вход по аккаунту


Graphical Abstract (Angew. Chem. Int. Ed. Engl. 21995)

код для вставкиСкачать
International Edition in English
A Journal of the
Deutscher Chemiker
Pages 129-248
The cover picture shows the structure, generated by molecular mechanics calculations. of a chroinophoric self-assembled superlattice with a very large second-order
nonlinear optical response (blue: benzylic coupling layer; green : stilbazolium chromophore layer with high polarizability ; violet and yellow: siloxane capping layer;
white spheres: iodide counterions). The synthesis and properties of the associated
real systems are one of the themes of the review by T. J. Marks and M. A. Ratner on
molecule-based assemblies with nonlinear optical properties on pp. 155ff. This article complements excellently that by N. J. Long on the “organometallic route” to
NLO materials in the previous issue.
The designation “scourge of mankind” has been attached to parasitic infections such
as Chagas’ heart disease, sleeping sickness, and malaria. In many countries of the
world they lead to human misery and massive socio-medical problems. Several
approaches are possible for the design of chemotherapeutic agents that can interfere
as enzyme inhibitors with the metabolism of parasites. For instance. structural
motifs of an enzyme and its natural substrates can be expolited to control the kinetics
of the enzyme -substrate interactions, and thus substrate analogues can influence
the enzyme as inhibitors at various stages of the catalytic cycle. The results may be
irreversible inhibition, destabilization of the enzyme’s structure, or an alteration of
its substrate specificity. Glutathione reductase and trypanothione reductase are
target enzymes for this strategy of drug design in the tight against tropical diseases.
R. H. Schirmer,* J. G. Miiller,
R. L. Krauth-Siege1 ................... 141 154
Disulfide-Reductase Inhibitors as Chemotherapeutic Agents: The Design of Drugs
for Trypanosomiasis and Malaria
The rational construction of supramolecular assemblies with preordained collective properties is an important theme in many areas of contemporary
chemistry. The advances made in this respect with
regard to polymeric NLO materials, and what problems must still be addressed before technologically
viable NLO building blocks become readily available, are surveyed by the authors of this review.
Superlattices of the type shown schematically on
the right should be among the most promising materials.
T. J. Marks,*
M . A. Ratner* ...........................
Design, Synthesis, and Properties of
Molecule-Based Assemblies with Large
Second-Order Optical Nonlinearities
Since the ligation of peptide fragments in vivo is meaningless, no natural enzyme is
capable of replacing chemical coupling methods, which have the danger of racemization in segment condensation. Native proteases and those altered by protein design
as well as catalytic antibodies may serve as peptide ligases, as demonstrated recently
with subtiligase in the chemoenzymatic synthesis of RNase A.
H.-D. Jakubke* .........................
Catalytic and enantioselective are
two new efficient processes for
P H 2 P h
C-C bond formation developed
from fundamental reactions of
organolithium compounds. Koga
et al. have achieved the benzylation
of Li enolates in the presence of
both chiral (L*) and achiral (L) ligands [Eq. (a)], and Denmark et al. describe the addition of RLi to aryl imines
[Eq. (b)] with very good selectivities, R = Me, vinyl.
D. J. Berrisford* ........................
Peptide Ligases--Tools for Peptide
Catalytic Asymmetric C-C Bond Formation: New Enolato- and Organolithium
Strontium-% is one of the most poisonous radionuclides. Its toxicity results from its
long half-life of 28.5 years and permanent deposition in the blood-forming bone
system. Strontium-90 is formed in high yields during the nuclear fission o f uranium235 and plutonium-239. The classic analytical procedure for the determination of
90Sr, which relies on the 8- -radiation of the daughter nuclide yttrium-90, necessitates the chemical removal of all accompanying nuclides. This method requires the
Sr/Y ratio to be at equilibrium which takes about two to three weeks to achieve--far
too long for the analysis of acute contaminations. Three communications deal with
new procedures for ultra-trace analysis using complex physical detection methods
(resonance ionization and accelerator mass spectrometry) and high-performance
separation techniques (high-performance ion chromatography, HPIC) are presented. In accordance with the strategies of the German Federal Ministry of the Environment. Nature Conservation, and Nuclear Safety. precision methods are described
for the determination of the strontium-90 content in aerosols. These techniques yield
data for calculations of the spread of contaminants, which in turn yield results that
can be verified in various samples with the aid of the novel fast detection method
(HPIC with on-line detectors). The three analytical procedures are set up in a
modular manner and can therefore be utilized in variable combinations. They also
indicate the high level of refinement achieved by modern ultra-trace analyses.
