Angewandte Chemie International Edition

Cover image for Vol. 53 Issue 52

Editor: Peter Gölitz, Deputy Editors: Neville Compton, Haymo Ross

Online ISSN: 1521-3773

Associated Title(s): Angewandte Chemie, Chemistry - A European Journal, Chemistry – An Asian Journal, ChemistryOpen, ChemPlusChem, Zeitschrift für Chemie

Flashback: 50 Years Ago

Angewandte Chemie International Edition was first published in 1962, the mother journal first in 1888. In this monthly flashback, we feature some of the articles that appeared 50 years ago. This look back can open our eyes, stimulate discussion, or even raise a smile.

Archive: 2013 2012

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 51, 13962

    The chemical effects of nuclear reactions, which can involve “recoil atoms” that have high kinetic energies, were first reported in 1934. 30 years later, the recoil chemistry of tritium was of particular interest as it could be easily produced and was the only radioactive isotope with the chemical properties of hydrogen, and Friedrich Schmidt-Bleek and F. Sherwood Rowland summarized the recoil reactions of tritium with organic compounds in a Review. Rowland shared the Nobel Prize in Chemistry 1995 with Paul J. Crutzen and Mario J. Molina for their work on the formation and decomposition of ozone.

    Diazonium species were the subject of two Communications. In the first report, T. Severin and J. Dählstrom described the synthesis of quinonoid diazo compounds from 2-(p-nitrophenyl)dimedone. In the second report, K. Bott discussed the synthesis of three stable aliphatic diazonium ions. The identities of these compounds were confirmed by the characteristic signals for the N≡N group in the infrared spectrum and by elemental analysis.

    Siegfried Hünig and Helmut Quast reported on the detection of a heterocyclic nucleophilic carbene, which was produced by deprotonation of 3-methylbenzthiazolium salts. At that time, there was no reported reaction that could be proved to proceed via a carbene and not the corresponding dimer. In this case, the presence of the carbene was confirmed by comparing the reaction products of the carbene or the dimer with azidinium salts.

    Read more in Issue 12/1964.

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 44, 11683

    Guilio Natta, who shared the 1963 Nobel Prize for Chemistry with Karl Ziegler, published a Review on the stereospecific homopolymerization of cyclopentene. Use of MoCl5/Al(C2H5)3 as catalyst was found to give the cis-polypentenamer, whereas use of WCl5/Al(C2H5)3 resulted in formation of the trans-polypentenamer.

    Rolf Huisgen et al. reported on the stereospecific addition of ketenes onto enol ethers to form 3-alkoxycyclobutanones. The cis or trans configuration of the enol ethers is retained in the product, and the reaction proceeds via a resonance-stabilized intermediate or a multistep cycloaddition, depending on the geometry of the starting materials.

    Wilhelm P. Neumann et al. published two Communications on stannanes. The first report discussed the synthesis of octabenzylcyclotetrastannane, which contains a four-membered ring of tin atoms. The target product was synthesized from dibenzyltin hydride, which itself was produced in situ from dibenzyltin dichloride and ignites spontaneously on filter paper in contact with air. The second Communication was on the synthesis of organic di- and polystannanes by the condensation of organotin hydrides with organotin oxides.

    Read more in Issue 11/1964.

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 39, 10270

    Hubert Schmidbaur et al. published three back-to-back Communications. The first two were on gallium chemistry, namely the reaction of organosilanes with gallium trihalides to form organogallium dihalides, and the use of gallium trichloride in the cleavage of siloxanes; and the third Communication was on alkali metal double silanolates M1{M2[OSi(CH3)3]2} (M1=Na or K, M2=Li or Na). Schmidbaur was previously Chairman of the Editorial Board of Angewandte Chemie, and published an Essay on coordination chemistry at carbon in the 125th Jubilee Issue (Angew. Chem. Int. Ed. 2013, 52, 176); a Review on argentophilic interactions is in press in this journal.

