Volume 24, Issue 12
Currently known as: Angewandte Chemie International Edition
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510091
The cover shows two toadstools (Agaricus xanthoderma). These fungi stain intense chrome yellow when bruised and develop a phenol-like odor. They turn orange-yellow upon treatment with alkalis. Furthermore, extracts of these toadstools exhibit antibiotic activity. All these remarkable effects are caused by compounds that are surprising to encounter in nature. Further details are reported by W. Steglich et al. on page 1063 (photograph: A. Bresinsky, Regensburg).
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510092
Prof. Dr. Guido R. Hartmann, Dipl.-Biol. Peter Heinrich, Dipl.-Biol. Margit C. Kollenda, Dipl.-Biol. Bernhard Skrobranek, Dr. Maximilian Tropschug and Dipl.-Biol. Wolfgang Weiß
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510093
The lipophilic antibiotic rifampicin has long been used successfully to treat tuberculosis. Its mechanism of action, however, has only recently been elucidated. Rifampicin disrupts the metabolism of Eubacteria by binding strongly to a single, highly specific binding site of the DNA-dependent RNA polymerase, thereby inhibiting RNA synthesis.
Dr. Uwe Englisch, Dr. Dieter Gauss, Dr. Wolfgang Freist, Dr. Sabine Englisch, Dr. Hans Sternbach and Prof. Dr. Friedrich von der Haar
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510151
The transcription and translation of genetic information requires a high level of accuracy. In many cases, the difference in binding energies of the correct and incorrect substrates is insufficient to guarantee such accuracy. Therefore, a proofreading step and, if necessary, a correction step are required. The wrong intermediate thereby undergoes enzymatic hydrolysis.
Prof. Dr. Albrecht Rabenau
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510261
Quartz single crystals for oscillators, synthetic emeralds, CrO2 for magnetic tapes, silicate-rich zeolites—these and many other substances may be prepared by hydrothermal synthesis. These heterogeneous reactions, which are carried out in aqueous medium above 100°C and 1 bar, represent a special case of chemical transport phenomena. Under hydrothermal conditions, substances that are otherwise only sparingly soluble dissolve readily as complexes, the formation of which may involve water or “mineralizers.”
Dr. Tevfik Severengiz, Prof. Dr. Wolf-Walther du Mont, Priv.-Doz. Dr. Dieter Lenoir and Heike Voss
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510411
Tellurium compounds are increasingly used in organic synthesis. The first telluroacetic acid derivative, the ester 3, was identified by its mass spectrum. 3 decomposes spontaneously to give (Z)- and (E)-2,3-bis(trimethylsiloxy)-2-butene and tellurium. The starting material 2 is obtainable from 1 and acetyl chloride.
Prof. Dr. Lutz F. Tietze and Dipl.-Chem. Uwe Beifuss
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510421
The terminology of stereoselective synthesis is rapidly coming to resemble the legendary Tower of Babel. “Induced” and “non-induced diastereoselective” are the most recent newcomers. Whether these unquestionably useful terms will find acceptance is a matter for the future to decide. They were introduced in order to explain the title reaction in which 1,2-disubstituted cyclohexanes with a trans: cis selectivity of > 99 : 1 are formed.
Prof. Dr. Michael Pirrung
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510431
Two annelated tetrahydrofuran structural units—partial structures of the aflatoxins and caryoptins—can be prepared by irradiation of cyclobutanones such as 1. Thus, the cyclic acetal 2 is formed by an intramolecular trapping reaction of a photochemically generated oxacarbene.
Prof. Dr. Michael Pirrung and Dipl.-Chem. Gerard M. McGeehan
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510441
The biosynthesis of ethylene, which functions as a fruit-ripening hormone in plants, from methionine via aminocyclopropane carboxylic acid is inhibited by 1. In the presence of apple tissue, 1 slowly forms 1,4-pentadiene 2 via a radical pathway; this is accompanied by inhibition of the ethylene-forming system.
Dr. Y. Tamaru, H. Higashimura, K. Naka, M. Hojo and Prof. Dr. Z. Yoshida
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510451
The formation of bis-lactones of type 2 from 1 (XH) and CO is catalyzed by PdII. Substituents on C-2 and C-3 are largely tolerated. In comparison, 1 (XAc) forms only open-chain 1,3-dienes in the presence of Pd0.
Prof. Dr. Emanuel Vogel, Brigitte Neumann, Dr. Wolfgang Klug, Dr. Hans Schmickler and Dr. Johann Lex
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510461
A “Perturbed annulene”—this is one way to view the much discussed dipleiadiene, 1, which has finally been obtained in the course of an investigation having an entirely different goal. Although 1 is formally a naphthalene that is peri-bridged by butadiene structural units, it exhibits pronounced paratropism.
