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N-(2 4-Dinitrophenyloxycarbonyl)amino Esters - New N-Activated Amino-Acid Derivatives.

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occurs in the region of the second light reaction of photosynthesis (photo-oxidation of water), for this is not required
for cyclic phosphorylation. Higher concentrations - generally
about ten times greater - cause inhibition of the cyclic
photophosphorylation, i. e. formation of ATP, as well (see
Table). In this respect, the imidazoles and benzimidazoles
described here differ from the herbicides of the urea and
triazine types, which only affect the cyclic phosphorylation
at extremely high concentrations, if at all. The inhibition of
the formation of ATP by the benzimidazoles is due to an
uncoupling and not to a disturbance of the cyclic electron
transport, because photosynthetic reduction of NADP by an
artificial electron donor (diaminodurol/ascorbate [2]) is not
inhibited even by much higher concentrations of herbicide.
Hence the electron transport in the region of the first light
reaction is unaffected.
The benzimidazole derivatives listed in the table were
prepared by condensation of the correspondingly substituted
o-phenylenediamines with excess trifluoroacetic acid at
80-100 O C or by substitution of 2-trifluoromethylbenzimidazole (I) [61. Compound ( 6 ) was made by bromination of ( I )
with a twofold molar excess of bromine in boiling water.
Compound (7) is obtained in 6 0 % yield by nitrating ( I ) with
By Dr. B. Fell and Dipl.-Chem. J. M. J. Tetteroo
Institut fur Technische Chemie, Tecbnische Hochschule,
Aachen (Germany)
During hydrocarboxylation 111 of higher n-alkynes under
normal pressure to give qB-unsaturated carboxylic acids,
the length of the inhibition time and the rate of the reaction
depend on the intensity of the incident light [2]. We have
found that if the reaction is carried out in ultraviolet light,
open-chain or cyclic mono-olefins can also be converted into
the corresponding carboxylic acids in good conversions and
high yields, although these compounds can otherwise seldom
be hydrocarboxylated. The results obtained are shown in the
table. Each charge comprised 0.25 mole of olefin, 0.15 mole
of nickel carbonyl, 5 moles of water, 0.5 mole of HCI (added
in the form of concentrated hydrochloric acid), and 200 ml of
acetone. The ultraviolet radiation source was a 7 0 watt Q 81
immersion lamp from Messrs. Quarzlampen GmbH, Hanau
(Germany); the reaction temperature was 55-60 "C.
Olefin
Light
Cyclohexene
Darkness
Daylight
Ultraviolet
Ultraviolet
n- 1-0ctene
Darkness
Daylight
Ultraviolet
Ultraviolet
6
Daylight
Ultraviolet
Ultraviolet
6
cis-n-4-Octene
HNO3 (sp. gr. = 1.52) at 60-70°C and recrystallization from
xylene. The N-methyl derivative (10) is formed by treating
the sodium salt of (4) with methyl iodide in acetonitrile at
50 "C. The trihaloimidazoles (8) and (9) were made according
to [7].
Received: July 12th, 1965
[ Z 39/864 IEl
German version: Angew. Chem. 77, in press.
[I] A similar relationship between the half-neutralization potential of substituted N-phenyl amides and the inhibition of the
Hill reaction was recently observed: N.D. Camper and D. E.
Morefund, Biochem. biophysica Acta 94, 383 (1965).
[Z] A.Trebst and E. Pistoriirs, 2. Naturforsch. 206, 143 (1965).
[3] Duplicate experiments were carried out on 3 ml samples
containing chloroplast fragments (PlsLfrom spinach [41, 0.2 mg
of chlorophyll), 8 0 pmole of tris buffer at pH 8.0, 5 pnole of
MgC12, 10 p o l e of potassium phosphate, lOpnole of ADP, and
either 20 pmole of K3[Fe(CN)6] or 0.3 pmole of vitamin K3.
The mixtures were exposed to 35000 lux for 15 min under
nitrogen. The oxygen produced was determined manometrically
and the amount of ATP formed was determined enzymatically
with phosphoglycerokinase, triose phosphate dehydrogenase,
phosphoglyceric acid, and NADH2. The control value for the
oxygen production without addition of inhibitor was 1300 mm3
per mg of chlorophyll per h.
[4] M. B. AIIen, F. R . Whatley, and D. I. Arnon, Biochim. biophysics Acta 32, 32 (1959).
[S] The pI50 of (9) is relatively high in consideration of its PKa,
but this is because [9) is more lipophilic than (8). Better correlations between the PKa and pI50 are generally obtained by
inclusion of partition coefficients.
[6] Synthesis of (Sj ; K . H . Biichei, F. Korte, and R. B . Beechey,
Angew. Chem. 77, 814 (1965); Angew. Chem. internat. Edit. 4,
788 (1965).
[71 J. E. Bafuban and F. L. Pyman, J. Chem. SOC.(London) 121,
947 (1922); H. Punly and K . Gunderrnann, Ber. dtsch. chem.
Ges. 41, 3999 (1908).
790
Photo-initiated Hydrocarboxylation of
Mono-olefins
6
6
9
6
9
No reaction
A mixture of isomeric
nonanoic acids [a]
9.1
86.5
98
70
70
17
[a] 37 % 1-nonanoic acid, 61 % 2-nonanoic acid, 1 % 3-nonanoic acid,
and 1 % 4-nonanoic acid.
[b] 2 % 2-nonanoic acid, 3.5 % 3-nonanoic acid, and 94.5 % 4-nonanoic
acid.
