bluuebunny/crossref_metadata_2025 huggingface dataset:
What every doctor needs to know about chronic kidney disease
Authors: Kazmi Isma , Gullapudi Latha , Taal Maarten W
Published: August 2018

Chronic kidney disease is a global health problem that affects over 10% of adults worldwide. All doctors should have a basic knowledge of chronic kidney disease because it may complicate the management of many other medical conditions and is associated with numerous adverse outcomes. Chronic kidney disease should be regarded as a clinical syndrome rather than a specific diagnosis and attempts should always be made to identify the cause. Simple risk prediction tools have been developed to inform management decisions. Management is directed at slowing progression of chronic kidney disease and reducing the associated cardiovascular risk by treating hypertension, use of angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers as first-line therapy in high-risk cases, treatment with statins and lifestyle measures. Patients at high risk of rapid progression or requiring specific therapy as well as those with chronic kidney disease stage 4 or 5 should be referred to a nephrology service.
Pain and pain syndromes
Authors: Dunne Francis J , Getachew Henok , Cullenbrooke Finola , Dunne Ciaran
Published: August 2018

The two main categories of pain, nociceptive and neuropathic, are caused by tissue damage and nerve damage respectively. Psychogenic pain is also described in the literature but it is becoming a pejorative term as the concept of central control of pain is now gaining momentum. There is considerable overlap in brain areas that deal with pain and where mood disorders develop. Some neurotransmitters, e.g. serotonin and noradrenaline, are involved in receiving and processing signals and regulate mood as well. It is no coincidence that many drugs used to treat mood disorders are effective when used for pain relief. This article highlights this interplay of neurotransmission and affective/pain symptomatology.
Nurses' approaches to ethical dilemmas: An example of a public hospital
Hemşirelerin etik ikilemlere yaklaşımları: Bir kamu hastanesi örneği
Authors: Demirsoy Nilüfer , Türe Yılmaz Aysun , Şaylıgil Ömür
Published: August 2018

Aim: In this study, the ethical conflicts faced by the nurses working in the secondary health care facility in Eskişehir were investigated with the Nursing Ethical Dilemma Test .Method: It  was  a  descriptive  study. 233 nurses working in a secondary health care facility in Eskişehir were reached. The data were evaluated in the SPSS-21.00 statistical program,Pearson correlation and descriptive statistical techniques were used in the analysis.Findings: The average age is 32,53 ± 6,23. Nurses' Principle Thinking average point (17,64 ± 11,34); Practical Thinking average point (6,16± 5,07) ;  acquaintance average point (13,86± 3,91) was determined that found to be well below the average in every three types of points.Conclusion: When the obtained data were analyzed,it was determined that the nurses frequently encountered situations with ethical problems during their professional lives,but they were nor sufficient to take ethical principles into account when deciding an ethical issues,and the most basic reason was not at the level of prefence with environmental factors. Extended English summary is in the end of Full Text PDF (TURKISH) file.ÖzetAmaç: Bu araştırmada Eskişehir ilinde İkinci basamak sağlık kurumunda çalışan hemşirelerin karşı karşıya kaldıkları etik ikilemlerin, “Hemşirelik Etik İkilem Testi’ile düzeylerinin incelenmesi amaçlanmıştır.Metod: Araştırmanın tipi tanımlayıcıdır.  Eskişehir’de İkinci basamak sağlık kurumunda çalışan 233 hemşireye ulaşılmıştır.  Veriler SPSS-21.00 istatistik programında değerlendirilmiş,  analizinde Pearson korelasyonu ve tanımlayıcı istatistik teknikleri kullanılmıştır.Bulgular: Hemşirelerin Yaş ortalaması 32,53 ± 6,23’dir. Hemşirelerin İlkesel Düşünme (İD) puan ortalaması (17,64 ± 11,34) ;  Pratik Düşünme (PD)  puan ortalaması (6,16 ± 5,07);Aşinalık puan ortalaması (13,86± 3,91) olarak[N1]  belirlenmiş, her üç puan türünde de ortalamanın çok altında puan aldıkları tespit edilmiştir.Sonuç: Elde edilen veriler analiz edildiğinde, hemşirelerin mesleki yaşantıları süresince sıklıkla etik sorun içeren durumlarla karşılaşmış olduğu, fakat etik sorunlara yönelik karar verirken etik ilkeleri göz önünde bulundurma konusunda oldukça yetersiz oldukları, bunun en temel nedenin çevresel faktörler etkisi ile istendik düzeyde olmadığı belirlenmiştir.
KEMITRAAN DAN KNOWLEDGE MANAGEMENT SEBAGAI STRATEGI ADAPTASI PERUBAHAN LINGKUNGAN BISNIS UNTUK MENINGKATKANKEUNGGULAN BERSAING BERKELANJUTAN (Studi Empirik Kemitraan Pemasok Tembakau PT Djarum di Kabupaten Temanggung)
Authors: Sofani Agung , Miyasto Miyasto , Djastuti Indi
Published: August 2018

Changes in the business environment are unavoidable in an industry. To survive in the competitive, businesses must be able to adapt to changes in the external business environment. The ability of businesses to adapt to the changing business environment becomes a key aspect needed to achieve competitive advantage in the long-term (sustainable) perspective. Based on this phenomenon, the study aims to examine the effect of partnership perspective and knowledge management in building the adaptability of the changing business environment and enhance the sustainable competitive advantage.The data regarding the partnership perspective, knowledge management, adaptation to the business environment and sustainable competitive advantage obtained through interviews using questionnaires. The sample was PT Djarum tobacco suppliers partner in Temanggung. Structural Equation Modeling (SEM) was run by AMOS, the software was used to analyze the data obtained.Statistical analysis showed that the partnership perspective, and knowledge management, positive and significant impact on the adaptability of the business environment changes; adaptability of the business environment changes proved to be positively and significantly impact to sustainable competitive advantage. Directly, partnerships and knowledge management perspective also positively and significantly impact to sustainable competitive advantage.
PERAN CAREER PLATEAU DAN KEPUASAN KERJA DALAM MEMBENTUK TURNOVER INTENTION
Authors: Sijabat Rauly
Published: August 2018

High employee turnover rates are a classic problem that companies often encounter. The high turnover intensity can create instability and uncertainty about the condition of the workforce and the company itself. The results of previous research studies that have not been conclusive, led this study to examine the turnover intention with the career plateau approach and job satisfaction.Model and hypotheses were tested using primary data obtained through interviews using questionnaires on 100 respondents. The data obtained are then analyzed by using Structural Equation Modeling (SEM) analysis technique. The result of statistic test showed that career plateau proved to have a significant negative effect on job satisfaction, the career plateau proved to have a significant positive effect on turnover intention, and job satisfaction had a negative effect on turnover intention.
Rootstock’s and scion’s impact on lemon quality in southeast Spain
Authors: Legua Pilar , Martinez-Cuenca Maria R. , Bellver Ricardo , Forner-Giner María Á.
Published: August 2018