    Rudolf Criegee and Fritz Zanker reported on the synthesis of dimethyl “Dewar tetramethylphthalate”, which is a crystalline derivative of Dewar benzene that can be prepared in decagram quantities and is more stable than related unsubstituted species. Criegee was an influential figure in German organic chemistry and both the Criegee intermediate and the Criegee rearrangement bear his name.

    Herbert Roesky et al. published a Communication on the preparation of difluorodiazine (N2F2) by the treatment of sodium azide with elemental fluorine. The reaction proceeds through the dimerization of a biradical intermediate. Roesky is one of the authors who have published most manuscripts in Angewandte Chemie since 1946 (for a more complete list, see Angew. Chem. Int. Ed. 2013, 52, 2714). His most recent contribution is a Communication on cumulene structures.

    Read more in Issue 10/1964.

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 31, 7974

    Noble gas fluorides were first reported in 1962, and two years later progress in the field, including xenon difluoride, tetrafluoride, and higher fluorides, as well as krypton fluorides, were summarized in a Review by one of the protagonists, Rudolf Hoppe from the University of Giessen.

    In another Review, Gottfried Schill discussed the directed synthesis of catena compounds (now more commonly known as catenanes). These interlocked ring systems were initially formed in very low yields in statistical reactions, however Schill and co-workers developed a directed synthesis to avoid extra-annular ring closure.

    Ernst Otto Fischer, who shared the 1973 Nobel Prize in Chemistry with Geoffrey Wilkinson, published a Communication on tungsten carbonyl carbene complexes. Reaction of W(CO)6 with LiC6H5 resulted in the formation of an orange crystalline compound [N(CH3)4][W(CO)5COC6H5], which was protonated and methylated to give W(CO)5(COC6H5)(CH3) as diamagnetic orange–red crystals. W(CO)5(COCH3)(CH3) was obtained when W(CO)6 was reacted with LiCH3  in an analogous manner.

    Margot Becke-Goehring reported on a pentavalent phosphorus–nitrogen compound. Reaction of aqueous methylammonium chloride with PCl5 led to the formation of P4[N(CH3)]6Cl8 , which was postulated to have a cage structure. Becke-Goehring was made Vice-Chancellor of the University of Heidelberg in 1966, and was the first woman appointed to such a role in a West German University.

    Read more in Issue 8/1964.

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 27, 6846

    Which elements was the milky way formed from? The chemical composition of the stars was discussed in a Review by A. Unsöld, who outlined the evolution of stars and the milky way, and the quantitative analysis of stellar spectra to determine elemental abundance in the atmospheres of various stars. The analysis showed that the first stars were formed from an almost spherical cloud of hydrogen. Topics of other Reviews included heat-resistant films and fibers (F. T. Wallenberger) and the synthesis of the corrin system (A. Eschenmoser et al.).

    R. Köster et al. from the Max Planck Institute for Coal Research, which celebrates its centenary this year, published two Communications on boron and aluminum radicals. The first report was on the generation of boron and aluminum free radicals by dehalogenation of the corresponding chloro compounds, and the second was on the formation of organic carboranes by radical reactions.

    Alan MacDiarmid, who shared the Nobel Prize in Chemistry 2000 with Alan Heeger and Hideki Shirakawa for their work on conductive polymers, published a Communication on compounds containing the Si–N–B linkage. Compounds such as [(CH3)3Si]2NBF2 were prepared by reacting lithium bis(trimethylsilylamide) with BF3. Competition was fierce even 50 years ago: an alternative route to these compounds was published by P. Geymayer around the same time in Angewandte Chemie.

    Read more in Issue 7/1964.

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 23, 5728

    Weight loss and hemorrhage, or even immunization against tuberculosis are just some of the biological actions of lipids produced by the tubercle bacillus, as discussed in a Review by E. Lederer. The biosynthesis and structure of these compounds were also outlined.

    Burchard Franck published two Communications on secalonic acids, which are the pale yellow main pigment of ergot (Calviceps purpurea). In the first Communication, the chromatographic separation and physical properties of secalonic acids A and B were discussed, and in the second Communication, the authors outlined how mass spectrometry and NMR spectroscopy were used to confirm the structures of the acids.