The unconverted olefin is partly isomerized. For example,after
hydrocarboxylation of I-octene in daylight, the unconverted
olefin consists of 87.1 % starting material, 2.8 % cis-2-octene,
and 10.1 % trans-2-octene. After irradiation with ultraviolet
light, however, the percentages are 28.8, 13.6, and 57.6 %,
respectively. After the reaction with cis-4-octene, the unchanged olefin comprises 9 2 % starting material, 5 % transn-4-octene, and 3 trans-n-3-octene.
Received: July 19th, 1965
[ Z 26/850 IE]
German version: Angew. Chem. 77, 813 (1965)
[ I ] W. Reppe et al., Liebigs Ann. Chem. 582, 1 (1963); E. R. H.
Jones, T. Y . Shen, and M. C. Whiting, 5. chem. Soc. (London)
19S1,766.
[2] J. M. J . Tetteroo, Doctorate Thesis, Technische Hochschule
Aachen, 1965.
N-(2,4-Dinitrophenyloxycarbonyl)amino Esters New N-Activated Amino-Acid Derivatives
By Dr. J. Gante
lnstitut fur Organische Chemie der Freien Universitat Berlin
(Germany)
Reaction of amino esters with bis-(2,4-dinitrophenyl) carbonate [ 1] in a molar ratio of 1: 1 in anhydrous ethyl acetate
or ethyl acetate/ether (1 :2 v/v) at ro3m temperature followed
by precipitation with petroleum ether gives the N-(2,4dinitrophenyloxycarbony1)amino esters ( l o ) - ( l d ) .
Angew. Chem. internat. Edit./ Vol. 4(1965) No. 9
R
Compounds ( l a ) - ( I d ) are colorless to pale yellow crystalline
solids which as N-activated amino esters are suitable for
peptide syntheses. For example, reaction of ( l a ) - ( I d ) with
an equimolar amount of Cbo-glycine led to the formation
0-CO-NH-CH-CO~R'
I
(I)
NOz
R'
R
Yield
~
I
"cl
I %I
M'p'
-H
-CHJ
77
45
85-86
80-81
-CHz
54
83-84
72
87-88
~~
Specific rotation
[a]:
[zl'd
(c
=
-53.9
~
= -43.4
1, Ethyl acetate)
of the dipeptides (2a)-(2d) with liberation of 2,4-dinitrophenol and carbon dioxide. The condensation is carried out
M.p.
Yield
R
Specific rotation
1"CI
[%I
-
-H
-CH3
64
79-80
35
Oil
-CH,
36
77-78
41
97
-CHz-S-CHz-
either by melting a mixture of the reactants at llO°C or
leaving it standing in pyridine or chloroforrn/pyridine ( 5 : 1
v/v) at room temperature for 3 days.
GHs
[a]: = --13,3"
(c 0.47,Acetone)
[a]&5 -38.6'
(c = 1, Ethanol)
-
~
Received: July 22nd, 1965
IZ 28/853 IEI
German version: Angew. Chem. 77, 813 (1965)
[ l ] R . Glatthardand M. Matter, Helv. chirn. Acta 46, 195 (1963).
CONFERENCE REPORTS
The Kinetics of Proton Transfer Processes
A discussion meeting was held by the Faraday Society on
"The kinetics of proton transfer processes" in Newcastleupon-Tyne (England) from April 12 to 14, 1965, at which 20
papers were read.
F r o m t h e lectures:
In his introductory lecture, M . Eigen (Gottingen, Germany)
outlined the general aspects of proton transfer processes.
The rate of proton transfer is determined essentially by the
distance between the proton donor and the proton acceptor
at the moment of reaction; therefore, formation of hydrogen
bonds between the two participants favors fast proton exchange. The rate constants of the recombinations
H3Of
+ base
and
HO- + acid
have been determined for numerous systems in aqueous solution. They approach the value characteristic of a diffusioncontrolled reaction (k = 1010-1011 mole-lsec-1). If the
basicity of the acceptor is greater than that of the donor, the
reaction is diffusion-controlled and is independent of the
(positive) pKa difference. If, on the other hand, ApK, < 0,
log k will be a linear: function of ApK,. When log k is
plotted against ApKa, the gradient cc decreases from 1 to 0
as ApK, becomes more positive. The width of the ApKa
region for 0 < cc < 1 depends on the nature of the reactants [I].
[ l ] Cf. M. Eigen, Angew. Chem. 75,489 (1963).
Angew. Chem. internat. Edit. 1 Vol. 4(1965) / No. 9
Brmsted's equation for acid and base catalysis stipulates a
linear relationship between log k and the pKa value of a
catalytically active acid or base:
log k = apKa c
where OL and c are constants.
As long as the branches of the potential curves closely approximate to straight lines, cc remains approximately constant. With increasing deviation from a linear shape, cc must
decrease and eventually become zero. Relaxation measurements carried out on numerous systems (e.g. the halogenation of acetylacetone, acetone, and bromoacetylacetone)
indeed reveal a continuous change in the value of OL between
1 and 0, when pKa of the catalysing species varies. However,
many reactions (e.g. mutarotation of glucose, hydration or
dehydration of carbonyl compounds, hydrolysis of esters)
behave differently. These reactions are governed by general
acid-base catalysis:
HS HA
HSH+ B
+
B
+
+
+
+ HSH+ + HA + SH
The plot of log k against ApK, often gives apparently too
high rate constants. This finding is explained by simultaneous
attack of the acid HA and the base B at the substrate SH,
which is aided by the amphoteric nature of water. Eigen
proposes the following transition complex formed by a concerted mechanism:
/H....
..... H
/
s..._.. /o....
"'H
"'HA
-
s\
H\ /H
H
Q..
HA
79 1
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acid, dinitrophenyloxycarbonyl, esters, amin, new, derivatives, activated
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