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  • Organic Chemistry  (68,935)
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  • Wiley-Blackwell  (68,935)
  • Böhlau  (6)
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  • 1
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    Böhlau
    Publication Date: 2023-09-14
    Description: In 1923 Count Richard Coudenhove-Kalergi, offspring of an aristocratic family in the Austro-Hungarian Monarchy, published the book Paneuropa which was soon translated into almost all important languages of the world. A movement was launched under the same name and soon became the synonym for all efforts concerning the creation of a united Europe in the interwar period and even beyond. The Count was convinced of the necessity to create Paneurope the main reasons being the danger of a second world war, Bolshevist Russia and the economic power of the United States of America. Since 1925 Paneurope Unions were founded in nearly every European capital; the headquarter were Vienna (Hofburg). But the movement failed in mobilizing the masses. Coudenhove who was the embodiment of Paneurope was only in contact with statesmen, industrial leaders and intellectuals. His great merit was the confrontation of European governments with the idea of a united Europe, the rising of European question. Despite of all his efforts European politicians were not able to realize the importance of "United States of Europe" in those days. Nationalism was too strong and there seemed to be no willingness to give up parts of the own sovereignity and to develop a better understanding for democracy. The study presents a comprehensive view of the Paneuropean Movement during the interwar period including records of the Moskow Archive (captured material). It opens with a biographical sketch followed by the political program and how it was adapted to the political situation of those days; other main items are fund raising, financial organisation and propaganda. Also, there is an analysis of Paneurope in interaction with contemporary Austrian and European policies. Another chapter is dedicated to the ideas to unite Europe economically (since 1933) or on a cultural basis (saving the Abendland). The longitudinal views are completed by sectional views which focussed on the way how Coudenhove and his Paneurope Movement dealt with ideologies and mental streams of these days; They fought Bolshevism and since 1933 against National Socialism; they sympathized with Italian Fascism; Paneurope was anti-democratic and aristocratic. Some of the aims were revolutionary but many people regarded them as utopian. In comparison with the European Union there are certain parallels between European Union and Paneurope. Today we can see Paneurope - with restrictions - as an avant-garde of the European Union.
    Description: Im Jahr 1923 veröffentlichte der altösterreichische Graf Richard Coudenhove-Kalergi das Buch "Paneuropa", es wurde in fast alle Weltsprachen übersetzt und die gleichnamige Bewegung sollte alsbald das Synonym für sämtliche Europa-Vereinigungsbestrebungen in der Zwischenkriegszeit und darüber hinaus werden. Coudenhove sah in Paneuropa einen Weg, um einem weiteren Weltkrieg, der ideologischen Bedrohung durch die bolschewistische Sowjetunion und der großen amerikanischen Wirtschaftskonkurrenz entgegen zu treten. Ab 1925 entstanden in fast allen europäischen Hauptstädten sog. Paneuropa-Unionen, das Zentralbüro befand sich in der Wiener Hofburg. Paneuropa wurde nie eine Massenbewegung, Coudenhove, mit dem die Bewegung stieg und fiel, blieb auf der elitären Ebene der Politiker, Wirtschaftsfachmänner und Intellektuellen. Es war sein Verdienst, die europäischen Regierungen erstmals mit der Europafrage konfrontiert zu haben, wenngleich die damaligen Politiker nicht in der Lage waren, die Vereinigung des europäischen Kontinents zu bewerkstelligen. Zu stark waren die Staaten an ihre eigene Nation gefesselt sowie am Unvermögen, Souveränität in Teilbereichen aufzugeben und mit der Demokratie umzugehen. In dieser Arbeit wird unter erstmaliger Berücksichtigung des Moskauer Archivbestandes (Beuteakten aus dem Zweiten Weltkrieg) eine gesamtheitliche Darstellung der Paneuropa-Bewegung in der Zwischenkriegszeit geboten. Zunächst wird der Gründer der Paneuropa-Bewegung biografisch dargestellt; unmittelbar vor dem chronologischen Abriss der Paneuropa-Bewegung erfolgt die Analyse des Paneuropa-Programms und dessen Anpassung an die damaligen politischen Verhältnisse; die Erörterung organisatorischer Fragen wie bspw. die Finanzierung und propagandistischer Themen ergänzen diesen Schwerpunkt. Im Anschluss wird Paneuropa, in die europäische aber auch österreichische Politik der damaligen Zeit eingebunden, dargestellt; Schließlich erfolgt die Darstellung des Versuches ab 1933, Paneuropa wirtschaftlich bzw. gegen Ende der Bewegung kulturell zu vereinigen (Rettung des Abendlandes). Der Längsschnittdarstellung folgt die Querschnittdarstellung, nämlich über den Umgang Paneuropas bzw. Coudenhoves mit den Ideologien und geistigen Strömungen der damaligen Zeit. Im Vergleich zwischen Paneuropa und Europäischer Union findet man einige Parallelen, sodass man - - mit Einschränkungen - durchaus Paneuropa als Avantgarde für die Europäische Union bezeichnen kann.
