bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses and Structures of 2,6‐Substituted Barbaralanes
Authors: Quast Helmut , Becker Christian , Witzel Martina , Peters Eva‐Maria , Peters Karl , von Schnering Hans Georg 
Published: June 2010

AbstractSeveral 2,6‐substituted barbaralanes, viz. 1d–g, have been synthesised from Meerwein's diketone (2). Treatment of dinitrile 3 with hydrochloric acid in boiling methanol followed by hydrolysis of the intermediate Pinner salt yields the dimethyl dicarboxylate 4 which is brominated to afford the exo,exo dibromo diester 5. Reductive cyclisation of 5 gives rise to the formation of dimethyl 2,6‐barbaralanedicarboxylate (1d). – Addition of (phenylethynyl)cerium(III) chloride to 2 followed by acid‐induced dehydration of the resulting endo,endo diol 6 yields the bis(phenylethynyl)diene 7, which is cyclised to the bis(phynylethynyl)barbaralane 1e by allylic bromination and subsequent treatment of the exo,exo dibromide 8 with the zinc‐copper couple. Likewise, the exo,exo dibromo disulphone 11, which is obtained from 2 via the bis(vinyl sulphide) 9 and the bis(vinyl sulphone) 10, is converted into the bis(phenylsulphonyl)barbaralane 1f. – Trifluoromethylation of diketone 2 with trimethyl(trifluoromethyl)silane in the presence of a source of fluoride ions affords a mixture of the O silylated endo,endo diol 12 and the oxatwistane 13. Hydrochloric acid converts the latter into the hydroxy ketone 16, which yields 12 on treatment with trimethyl(trifluoromethyl)silane and tetrabutylammonium fluoride. Desilylation of 12 to furnish the endo,endo diol 14 requires prolonged treatment with hydrofluoric acid under phase‐transfer catalysis. Vigorous conditions are also necessary for the dehydration of 14 with phosphorus oxychloride in pyridine to afford the bis(trifluoromethyl)diene 15. Cyclisation of 15 to the bis(trifluoromethyl)barbaralane 1g is performed in the usual way by allylic bromination and subsequent reduction of the dibromide 17 with the zinc‐copper couple. – The configurations and conformations in the crystals have been elucidated by X‐ray diffraction analyses for the bicyclo[3.3.1]nonane derivatives 5, 8, and 11 as well as the barbaralanes 1f and h. In the solid state, 1f appears to exist as a single non‐rearranging valence tautomer. The atomic distances found for 1h indicate the presence of equilibrating non‐equivalent valence tautomers. The results are compared to those from X‐ray diffraction analyses of other degenerate barbaralanes and heterobarbaralanes.
Reaction of 4′‐Benzyloxy‐2‐(4‐pyridinyl)acetophenone with Ethylmagnesium Chloride: UnusualC‐Benzylation and in situ Reduction by β‐Hydrogen Transfer
Authors: Haroutounian Serkos A. , Couladouros Elias A. 
Published: June 2010

AbstractIn solution, 4′‐benzyloxy‐2‐(4‐pyridinyl)acetophenone (1) mainly exists as enol4which does not undergo typical Grignard addition reactions. Treatment with an excess of ethylmagnesium chloride, however, initiates an unusual sequence of transformations leading to formation of theC‐benzylated compounds2and3.
Rearrangement of a Bicyclo[3.2.0]hept‐2‐ene to a Bicyclo[4.1.0]hept‐4‐ene
Authors: Behrendt Uwe , Gabor Barbara , Mynott Richard , Butenschön Holger 
Published: June 2010

AbstractThe chemistry of the highly substituted cyclobutanone derivative 2, which is easily accessible from 1, is dominated by the steric hindrance caused by the substitutents: Reduction with hydride reagents and nucleophilic additions with methyllithium are less stereoselective than corresponding reactions with less substituted bicyclo[3.2.0]hept‐2‐en‐6‐one derivatives, but under certain conditions, the exo product predominates, with methyl‐, benzyl‐, ethenyl‐, and ethynylmagnesium halides no nucleophilic addition at the carbonyl group is observed, presumably as a result of the steric hindrance. Instead, an unexpected rearrangement to the bicyclo[4.1.0]heptane carbon skeleton occurs with complete diastereoselectivity and high yields. The rearrangement is rationalized by an increase of the carbocationic character of the carbonyl carbon atom as a result of a coordination of the carbonyl oxygen atom at the Lewis acidic magnesium. This facilitates rearrangement of a cyclobutyl carbenium ion to a cyclopropylmethyl carbenium ion, the latter being stabilized by the amino group. Remarkably, with Grignard reagents derived from propargyl or allyl halides, no rearrangement is observed. The constitutions and configurations of the products were determined by 1H‐ and 13C‐NMR spectroscopy using techniques including NOESY and 2D‐INADEQUATE.
Fluoroselenenylation of Acetylenes with Xenon Difluoride–Diorganyl Diselenides; Synthesis and Structure Elucidation of Functionalized Vicinal (E)‐Fluoro(organylseleno)olefins
Authors: Poleschner Helmut , Heydenreich Matthias , Schilde Uwe 
Published: June 2010

