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Biochemical and Genetic Aspects of Ribosome Specificity in Protein Synthesis.

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New Synthesis of 2 H-Benzazulenes
By Klaus Hafner and Woljgang Rieper[*l
Acenaphthylene ( I ) combines with ethoxycarbonylcarbene,
generated by thermolysis of ethyl diazoacetate, t o give the
stable cyclopropane derivative (21,which can be converted
into phenalenium perchlorate (3) via a multi-step synthesis "1.
H, /cOOC, H,
A
leads directly to ethyl 7,9-dimethyl-2H-benz[cd]azulene-4carboxylate (7a) (m.p. 93-94 "C) in 55-60% yield. Cycloaddition t o the 1,2 bond of (4a) giving (5a) is probably
followed by valence isomerization of the latter to the crossconjugated tricyclic compound (Caj, which undergoes a
hydrogen shift t o give the stable molecules (7a).
Cycloaddition t o the 3,4-bond of (4a), which is also characterized by a high bond order, was not observed. In the case
of (4b) and also (4c) [41, cycloaddition occurs exclusively at
the 1,2-bond t o give (7b) (m.p. 79-81 "C, 64%) and (7c)
(m.u. 106-108 O C , 59 %) (cf. ref. [ 5 9 .
In contrast t o 2H-benz[cd]azulene[2bl and its 7,9-dimethyl
derivative 161, compounds (7a), (7b), and (7c) can be isolated
at room temperature and can be stored below 0 ° C in the
absence of atmospheric oxygen. Like 3,4,7,9-tetramethyl2 H-benz[cd]azulene [2aJ they form trinitrobenzene adducts,
and the heptafulvene system is reversibly protonated in position 1 t o the bridged benzotropylium cation (8) by 70%
The derivatives (4a)-f4c) of cycIopent[cdlazulene, a n isomer
of ( I ) , react similarly with carbenes (carbenoids) to yield
1,2-cycloaddition products. Unlike (2), however, these products isomerize under the reaction conditions t o the hitherto
rather inaccessible 2 H-benz[cd]azulene system (7) [*I which
warrants interest as an isomer of phenalene.
The copper-catalyzed decomposition of ethyl diazoacetate in
the presence of (4a) [31 in methyl cyclohexane at 9Ck100 "C
perchloric acid. The structures of compounds (7) were
established by elemental analysis, molecular-weight determination, and U V and N M R spectra.
Received: December 23, 1969
[Z 143b IE]
German version: Angew. Chem. 82, 218 (1970)
.-.
[*] Prof. Dr. K. Hafner and Dr. W. Rieper
F===l
CH3
(7)
Institut fur Organische Chemie derTechnischen Hochschule
61 Darmstadt, Schlossgartenstrasse 2 (Germany)
[l] R . Pettit, J. Amer. chem. SOC.82, 1972 (1960).
[2] a) K . Hafner and H. Schaum, Angew. Chem. 75, 90 (1963);
Angew. Chem. internat. Edit. 2, 95 (1963); b) V . Boekelheide
and C. D . Smith, J. Amer. chem. SOC.88, 3950 (1966).
[3] K . Hafner and J . Schneider, Liebigs Ann. Chem. 624, 37
(1959).
[4] K . Hafner and K . F. Bangert, Liebigs Ann. Chem. 650, 98
(1961).
[5] K . Hafner and R. Fieischer, Angew. Chem. 82, 217 (1970);
Angew. Chem. internat. Edit. 9, 247 (1970).
[6] W. Rieper, Dissertation, Technische Hochschule Darmstadt 1968. 7,9-Dimethyl-2H-benz[cd]azulenewas prepared by
thermolysis of 4-(3,3-diethoxypropyl)-6,8-dimethylazulene at
150-180 "C/lO-j torr and isolated as the trinitrobenzene
adduct 1m.p. 170-171 "C (decomp.)].
CONFERENCE REPORTS
Biochemical and Genetic Aspects of Ribosome
Specificity in Protein Synthesis
By Orio Ciferri[*l
70 S type of ribosomes, prepared from prokaryotic organisms
o r cell organelles (mitochondria and chloroplasts) of eukaryotic organisms, catalyze the reactions for protein synthesis
in vitro only in the presence of polymerizing enzymes obtained
from prokaryotes o r organelles. No activity is evident when
such ribosomes are tested in the presence of preparations of
polymerizing enzymes extracted from the cytoplasm of the
eukaryotic organisms. Ribosomes of the 80 S type, like those
present in the cytoplasm of eukaryotes, are active in vitro only
248
in the presence of preparations of polymerizing enzymes from
the cytoplasm of such organisms.
Transfer factors T and G, which may be separated from the
preparations of polymerizing enzymes, appear t o be strictly
ribosome specific. Indeed only one transfer factor T and one
transfer factor G, specific for 70 S ribosomes, are present in
the extract from cells of E. coli. In contrast, two transfer
factors G and two transfer factors T, each specific for just one
type of ribosome, may be detected in the non-photosynthetic eukaryotic alga Protothecu zopfii. Two ribosome specific
transfer factors G have been demonstrated also in the case of
the yeast Saccharomyces cerevisiae.