    Keywords: Europa-Integrationsgeschichte ; Europäische Außenpolitik ; Sozial- und Wirtschaftsgeschichte ; Geschichte der Zwischenkriegszeit ; Österreichische Außenpolitik ; Deutschland ; Frankreich ; Paneuropa-Union ; Völkerbund
    Language: German
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  • 2
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    Böhlau
    Publication Date: 2024-03-23
    Description: The intention of this paper is to give a correct inside in the review of the discussed periods. It tries to achieve this by using the means of Art History and Political History to get an exact inside. The allegorical representation of the Austria in this case is the means to get it. It stands for the specific aspects of the time, so for instance the dynastic Austria with the crown of Emperor Rudolph II. meaning the predominance of the ruling Habsburgs, the civic Austria with the mural crown showing the ideas of the middle class, especially in the German speaking parts of the country, with the acceptance of the predominance of the state over the ruler, according to Hegel, or also the victorious Austria with the laurel wreath as a symbol of the conquest of the revolution of 1848. The Habsburg monarchy including many different nations was the proper breeding ground of dissatisfaction and diversified nationalistic ideas. So the representation of the Austria is an important means of showing these ideas. The periods the paper is working on are roughly speaking starting with the time of the beginning of the position of the monarchy as one of the ruling powers of Europe until her dissolution and the end of World War I. Different aspects of art history are also dealt with. So for example the 13 portraits of Habsburg rulers in the Museum Nordico at Linz, which are positioned in the time of Rudolph II. and mark the beginning of the representation of the allegory of the Austria, or the designs for monuments by Otto Wagner which are dealt with in the many books on this architect only as a side issue, whereas they are a very important part of wagners work and show his national feelings, towards his fatherland. It is furthermore interesting to look at the nationalistic problems shown in this paper and compare them with contemporary Europe and the overcoming of them. These ideas are not new, the date back to the 19th and especially the beginning of the 20th century when the Monarchy tried to overcome the problems with the slogan of Großösterreich (Greater Austria). During World War one followed the idea of Mitteleuropa (Central Europe) including Turkey and the institution of a Polish State to hold off revolutionary Russia
    Description: Diese Arbeit ist der Versuch, durch die Verbindung von kunsthistorischen und politikgeschichtlichen Erkenntnissen ein genaueres korrekteres Bild der behandelten Epochen zu erhalten. Die Allegorie der Austria ist dabei das Instrument zur genauen Evaluierung der jeweiligen nationalen und staatspolitischen Vorstellungen. Die Allegorie der Austria verkörpert dabei sehr genau die jeweiligen politischen Konstellationen. Die dynamische Austria mit der rudolphinischen Hauskrone bedeutet die Prädominanz des Herrscherhauses, die bürgerliche Austria mit der Mauerkrone die Vorstellungen dieser Bevölkerungsschicht, vor allem im deutschsprachigen Teil von Österreich, die Stellung des Staates über dem Herrscher der Sinne Hegels, sowie auch die siegreiche Austria mit dem Lorbeerkranz als Zeichen der Überwindung der Revolution von 1848. Gerade im Vielvölkerstaat der Habsburger, wo die divergierenden gesamtstaatlichen und nationalen Sichtweisen zu Konflikten führen mußten, ist so die Allegorie der Austria ein wichtiger Hinweis auf die jeweilige Stellung der