In terms of growth, yield and fruit quality, three lemon varieties (‘Fino49’ F49, ‘Verna50’ V50 and ‘FinoElche’ FE) were tested on three new hybrid root stock selections (Forner-Alcaide 2324, Forner-Alcaide 418 and Forner-Alcaide 5). Yield was weighed within a nine year period and fruit quality was determined in two harvests. Tree size was similar on the Forner-Alcaide 5 and Forner-Alcaide 2324 rootstocks, but reduced by 50% on Forner-Alcaide 418. Forner-Alcaide 2324 and the Forner-Alcaide 5 rootstocks showed similar cumulative yield, while it was decreased by 66% in Forner-Alcaide 418. In all cases, ‘Verna50’ was the less efficient scion. Rootstock was found to significantly affect fruit quality variables. The Forner-Alcaide 418 rootstock induced the lowest peel thickness and peel percentage, but the highest juice content and colour index. Forner-Alcaide 5, together with Forner-Alcaide 418, showed the highest total soluble sugars. In conclusion, both the Forner-Alcaide 5 and Forner-Alcaide 2324 rootstocks generate standard tree size and high yield in the varieties tested, together with great fruit quality, being a suitable alternative for replacing C. macrophylla rootstock when used in lemon varieties. Forner-Alcaide 418 reduces tree size without decreasing yield efficiency and improves alternate-bearing of the harvest. Thus, it may have use in intensifying citrus production as it behaves as a dwarfing rootstock.
“An American near Rome” … and not only! Presence of the eastern cottontail in Central Italy and potential impacts on the endemic and vulnerable Apennine hare
Authors: Dori Paolo , Scalisi Marco , Mori Emiliano
Published: August 2018

The eastern cottontail Sylvilagus floridanus has been introduced to Italy for hunting purposes since the 1960s. This species is currently present in northern Italy, with some small populations in Central Italy. Data for Central Italy are scanty, but they deserve research attention because this lagomorph is responsible for the spread of disease to an endemic vulnerable species, the Apennine hare Lepus corsicanus. In this work, we summarized the distribution of alien cottontails, over 50 years after their first releases, with special regard to areas where the endemic species is present. Eradication should be recommended where the alien species coexists with the endemic one.
A report on the reports of the stanford literary lab: A reason why the digital humanities may find it difficult to change literary history
Authors: Candel Daniel
Published: August 2018

The present article studies eight of the twelve reports of the Stanford Literary Lab (SLL) to understand why the revolutionary practices of the lab, and by extension of the digital humanities, have not yet changed literary history, as the lab itself admits. The article examines the reports with two related cultural-semantic tools, each of which is introduced via the Pixar movieBrave. First, the interpretations of the reports are placed within a basic semantic grid organized into four quadrants by a nature-society axis and a past-present axis, which shows that the interpretations are invariably situated in the present-society quadrant. This analysis, while necessary, merely proves that SLL operates within a certain cultural climate. The real test lies in ascertaining whether this cultural climate affects the interpretation of novel data. To do so, the article looks for the reaction of SLL to novel data in two reports. The reports are shown to domesticate novelty by explaining it through standard alethic/deontic patterns, even though the data are novel precisely because the patterns largely fail to explain them. The article closes by asking whether such patterns limit or enable thinking and what this means for the digital humanities.
Absorptionsspektren und chemisches Verhalten mehrkerniger Carbonylferrate
Authors: Hieber W. , Beutner H.
Published: August 2018

Absorptionsspektren der bekannten mehrkernigen Carbonylferrat-Anionen im sichtbaren Gebiet zeigen eine mit der Zahl der Metallatome zunehmende Verschiebung ihrer charakteristischen Absorptionsbanden nach längeren Wellen. Auf Grund dieser Spektren werden einige typische Disproportionierungs-Reaktionen mehrkerniger Carbonylferrate unter Bildung von Tetracarbonylferrat und eines höherkernigen Carbonylferrats bzw. Fe (OH)2 · aq. festgestellt. Unter CO-Druck im Autoklaven werden sämtliche Carbonylferrate zu Tetracarbonylferrat reduziert; in angesäuerten Lösungen findet man stets das Hydrogenhendekacarbonyltriferrat-Ion [Fe3(CO)11H] Θ.
Solanum-Alkaloide. XIX. Mitt.: Isolierung von Solanocapsin aus Solanum pseudocapsicum L., Solanum capsicastrum Link und Solanum hendersonii hort.
Authors: Schreiber Klaus , Ripperger Helmut
Published: August 2018

Das in Blättern und Wurzeln von Solanum pseudocapsicum L. vorkommende Steroidalkaloid Solanocapsin wurde zusätzlich aus unreifen Früchten dieser Pflanze sowie aus Blättern und grünen Beeren von Solanum capsicastrum Link und Solanum hendersonii hort. isoliert.
Chemical Dissection of Mammalian cells with Liberation of biologically intact Viruses
Authors: Kovács Ernest
Published: August 2018

Ein stark cytolytisch wirkendes Reagenz (10% Natriumdesoxycholat in gesättigter Harnstofflösung in bidest. Wasser) wurde für die Auflösung infizierter Zellkulturen, ohne wesentlichen Verlust an Poliovirus-Titern angewandt. Die Zellysate wurden rasch weiter verdünnt und gegen bidest. Wasser dialysiert, bis zu einer Harnstoff- bzw. Desoxycholat-Konzentration. die nicht mehr zellschädigend wirkt. Ribonuclease-Behandlung solcher Lysate oder Dialysate vermindert die Infektiösität nicht; dieser Befund wird als ein Zeichen der biologischen Integrität der HDC-behandelten Viruspartikeln aufgefaßt. Die Anwendung der Prozedur zur Isolierung des MM-Virus aus Mäusegehirn und infektiöser Nucleinsäure desselben, wurde auch erfolgreich durchgeführt. Ähnlich wurde der lipidhaltige Vaccinevirus durch HDC-Lösung aus Chorioallantois-Membran oder aus HeLa-Zellkulturen in „totaler Ausbeute“ isoliert. Schließlich wurden mit Hilfe der HDC-Methode in arretierte Infektion der HeLa-Zellen logarithmische Mengen von Poliovirus freigesetzt. Diese Tatsache unterstreicht die Anwendungsmöglichkeiten dieser Technik.
Eigenschaften eines Homogenisats von Hefe I*
Authors: Ohlmeyer P.
Published: August 2018

