Volume 24, Issue 2
Currently known as: Angewandte Chemie International Edition
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198500771
The cover page shows a stereograph of the structure of cyclosporine. This natural cyclopeptide contains a novel amino acid, a threonine derivative with a butenyl group which quasi bridges the ring. This amino acid is essential for the immunosuppressive activity of cyclosporine. More about the structure-activity relationships and about the synthesis of cyclosporine and analogues are reported by R. M. Wenger in a review article on page 17.—An optimal picture of the spatial architecture of the molecule is obtained if the stereograph is viewed through a mirror stereoscope; the three-dimensional structure in Figure 2 on page 79 can be seen quite readily with the aid of a lens stereoscope or even with the naked eye.
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198500772
Dr. Roland Maurice Wenger
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198500773
Unusual structure and unusual activity characterize cyclosporine 1, a neutral, hydrophobic cyclopeptide consisting of eleven amino acids. No more than ten years have passed since its discovery and it is already being employed clinically as an immunosuppressant. Among other things it prevents graft rejection following bone-marrow and organ transplantations.
Prof. Dr. Hans-Dieter Jakubke, Dr. Peter Kuhl and Dr. Andreas Könnecke
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198500851
The direct reversal of the mode of action of proteases—formation instead of degradation of peptides—has been achieved by use of physicochemical principles. The advantages of protease-catalyzed peptide synthesis include the stereospecificity and the rare necesity of having to protect the side chain; disadvantageous is that the proteases are sometimes substrate specific. The method is used, inter alia, in the synthesis of the sweetener aspartame and in the conversion of porcine insulin into human insulin.
Prof. H. M. R. Hoffmann and Dr. Jürgen Rabe
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198500941
Some 10% of the structurally elucidated natural products belong to the α-methylene-γ-butyrolactones, e.g. germacranolides, eudesmanolides, and guaianolides. Of special importance are the cytotoxic properties of some of the compounds of this group of substances. The syntheses of these lactones containing the structural unit 1 are not only of practical interest but also important as examples for the construction of compounds with unusual arrangement of the functional groups.
Prof. Dr. Hans Bock and Dipl.-Chem. Ralph Dammel
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501111
The presumably linear CNSi group is present in phenyl silaisocyanide 3, an organosilicon compound with terminal silicon of coordination number 1. 3 was generated pyrolytically from the triazidosilane 2 and characterized by photoelectron spectroscopy.
Dipl.-Chem. Thomas Poll, Dipl.-Chem. Joachim O. Metter and Prof. Dr. Günter Helmchen
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501121
A seven-membered ring chelate structure, hitherto unknown in the case of titanium compounds, characterizes the complex 1. Presumably, this complex is the reactive species in solution in the TlCl4-catalyzed Diels-Alder reaction of allyl lactates with dienes. An X-ray structure analysis of the complex shows that the Re-side of the CC double bond is well shielded by one of the chlorine atoms.
Harold E. Helson, Prof. Dr. K. Peter C. Vollhardt and Dr. Zhen-Yu Yang
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501141
Novel benzenoid hydrocarbons such as 1 can be obtained from a naphthalene derivative in several cobalt-catalyzed steps. Although 1 contains a [4n + 2]π-system, its electronic structure must by described in terms of cyclobutadiene units. Compounds such as 1 are of interest for the synthesis of “organic metals”.
Prof. Dr. Otto J. Scherer, Dipl.-Chem. Richard Walter and Prof. Dr. William S. Sheldrick
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501151
A similar coordination behavior as isocyanide ligands is exhibited by R2NPNR ligands, since bridging isocyanide ligands are replaced by trivalent phosphazenes in the synthesis of the cluster 2 from the cluster 1. 2 represents the first cluster in which an amino(imino)phosphane is found to function as face-bridging ligand; a μ3-η2-CNCMe3 ligand is also present.
Dr. Gerald Henkel, Dipl.-Chem. Klaus Greiwe and Prof. Dr. Bernt Krebs
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501171
The unusual planar manganese(III)-sulfur complex [Mn(S2C6H3Me)2]−1 is formed on reaction of MnCl2·4H2O with toluene-3,4-dithiolate in methanol in the presence of atmospheric oxygen. A further product is the square-pyramidal complex containing an additional apical MeOH group. Reaction under anaerobic conditions leads to formation of the manganese(II)-sulfur complex [Mn(S2C6H3Me)2]2−, which differs from 1 through its strongly distorted tetrahedral coordination.
Dipl.-Chem. Burkhard Standke and Prof. Dr. Martin Jansen
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501181
Crystalline silver(III) oxide, which is stable over prolonged periods at −20°C, was obtained by anodic oxidation of AgClO4, AgBF4 or AgPF6 (not AgNO3) in aqueous solution. The oxide of definite composition Ag2O3 was hitherto unknown. It arouses interest as a possible component of the anodes in zinc/silver oxide primary cells. According to an X-ray structure analysis, the silver atoms in Ag2O3 are coordinated by an almost square-planar array of oxygen atoms. The AgO4 groups are coupled via common oxygen atoms to give a three-dimensional network.
Dr. Dieter Lentz, Irene Brüdgam and Prof. Dr. Hans Hartl
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501191
The synthesis of the first bis(fluoromethylidyne) cluster, [Fe3(CO)9(μ3-CF)2], was accomplished quite easily by reaction of Fe(CO)5 or Fe2(CO)9 with CFBr3. The two CF-ligands and the Fe3-unit form a trigonal bipyramid with the CF-ligands in the apical positions. The formation of a FCCF-complex could be ruled out.