AbstractWe carried out the fluoroselenenylation of hex‐3‐yne with xenon difluoride and functionalized diselenides (dimethyl acetal‐ and carboxylic acid ester‐substituted) to the corresponding substituted vicinal (E)‐fluoro(organylseleno)olefins. Consecutive reactions afforded crystalline 2,4‐dinitrophenylhydrazone and carboxylic acid derivatives. Nonfunctionalized vicinal (E)‐fluoro(organylseleno)olefins were alkylated with trimethyloxonium tetrafluoroborate, triethyloxonium tetrafluoroborate, and methyl trifluoromethanesulfonate to the corresponding fluoroalkenyldiorganylselenonium salts which were characterized either as tetrafluoroborate or as tetraphenylborate salts. X‐ray analysis of [(E)‐4‐fluorooct‐4‐en‐5‐yl]dimethylselenonium picrate (11) proved unambiguously that the fluoroselenenylation of acetylenes with XeF2–R2Se2 and XeF2–PhSeSiR3 reagents proceeds via trans additions.
New Sesquiterpene Ethers from Vetiver Oil
Authors: Weyerstahl Peter , Marschall Helga , Splittgerber Ute , Wolf Dietmar 
Published: June 2010

AbstractThe four new sesquiterpene ethers 7β,10β‐epoxy‐4βH‐eremophila‐1,11(12)‐diene (4), 10β,11‐epoxy‐4βH‐eremophil‐1‐ene (5), 4α,7‐epoxy‐10βH‐spirovetiva‐2,11(12)‐diene (6) and 6α,12‐epoxy‐7βH,10βH‐spiroax‐4‐ene (8) were isolated from the unpolar part of the Haitian Vetiver oil and characterized by their spectral data.
Terminally Protected 1‐Phenyl‐1,5‐hexadiyne‐3,4‐diones as First Members of the Class of Dialkynyl‐1,2‐diones
Authors: Faust Rüdiger , Weber Christian 
Published: June 2010

AbstractReaction of lithiated 1‐(1‐ethoxy‐3‐phenyl‐prop‐2‐ynyl)‐1H‐benzotriazole (3) with various acetylenic aldehydes followed by periodinane oxidation and hydrolysis yields terminally protected 1‐phenyl‐1,5‐hexadiyne‐3,4‐diones 7a–d as the first examples of dialkynyl‐1,2‐diones.
Stereoselective Synthesis of Alcohols, XLIX. Tetrahydro‐4‐pyranols and 4‐Piperidinols by Intramolecular Allylboration Reaction
Authors: Hoffmann Reinhard W. , Hense Achim 
Published: June 2010

Abstracttrans‐ and cis‐3‐Vinyltetrahydropyran‐4‐ol (11) and (12) as well as derivatives of trans‐ and cis‐3‐vinyl‐4‐piperidinol (25) and (33) were synthesized by essentially stereospecific intramolecular allylboration reactions: The (Z)‐allylboronates 15 and 32 were converted into the cis‐disubstituted heterocycles the (E)‐allylboronates 9 and 23 into the trans‐disubstituted heterocycles.
Partially Benzoanellated Centrohexaquinanes: Oxidative Degradation of Centropolyindanes by Using Ruthenium(VIII) Oxide and Ozone
Authors: Gestmann Detlef , Kuck Dietmar , Pritzkow Hans 
Published: June 2010