Ansätze mit Homogenisat aus roter Hefe trübten sich und begannen nach einiger Zeit zu atmen. Die Atmung ging auf Teilchen zurück, die sich in Kochsaft aus roter Hefe vermehren ließen.
Spektroskopische Untersuchungen an Komplexverbindungen II EPR-Spektren des monomeren Kobalt-tetracarbonyls.
Authors: Keller H. J. , Wawersik H.
Published: August 2018

An Hand von EPR-Spektren konnte ein monomeres Kobalt-tetracarbonyl-Radikal nachgewiesen werden. Die erhaltenen Ergebnisse machen eine planare Struktur mit D4h-Symmetrie wahrscheinlich, wobei das ungepaarte Elektron hauptsächlich auf eine Metall-Bahnfunktion der Symmetrie a1u lokalisiert ist.
Untersuchungen über das Myeloblastose-Virus des Huhnes (BAI Stamm A):
Authors: Bauer Heinz , Bahnemann Hans , Schäfer Werner
Published: August 2018

Es werden Methoden zum qualitativen und quantitativen Nachweis des Myeloblastose-Virus und zur Auswahl der dafür geeigneten Zellen beschrieben. Die im Zusammenhang damit durchgeführten vergleichenden Untersuchungen mit anderen Viren der Hühner-Leukose-Gruppe ergaben, daß die verwendeten Hühnerfibroblasten eine wahrscheinlich genetisch bedingte Resistenz gegen die Leukose-Viren besitzen können. Diese Resistenz ist relativ spezifisch und macht es notwendig, jedes Zellmaterial vor Verwendung im Versuch zunächst auf Empfänglichkeit gegenüber dem speziellen Leukose-Virus-Typ zu prüfen. Mit den neu entwickelten Testen wurde die Bildung von infektiösen Einheiten und Antigen des Myeloblastose-Virus in Hühnerfibroblasten-Kulturen verfolgt.
Reduktion der Ederschen Lösung im Ultraschallfeld
Authors: Wawrzyczek Wiktor , Bielinski Zdzislaw , Polak Kazimierz
Published: August 2018

In dieser Arbeit hat der Autor bewiesen, daß wäßrige Sublimatlösungen, bei Anwesenheit von Ammoniumoxalat, im Ultraschallfeld Reduktionsprozessen unterliegen. Die ausgeschiedene Kalomelmenge hängt von der Konzentration der HgCl2-Lösung und von der Beschallungsdauer ab. Die Kalomelausbeute ist ebenfalls von der Art des sich in der beschallten Lösung befindlichen Gases abhängig. Am günstigsten verläuft der Reduktionsprozeß wenn Argon, am ungünstigsten wenn Wasserstoff beigemischt wird. Eine geringe Zugabe von Aceton zur Ederschen Lösung verursacht gänzliche Reduktionshemmung. Glycerin, eine Flüssigkeit mit nur geringem Dampfdruck, hemmt erst in größeren Mengen den Reduktionsverlauf. Edersche Lösung, mit Salzsäure angesäuert, wird nicht reduziert.
Weitere Untersuchungen zur Aminosäuresequenz des Proteins im Tabakmosaikvirus
Authors: Anderer F. A. , Wittmann-Liebold B. , Wittmann H. G.
Published: August 2018

The amino acid sequence of TMV strain vulgare (common strain) was partly reinvestigated with recently modified methods. The results show a reversion of the amino acid sequence of position 44 with 45 and position 125 with 126. An additional amide group was found in position 126, but positions 95 and 106 are free dicarboxylic acids.
The Significance of Metabolic Energy and the Ion Pump for the Receptor Potential of the Crayfish Photoreceptor Cell
Authors: Stieve H. , Bollmann-Fischer H. , Braun B.
Published: August 2018

Isolated crayfish retinas were poisoned by dinitrophenol (DNP) or ouabain (OU). The changes of the extracellularly recorded receptor potential (ReP) evoked by short or long stimuli were measured.

The changes of the shape of the ReP after poisoning by OU are the same, except the transient increase, as appear after depolarizing the retina by high external potassium concentration. DNP has different effects on the ReP. It causes a prolongation of the amplitude hmax and an increase of the shape quotient hmax/he (Fig. 9).

Expecially the rate of decrease of the excitability under different stimulus programs was measured (Tab. 5).

DNP experiments show that the inexcitability occurs the earlier the higher the incident light intensity is.

The time needed depends on the stimulating efficiency of the light rather than on the direct amount of energy.

The loss of excitability rather depends on the energy of the total light applied than on the stimulus pattern.

Concerning the inexcitability OU shows the same effect as DNP: it occurs the earlier the more the retina is excited.

These results contradict the hypothesis that the receptor potential is a consequence of a light induced change of the activity of an electrogenic pump mechanism. Fig. 10 shows the electrogenic pump mechanism (EPM) as opposed to the conductance increase mechanism (CIM).
Immunosuppressive Action in Vitro by a Bovine Spleen Extract
Authors: Morales V. H. , Garcia-Giralt E.
Published: August 2018

An extract from bovine spleen which has been shown to have immunosuppressive properties, inhibited the stimulation of DNA synthesis in mouse lymphocytes by phytohaemagglutinin and by allogeneic cells. It was also found that the lymphocytes from animals treated with the extract did not respond in vitro to an antigeneic stimulation.
Eine neue Variante des CaIn2-Gitters: Zur Kenntnis der Phase Ca0.95
Li 1.05Sn / A New Variant of the CaIn2-Type: The Phase Ca0.95Li1.05Sn
Authors: Müller Wiking , Voltz Reiner
Published: August 2018

The intermetallic phase Ca0,95Li1,05Sn has been prepared and its crystal structure determined. It crystallizes trigonal, a = 4.94 ± 0.01, c = 10.90 ± 0.02 Å, c/a = 2.21, space group P3ml-C3v
1 in a new stacking variant of the CaIn2-type.
Zur Darstellbarkeit von 2.2′-disubstituierten 3.3′ - Spirobi- [3H-naphtho(2.1-b)pyranen] / About the Synthesis of 2,2′-Disubstituted 3,3-Spirobi-[3H-naphtho (2,1-b)pyrans]
Authors: Paal G. , Arnold G.
Published: August 2018

In both α-positions relative to the spiro-C-atom substituted spirobipyrans have the expected spiropyran structure, in spite of their exceptional behaviour that their pyrylium salts can not be isolated generally. Strong steric effects are responsible for the instability of those pyrylium salts, as it can be shown by UV- and IR-spectroscopic investigations.
Sign and Orientation Determination of the Principal Axis of the Electric Field Gradient in Fe57 Enriched Deoxygenated Myoglobin Single Crystals
Authors: Gonser Ulrich , Maeda Yutaka , Trautwein Alfred , Parak Fritz , Formanek Helmut
Published: August 2018