Öffentlichkeit zu der angedeuteten Problematik. Der in der Arbeit vorgegebene Zeitraum umfaßt die Periode vom Beginn des Aufstiegs Österreichs zur Großmacht bis zum Ende der Monarchie nach dem ersten Weltkrieg. Dabei werden verschiedene künstlerische Aspekte in einer neueren und genaueren Betrachtungsweise angesprochen, wie zum Beispiel der Zyklus von 13 Porträts aus dem Umfeld von Rudolph II. im Linzer Museum Nordico, die in der großen Ausstellung über diesen Herrscher "Prag um 1600" nicht repräsentiert waren und die am Beginn der Austria-Allegorie in der bildenden Kunst stehen, oder die Denkmalsentwürfe Otto Wagners, die im Großteil der Literatur über diesen Architekten nur als Gelegenheitsentwürfe bezeichnet werden, aber in Wahrheit ernstzunehmende Auseinandersetzungen Wagners mit der nationalen Kunst sind. Ein weiterer gedanklicher Ansatzpunkt ist der Vergleich des Ringens um einen modernen Gesamtstaat vor allem seit dem Anfang des 20. Jahrhunderts im Verhältnis zum heutigen Europa mit seinen überstaatlichen Strukturen. Dazu gehört die im Weltkrieg aufgekommene Idee von Mitteleuropa unter Einschluß der Türkei und der Wiedererrichtung des Königreiches Polen als Pufferstaat gegenüber dem revolutionären Russland. Hier ist schon lange vor der Gründung der europäischen Union der Versuch gemacht, den Kontinent friedlich zu einen.
    Keywords: allegorical representation of Austria ; Deutschland ; Monarchie ; Österreich ; Ungarn ; Wien ; thema EDItEUR::A The Arts
    Language: German
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  • 3
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    Böhlau | Böhlau
    Publication Date: 2023-07-19
    Description: In her early diaries the art historian Erica Tietze-Conrat discribes her eventfull life in Vienna in the 1920ies, were she had been in touch with all the important art circles of the time.. In 1937 and 1938 her journals give an interesting view of the networks between museumstafs, art dealers, art scholars and artists just before the outbreak of World War II.
    Description: In den frühen Tagebüchern beschreibt die Kunsthistorikerin Erica Tietze-Conrat ihr ereignisreiches Leben im Wien der 1920er Jahre, wo sie mit allen wichtigen Künstlergruppen in Kontakt stand. Die Aufzeichnungen von 1937 und 1938 geben einen interessanten Überblick über die Netzwerke zwischen Museumsmitarbeitern, Kunsthändlern, Kunstgelehrten und Künstlern in der Zeit vor dem Ausbruch des Zweiten Weltkriegs.
    Keywords: Vienna ; art ; culture ; history ; women ; jewish ; Wien ; Kunst ; Kultur ; Geschichte ; Frauen ; Jüdisch ; Deutschland ; England ; Erica Tietze-Conrat ; Frankreich ; Italien ; Kunsthistoriker ; Malerei ; Österreich ; Vereinigte Staaten
    Language: German
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  • 4
    Publication Date: 2024-04-01
    Description: The seventh volume of the Matriculation Book of the University of Vienna includes the period from 1715/16 to 1745/46. It represents the follow-up of the edition of the central student enrollments of the rectors of the University of Vienna, that was initially established in 1377. It is a first-class source for studies of the history of persons and the institution of the University of Vienna, as well as the social history of the scholarly world in the period of enlightenment. The register book includes informations about the scholarly staff and the students. Within 31 years there are 6.764 persons enrolled. In addition, the book contains information on the regional and social origins of university members. Apart from the critical edition of the matriculation text, the volume also includes a list of university rectors. Moreover it is accompanied by indices of persons and places.