AbstractThe oxidative degradation of benzo nuclei of various higher contropolyindanes with ruthenium (VIII) oxide or ozone was studied to further explore the chemistry of partially benzoanellated centrohexaquinanes. Besides the two tribenzotri‐quinacenes 12 and 15 which were used as model substrates for oxidation with RuVIII, centrohexaindane 1 was converted to the corresponding centrohexacyclic diketone 19 by using either RuO4 in stoichiometric amounts or O3 in dichloro‐methane/pyridine. Subsequent Wolff‐Kishner reduction of 19 gave pentabenzohexaquinane 4. Correspondingly, tribenzocentrohexaquinane 2 was degraded by sequential ozonolysis/reduction to the C2v‐symmetrical dibenzocentrohexaquinane 10 and monobenzocentrohexaquinane 11 in low yields (8–9% in each sequence). Due to the low efficiency of the ozonolyses, the parent centrohexaquinane 3 has remained elusive, yet. The deeply red centrohexacyclic 1,2‐diketone 19 was subjected to single‐crystal X‐ray structural analysis and found to bear an almost perfectly syn‐coplanar α‐dicarbonyl chromophore with a strong and extremely low‐energy UV/Vis absorption (λmax = 512 and 531 nm).
Concave Reagents, 18. Synthesis, Conformational Behavior, and Basicity of New Pyridine‐Bridged Calix[6]arenes
Authors: Ross Haymo , Lüning Ulrich 
Published: June 2010

AbstractCompounds 2–6 were synthesized by starting from the pyridine‐bridged calix[6]arenes 1. Most of these derivatives exist in a concave conformation like their parent compounds 1, but in some cases the conformational behavior is different. Relative basicities of 1–6 and of the open‐chain model compounds 7 were measured by a photometrical titration against thymol blue. An unexpectedly high basicity of 1–4 was found.
Synthesis of Novel Liquid‐Crystalline Allene Derivatives with Ferroelectric Properties
Authors: Stichler‐Bonaparte Jürgen , Kruth Holger , Lunkwitz Ralph , Tschierske Carsten 
Published: June 2010

AbstractSome new heterocyclic liquid‐crystalline compounds incorporating a 1,3‐disubstituted allene unit were synthesised. These axial‐chiral compounds were investigated by polarisation microscopy and differential scanning calorimetry. One of them was also synthesised in enantiomerically enriched form by enantioselective synthesis. It was found that the latter product exhibits a ferroelectric switchable chiral smectic C phase with an unexpectedly large value of the spontaneous polarisation.
The Chemistry of Unusual Macrolides, 3. δ‐Lactone Glycosides by C‐C Bond Cleavage of Concanamycin C and Elaiophylin Hydroperoxides
Authors: Boddien Claudia , Gerber‐Nolte Jutta , Zeeck Axel 
Published: June 2010

AbstractA cleavage method by which the prelactones of the plecomacrolides concanamycin C (2) and elaiophylin (8) can be obtained was developed. A hydroperoxide in the position of the hemiketal hydroxy group of 2 and 8 was generated selectively by treatment with H2O2/VO(acac2) or H2O2/WO3. Application of Fe2+ salts (Fenton reaction) to 3 and 9 led to the prelactone glycosides 11 and 15, the structures of which were established by spectroscopic analysis and comparison with the natural prelactone 10 and semisynthetic lactone 12, which both were obtained by a similar reaction sequence from the concanolide derivatives 4 and 6. The highly functionalized chiral δ‐lactone glycosides 11 and 15, which cannot be obtained by genetic engineering of the polyketide synthase of the parent plecomacrolides, represent the right‐hand side of the remarkably active ATPase inhibitor and will be of interest concerning structure‐activity relationships.
Synthesis of Azabenzisochromanquinone Antibiotics, I. Hetero Diels‐Alder Reactions of Isochromanquinones with 1‐Aza‐1,3‐dienes
Authors: Tödter Carsten , Lackner Helmut 
Published: June 2010

AbstractThe total synthesis of a novel type of benzisochromanquinone antibiotics 2 containing nitrogen in the aromatic ring A is described. Three different isochromanquinone building blocks (6, 10, and 14) were subjected to cycloaddition reactions with five diverse 1‐aza‐1,3‐butadienes 15–17, 19 yielding three groups of structurally modified 6‐ and 9‐aza compounds: azaeleutherins 21–24, azaepinanaomycins 26–31, and 1‐methylazakalafungins 32–39. The regioselectivity of the reaction depends on the substituents at the diene and the structural symmetry of the quinone. The strategy provides a convenient access to a broad palette of structural variants. Particularly some azakalafungins show remarkable antibacterial and antitumor activities.
Synthesis, Resolution and Crystal Structure of a New Optically Active Nitroxide Radical
Authors: Benfaremo Nicholas , Steenbock Marco , Klapper Markus , Müllen Klaus , Enkelmann Volker , Cabrera Karin 
Published: June 2010