Single crystals of myoglobin enriched on Fe57 with a diameter of about 0.5 mm were prepared. After deoxygenation crystallographic alignment and Mössbauer measurements were carried out at 77°K. In the experiment eight different orientations were selected by rotating the crystal around the b axis, thus, b axis and γ-ray propagation direction remained perpendicular to each other. From the intensity ratio of the quadrupole split spectra we derive the sign and the orientation of the principal axis of the electric field gradient. We find Vzz to be positive and forming an angle of 40° to the b axis. From two alternatives consistent with our experiments we conclude that VZZ is most likely oriented along one of the four Fe-N directions in the heme.
Synthese von Diantimonpentoxid Sb2O5 / Synthesis of Diantimony Pentoxide Sb2O5
Authors: Schwarzmann Einhard , Rumpel Horst , Berndt Wolfgang
Published: August 2018

Sb2O3 and Sb2O4 can be converted under high oxygen pressure at 700 °C into deep yellow crystals of Sb2O5.
Zur Reaktivität von Isocyanaten mit Tris(dimethylamino)arsin / The Reactivity of Isocyanates with Tris(dimethylamino)arsine
Authors: Roesky Herbbert W. , Sidiropoulos Georg
Published: August 2018

As[N(CH3)2]3 reacts with the following isocyanates: FSO2NCO, n-C4F9SO2NCO, SO2(NCO)2 and (CH3)3SiNCO. The products which result from reaction of FSO2NCO and n-C4F9SO2NCO are the acyclic tri- and bisubstituted arsines

[xxx]

In contrast, SO2(NCO)2 and (CH3)3SiNCO form eight- and four-membered ring compounds, where the skeleton consists of the atoms As2S2N4 (3) and As2N2 (4). The new compounds were characterized by NMR and mass spectra.
Beitrag zur Schwingungs- und Elektronenanregungsspektroskopie des Dikobaltoctacarbonyls in Lösung / Contribution to the Vibration and Electronical Excitation Spectroscopy of Dicobaltoctacarbonyl in Solution
Authors: Christahl M. , Saus A.
Published: August 2018

The UV spectrum of dicobaltoctacarbonyl in a solution of n-heptane was reinvestigated under variing conditions of concentration, CO-pressure and temperature. From the influence of the temperature on the spectral change and from the comparison with the spectrum of the hydridocobalttetracarbonyl an attempt was made to correlate the absorption bands to the corresponding electron transfers. A qualitative term scheme is proposed. Furthermore, the photochemical formation of tetracobaltdodecarbonyl at room temperature and its delayed formation under gamma-rays is reported.
Übergangsmetall-Carben-Komplexe, CVIII1 µ-Methyliden-Komplexe des Rheniums / Transition Metal Carbene Complexes, CVIII1 µ-Methylidene Complexes of Rhenium
Authors: Fischer Ernst Otto , Lindner Tassilo Lothar , Fischer Helmut , Huttner Gottfried , Friedrich Peter , Kreissl Fritz Roland
Published: August 2018

The reaction of Re2(CO)10 and Re2(CO)9C(OCH3)R [R = C6H5; C6H4CH3-p] with lithium aryls and subsequent alkylation with trimethyloxonium tetrafluoroborate exceeds the stage of the carbene compound to form new μ-methylidene complexes.
Notizen: Kristall- und Molekülstruktur von (1-Diphenylphosphoryl-1 H-trifluormethyl)-diphenylphosphinat1 / Crystal and Molecular Structure of (1-Diphenylphosphoryl-1 H-trifluoromethyl)-diphenylphosphinate1
Authors: Hoehne Sigurd , Lesiecki Hans , Ebert Hans-Dieter , Lindner Ekkehard , Strähle Joachim
Published: August 2018

(1 - Diphenylphosphoryl -1 H - trifluoromethyl)-diphenylphosphinate crystallizes monoclinic in the centrosymmetric space group P21/c with 4 molecules in the unit cell. The crystal structure was refined to a R value of 0.027.
Z,E-Isomeric des Piperolides / Z,E-Isomerism of Piperolide
Authors: Hansel Rudolf , Schulz Jutta , Pelter Andrew , Ayoub Miqdad T.
Published: August 2018

HPLC-Studies of the piperolide-containing fraction from piper sanctum revealed the presence of a new piperolide-like substance, which has been isolated by column-adsorption chromatography on silica-gel in a yield of 0.1 per cent. The substance has been identified as (5E)-piperolide by spectroscopic techniques and by transforming it into the tetrahydroderivative, threo-4, which had been correlated with threo-3, a derivative of known configuration [1]. The (E)-isomer may be an artefact produced from the (Z)-isomer by the action of light. Both isomers when dissolved in benzene or chloroform and exposed to light, yield an equilibrium mixture of 5Z : 5E isomers in the ratio 62:38. Dehydrogenation of either threo- or erythro-3 with DDQ gives nearly the equilibrium mixture of (5E)- and (5Z) -piperolides.
Massenspektrometrische Untersuchungen an ungesättigten Kohlenwasserstoffen: Halogen-Wanderung bei Acetylenen und Olefinen / Mass Spectrometric Investigations on Unsaturated Hydrocarbons: Halogen Migration in the Molecular Ions of Acetylenes and Alkenes
Authors: Mayer Klaus K. , Matolović Ilona , Fischer Erich , Djerassi Carl
Published: August 2018

The migratory aptitude of halogens and simple nucleophilic substituents X in the molecular ions of alkynes 1-11 and alkenes 12-17 was investigated by electron-impact mass spectrometry using low and high resolution, metastable analysis and 2H-labelling.
Bis(diazadien)metall(O)-Komplexe, IV. Nickel(O)-bis(chelate) mit aromatischen N-Substituenten/ Bis(diazadiene)metal(O) Complexes, IV. Nickel(O)-bis(chelates) with Aromatic N-Substituents
Authors: Dieck Heindirk tom , Svoboda Michael , Greiser Thomas
Published: August 2018

With N-aromatic substituted diazadienes (DAD)

and R3 = R4 = aryl) nickel(O) forms complexes of composition (DAD)2Ni which are prepared preferably by reduction of Ni(II) salts in the presence of DAD. The groups R1, R2 and/or the o-substituents of the aryl system determine the conformation of the DAD and its sterical ligand properties. An X-ray structure analysis of (DAD)2Ni 17 (DAD = glyoxalbis( 2,6-dimethyl-phenylimine)) shows a dihedral angle of 44° between the two chelate planes. With twisted N-aryl substituents nickel seems to prefer planar coordination (formal low spin Ni(II)) of two DADs over tetrahedrally coordinated formal nickel(O) state.
Photochemical Reactions of Bromoanthracenes with N,N-Dimethylaniline in Solution
Authors: Fulara Jan , Latowski Tadeusz
Published: August 2018