J. Lantzsch, B. A. Bushaw, G. Herrmann,
H.-J. Kluge, L. Monz, S. Niess,
E. W. Otten, R. Schwalbach, M. Schwarz,
J. Stenner, N. Trautmann, K . Walter,
K. Wendt,* K. Zimmer .............. 381-183
Trace Analysis of the Radionuclides "Sr
and 89Sr in Environmental Samples I:
Laser Mass Spectrometry
F. Arslan, M. Behrendt, W. Ernst.
E. Finckh,* G. Greb, F. Gumbmann,
M. Haller, S. Hofmann. R. Karschnick,
M. Klein, W. Kretschmer, J. Mackiol,
G . Morgenroth, C. Pagels,
M. Schleicher .............................
Trace Analysis of the Radionuclides "'Sr
and 89Sr in Environmental Samples
I1 :Accelerator Mass Spectrometry (AMS)
J. Alfaro, T. Apfel, H. Diercks,
A. Knochel,* R. Sen Gupta,
K. Todter ...................................
186- 189
Trace Analysis of the Radionuclides 90Sr
and 89Sr in Environmental Samples 111:
Development of a Fast Analytical Method
By Kobe electrolysis of auxiliary-substituted malonic acid derivatives 1 with co-acids
2 the first diastereoselective coupling yielding 3 was achieved in up to 86 % &.
B. Klotz-Berendes, H. J. Schlfer.*
M. Grehl, R. Frohlich ............... 189-191
Diastereoselective Coupling of Anodically
Produced Radicals Bearing Chiral Amide
The coupling of an alkynyl and a butadienyl unit at the rhodium center of 1 is the key
step in the selective, stepwise trimerization of methyl propiolate HC=CR to hexadienyne 3 with [Rh(q2-0,CMe)(PiPr,),1 as a metal template. In MgCI, in ether, this
step occurs almost quantitatively, and the intermediates 1 and 2 were characterized
by X-ray crystal structure analysis.
iPr3P ,cR
I 7'
iPr3P R
/ c
R = C02Me
A Rhodium-Mediated, Stepwise Trimerizdtion of an Alkyne That Does Not Lead to a
Benzene but Selectively t o a Hexadienyne
iPr3P' ~ ~ ~ , , c - f ~ ' R
C 7
H. Werner,* M. Schiifer.
J. Wolf, K. Peters.
H. G. von Schnering .................. 191 -194
Under cathodic conditions a polymer film forms on an electrode when C,,O is first
reduced in the presence of Bu,NCIO, in toluene/acetonitrile and then oxidized.
Films with thicknesses of up to 3 bm can be produced by repeated cyclic voltammetry. Evidence for ionic as well as electronic conductivity of this fullerene polymer is
also provided.
M. Fedurco, D. A. Costa. A. L. Balch.*
W. R. Fawcett* ..........................
194- 196
New (E)-/knethoxyacrylates. the antifungal compounds 9-methoxystrobilurins 1, have been discovered. Strobilurins are currently of great interest as
lead structures for fungicides in crop protection.
S. Zapf, A. Werle, T. Anke.*
D . Klostermeyer, B. Steffan,
W. Steglich* ...............................
Electrochemical Synthesis of a RedoxActive Polymer Based on Buckminsterfullerene Epoxide
196- 198
9-Methoxystrobilurins - A Link Between
Strobilurins and Oudemansins
The 12 + 2 + 21 cycloaddition of two molecules of a phosphaalkyne and one molecule
of a terminal alkyne in the coordination sphere of iron(o) affords 1,3-diphosphinines
regiospecifically [Eq.(a)]. The coordinated and the oxidatively released 1.3-diphosphinines have cyclic delocalized x systems and are thus not only novel heteroarenes,
but also of interest as potential catalysts.