AbstractThe synthesis of the readily available racemate of the nitroxide radical 5 is described. The product exhibits exclusively the trans configuration. The cis product was not obtained. Optically pure enantiomers of 5 were isolated in gram quantities by chiral HPLC. Thus, separation of the enantiomers of a nitroxide radical was achieved for the first time. The structure of 5 was proven by a single‐crystal diffraction study.
Polar and Steric Substituent Effects in 5‐exo‐trig Cyclizations of 1‐Aryl‐4‐penten‐1‐oxyl Radicals
Authors: Hartung Jens , Hiller Margit , Schmidt Philipp 
Published: June 2010

AbstractA series of 1‐aryl‐substituted 4‐penten‐1‐oxyl radicals 2 were generated from parent N‐alkoxypyridinethiones 6. The intermediates 2 undergo 5‐exo‐trig cyclizations which are sensitive to polar and steric substituent effects. Thus, para groups in the aromatic ring alter the reactivity of radicals 2c–e by one order of magnitude without changing the stereochemical course of the 5‐exo‐trig reaction (cis:trans = 50:50). Substitution of the ortho methyl groups for hydrogen atoms of the phenyl group affects the cis‐ring closures more than the trans reactions which lead to trans‐selective alkoxyl radical reactions. Methyl groups at the terminal olefinic double bond cause a significant acceleration of K5‐exo in general and of the trans reactions in particular. Thus, trans‐2‐isopropyl‐5‐phenyltetrahydrofuran (8i) was the major product in the photoreaction of pyridinethione 6i in the presence of tri‐n‐butyltin hydride (98% yield, cis:trans, 30:70).
Metabolites of the Higher Fungi, 30.threo‐ anderythro‐Telfairic Acid and 2,3‐Didehydrotelfairic Anhydride from the FungusXylaria telfairii
Authors: Adeboya Monilola Oladunni , Edwards Raymond Leslie , Maitland Derek James , Laessó Thomas , Whalley Anthony James Seddon 
Published: June 2010

AbstractThree novel metabolites,threo‐ and erythro‐telfairic acid [threo‐ anderyhro‐(1′E,3′E)‐2‐(4‐carboxyhexa‐1,3‐dienyl)‐3‐methylsuccinic acid (3aand3b)] as well as 2,3‐didehydrotelfairic anhydride [1′E,3′E)‐2‐(4‐carboxyhexa‐1,3‐dienyl)‐3 methylmaleic anhydride (4)] have been isolated from the culture medium of the fungusXylaria telfairiiBerk. Their structures (apart from the absolute configuration of3aand3b) have been elucidated by chemical and physical methods.
The Conjugate Addition of Benzoyl(thioacetanilides) to Nitroalkenes Synthesis of Functionalized Thiophenes and Pyrroles
Authors: Bogdanowicz‐Szwed Krystyna , Palasz Aleksandra , Rys Barbara , Soja Dorota , Grochonski Jacek , Serda Pawer 
Published: June 2010

AbstractReaction of benzoyl(thioacetanilides) 1 with (E)‐β‐nitrostyrenes 2 yields 4‐aryl‐2‐arylimino‐3‐benzoyl‐5‐hydroxyimino‐2,3,4,5‐tetrahydrothiophenes 7. In PPA medium the oxime function of 7 undergoes dehydration and hydrolysis leading to 4‐aryl‐2‐arylimino‐3‐benzoyl‐2,5‐dihydro‐5‐oxothiophenes 9. Reaction of 7 with hydrochloric acid involves dehydration, hydrolysis and ring transformation to 1,4‐diaryl‐3‐benzoyl‐2,5‐dihydro‐5‐oxo‐2‐thioxopyrroles 10. Acetic anhydride reacts with 7 to yield 5‐acetylimino‐4‐aryl‐2‐arylimino‐3‐benzoyl‐2,5‐dihydrothiophenes 11.
Synthesis of N‐α‐(6‐Hydrazinonicotinoyl)‐Octreotide: A Precursor of a [99mTc] Complex
Authors: Krois Daniel , Riedel Christina , Kalchhauser Hermann , Lehner Harald , Angelberger Peter , Virgolini Irene 
Published: June 2010