    Emanuel Vogel also contributed two “classics” on triene systems. His first Communication dealt with the synthesis of bicyclo[4,2,0]octa-2,4,7-triene by the dehalogenation of 7,8-dibromobicyclo-[4,2,0]-octa-2,4-diene. The target product can isomerize to form cyclooctatetraene. In his second Communication, Vogel reported the use of NMR spectroscopy to derive the energy barrier for the norcaradiene–cycloheptatriene equilibrium.

    The use of anion-exchange thin-layer chromatography plates for the analysis of enzymatic reactions was reported by K. and E. Randerath.

    Read more in Issue 6/1964.

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 19, 4740

    Anabolic agents and ovulation control are just two uses of non-aromatic 19-norsteroids, which were discussed in a Review by T. B. Windholz and M. Windholz, who outlined total syntheses, aromatization, and intramolecular functionalization reactions. M. Schlosser continued his series of Reviews on organosodium and organopotassium compounds, and in this issue he discussed the preparation and synthetic applications of these species.

    R. W. Hoffmann and H. Häuser reported on the synthesis and cycloaddition reactions of tetramethoxyethylene. This compound is formed by the decomposition of bicyclo[2.2.1]heptadiene derivatives and reacts with compounds containing double bonds to form carbocyclic or heterocyclic four-membered rings. Hoffmann’s Essay on the changes in natural product synthesis over time was published in the 125th Jubilee Issue (Angew. Chem. Int. Ed. 2013, 52, 123).

    D. Söll and H. G. Khorana reported on the synthesis of ribodinucleotides with 3’-phosphate end groups in a procedure that avoids the use of an acid-labile protecting group. The target compounds can be polymerized to form ribopolynucleotides. Söll’s report on recoding the genetic code with selenocysteine was recently featured on the cover of Angewandte Chemie (Angew. Chem. Int. Ed. 2014, 53, 319–323).

    A. Engelbrecht and F. Sladky described the reaction of BaTeO4 and HSO3F, which they expected to form TeO2F2 but instead produced pentafluoro-orthotelluric acid (HTeOF5). The product was a glassy crystalline solid with a melting point of 40 °C and its stability was attributed to TeVI having an octahedral configuration.

    Read more in Issue 5/1964.

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 13, 3298

    Unsaturated fatty acids was the topic of a Review by L. D. Bergelson and M. M. Shemyakin, who described how carbonyl olefination reactions can be sterically controlled to produce either cis or trans olefins. The topic of saturated and unsaturated fatty acids, in particular trans fatty acids, is still very much in the foreground today (for a recent Essay see Angew. Chem. Int. Ed. 2013, 52, 5220).

    M. Schlosser (see Angew. Chem. Int. Ed. 2013, 52, 12483 for his Obituary) started a series of Reviews on organosodium and organopotassium compounds (such as phenylsodium or benzylpotassium). This first instalment concentrated on the properties, synthesis, and reactions of these compounds, including replacement of the metal and rearrangements.

    In the Communications section, F. Jellinek et al. reported the first synthesis of allylbis(cyclopentadienyl)titanium(III), which involved the reaction of [(C5H5)2TiIVCl2] and allyl Grignard reagents to form the product as purple crystals. G. Scheibe et al. used proton NMR measurements to investigate internal rotation in cyanine dyes. The NMR spectra of N,N-dimethyl-substituted dyes showed two signals of equal intensity for the two methyl groups, thus confirming that internal rotation is hindered.

    Read more in Issue 4/1964.

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 09, 2266

    Vitamin B12 had at that time been only partially chemically synthesized (the total synthesis was first published in 1973), and a Review by K. Bernhauer et al. summarized the latest developments in the field, including partial syntheses, coenzyme forms, and enzymatic functions. A Review by Albert Eschenmoser on the origin of the molecular structure of vitamin B12 was published in our Angewandte’s Centenary Issue (Angew. Chem. Int. Ed. Engl. 1988, 27, 5–39).

