Chem. Ber. 86,
616 (1953).
31.5 on complete reaction. The ultraviolet, infrared, mass and
proton magnetic resonance spectra of the dimers as well as
the products of their oxidative degradation [benzoic acld, obenzoylbenzoic acid, anthraquinone, 2,3-diphenyI-Az-inden1-one, and (o-benzoy1phenyl)benzoylbenzylmethane] indicate
that they are the stereoisomers (1)-(3) of l-benzyl-2,3-diphenylindane.
Received, October 13th, 1964
[Z 850/676 IEI
German version: Angew. Chem. 76, 989 (1964)
[I] Dosage rate of the “Co source (10000 Curie): 7 . 7 l~o 5 r/h.
Damped Oscillation of the Enzyme Synthesis
in Yeast
By Dr. W. Bernhardt, cand. med. K. Panten, and
Prof. Dr. H. Holzer [ I ]
Biochemisches lnstitut der Universitat Freiburg/Breisgau
(Germany)
When a disturbance enters a feedback system, the transition
from the regulator’s initial output to the new level consists of
either a sudden jump, an asymptotic change, or a damped
oscillation, depending on the nature of the feedback system.
While studying the regulation of DPN-dependent glutamate
dehydrogenase (DPN-GluDH) [2] in yeast, we found that
damped oscillations of the rate of enzyme synthesis can occur.
Synthesis of the enzyme is repressed by ammonium ions [3,4].
When repressed cells are transferred to a medium containing
glutamic acid as source of nitrogen, DPN-GluDH is synthesized as a result of “derepression”. After some time, a new
stationary content of DPN-GluDH, which is five to ten times
higher, is attained. As is shown in Figure 1, the transition
200
/lo,
Formation of l-Benzyl-2,3-diphenylindanes
from Stilbene in the Presence of Tin Tetrachloride
under the Influence of y-Radiation
By Dr. M. Salzwedel, V. Werner, and
Priv.-Doz. Dr. D. Schulte-Frohlinde
Strahlenchemisches Laboratorium,
Kernforschungszentrum Karlsruhe (Germany)
Irradiation of cis- or trans-stilbene in the presence of tin tetrachloride with y-rays from 6OCo [ l ] led to trimers plus three
isolable dimers (1)-(3) :
Fig. I . Rateof changeinthespecific activityof DPN-dependent glutamate
dehydrogenase in logarithmically growing cells of Saccharomyccs rerevisiae R 59. The cells were grown on a medium with NH: as sole source
of nitrogen (for details see [4]), depleted of nitrogen and glucose for 3 h,
and then administered L-glutamic acid and glucose at time zero.
Ordinate: Change in the specific activity pe; hour [activity units x
(mg protein) 1 x h-11. Fo; definition of activity units seo [4].
Abscissa: Time [hl
/I)
(21
(31
I
1
360
360
360
1
1
99-100
114-115
147-148
1
I
274
275
281
The G value for the consumption of the stilbene in a n equimolar mixture with tin tetrachloride was 105; the G value for
the formation of the mixture of isomers was calculated to be
A i i g r w . Chem. internat. Edit.
/ Vol. 3 (1964) / NO. 12
from the low to the high rate of synthesis of the enzyme proceeds by oscillations. These oscillations probably occur because the enzyme synthesis is part of a feedback system i n
which the ammonium ion acts as “co-repressor”. The transition does not occur in a sudden jump or asymptotically because the feedback system has a time lag. This time lad is due
to mainly two factors: 1. NH,O is released only slowly from
the glutamic acid corresponding to the slow accumulation of DPN-GluDH; 2. free ammonium ions accumulate in
the medium only after the NH?-dependent nitrogen reserves have been replenished. This interpretation is supported
by our finding that oscillations occur only when nitrogendeficient yeast cells are used for the experiments.
While the frequencies of oscillations observed for DPNH [5,61
and fermentation metabolites [7] are of the order of 1 min-1,
that for the enzyme synthesis is about 0.1-0.2 h-1. Oscilla-
803
Документ
Категория
Без категории
Просмотров
0
Размер файла
233 Кб
Теги
hydrogen, explosion, oxidation, peroxide, tetralin, acetone, comments
1/--страниц
Пожаловаться на содержимое документа