AbstractThe synthesis of the title compound 12 via [3 + 4] and [7 + 2] segment condensation, respectively, using minimal protection of amino acid side chains is presented. The need to include the 6‐hydrazinonicotinic acid into a complete peptide synthesis originates from the juxtaposition of two factors, namely from the poor regioselectivity of Boc2O towards the amino groups of octreotide 1 and secondly from the distinct chemical properties of N‐hydroxysuccinimide esters of 6‐hydrazinonicotinic acid derivatives in general. The structure of the ligated octreotide derivative 12 suitable for the preparation of a [99mTc]‐labelled metal complex was established by spectroscopic methods. The study is complemented by conformational considerations on the pharmacophore of 12 and the parent octapeptide 1, being based on circular dichroism spectroscopy and 2D‐NMR techniques.
Ringumlagerungen bei der Mitsunobu‐Alkylierung von Phthalazinonen und Indazololen
Authors: Knaack Martin , Müller Arndt , Fleischhauer Ilona , Charpentier Patricia , Emig Peter , Kutscher Bernhard 
Published: June 2010

Ring‐Rearrangement During the Mitsunobu Alkylation of Phthalazinones and IndazololsThe Mitsunobu alkylation of substituted phthalazinones and indazolols with cyclic hydroxy‐ and hydroxymethyl‐substituted amines was investigated. In addition to the expected derivatives ring‐narrowed and ring‐enlarged rearrangement products were isolated and characterized by NMR spectroscopy. The occurence of these products can be explained by the existence of a bicyclic intermediate. The results of the reaction of phthalazinones with optically active amine compounds show a stereospecific reaction mechanism. The reaction of the phthalazinones leads to N‐substituted products, while in the case of the indazolols O‐substituted derivatives were isolated. A postulated bicyclic intermediate, 1‐methyl‐1‐azoniabicyclo[3.2.0]heptane, was synthesized as chloride.
Wirkung von Distamycin A und Netropsin auf normale und zellwandlose Zellen von Escherichia coli W1655F+
Authors: Schuhmann Edith , Haupt Ina , Thrum H. , Taubeneck U. , May Ursula 
Published: June 2010

AbstractDistamycin A and netropsin are basic oligopeptide antibiotics. Though the chemical structure of both antibiotics is very similar, the action on grampositive and gramnegative bacteria is quite different. Distamycin A acts only on grampositive bacteria, while netropsin inhibits grampositive as well as gramnegative bacteria.Our experiments with the normal rod form and the stable protoplast type L‐form of E. coli W1655F+ have shown that distamycin A inhibits gramnegative bacteria to the same extent as netropsin, when wall‐less L‐form‐ells were used. The normal rod cells were inhibited by netropsin only. That means that the wall prevents the penetration of distamycin A as reported earlier for the macrolid antibiotics, actinomycin C and kirromycin.
Licht‐ und elektronenoptische Untersuchungen an Protein‐kristallen und Mikrotubuli in Hefeprotoplasten
Authors: May R. , Gottstein H. 
Published: June 2010

AbstractUnusual structures ‐ crystals, crystal‐associated microtubules, and bundles of microtubules ‐ have been observed in protoplasts, but not in normally grown cells of Saccharomyces carlsbergensis and S. cerevisiae. The leaflet‐like crystals (diameter 0.3‐3 μm, thickness 0.01‐0.1 μm) occurred in the cyto‐ and karyoplasm. Crystals perpendicularly sectioned to the plane frequently showed highly regular arrays of electron‐opaque lines (periodicity 15 nm). Lamellar, rectangular, and hexagonal patterns could be seen on crystals sectioned parallelly to the plane.Smaller microtubules (outer diameter 15 nm) packed to compact bundles or fixed on crystals occurred only in the karyoplasm and they did not show any direct relations to the thicker microtubulus (outer diameter 20 nm) of the spindle apparatus.It is suggested that the crystals could be aggregations of tubulin or virus protein.
Nachweismethoden und Verbreitung von Pektinolyse bei Bacillus‐Arten
Authors: Steinigeweg Rosmarie , Ottow J. C. G. 
Published: June 2010