    Description: Der siebente Band der Matrikel der Universität Wien erschließt den Zeitabschnitt von 1715/16 bis 1745/46. Es enthält die Fortsetzung der Edition der Hauptmatrikel der Rektoren der Universität Wien, die im Jahre 1377 begründet wurde. Sie stellt eine erstklassige Grundlage für die Erforschung der Personengeschichte und der Institutionengeschichte der Universität Wien , wie auch der Sozialgeschichte der Gelehrtenwelt dar. Das Matrikelbuch der Universität Wien enthält die Daten des wissenschaftlichen Personals wie der Studierenden, insgesamt sind 6.764 Personen aus einem Zeitraum von 31 Jahren eingetragen. Darüber hinaus enthält das Matrikelbuch Informationen über die regionale und soziale Herkunft der Universitätsmitglieder. Der kritischen Edition ist eine Namensliste der amtierenden Rektoren sowie ein Namens- und ein Ortsregister angeschlossen.
    Keywords: Edition of historical Sources ; History of Universities ; Austrian History ; History of Sciences ; Deutschland ; Flavius Josephus ; Franz Xaver ; Gramm ; Jesuiten ; Majuskel ; Paulus von Tarsus ; Rom ; Simon Petrus ; thema EDItEUR::N History and Archaeology::NH History
    Language: German
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  • 5
    Publication Date: 2023-07-19
    Description: The volume presents a collection of papers which clearly document a theological paradigm shift during the decades after World War II. Protestant, Catholic and Jewish experts from various specialist fields of theology, such as biblical scholarship (Old Testament and New Testament), liturgics, feminist and systematic theology, as well as Jewish studies provide a diverse picture of the theological change from anti-Jewish polemics to a respectful dialogue with Judaism. Moreover, the publication offers an insight into the biographical developments of the scholars involved, and through this a piece of reflective history of theology.
    Description: Der Band versammelt Beiträge, die eindeutig einen theologischen Paradigmenwechsel in den Jahrzehnten nach dem Zweiten Weltkrieg belegen. Evangelische, katholische und jüdische Expertinnen und Experten aus unterschiedlichen theologischen Fachrichtungen wie der alt- und neutestamentlichen Bibelwissenschaft, der Liturgiewissenschaft, der feministischen und systematischen Theologie sowie der Judaistik zeichnen den Wandel von antijüdischer Polemik hin zu einem respektvollen Dialog mit dem Judentum facettenreich nach. Die Publikation gibt zudem Einblick in die biografische Entwicklung der involvierten Forschenden und bietet damit ein Stück reflektierter Theologiegeschichte.Der Sammelband dokumentiert die Beiträge des internationalen Forschungskolloquiums „Der ‚jüdisch-christliche‘ Dialog verändert(e) die Theologie. Ein Paradigmenwechsel aus ExpertInnensicht“, das im Rahmen des FWF-Projektes „Die Hebräische Bibel im ‚jüdisch-christlichen‘ Dialog in Österreich und Deutschland nach 1945“ am 4. und 5. April 2014 an der Katholisch-Theologischen Fakultät der Karl-Franzens-Universität Graz stattfand.
    Keywords: „Jewish-Christian“ Dialogue ; Hebrew Bible ; Reception History ; Germany ; Austria ; post 1945 ; „Jüdisch-christlicher“ Dialog ; Hebräische Bibel ; Rezeptionsgeschichte ; Deutschland ; Österreich ; nach 1945 ; Altes Testament ; Israel ; Juden ; Judentum ; Kirchen und Judentum nach 1945
    Language: German
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  • 6
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    Böhlau | Böhlau
    Publication Date: 2023-07-19
    Description: The years 1989/1990 saw the fall of the Iron Curtain. Following forty years of significant restrictions, legal and non-bureaucratic travel from East-Central and Eastern European countries was once again possible and travelling and returning to those countries became just as easy. Immediately following the end of the East-West conflict, people from East-Central and Eastern European countries took advantage of their new freedom of travel. Many sought to emigrate to Western countries. However, when faced with such immigration, the euphoria which met the end of the political divisions in the West evaporated quickly. Several polls and surveys, projections and prognoses served to unsettle people more than the reality of immigration. This gave rise to a sometimes blind and specious – yet nevertheless politically effective – fear of a new mass migration of peoples. Now, more than ten years after the fall of the Iron Curtain, the actual scale and development of the East-West migration in Europe be clearly evaluated. This book attempts to do just that, including a comprehensive overview and eleven country-specific chapters. Each chapter includes a historical review, an account of the most important changes since 1989/1990 and a forecast of future migration developments.