D . Bohm, F. Knoch, S. Kummer,
U. Schmidt, U. Zenneck* .......... 198-201
Targeted Synthesis at Iron(o) Centers and
Oxidative Release
In the gas phase, sulfur and monopositive metal ions
(Sc-Zn) react to form novel metallo- and metallapolysulfmes [MS,]'. The structures of these complexes were calculated by a b initio methods. The
lowest energy structure of [Cu(cyclo-S,,)]+, in
which the octahedrally coordinated Cu' ion is located i n the center of the S,, cycle, is shown in the
picture on the right.
I. Dance,* K. Fisher,
G. Willett ...................................
201 -203
Formation and Structures of New
Metallo- and Metallapolysulfanes, [MSJ'
(r = 2-16)
UV/Vis, resonance Raman, and EPR spectroscopy served in characterizing the
alkyIperoxoiron(1n) complex 2, an intermediate in the oxidation of alcohols R’OH
with alkyl hydroperoxides ROOH catalyzed by p o x 0 complex 1. The results discussed may provide insight for studies of monooxygenases.
Formation of an Alkylperoxoiron(nr)
Complex during Oxidations Catalyzed
by pOxodiiron(rI1) Complexes
J.-M. Vincent, S. MCnage, J.-M. Latour,
A. Bousseksou, J.-P. Tuchagues,
A. Decian. M. Fontecave * ........ 205 -207
A bent Fe, chain in which the central Fe atom has
two C I S 0x0 bridges is the distinguishing feature of
complex 1 (structure on the right) The resulting
strong antiferromagnetic interactions between the
metal atoms are evident in interesting magnetic and
spectroscopic properties.
S. Menage, E. C. Wilkinson,
L. Que, Jr., M. Fontecave* ....... 203-205
A New Type of Trinuclear Oxoiron(rr1)
Bis-monodentate 4,4‘-bipyridine ligands link p,-chloro-bridged Cu’
dimers to form an extended structure
containing channels that are of comparable size to those in some zeolites
(drawing on the right; dark spheres,
Cu; large shaded spheres, CI).
0 . M. Yaghi,* G . Li .................. 207 - 209
Discrete neutral assemblies in solution can be studied with the analytical method
described here. A prerequisite is that one of the components contains an ion-complexing site, for example a crown ether unit. When alkali metal ions are added,
charged assemblies form, which can be examined by electrospray mass spectrometry
(ESMS) without disruption of their hydrogen bonds. IL in the title stands for ion
K. C. Russell, E. Leize, A. Van Dorsselaer,
J.-M. Lehn* ............................... 209-213
Mutually Interpenetrating Sheets and
Channels in the Extended Structui-e of
Investigation of Self-Assembled Supramolecular Species in Solution by IL-ESMS,
a New Mass Spectrometric Technique
Rather than C-H or C-C bonds, Pr’ activates C-F bonds in the gas phase in a
variety of aliphatic and aromatic fluorocarbons; PrF’ and P r o + react analogously.
This first general example of preferential C - F bond activation in the gas phase
allows interesting conclusions to be drawn regarding the importance of 4 f electrons
for the reactivity of isolated lanthanide species. The existence of neutral PrF and
PrF, in the gas phase was also proven by neutralization - reionization mass spectrometry (NRMS).
C. Heinemann, N. Goldberg,
I. C. Tornieporth-Oetting,
T. M. Klapotke, H. Schwarz* ... 213-217
Simultaneous reduction of the activation energy for
the exo reaction and increase of that for the rndo
reaction explain how a cyclic porphyrin trimer that
can bind diene 1 and dienophile 2 in its cavity increases the e m selectivity of a Diels-Alder reaction
and accelerates it dramatically.
C. J. Walter.
J. K. M. Sanders* ......................
Gas-Phase Activation of Fluorocarbons by
“Bare” and “Coordinated” Praseodymium
Free-Energy Profile for a Host-Accelerated
Diels-Alder Reaction : The Sources of exo
Lithiated 1 and unreacted n-butyllithium in a 2:2 ratio make up the title aggregate 2,
which is formed in the reaction of 1 with two equivalents of n-butyllithium (shown
below). Species such as 2 can be regarded as intermediates in heteroatom-facilitated
lithiation reactions.