AbstractUsing 4 different methods, a total of 126 Bacillus strains representing 33 different species, was examined for their ability to degrade methoxylated and demethylated pectin. The highest number of pectinolytic strains (35) was found with a newly developed, tubed polypectate‐gel, which gave complete liquefaction upon pectinolysis. The pectinolytic activity appeared to be restricted to 8 recognized species belonging to 5 groups: The B. maceranspolymyxa group, the B. licheniformis‐pumilius‐subtilis group, B. pantothenticus, B. alvei, and B. lentus. However, not all strains of a single species revealed a positive pectinolytic activity. Thus, only a part of the strains of the second and fifth group were found to be pectinolytic. Pectinolysis with B. alvei (ILM 21, JO 42) and B. lentus (CCM 35, CCM 2214) was recorded not until a prolonged incubation in the tubed pectate‐gel was used.Pectinolysis of selected B. licheniformis and B. pantothenticus strains was stimulated markedly by ammonium‐ and phosphat‐ions at various pH levels. The simultaneous addition of calcium and phosphate to the medium decreased the intensity of pectinolysis clearly. Calcium, if added solely, stimulated pectinolytic activity of B. pantothenticus strains only at a reduced concentration.
Bakterielle Ornithinlipide
Authors: Thiele O. W. , Schwinn G. 
Published: June 2010

AbstractAus der Fraktion der polaren Lipide von Brucella melitensis, Br. abortus und Bordetella pertussis wurde ein phosphatfreies Lipid isoliert, das aus vier Bausteinen besteht: Ornithin, Athylenglykol und zwei Fettsäuren. Äthylenglykoll ist darin esterartig mit Ornithin und mit einer der beiden Fettsäuren (bei den Brucellen vorwiegend Lactobacillussäure) verbunden, während die andere Fettsäure (vorwiegend Palmitin‐ und Stearinsäure) amidartig mit einer Aminogruppe des Ornithins verbunden ist. Es wird ein Überblick über die bisher bekannten Ornithinlipide anderer Bakterienspecies gegeben.
Vorkommen von Mucopolysacchariden bei Pasteurella multocida: Isolierung von Hyaluronsäure aus A‐ und B‐Serotyp‐Stämmen
Authors: Hubald J. , Erler W. , Feist H. , Flossmann K.‐D. 
Published: June 2010

AbstractIn zwei Stämmen von P. multocida des serologischen Typs A bzw. B nach CARTER, die in chemisch definierten Nährmedien kultiviert wurden, konnte in unterschiedlicher Quantität Hyaluronsäure nachgewiesen werden. Diese war fest an der Zelle gebunden und ließ sich nach Ablösung mit Papain und nachfolgenden Reinigungsschritten mit chromatographischer Trennung an ECTEOLA‐Cellulose isolieren. Bei Verwendung von 3H‐ bzw. 14C‐Glucosaminhydrochlorid als radioaktive Präkursoren war eine Markierung der Hyaluronsäure möglich. Die Hauptmenge der Radioaktivität war im Gluscoamin wieder nachweisbar. Die Bedeutung der Hyaluronsäure als Kapselsubstanz für P. multocida wird diskutiert. Obwohl auch bei einem B‐Typ‐Stamm Hyaluronsäure gefunden wurde, scheint diese für den serologischen Typ A besondere Bedeutung zu haben, da sie hier in wesentlich höherer Menge nachgewiesen wurde.
Flow microcalorimetry of a respiration‐deficient mutant of Saccharomyces cerevisiae
Authors: Loureiro‐Dias M. C. , Arrabaca J. D. 
Published: June 2010

AbstractIn aerobic batch cultures in mineral medium with glucose of a respiration‐deficient mutant of Saccharomyces cerevisiae, growth parameters were estimated and the heat evolved was measured by a flow microcalorimeter. A growth enthalpy of – 163.6 joule per mole of glucose consumed was measured. Under anaerobic conditions, the value was – 134.6 joule, closer to the expected for alcoholic fermentation alone. The difference was found to be due to cyanide‐resistant respiration under aerobic conditions.
Isolierung von Streptothricin‐resistenten Mutanten aus Escherichia coli K12, Stamm A19
Authors: Seidel L. , Haupt Ina 
Published: June 2010

AbstractMutants with various levels of resistance to streptothricin were isolated from Escherichia coli K12, strain A19 after mutagenesis with N‐methyl‐N'‐nitroso‐guanidine and ethylmethane‐sulfonate. Nourseothricin, a mixture of streptothricin F. and D was the selection agent. Spontaneous resistant mutants could not be found. The streptothricin‐resistant mutant E. coli A19 Stcr 2/2/1 shows cross‐resistance to some of the aminoglycoside antibiotics investigated, but no cross‐resistance to chloramphenicol and chlortetracyclin. These results indicate similar mechanisms of action of streptothricin and aminoglycoside antibiotics.