Major products of the photolysis of 9-bromoanthracene and 9,10-dibromoanthracene in benzene and acetonitrile as well as photochemical reaction products of the two bromoanthracenes with N,N-dimethylaniline in these solvents have been isolated and identified. The mechanisms of partial reactions are discussed and attention is paid to the medium effect on the photochemical transformations.
Preparation and Structure of Tetraphenylphosphonium Aquotetrachlorothionitrosylosmium(II), [PPh4][(H2O)Os(NS)Cl4]
Authors: Pandey Krishna K. , Roesky Herbert W. , Noltemeyer Mathias , Sheldrick George M.
Published: August 2018

Trithiazyltrichloride reacts with osmium trichloride to give a green product of composition Os(NS)Cl3 (1). Addition of [PPh4]Cl to 1 in aqueous solution yields [PPh4]2[Os(NS)Cl5] (2) which is converted to [PPh4][(H2O)Os(NS)CI4] (3) by recrystallisation from a 1:1 water/methanol mixture. Crystals of 3 are monoclinic, space group P21/c, with a = 1103.3(2), b = 1959.8(3), c = 1254.3(2) pm, β = 96.51(3)° and Z = 4. The structure was solved by automated Patterson interpretation and refined to R = 0.029 for 3177 unique observed diffractometer data. The osmium atom is octahedrally co-ordinated with H2O trans to the NS group. The Os-N-S unit is almost linear [174.9(3)°] with Os-N 173.1(4) and N-S 151.4(5) pm. The anions form dimeric units in the crystal, each held together by four O-H···Cl hydrogen bonds
Electron Donor-Acceptor Properties of 10(S)-Chlorophyll a
Authors: Hynninen Paavo H.
Published: August 2018

Evidence for the self-aggregation of 10(S)-chlorophyll a ( = chlorophyll a′) in nonpolar solvents has been obtained by means of absorption spectroscopy in the visible and infrared regions. The visible absorption spectrum of chlorophyll a′ exhibits a shoulder at 680 nm in aliphatic hydrocarbon solvents and the infrared spectrum measured in carbon tetrachloride contains an “aggregation peak” at 1650 cm-1. IR spectroscopy shows, in addition, that the C-10 epimers of chlorophyll a are both present as monomers in tetrahydrofuran. However, in the presence of a small amount of aliphatic alcohol or water, the IR spectrum in tetrahydrofuran at lowered temperatures exhibits an intense, wide absorption band at ～ 1650 cm-1 which was interpreted as arising from the hydrogen bonding of the hydroxyl group to the C-9 keto carbonyl of the chlorophyll
Zur Darstellung und Kristallstruktur von Barium-1,1-dicyanoethylen-2,2-oxo-thiolat-Tetrahydrat — ein Salz mit dem Anion [O(S)CC(CN)2 ]2- / Synthesis and Crystal Structure of Barium-1,1-dicyanoethylene-2,2-oxo-thiolate Tetrahydrate — a Salt with the Anion [O(S)CC(CN)2]2-
Authors: Hummel Hans-U.
Published: August 2018

By reaction of COS with malonitrile in presence of potassium ethanolate in ethanol K2O(S)CC(CN)2 · H2O is obtained. It reacts with Ba(NCS)2 ·3H2O in ethanol to form colourless crystals of BaO(S)CC(CN)2 · 4H2O. The space group of the barium salt is Pn21a (standard: Pna21) with Z = 4. The structure consists of Ba2+ and [O(S)CC(CN)2 ]2 - ions. The barium ion is bound to three nitrogen and six oxygen atoms. The coordination polyhedron is a tricapped trigonal prism. The anion [O(S)CC(CN)2 ]2 - is not exactly planar and is involved in several hydrogen bondings.
Kaliumlithiumsulfid, KLiS: Das erste Interalkalimetallsulfid / Potassium Lithium Sulphide, KLiS: The First Inter Alkaline Metal Sulphide
Authors: Sabrowsky Horst , Thimm Alfred , Mertens Petra
Published: August 2018

The compound KLiS has been prepared and its crystal structure is determined by X-ray diffraction techniques. The hygroscopic, yellow compound crystallizes in the tetragonal space group P4/nmm (Z = 2) with the cell parameters a - 431.79(4), c = 696.20(9) pm. The structure was solved from 2100 counter reflections (356 symmetry independent reflections) through a Patterson synthesis and refinement by Fourier syntheses to a least squares residue of 0.026. The structure is characterized by c-centered squares of lithium layers interspersed by anti-parallel ordered K-S-pairs forming an anti-PbFCl-type geometry.
Cyclische Triphosphenium-Ionen: Selektiver intramolekularer Ligandenaustausch in einer nucleophilen Substitution am zweifachkoordinierten Phosphor [1] / Cyclic Triphosphenium Ions: Selective Intramolecular Exchange of Ligand in a Nucleophilic Substitution at the Two-Coordinate Phosphorus [1]
Authors: Lochschmidt Siegfried , Schmidpeter Alfred
Published: August 2018

Phenyl substituted di-, tri- and tetraphosphines with the donor-functions in 1,2- or 1,3-position effectively replace Ph3P from Ph3P-P-PPh3
+AlCl4
−yielding cyclic five- and six-membered triphosphenium cations. In the 1:1-products of PhP(-CH2-CH2-PPh2)2 (4) and MeC(-CH2-PPh2)3 (2) the unused third phosphine function may interact as a nucleophile with the central phosphorus leading to a threefold T-shaped or pyramidal coordination thereof, respec­tively. From this attack, in the former case only, a rapid intramolecular exchange (ΔH≠ = 9.6 kcal mol-1; ΔS≠= −9.9 cal mol-1 K-1) results, involving the two phosphine functions in the apical sites of the T-shaped transition geometry. This mechanism is suggested to describe the nucleophilic substitution at two-coordinate phosphorus in general. The cyclic triphosphenium cations can be protonated (and in part alkylated) to yield cyclic triphosphine-dionium cations.
Elektrochemisches Verhalten von Dibenzodichalkogeninen und verwandten Verbindungen / Electrochemical Behavior of Dibenzodichalcogenins and Related Compounds
Authors: Stende Klaus-Wilhelm , Klar Günter , Knittel Dierk
Published: August 2018