The Formation of a Mixed Organolithium Aggregate Li,R,nBu,
(R = 2,6-(CH,NMe2),-3.5-Me,C,HCH,)
during the Heteroatom-Assisted Lithiation
of 1,3-Bis(dimethylaminomethyl)-2,4.6trimethylbenzene
/ \
P. Wijkens, E. M. van Koten,
M. D. Janssen, J. T. B. H . Jastrzebski,
A. L. Spek. G. van Koten* ........ 219-222
4 BULl
Nearly complete inversion of configuration is seen during decarboxylation of the
potassium salt I of an r-chiral carboxylic acid to give ether 2. Since 2 is an intermediate in the synthesis of inhalational anesthetics. and its enantiomers may have
different pharmacological profiles. the determination of the stereochemical outcome
of this C - - C bond cleavage is of particular interest.
205 "C
K. Ramig,* L. Brockunier.
P. W. Rafalko. L. A. Rozov ....... 222-223
Carbon-Carbon Bond Cleavage with
Inversion of Configuration : Conversion of
(R)-(+ )-I -Methoxytetrafluoropropionic
Acid to (S)-(
-)-I ,2,2,2-Tetrafluoroethyl
Methyl Ether
99% ee
>99.9% ee
Depending on the tether length of the diphosphonate
group, hydrothermal reactions of VCI, with diphosphonic acids of the class (H,O,P)(CH,),(PO,H,)
the presence of templating organic cations yield
one-. two-, and three-dimensional framework structures of the V-O-RPOi- system. The picture shows
a section of the three-dimensional framework of
[H,N(CH,)2NH31[(Vo)4(OH),(H,0),(0,P(CH,)3PO,] J .4H ?O.
V. Soghomonian,
Q. Chin, R . C. Haushalter.*
J. Zubieta* .................................
A general high-temperature approach
J. R. Long, A. S. Williamson.
R. H. Holm* ..._......._._.....
Investigations into the Targeted Design of
Solids: Hydrothermal Synthesis and
Structures of One-, Two-, and ThreeDimensional Phases of the OxovanadiumOrganodiphosphonato System
to reducing the dimensionality of
cluster frameworks is formulated and
employed in deconstructing the twodimensional Re,Se,CI, structure. The
resulting new phases with [Re,Q,]'+
(Q = S, Se) cores exhibit two-dimensional [Re,Se,CI,]- sheets. one-dimensional [Re,Q,CI,J'chains. and
[Re,Q8C16]4- clusters. The structures
of these phases are presented along
with that of TI,Re,Se,CI, which contains the unprecedented molecular
cluster [Re,Se,C1,]4- 1.
Dimensional Reduction of Re,Se,CI, :
Sheets, Chains, and Discrete Clusters Composed of Chloride-Terminated [Re,Q812
(Q = S, Se) Cores
Elimination of alcohols from the Ir"' complexes 1 to give 2 is feasible and competes
favorably with ,&H elimination to give 3. This supports proposals that 0 - H reductive elimination is the product-forming step in industrially important processes such
as CO hydrogenation and alcohol homologation. The ancillary n-donating chloride
has a paramount role in this process. L = PEt,, PMe,.
CIL3 If'.
[IrCIL,] + CH,OH
0. Blum, D. Milstein* ......._.......229-231
Direct Observation of 0 - H Reductive
Elimination from Ir"' Complexes
The answer to the question in the title may well be Rh'. Although initial studies
suggested a mechanism involving a Rh"' species of type 2, the activation of the
benzene C-H group by 3 now appears to proceed via the intermediate 1.
231 -233
Does the Facile Inter- and Intramolecular
C - H Bond Activation by Tp*-Rh
Complexes Proceed via Rh' or Rh'"
P. J. Perez, M. L. Poveda,
E. Carmona * .............................
The reduction of Lal, with La metal at roughly
750°C proceeds via metallic LaI, to LaI, the first
halide with a hexagonal close-packed NiAs-type
structure (projection along c shown on the right).