Prof. Dr. Giovanni Minghetti, Dr. Alberto Albinati, Dr. Anna Laura Bandini and Dr. Guido Banditelli
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501201
The first compound in which a hydride- and an alkylidene-ligand bridge two Pt-atoms is present in the complex cation 2, which is formed on reaction of the complex 1 with styrene. 2 was characterized NMR spectroscopically and by an X-ray structure analysis. the PtPt distance of 2.735(1) Å indicates that there is bonding interaction between the two metal atoms.
Priv.-Doz. Dr. Helmut Fischer, Dr. Friedrich Seitz, Jürgen Riede and Dr. Jürgen Vogel
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501211
[CNCR2]⊕, a cation unknown in the free state, is present as terminal ligand bound to a metal in the salts 1, MCr, W, RPh. On exposure to low-energy radiation (λ>300 nm) the complexes 1 fragment with cleavage of CR2; with exclusively short-wave radiation, however, they are stable. The complexes 1 thus belong to the few compounds in which fluorescence from higher ecited states is observed.
Prof. Dr. Alfred Schmidpeter, Dipl.-Chem. Konstantin Karaghiosoff, Cornelia Cleve and Dr. Dietmar Schomburg
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501231
Novel simple heteroarenes, the title compounds 1, can be prepared from thiocarboxamides by alkylation at the sulfur and a subsequent condensation with phosphorus trichloride. 1, RR′Ph, crystallizes isomorphically with the N-analogue.
Prof. Dr. Alfred Schmidpeter, Dipl.-Chem. Christian Leyh and Dipl.-Chem. Konstantin Karaghiosoff
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501241
A five-membered ring containing two phosphorus atoms of coordination number two is present in the novel heteroarenes 2. Remarkably, even triethylamine is suitable for the reaction 1 2. The two double bonds can be formed only pairwise.—Acyclic analogues of 2 are unknown.
Dipl.-Chem. Andreas Hafner, Prof. Dr. Wolfgang von Philipsborn and Priv.-Doz. Dr. Albrecht Salzer
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501261
Functionalized polylefins can be synthesized from the title compound 1; uncomplexed sorbaldehyde is a poor candidate for such syntheses (side reactions). Depending on the substituents and conditions, the products of type A or—with Fe(CO)3 migration—type B are formed. The triolefin B, R1CHO, R2H, can undergo further reaction.
Prof. Dr. Lutz F. Tietze and Dipl.-Chem. Andreas Bergmann
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501271
The 1,4-dihydropyridine nucleosides 4 are formed in almost quantitative yield when 2-hydroxytetrahydropyridines 3 are heated in toluene in the presence of a (4 Å) molecular sieve. The tetrahydropyridines 3 are likewise formed almost quantitatively on irradiation of a mixture of a N-glycosyl enaminecarbaldehyde 1 and an alkene 2. The method enables wide variation of the substituents and labeling of the dihydropyridine ring (R1=sugar residue, R2, R3=H, CH3, CO2CH3, CO2tBu).
Prof. Dr. Hans Paulsen and Dr. Holger Tietz
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501281
The trisaccharide building block 1, which is capable of linkage and suitable for glycoside synthesis, is formed on reaction of N-acetylneuraminic acid with lactosamine. For glycoside couplings with 1, the trimethylsilyl triflate method can be used; this allows the N-acetylneuraminic-containing building block to be coupled to any desired saccharide.
Dr. Klaus Lichtwald and Dr. Michael Przybylski
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501301
Two isomeric “dimers” are formed from aldosterone 1 on proton-catalyzed cleavage of two water molecules. The dimers could be characterized mass spectroscopically. With the prerequisite that they are also formed under physiological conditions, the existence of such aldosterone derivatives had to be taken into account when considering molecular events in aldosterone activity.
Dr. Hans-Eckart Radunz and Günter Schneider
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501311
3-Substituted hexahydroindane derivatives are of interest as starting compounds for the synthesis of rigid prostaglandin analogues. They could be obtained with unexpectedly high stereoselectivity from the carboxylic acid 1. The acid 1 reacts with N-bromosuccinimide to give the bromide 2. This is converted into the acetate 3, which has the same relative configuration at the centers 3, 3a, and 7a as in the naturally occurring prostaglandins.
Prof. Dr. Henri Brunner, Dipl.-Chem. Heike Kauermann, Dr. Ulrich Klement, Dr. Joachim Wachter, Dipl.-Chem. Thomas Zahn and Prof. Dr. Manfred L. Ziegler
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501321
The first complex with AsS as ligand, the trinuclear cluster 1, was obtained from the dinuclear complex [(C5Me5)2Mo2As2S3] and Co2(CO)8 and characterized by X-ray structure analysis. It is concluded from the bond lengths that AsS has a bond order of 1 and functions as a 5e-donor.—The cluster 2 was prepared analogously.
Prof. Dr. Henri Brunner, Norbert Janietz, Dr. Joachim Wachter, Dipl.-Chem. Thomas Zahn and Prof. Dr. Manfred L. Ziegler
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501331
The synthesis of novel tri- and tetranuclear clusters in the MoFeS system can be accomplished by addition of Fe(CO)5 or Fe2(CO)9 to the complex [(C5Me5)2Mo2S4]. An example is 1, a 62e-“heterocubane”. It contains five MM bonds (not shown); the FeFe distance (no bonding) is 3.334 Å.
Dr. Howard M. Colquhoun, Simon M. Doughty, Alexandra M. Z. Slawin, Dr. J. Fraser Stoddart and Dr. David J. Williams
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501351
The first example of a nitrogen-containing crown ether acting as both a first and second sphere ligand towards a transition metal is found in the rhodium complex 1. This complex contains a crystallographic center of symmetry and is stabilized by intramolecular hydrogen bridges.
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501361
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501371
Michael F. Lappert
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198501372