The electrochemical behavior of thianthrenes 1-4, of selenanthrenes 5-8 (dibenzo-1,4-dichal- cogenins). of 2,2′-dithiobiphenyls 9 and 10 (dibenzo-1,2-dichalcogenins) as well as of the related compounds 11-13 were studied by cyclic voltammetry in acetonitrile. All dibenzodichalcogenins can be [oxidised in two one-electron-steps, the processes being totally reversible for 7, nearly reversible for 2 and 9, quasireversible for 1, 3, 4,10 and 13, and irreversible in all other cases. For 1- 4, 7, 9, 10 and 13 the diffusion coefficients of the electrochemically active species and the rate constants of the electron transfer are calculated from the potentials measured. Electrolysis of 9 in dichloromethane with tetrabutylammonium perchlorate as supporting elec­trolyte yields [dithiobiphenyl] + [C104]- (14), while oxidation by nitrosyl hexachloroantimonate gives [(dithiobiphenyl)2] + [SbCl6]- (15).
Pentaalkyl-Derivate des 2 ,3 - Dihiydro-1,3-diborols/Pentaalkyl Derivatives of the 2,3-Dihydro-1,3-diborole
Authors: Knörzer G . , Siebert W.
Published: August 2018

Double hydroboration of acetylene, propyne-1 and t-butylacetylene with HBCl2 · OEt2/BCl3 leads to the 1,1-bis(dichloroboryl)alkanes 2d, e, f, in which halogen exchange is achieved by BI3 to give 3d, e, f. Redox reactions between butyne-2, hexyne-3 and 3 result in the formation of compounds 4, which are alkylated with AlMe3 and AlEt3 to give the pentaalkyl derivatives 1d, e, f. Reactions of 1 with [(C5H5)Co(C2H4)2] an [(C5H5)N iCO]2 lead to the complexes 5 and 6.
Asymmetrische Katalysen, 71 / Asymmetric Catalyses, 71
Authors: Brunner Henri , Huber Christian
Published: August 2018

The enantioselective hydrosilylation of acetophenone with diphenylsilane in the solvents toluene and CCl4 was catalysed with a [Rh(COD)Cl]2/2-pyridineoxazoline catalyst. The “CCl4-effect” (higher enantioselectivity and reactivity) was already confirmed with stoichiometric quantities of CCl4 with respect to the Rh-catalyst. The influence of other halogenated solvents on the hydrosilylation was investigated.
An Unusual Geometry of Five-Coordinate Copper(II): The Structure of Cu(terpy)I2 and Spectroscopic Investigations of Complexes Cu(terpy)X2 (X: I, NCS)
Authors: Kutoglu Ali , Allmann Rudolf , Folgado José-Vicente , Atanasovc Michail , Reinen Dirk
Published: August 2018

The structure of the compound Cu(terpy)I2 (terpy 2,2′: 6′, 2″ terpyridine) was determined at room temperature. It is monoclinic, space group I2/c with a = 13.689(3), b = 9.510(2), c = 11.605(3) Å, β = 97.59(4)° and Ζ = 4. The copper(II) ions are five-coordinated by the three nitrogen atoms from the terpy ligand and the two iodine atoms. The CuN3I2 polyhedron exhibits the same unusual “reverse” geometry as is observed for Cu(terpy)(NCS)2. Single crystal EPR measurements of the iodide and the isothio-cyanate complexes confirmed the structural results, excluding the possibility of a dynamically averaged geometry.
Cyclisierung von Amidoximen mit Oxybis(diphenylboran) / Cyclization of Amidoximes with Oxybis(diphenylborane)
Authors: Möhrle Hans , Bluhme-Hensen Karin , Middelhauve Birgit , Mootz Dietrich , Wunderlich Hartmut
Published: August 2018

Substituted amidoximes when reacted with oxybis(diphenylborane) do not yield ester chelates as main products but boron heterocycles. The compound obtained from p-toluamidoxime was found by crystal structure analysis to be 2-phenyl-4-(4-methylphenyl)-2,3-dihydro-1,3,5,2-oxadiazaborol (9). The conformation of the molecule is determined by angles of 29.1 and 24.4° between the planes of adjacent rings. Except N–O all bonds in the heterocyclic ring contain significant π character. Molecules are linked to chains by a weak bifurcated hydrogen bond. 9 crystallizes with the monoclinic space group P21/c, Ζ = 4, a = 5.574(2), b = 18.274(4), c = 12.754(4) Å, β = 106.41(2)°. Refinement of 227 parameters using 1709 observed reflections converged at R = 0.037.
Design, Synthesis and Biological Evaluation of Antagonists of LHRH by Criteria of Potency, Safety and Solubility
Authors: Ljungqvist Anders , Feng Dong-Mei , Bowers Cyril , Hook William A. , Folkers Karl
Published: August 2018

Some analogs of Antide and congeners with higher water solubility have been synthesized by substitutions in positions 1, 5 or 6 with hydrophilic residues. In position 1, D-3-Qal has been incorporated in four peptides and D-3-Pal in one peptide. In positions 5 and 6, D and L-3-Pal, PzAla and (DSer)Lys have been tried. In one peptide, D—(AcDSer)Lys was substituted in position 6.

Most of the new analogs had lower AOA (antiovulatory activity) than the parent compounds but three potent analogs were identified. The first one, [N — Ac— D — 3-Qal1,DpClPhe2,D— 3-Pal3,c-PzACAla5,D — PicLys6,ILys8,D — Ala10]— LHRH, had 55% AOA at 0.25 μg and 100% at 0.5 μg. Its ED50 for in vitro histamine release was 171 ± 17 μg/ml which is an increase from 49±4.8 μg/ml for the parent compound with N—Ac-D-2-Nal [1].

The second analog, [N — Ac— D — 2-Nal1,DpClPhe2,D — 3-Pal3,PicLys5,D — (DSer)Lys6,ILys8,D—Ala10] — LHRH, had 69% AOA at 0.25 μg and 95% at 0.5 μg. This analog released somewhat more histamine than the parent analog featuring D-PicLys6, the ED50 being 18 μg/ml compared to 93 ± 11 for the parent analog.