    Description: 1989/90 fiel der Eiserne Vorhang. Nach mehr als 40 Jahren erheblicher Einschränkungen wurde die legale und unbürokratische Anreise aus den Staaten Ostmittel- und Osteuropas wieder möglich. Genauso leicht wurde die Ein- und Rückreise dorthin. Unmittelbar nach Ende des Ost-West-Konflikts begannen die Bürger Ostmittel- und Osteuropas, von dieser neuen Reisefreiheit Gebrauch zu machen. Etliche versuchten, in ein westliches Land auszuwandern. Angesichts solcher Zuwanderung verflog die Euphorie über das Ende der politischen Spaltung Europas im Westen relativ rasch. Mehr noch als die tatsächliche Migration beunruhigten aber diverse Umfragen, Hochrechnungen und Prognosen die öffentliche Meinung. Es entstand eine teilweise unreflektierte und vordergründige, aber politisch höchst wirksame Angst vor einer neuen Völkerwanderung in Europa. Mehr als zehn Jahre nach dem Fall des Eisernen Vorhangs können nun tatsächliche Größe und Entwicklung der Ost-West-Wanderung in Europa klar abgeschätzt werden. Damit befasst sich dieses Buch. Es enthält eine Übersichtsdarstellung und elf Länderkapitel. Diese beinhalten jeweils einen historischen Rückblick, eine Darstellung der wichtigsten Veränderungen seit 1989/90 und eine Einschätzung der zukünftigen Migrationsentwicklung.
    Keywords: Migration ; European Migration ; European East-West Migration ; Fall of the Iron Curtain ; Migration Policy ; Labour Migration ; Asylum Seeker Migration ; Ethnical Migration ; Migration ; Europäische Migration ; Europäische Ost-West Migration ; Fall des Eisernen Vorhangs ; Migrations-Politik ; Arbeitskräfte-Wanderung ; Asylsuchende Migration ; etnische Migration ; Auswanderung ; Deutschland ; Einwanderung ; Kalter Krieg ; Polen ; Rumänien ; Sowjetunion ; Tschechien ; Ungarn ; bic Book Industry Communication::J Society & social sciences::JF Society & culture: general::JFF Social issues & processes::JFFN Migration, immigration & emigration
    Language: German
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  • 7
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compound, an analogue of [Leu5]-enkephalin with L-o-carboranylalanine replacing L-phenylalanine in position 4, was prepared by fragment condensation. The analogue has a 3-fold higher affinity for rat brain opiate receptors in the [3H]naloxone competition assay than natural [Leu5]-enkephalin. Like [Leu5]-enkephalin and Na-acetyl-[Leu5]-enkephalin, the N-terminal tripeptide fragment, H · Tyr-Gly-Gly · OH, had no melanotropic activity in the Rana pipiens frog skin assay.A convenient, direct synthesis of methyl t-butoxycarbonyl-L-propargylglycinate is described, and the 13C-NMR. spectra of L-o-carboranylalanine recorded. The procedure was extended to the preparation of BOC · Car-Leu · OMe from BOC · Pra-Leu · OMe. A number of new propargylglycine derivatives are reported.
    Additional Material: 3 Ill.
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  • 8
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conversion of primary, secondary and vinylic halides to the two C-atoms homologated phenylselenomethyl ketones 8 is described. The method involves addition of the readily available phenylselenoacetaldehyde 5 to the Grignard reagents 9 and oxidation of the resulting β-hydroxy-selenides 10 (Scheme 3).