Prof. Dr. Dietrich Döpp, Prof. Dr. Carl Krüger, Dipl.-Chem. Hamid Reza Memarian and Dr. Yi-Hung Tsay
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510481
The captodative olefin 2 can undergo smooth addition to acylnaphthalene 1 (RH, Me, Ph) to give the 1,4-photocycloadduct 3. Such reactions of naphthylcarbonyl derivatives are extremely rare and synthetically useful.
Dipl.-Chem. Harry Schulz and Prof. Dr. Fritz Beck
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510491
Quantitative current yields without formation of CrIII salts are achieved in the oxidation of 2-propanol to acetone at ceramic Ti/Cr2O3 anodes. The postulated reaction mechanism is analogous to that formulated by Westheimer for homogeneous oxidation with chromic acid. The lifetimes of the electrodes, however, are too short for use of the reaction on an industrial scale.
Dr. Hermann Allgaier, Prof. Dr. Günther Jung, Priv.-Doz. Dr. Rolf G. Werner, Dr. Ursula Schneider and Prof. Dr. Hans Zähner
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510511
A decosapeptide that is highly effective against acne has been isolated from a culture filtrate of Staphylococcus epidermidis Tü 3298. The molecule contains four disulfide bridges derived from meso-lanthionine, β-methyllanthionine, and the newly discovered amino acid S-(2-aminovinyl)-D-cysteine. The structure elucidation was achieved by enzymatic and hydrolytic fragmentation and desulfurization with Raney nickel followed by sequence analysis.
Prof. Dr. Nils Wiberg, Klaus Schurz and Dr. Gerd Fischer
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510531
The SiN bond of the silaketimine 2, which is obtained by “thermal salt elimination” from the lithium compound 1, can undergo numerous addition reactions. For example, reaction with methyl vinyl ether affords the [2+2] cycloadduct 3.
Doc. Dr. Ryszard W. Adamiak, Dr. Ewa Biała and Dr. Bohdan Skalski
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510541
The pyridinium group at C-6 of the purine 1, RMe, has proved to be a good leaving group, making possible an efficient two-step synthesis of the biochemically important derivatives 2, XN3, SCH2CH2OH, OCH3. Older methods, which required more steps, afforded lower overall yields.
Dipl.-Chem. Annegret Hembrock, Prof. Dr. Hans J. Schäfer and Dr. Gesine Zimmermann
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510551
Anodic oxidation results in comparatively good chemoselectivity; the ratio of attack at tertiary to attack at secondary C atoms is 12 : 1 for decalin. The regioselectivity of anodic oxidation may be controlled by inductive effects in the case of chlorides (e.g., chlorocyclohexane) and fatty acids. Remarkably, the steroids androstane and cholestane undergo oxidation mainly at C-6.
Ralf Riedel, Dr. Hans-Dieter Hausen and Prof. Dr. Ekkehard Fluck
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510561
Only one bond of the P4 tetrahedron is opened to form the title compound 1, a derivative of P4H2. 1, along with the diphosphene derivative 2, was isolated as orange, air-stable crystals (R2,4,6-tri-tert-butylphenyl).
Dr. Dieter H. Buss, Dipl.-Chem. Gottfried Schaumberg and Prof. Dr. Oskar Glemser
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510571
Manganese dioxide with both very small and very large surface areas and uniform particle sizes was prepared from Mn(NO3)2 and KMnO4 at pH 1 and 2 and at pH 0 (see figure), respectively. A computer controlled the mixing of the reagents so that the potential remained constant. The reagents were used in nearly stoichiometric amounts.
Prof. Dr. Heinz P. Fritz, Dr. Gerhard Müller, cand. chem. Gabriele Reber and Dipl.-Chem. Michael Weis
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510581
A new type of phosphorus ylide is represented by the title compound 1, which is obtained as dark red, flat prisms in high yields from CSe2 and nBu3P. Derivatives of 1 might exhibit the properties of “organic metals.”
Dipl.-Chem. Ralf Braun, Dipl.-Chem. Matthias Kummer, Prof. Dr. Hans-Dieter Martin and Prof. Mordecai B. Rubin
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510591
A new, theoretically interesting, unstable benzene dimer, the title compound 1, was synthesized by photolysis of the barrelene-o-quinone adduct. The Arrhenius parameters for the decomposition of 1 to form benzene were determined.