The third analog is:

[N — Ac— D— 2-Nal1,DpClPhe2,D— 3-Pal3,c-PzACAla5,D—PzAla6,ILys8,DAla1]— LHRH. The AOA for this analog was 63% at 0.25 μg and the ED50 for histamine release 88±6.4 μg/ml.
Keto-Enol-Tautomerism and Configurational Isomerism of 2,6-Disubstituted 4-Piperidone-3,5-dicarboxylates
Authors: Holzgrabe Ulrike , Friedrichsen Willy , Hesse Karl-F.
Published: August 2018

The dialkyl 2,6-dialkylsubstituted 4-piperidone-3,5-dicarboxylates were synthesized by a Mannich procedure. Depending on the substitution at the nitrogen keto-enol-tautomerism and a configurational isomerism at C 2 is observed. The structure of the N-substituted piperidone 24 E (C18H29NO5) has been determined by X-ray analysis: it is characterized by an enol structure of the β-ketoester and an axial position of the alkyl group at C 2 and an equatorial one of the alkyl group at C 6. The O–H···O hydrogen bond shows characteristic values of a strong hydrogen bond. The N-unsubstituted piperidones adopt a ketone structure with the allequatorial position of all substituents. This stereochemistry is confirmed for other enolic and ketone analogues by NMR spectroscopic methods. To work out the reason for the different thermodynamic stabilities of the different stereochemical structures of N-substituted and N-unsubstituted piperidones, various semiempirical calculations were done for series of simple pairs of carbonyl/enol tautomers, substituted acetoacetates, oxoglutarate as well as of systematically varied substituted cyclohexanone, 4-oxacyclohexanone and 4-piperidone derivatives.
Notizen: Two New Phloroglucinol Derivatives with Phosphodiesterase Inhibitory Activity from the Leaves of Eucalyptus robusta
Authors: Cheng Qi , Snyder John K.
Published: August 2018

Two simple, new phloroglucinol derivatives have been isolated from the leaves of Eucalyptus robusta Smith, used in the Chinese traditional medicine Da Ye An. These phenolic compounds were purified using a phosphodiesterase inhibition bioassay to guide the isolation. Both compounds had moderate activity in this bioassay.
Reaktive E=C (p-p)π-Systeme, XL. / Reactive E=C(p-p)π Systems, XL.
Authors: Albers Thomas , Grobe Joseph , Le Van Duc , Krebs Bernt , Läge Mechtild
Published: August 2018

The reaction of bis(trifluoromethyl)arsane 2 with secondary amines R2NH in a molar ratio of 1:3 at -60 °C allows the preparation of trifluoromethyl arsaalkenes of the type F3CAs=C(F)NR2 in moderate yields (15-35%) [NR2 = NMe2 (3a), NMeEt (3b), NEt2 (3c)]. The main product of the reaction of 2 with Me2NH is the 1,1-diamino compound F3CAs=C(NMe2)2 (4a). With ethyl(isopropyl)- or di(isopropyl)amine the corresponding derivatives F3CAs=C(F)NEt(iPr) (3d) and F3CAs=C(F)N(iPr)2 (3e), respectively, are formed only in traces (3d), or not at all (3 e). However, 3d and 3e can be prepared by reacting perfluoro-2-arsapropene with the corresponding secondary amines. The new compounds 3 a to 3 e can be stored at 20 °C in chloroform solution for hours without decomposition and show Z configuration without exception. The molecular structure of 1-(diethylamino)-1,3,3,3-tetrafluoro-2-arsapropene 3c, determined by an X-ray diffraction study on single crystals, indicates a strong electronic interaction of the lone pair on nitrogen with the AsC double bond. This results in a trigonal planar arrangement at the nitrogen atom, a strongly shortened sp2-CN-bond (1.312 Å), an elongated AsC distance (1.867 Å), and an almost planar skeleton of the molecule.
The New Tetrafunctional π Acceptor Ligand 3,6-Bis(2′-pyrimidyl)-1,2,4,5-tetrazine (bmtz): Diruthenium Complexes of bmtz and of its 1,4-Dihydro Form
Authors: Kaim Wolfgang , Fees Jörg
Published: August 2018

Synthesis, physical properties and the coordination with two [Ru(bpy)2]2+ complex fragments are described for 3,6-bis(2′-pyrimidyl)-1,2,4,5-tetrazine (bmtz), the first compact ligand which offers four equivalent α-diimine chelate sites. Spectroelectrochemistry of intensely blue {(μ-bmtz)[Ru(bpy)2]2}n+, n = 4, reveals a very facile reduction (n = 3) at -0.40 V vs. FeCp2
+/o and a metal oxidation (n = 5) at + 1.18 V to a diruthenium(II/III) mixed-valent form which exhibits an intervalence transfer absorption at 1490 nm. The corresponding complex {(μ-H2bmtz)[Ru(bpy)2]2}4+ with the 1,4-dihydro form H2bmtz of the tetrafunctional ligand is oxidized in two steps at 0.58 and 1.07 V vs. FeCp2
+/o.
Synthese und Kristallstrukturen der neuen Zinn-Chalkogen-Vierringe [{Cp(Ph3P)Ni}2Cl2Sn2E2] (E = Se, S) / Synthesis and Crystal Structures of the New Four-M em bered Tin-Chalcogen Rings [{Cp(Ph3P)Ni}2Cl2Sn2E2] (E = Se, S)
Authors: Kraus Harald , Merzweiler Kurt
Published: August 2018

[{Cp(Ph3P)Ni}SnCl3] reacts with Se(SiMe3)2 within several days to give [{Cp4(Ph3P)3Ni5Sn6Se9] (1). If the reaction is stopped after 16h, green crystals of the intermediate [{Cp(Ph3P)Ni}2Cl2Sn2Se2] (2) can be isolated. According to the X -ray structure determination, 2 consists of a planar Sn2Se2 ring with terminal {Cp(Ph3P)Ni} and Cl substituents in a trans arrangement. The analogous reaction of [{Cp(Ph3P)Ni}SnCl3] with S(SiMe3)2 leads to the sulfur derivative [{Cp(Ph3P)Ni}2Cl2Sn2S2] 3 which has an analogous structure.
Die zu BaMg2Cu8V6O26 isotypen Cadmium-Kupferoxovanadate KCd0,67Cu4,33V3O13, RbCd0,5Cu4,5V3O13 sowie TlCd0,5Cu4,5V3O13 /The BaMg2Cu8V6O26 isotypic Cadmium-Cooperoxovanadates KCd0,67Cu4,33V3O13, RbCd0,5Cu4,5V3O13 and TlCd0,5Cu4,5V3O13 /
Authors: Mertens B. , Müller-Buschbaum Hk.
Published: August 2018