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  • 9
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of Stilbenyl Derivatives of 1,2,4-OxadiazolesSchiffs bases derived from 3- and 5-(p-formylphenyl)-phenyl-1,2,4-oxadiazoles and chloroanilines are reacted with various p-tolyl substituted aromatic heterocycles in the presence of dimethylformamide and potassium hydroxide to yield the corresponding heterocyclic substituted stilbenes (‘Anil synthesis’). The reactivity of 5-[4-(chlorophenylimino-methyl)phenyl]-3-phenyl-1,2,4-oxadiazoles is very low and side reactions will predominate.
    Additional Material: 1 Ill.
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  • 10
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Perhalomethylthio)heterocycles. XIX. Mitt.: s. [1]. . Acid-catalyzed substitutions on (perchlorofluoromethylthio)pyrroles and their agro-biological activitiesIn the presence of C4F9SO3H the (perhalomethylthio)pyrroles 1a-c react with Cl3-nFnCSCl (n = 1-3) to give mixtures of the 2,5- and 2,4-disubstituted pyrroles 2a-f and 3a-h. 2a and 3a react with CF3SCl (catalyst CF3SO3H) yielding 2,3,5-tris (trifloromethylthio)pyrrole (4a), which under similar conditions reacts further to give 2,3,4,5-tetrakis (trifluoromethylthio)pyrrole (5). As a by-product during the conversion of 3a to 4a 2,3,4-tris (trifluoromethylthio)pyrrole (4b) is formed. The pyrroles 2a, 4a and 5 form the mercury salts 6a-c; compound 5 yields also a silver salt 7. The 1H- and 19F-NMR. spectra are discussed and the agro-biological properties of the compounds investigated.
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  • 11
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1451-1457 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new way to vinylic ethers from acetalsAcetals react at low temperatures in presence of a Lewis acid (aluminium chloride or magnesium bromide) with tertiary amine to give in good yields the vinylic ethers corresponding to the elimination of one molecule of alcohol.
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  • 12
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition Reaction of 3-Dimethylamino-2,2-dimethyl-2H-azirine with Phenylisocyanate and Diphenylketene3-Dimethylamino-2,2-dimethyl-2H-azirine (1a) reacts with carbon disulfide and isothiocyanates with splitting of the azirine N(1), C(3)-double bond to give dipolar, fivemembered heterocyclic 1:1 adducts. In some cases, these products can undergo secondary reactions to yield 1:2 and 1:3 adducts. In this paper it is shown that the reaction of 1a with phenylisocyanate also takes place by cleavage of the N(1), C(3)-bond, whereas with diphenylketene N(1), C(2)-splitting is observed.The reaction of 1a and phenylisocyanate in hexane at room temperature yields the 1:3 adduct 2 in addition to the trimeric isocyanate 3 (Scheme 1). A mechanism for the formation of 2 is given in Scheme 5. Hydrolysis experiments with the 1:3 adduct 2, yielding the hydantoins 4-6 and the ureas 7 and 8 (Schemes 3 and 5), show that the formation of this adduct via the intermediates d, e and f is a reversible reaction.The aminoazirines 1a and 1b undergo an addition reaction with diphenylketene to give the 3-oxazolines 14 (Scheme 8), the structure of which has been established by spectral data and oxidative degradation of 14a to the 3-oxazolin-2-one 15 (R1 — R2 — CH3, Scheme 9).
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  • 13
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H-NMR. Spectroscopic Analysis of Prochiral Allenic Esters Using Optically Active Europium Shift ReagentsThe prochiral allenic methyl esters 1-4 (cf. Scheme) show in the presence of 1 mol-equiv. tris[3-(heptafluorobutyryl)-(+)-camphorato]europium (III) (Eu (hfc)3) in 1,1,2-trichloro-1,2,2-trifluoroethane (TCFE) induced unlike 1H-NMR. shift differences (ΔΔδ) for the enantiotopic protons and methyl groups on C(4), respectively (cf. Fig. 2 and 3). This effect allows to determine directly the 2JH,H coupling constants of the geminal protons on C(4) of the allenic esters 1 (15.5 Hz) and 2 (14.5 Hz) (cf. Table 2).