Prof. Dr. Henri Brunner, Norbert Janietz, Walter Meier, Gertrud Sergeson, Dr. Joachim Wachter, Dipl.-Chem. Thomas Zahn and Prof. Dr. Manfred L. Ziegler
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510601
The wide range of coordination possibilities for disulfur ligands is exemplified by the title compound. The Fe2 complex contains two S− ligands that are arranged perpendicularly to each other, while the Co2 complex shown on the right represents a new type of structure.
Prof. Dr. Wolfgang A. Herrmann, Heinz-Josef Kneuper and Dr. Eberhardt Herdtweck
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510621
A substituent-free Pb atom that is bonded though double bonds to two organomanganese fragments is present in complex 2, which is surprisingly easy to prepare from the mononuclear complex 1 and PbCl2 in tetrahydrofuran (THF). The MnPbMn skeleton is nearly linear.
Dipl.-Chem. Sabine Hilbig, Thomas Andries, Prof. Dr. Wolfgang Steglich and Prof. Dr. Timm Anke
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510631
The toadstool Agaricus xanthoderma, which has a phenol-like odor, exhibits interesting properties. The strong antibiotic activity of its extract is due to 4-diazo-2,5-cyclohexadien-1-one 1; the yellow coloration of bruised fungi is caused by the diazamerocyanin 2 and by a p-hydroxyphenylazo derivative of glutamic acid.
Prof. Dr. Günther Maier, Dipl.-Chem. Jochem Henkelmann and Dr. Hans Peter Reisenauer
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510651
The limits of stability of boraethenes—not containing bulky substituents—appear to have been reached with 2. Compounds 2 are formed by the thermal cycloreversion of Diels–Alder adducts and can be isolated in an argon matrix or trapped with, e.g., benzophenone (XOCH3, N(CH3)2).
Prof. Dr. Ulrich Schöllkopf, Dr. Hans-Jürgen Neubauer and Dipl.-Chem. Manfred Hauptreif
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510661
The scope of application of the bislactim ether method in the synthesis of amino acids has been broadened by the use of the chloride 1. Compound 1 serves as a cationic synthon, which reacts with nucleophiles. A prime example is the synthesis of 2, which can be hydrolyzed to give the title compounds 3.
Dr. Inga Hoppe, Prof. Dr. Ulrich Schöllkopf, Martin Nieger and Dr. Ernst Egert
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510671
α-Amino phosphonic acids, analogues of α-amino carboxylic acids, are of interest because of their potential biological activity. The title reaction makes possible the preparation of (easily separated) diastereomers, which can be saponified to give penicillamine analogues (RC(CH3)2OCH3).
Prof. Dr. Alfredo Ricci, Dr. Mariella Fiorenza, Dr. Alessandro Degl'Innocenti, Dr. Giancarlo Seconi, Dr. Pasquale Dembech, Dipl.-Chem. Konard Witzgall and Prof. Dr. Hans Jürgen Bestmann
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510681
A highly selective nucleophilic formylation is possible under mild conditions with bis(trimethylsilyl) ketone 1, a strawberry-colored oil. Thus, it reacts for example, with 2-cyclohexenone, undergoing 1,4-addition to give 2, which in turn yields 3 in the presence of moisture.
Dipl.-Chem. Jutta Borm, Prof. Dr. Gottfried Huttner and Dr. Laszlo Zsolnai
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510691
A Z-diphosphene fragment as side-on and end-on coordinated ligand as well as a μ3-P--tBu bridge are present in the triangulo Cr3 cluster 1, which is formed by thermal decomposition (100°C) of tBuP[Cr(CO)5]2.
Prof. Dr. Waldemar Adam and Dr. Axel Griesbeck
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510701
5-Methyl-4-methylene-1,2-dioxolane-3-one 2 exhibits unexpectedly high thermal stability. The first α-methylene-β-peroxylactone was obtained by regiospecific photooxygenation of the α,β-unsaturated carboxylic acid 1 to give the hydroperoxide followed by acid-catalyzed dehydration.
Prof. Dr. Waldemar Adam, Dr. Klaus Hannemann and Prof. Dr. R. Marshall Wilson
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510711
Confirmation of the theory of Salem and Rowland that the position of radical orbitals determines the lifetimes of triplet diradicals has been achieved by trapping of the diradicals 1a–1c as the peroxides. The lifetime decreases by more than four orders of magnitude on going from 1a to 1c.
Hans-Helmut Görtz and Jürgen Hartmann
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510731
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510732
Hans Georg von Schnering
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510733
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510741
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510751
Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198510801