This arrangement does not provide suitable interstitial sites for hydrogen atoms. The extreme c/u ratio
(2.47) affords markedly strong La-La bonding in
the a,b plane. Extended Hiickel band calculations
suggest that La1 is a strongly anisotropic metal.
J. D. Martin, J. D. Corbett* ....... 233-235
LaI: An Unprecedented Binary Rare Earth
Metal Monohalide with a NiAs-Type Structure
" b
An amphiphilic calixl6jarene host effectively binds to ferrocenyl groups covalently
attached to a self-assembled monolayer on gold. Electrochemical evidence indicates
that the calixarene binds the protruding ferrocenyl groups by including them in its
lipophilic end (schematic representation below).
Replacing the N atom with an As or P atom in antineoplastically active phospholipids
1 and 2 (Z = N) leads to homologous compounds (Z = As, P) that are equally
effective against tumors and have fewer side effects than the N-containing phospholipids. This marks definite progress in cancer treatment with chemotherapeutically
active phospholipids.
L. Zhang, L. A. Godinez, T. Lu,
G . W. Gokel, A. E. Kaifer* ....... 235-238
Molecular Recognition a t an Interface:
Binding of Monolayer-Anchored Ferrocenyl Groups by an Amphiphilic Calixarene Host
J. Stekar,* G. Nossner, B. Kutscher,
J. Engel, P. Hilgard ....................
Synthesis, Antitumor Activity, and Tolerability of Phospholipids with Nitrogen Ho-
* Author
to whom correspondence should be addressed
The Bourbaki Gambit
C. Djerassi
Amorphous Inorganic Materials and Glasses
Methods of Immunological Analysis, Vols. 1-3
N. A. Staines
A. Feltz
R. F. Masseyeff, W H. Alberts,
H . Hopf, A . Plugens ..........................
H . Reuter ...........................................
K.-H. Gliisenkamp .............................
Keyword Index 244
Events 138
Preview 246
Author Index 245
d'; VCH Verlugs~eselbchaft mhH. D-69451 Weinhrrm, 199.5
$ fO.OO+ .25/0
A n g r w . Clxm. lnr. Ed. EnKI. 1995, 34. No. .?
The following reviews will appear in future issues:
Digitalla Research in Berlin-Buch- Retrospective and Perspective Views
K. R. H . Repke et al.
Atom Economy -A Challenge for Organic Synthesis:
Homogeneoua Catalysis Leads The Way
B. M. Trost
Vitamin B12:How the Problem of Its Biosynthesis Was Solved
A. R. Battersby et al.
Enzymes in Organic Synthesis: Application to the Problems of Carbohydrate Recognition (Part 1)
C.-H. Wong et al.
Covalent Inorganic Azides
T. M. Klapotke and I. C. Tornieporth-Oetting
Enzymes in Organic Synthesis: Applications to the Problems of Carbohydrate Recognition (Part 2)
C.-H. Wong et al.
Preparative Solid-state Chemistry Using High-Power CO, Lasers
H. Muller-Buschbaum and S. Mohr
Probing Protein Structure and Function with an Expanded Genetic Code
P. G. Schultz et al.
Calixarenes, Macrocycles with (Almost) Unlimited Possibilities
V. Biihmer
Carbon-Hydrogen Bonds of D N A Sugar Units as Targets for Chemical Nucleases and Drugs
B. Meunier et al.
Anticougulatory Substances of Bloodsucking Animals: From Hirudin to Hirudin Mimetics
J. Dodt
Model Reactions in Photosynthesis --Photo-Induced Charge Transfer and Energy Transfer between Connected Porphyrin and
Quinone Units
H. Kurreck and M . Huber
Basic Principles of Thermoanalytical Techniques and Their Possible Applications in Preparative Chemistry
H. K. Cammenga and M. Epple
Combinatori;il Synthesis and Multidimensional N M R : An Approach to Understanding Protein-Ligand Interactions
S. L. Schreiber and J. K . Chen
The Ciitalytic Oxidative Coupling of Methane
J. H. Lunsford
Recent Trends in Photoaffinity Labeling
M. Goeldner
Без категории
Размер файла
524 Кб
abstract, int, angel, engl, chem, 21995, graphical
Пожаловаться на содержимое документа