    Emanuel Vogel published a Communication on the properties of the cyclodecapentaene system. The system contains 10 π electrons and can thus be expected to have an aromatic character. The proton NMR spectrum of 1,6-methanocyclodecapentane showed it to have a strong ring current, however, it shows olefinic reactivity and cannot be classified as a classical aromatic compound.

    Georg Wittig reported a new synthesis of tetraarylphosphonium salts. Reactions of triarylphosphines and o-fluorophenyllithium with either fluorene or methyl iodide at −40 °C resulted in the corresponding tetraarylphosphonium salt or its o-methyl derivative.

    Max Schmidt reported the synthesis of 1,1,1,3,3,3-hexamethyldigermazane ((CH3)3Ge-NH-Ge(CH3)3). The reaction of trimethylgermanium chloride with ammonia produced the target compound as a colorless liquid. Reaction of dimethylgermanium dichloride under the same conditions resulted in the formation of [(CH3)2GeCl]3N.

    Read more in Issue 3/1964.

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 05, 1184

    Defensive substances was the topic of a Review by H. Schildknecht. In this case, the substances were the compounds used for defensive secretion by arthropods, including beetles, earwigs, and millipedes. Analysis of the defensive substances showed them to contain quinones, carboxylic acids, and aromatic aldehydes.

    Rolf Huisgen reported his latest results on 1,3-dipolar cycloaddition reactions in two Communications, including the reactions of either azlactones (oxazolones) or mesoionic compounds as 1,3-dipoles in the synthesis of functionalized pyrroles. He also summarized kinetic investigations into the valence tautomerism of cyclooctatetraene in a Review.

    Ernst Otto Fischer, who shared the 1973 Nobel Prize in Chemistry with Geoffrey Wilkinson, also published two Communications—on the topic of dicyclopentadienyl complexes. The first report was on the synthesis of dicyclopentadienyleuropium by reacting metallic europium with cycopentadiene in liquid ammonia, and the second dealt with the reaction of [C5H5MoC6H6(CO)]PF6 with hydride ions to form the π complex C5H5MoC6H5. For an account of the history of sandwich complexes, see Angew. Chem. Int. Ed. 2012, 124, 6052–6058.

    Heinz Staab reported the synthesis of the hitherto elusive formyl chloride on a preparative scale by the reaction of 1-formylimidazole with HCl at −60°C in chloroform. The synthesis is particularly practical as the imidazolium chloride byproduct precipitates from the solution and can be removed by filtration.

    Read more in Issue 2/1964.

  • 50 Years Ago ...
    Angew. Chem. Int. Ed. 2014, 53, No. 01, 27

    Manfred Eigen, who was awarded the 1967 Nobel Prize in Chemistry together with Ronald G. W. Norrish and George Porter, published a classic Review on proton transfer mechanisms and the modes of acid–base and enzymatic catalysis. The systems discussed include proton mobility in ice crystals, and pseudo acids. A review of his latest book entitled From Strange Simplicity to Complex Familiarity: A Treatise on Matter, Information, Life and Thought appeared in Issue 52/2013.

    Albert Eschenmoser et al. reported on the use of N,N-dimethylformamide dineopentylacetal for the esterification of carboxylic acids with benzyl alcohols. Use of this reagent is advantageous as only one equivalent of the alcohol is required and only volatile by-products are produced in some cases. Eschenmoser’s most recent contribution is a grand Review on prebiotic chemistry (Angew. Chem. Int. Ed. 2011, 50, 12 412).

    The preparation of pure disulfur monoxide was reported by P. W. Schenk and R. Steudel, who reacted thionyl chloride with metal sulfides that act as dehalogenating reagents. The reaction of thionyl chloride and silver sulfide provided disulfur monoxide in 96 % purity.

    H. Rheinheckel published two Communications on triethylaluminum, and reported how an ice-cold mixture of triethylaluminum and carbon tetrachloride exploded when the ice bath was taken away. The explosion was so violent that the hood was destroyed and not a single fragment of glass could be found.

    Read more in Issue 1/1964.