Extracts prepared from dark-grown cells of the photosynthetic
flagellate Eugtena gracilis display polymerizing activity only
Angew. Chem. internat. Edit. J Vol. 9 (1970) J NO. 3
on ribosomes of the 80 S type. On exposure to light, which
induces the synthesis of the photosynthetic apparatus, a
polymerizing activity specific for 70 S ribosomes becomes
evident.
Ribosome specificity is not limited to the factors responsible
for peptide chain elongation. Indeed the initiation factors,
prepared from E. coli, catalyze the reactions for peptide chain
initiation also on Bacillus sztbtilis ribosomes and o n the ribosomes prepared from the mitochondria of the fungus Neurospora crassa.
The development of such studies at the genetic and biochemical levels may provide some interesting clues o n the
evolutionary relations that may exist between prokaryotic
and eukaryotic organisms. In addition, within the latter
group of organisms such studies may give some information
o n the genetic and metabolic autonomy of cellular organelles.
[VB 222 IE]
Lecture at Gottingen o n November 13, 1969
German version: Angew. Chem. 8 2 , 2 5 9 (1970)
rearrangement to the formation of the phosphinic esters
( 7 a ) and (76) [61 and 71 % resp.; N M R (CDC131: 6 (0CH.d3.6-3.7 ppm, doublet, JPOCHz 11 Hz].
[*I Prof. Dr. 0. Ciferri
lstituto di Genetica
Universita d i Pavia
Pavia (Italy)
Recent Investigations on the Synthesis and
Reactivity of Diazo Compounds
By Manfred Regitz [*I
Aliphatic diazo compounds can be prepared via three different but complementary routes by diazo group transfer
with tosyl azide. Diacylmethanes react directly with the diazotransfer agent (Route A) 111, whereas monoacylmethanes
react only after previous formylation 111 (Route B). Diazomethane and non-acylated derivatives are accessible only via
enamines of suitable structure (Route C).
B
A
C
The analogously generated carbenes (6d) and ( 6 e ) , o n the
other hand, undergo O H insertion to give the phosphine
oxides (8d) and (8e) 1100 and 81% resp.; N M R (CDC13):
6 (OCH3) = 3.4-3.5 ppm, singlet], while (6c) follows both
routes [61% (7c) and 22% (8c)l.
Depending on the size of the ring the photolysis and thermolysis of 2-0x0-1-diazocycloalkanes proceed either via ring
contraction and hydride shift (2-cycloalken-1-ones) or transannular carbene insertion (bicyclic ketones) 151.
-TsNH2
CHO
TsN,
Lectures at Leverkusen o n December 1 I , 1969,
and at Karlsruhe on December 13, 1969 f V B 227 IEI
German version: Angew. Chem. 82, 224 (1970)
-TsNHCHO
[ * j Doz. Dr. M. Regitz
R'.
>C=N2
R2
Route A: R1 and R2 = acyl
Route B: R1 or RZ = acyi
Route C: R1 and Rz = H o r alkyl
The synthesis of phenyldiethylphosphonodiazomethane
( I b ) 121 and diphenylphosphinyldiazomethanes( 5 ) 131 and of
2-0x0-1-diazocycloalkanes serve as model examples for
routes A and B respectively. The carbenes (2) obtained
photolytically from ( I ) add to benzene to give the 2 : 1
adducts ( 3 ) and the stable norcaradienes (4);the N M R
spectrum largely rules out a n isomeric cycloheptatriene
structure for ( 4 ) (CDC13, 6 = 5.7-6.3 ppm, 4 olefinic
protons; 6 = 3.5-4.0 ppm, 2 cyclopropane protons).
Diphenylphosphinylcarbenes ( 6 ) have been investigated,
particularly with regard to their rearrangeability. Thus
photolysis of (5a) and (5b) in methanol leads via a Wolff
Angew. Chem. internat. Edit.
/ Vol. 9 (1970) 1 No. 3
Institut fur Organische Chemie der Universitat
66 Saarbriicken (Germany)
[l] M . Regitz, Angew. Chem. 7 9 , 786 (1967); Angew. Chem.
internat. Edit. 6, 733 (1967).
121 M . Regitz, W. Anschiitz, and A.Liedhegener, Chem. Ber. IOI,
3734 (1968).
[31 M . Regitz and W. Anschiitz, Chem. Ber. 102, 2216 (1969).
[4j M . Regitz and J . Ruter, Chem. Ber. 101, 1265 (1968).
[51 M . Regitz and J . Ruter, Chem. Ber. 102, 3877 (1969).
Recent Investigations of Plant Pigments
By Conrad H . Eugster *I
1. Carotenoids. Most of the almost 180 carotenoids known
to date have chiralic character. Until quite recently nothing
was known about their absolute configuration (with the exception of capsanthin). Chemical correlation of the enantio-
249
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ribosome, synthesis, aspects, protein, specificity, genetics, biochemical
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