Single crystals of KCd0,67Cu4,33V3O13 (I), RbCd0,5Cu4,5V3O13 (II) and TlCd0,5Cu4,5V3O13 (III) have been prepared by crystallization from melts. X-ray analysis led to monoclinic symmetry, space group C2
2h-P21/m (Nr. 11) and the lattice constants (I) - (III): a = 10.728(1), 10.746(3), 10.746(3), b = 6.155(1), 6 .163(2), 6.175(2), c = 8.363(2), 8.350(2), 8.337(3) Å , β = 97.69(2), 97.73(2), 97.61(5)°, Z = 2. The crystal structures are isotypic to the BaMg2CU8V6 O26 type. Cu2+ occurs in square pyramidal and unusual trigonal bipyram idal coordination by oxygen . The MgO6 octahedra of the aristo type BaMg2Cu8V6O26 are statisti­cally occupied by cadmium and copper. The distortion of the (Cd /Cu)O6 octahedra is discus­sed with respect to the polyhedra network.
SrZn(VO)(PO4)2 und BaCd(VO)(PO4)2: Zum BaZn(VO)(PO4)2-Typ verwandte, jedoch nicht isotype Vanadylphosphate / SrZn(VO)(PO4)2 and BaCd(VO)(PO4)2: Vanadylphosphates Related but not Isotypic to the BaZn(VO)(PO4 )2 Type
Authors: Meyer S , Mertens B , Müller-Buschbaum Hk
Published: August 2018

Single crystals of the compounds SrZn(VO)(PO4)2 (I) and BaCd(VO)(PO4)2 (II) have been prepared by solid state reactions in evacuated quartz tubes. X-ray investigations confirmed orthorhombic symmetry, space group D152h-Pbca, lattice constants a/b/c (I): 9.066(1)/9.012(1)/17.513(1) Å and (II); 8.838(4)/8.915(4)/19.374(9) Å, Z = 8. Initially assumed isotypies of (I) and (II) to BaZn(VO)(PO4)2 proved to be erroneous considering significant details of the connectivity of the ZnO4 and PO4 tetrahedra (I) and the coordination sphere of cadmium (II), respectively. The similarities and differences of the crystal chemistry relation to (I) and (II) are discussed with respect to BaZn(VO)(PO4)2. The Coulomb terms of the lattice energies of vanadyl M2(VO)(PO4)2 and divanadyl M(VO)2(PO4)2 phosphates are shown.
Mehrkernige CpZr(IV)-und CpHf(IV)-Komplexe mit Oximatobrücken / Polynuclear CpZr(IV) and CpHf(IV) Complexes with Oximato Bridges
Authors: Braunwarth Wolfgang , Thewalt Ulf
Published: August 2018

The mono-cyclopentadienyl metal complexes CpZrCl3(dme) and CpHfCl3(dme) react with acetone oxime in the presence of triethylamine to form the isotypic dinuclear complexes [CpMCl2]2(μ-ONCMe2)2(μ-HONCMe2) (1: M = Zr; 2: M = Hf). 1 and 2 contain two oximato bridges and one oxime bridge. In the presence of water the reaction gives, with partial hydrolysis, the cyclic trinuclear compounds [CpZrCl]3(μ3-O)(μ3-OH)(μ-ONCMe2)3·½Me2CNOH (3) and [CpHfCl]3(μ3-O)(μ3-Cl)(μ-ONCMe2)3·CH2Cl2 (4). In 1 to 4 the bridging oximato groups are side-on bonded via O and N to one metal atom and via (only) O to the other metal atom. The metal atoms of 1 to 4 exhibit an 18-electron configuration.
Structure and Energy Spectra of Molecules Containing Anti-Aromatic Ring Systems. IV. Aromaticity and Anti-Aromaticity in Electronic Ground and Excited States
Authors: Dietz Fritz , Vogel Henryk , Schleitzer Anna , Tyutyulkov Nikolai , Rabinovitz Mordecai
Published: August 2018

Using various criteria to characterize the terms aromaticity and anti-aromaticity it is shown that the non-benzoid aromatic azulene and the benzoid aromatic naphthalene should have anti-aromatic properties in the first excited singlet state.
[(N, N’, N”-Tricyclohexyl)-N”- cyclohexylcarbamoylguanidinium] Tetrachloroaurate(III) as a Product of the Reaction of Dicyclohexylcarbo- diimide with HAuCl4 . aq
Authors: Schneider Wolfgang , Bauer Andreas , Schmidbaur Hubert
Published: August 2018

Reaction of tetrachloroauric(III) acid hydrate with dicyclohexylcarbodiimide (dcc) in dichloromethane in the presence of equimolar amounts of triethylamine leads to a complex reaction mixture. One of the components was shown by X-ray crystallography to be [(N, N’, N”-tricyclohexyl)- N”-cyclohexylcarbamoylguanidinium] tetrachloroaurate( III) (1) which contains as a cation the addition product of dcc with the corresponding urea.
A Novel Access to Tertiary and Secondary ortho-Aminophenylphosphines by Protected Group Synthesis and Palladium Catalyzed P-C Coupling Reactions
Authors: Heßler Antonella , Kottsieper Konstantin W. , Schenk Stefan , Tepper Michael , Stelzer Othmar
Published: August 2018

The dilithium salt 1a formed by ortho-metallation of N-tert-butoxycarbonylaniline (BOC-aniline) 1 with two equivalents of tert-butyllithium reacts with the chlorophosphines Ph3-nPCln (n = 1 -3) to yield the BOC protected ortho-aminophenylphosphines 2 - 4 in high yields. On deprotection of 2 - 4 with trimethylchlorosilane in the presence of phenol the HCl adducts of the ortho-aminophenylphosphines 5 -7 are formed which may be deprotonated with KOH or NaOH to give the neutral phosphines 5a -7a. The novel secondary phosphine 8 with two ortho-aminophenyl groups is accessible by cleavage of the P-C bond in 7a with metallic lithium and subsequent hydrolysis. The bifunctional P,N ligands 6 or 6a are alternatively accessible by Pd-catalyzed P-C coupling of ortho-iodoaniline with phenylphosphine. If a 1:1 stoichiometry is employed in the coupling reaction of ortho-iodoaniline and phenylphosphine the chiral secondary phosphine 9 is formed.
X-Ray Structure of 6(E)-[2(Z)-(Hydroxyimino)-2-phenylethyIidene]- 7,7,8,8,9,9-hexamethyl-3-phenyl-1,2-oxazaspiro[4.4]non-2-ene
Authors: Borowiak Teresa , Wolska Irena , Mayr Herbert , Baran Janusz
Published: August 2018

The X-ray crystallographic structure of the title compound, a product of a 1,3-dipolar cy­ cloaddition reaction of benzonitrile oxide to 3,3,4,4,5,5-hexamethyl-1,2-bis(methylene)cyclopentane, has been determined. Colourless plates crystallize in the orthorhombic space group Pbca with cell dimensions a = 13.698(2), b = 11.836(2), c = 29.157(4) Å, V= 4727.2(1.2)Å3, Z = 8, 3736 reflections, final R(F) = 0.063 and wR(F2) = 0.166. The crystals are racemic, the molecules of opposite chirality form centrosymmetric dimers via intermolecular hydro­ gen bonds O-H···N between their oxime groups. The molecules are highly strained and the geometrical consequences of the steric strain are discussed.