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  • 14
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1466-1474 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heterocyclic anellated derivatives of strychnine: Imidazo-, oxazolo- and (1,3-dioxolo)strychnineThe synthesis of imidazo-, oxazolo- and dioxolo-strychnine derivatives, anellated at the 2,3-position of the aromatic nucleus is described. The spectroscopic properties of these compounds and of some intermediates are given.
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  • 15
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 1475-1484 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: UV.-irradiation of pivalic and isobutyric acid and their methyl esters as well as of α-hydroxy isobutyric and malonic acid in solution lead to chemically induced dynamic nuclear polarization (CIDNP.) of parent compounds and of various reaction products. CIDNP.-effects and product distributions confirm α-cleavage of the C(α), CO bond to be the major mode of photodecomposition. Scavenger experiments indicate that decomposition of the molecules from a triplet excited state is roughly equally or more probable than from a singlet excited state. Quantum yields of educt disappearance are also given for the methyl esters of pivalic and isobutyric acid.
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  • 16
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sodiumthiophenoxide and sodiumphenylselenide react with N-benzyl- and N-hexyl-di-p-toluenesulfonamides (1 and 2) via displacement at the C-atom to afford the corresponding organosulfides and selenides in yields of 68-96%. In contrast, sodium cyanide converts disulfonamides to monosulfonamides by attack on the S-atom. The different selectivities of phenylsulfide and selenide as compared to cyanide anions with respect to attack on the C- and S-atoms are rationalized on the grounds of the HSAB (hard and soft acids and bases) principle of Pearson.
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  • 17
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    Helvetica Chimica Acta 62 (1979), S. 1497-1500 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The recently proposed structure of the carotenoid pigment prolycopene as the 7,9,7′,9′-tetra-cis isomer of lycopene has been unambiguously confirmed by a series of homonuclear Overhauser 1H-NMR. experiments at 270 MHz. Comparative measurements are reported for lycopene.
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  • 18
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The racemic sesquiterpene isocomene (1) has been synthesized starting from 1,7-octadien-3-one (2) in a stereoselective manner (Scheme 2). In the key step 4 → 5 the C(7), C(8)-bond was formed by an intramolecular thermal ene reaction. Further elaboration of 5 involved the ring contraction 6 → 7, the elimination 8 → 9 and the final olefin isomerization 9 → 1.
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  • 19
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metabolites of Microorganisms. The Aspochalasins A, B, C, and DThe structures of the antibiotic aspochalasin B (asposterol) and its inactive co-metabolites aspochalasin A, C, and D from Aspergillus microcysticus (Tü 502) were elucidated by extended spectroscopic studies and chemical degradation. The structures are: aspochalasin A = 10-isopropyl-14-methyl[11]cytochalasa-6, 13-dien-1, 17, 18, 21-tetrone (32), aspochalasin B = 17-hydroxy-10-isopropyl-14-methyl-[11]cytochalasa-6, 13, 19-trien-1, 18, 21-trione (11), and aspochalasin C = 17, 18-dihydroxy-10-isopropyl-14-methyl[11]cytochalasa-6, 13, 19-trien-1, 21-dione (29). Aspochalasin D (1) is a diastereomer of aspochalasin C (different configuration at C (17) or C (18)).
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  • 20
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metabolites of Microorganisms. Synthesis of 3-Isobutyl-4,5-dimethylisoindolin-1-one, a Degradation Product of Aspochalasin D3-Isobutyl-4,5-dimethylisoindolin-1-one (1) and 3-isobutyl-6, 7-dimethyl-isoindolin-1-one (6) were synthesized in a non-regioselective way. The structures could be assigned unequivocally by spectroscopic means. Compound 1 was identical with a degradation product of Aspochalasin D.
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  • 21
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    Helvetica Chimica Acta 62 (1979), S. 1531-1542 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexation in anhydrous methanol of Cu (II) and Zn (II) with diaza-polyoxamacrocyclic ligandsProtonation of five diaza-polyoxamacrocyclic ligands, (L = [2.1], [2.2], [2.1.1.], [2.2.1], [2.2.2]), and their complexing properties towards Cu2+ and Zn2+ cations have been studied in anhydrous methanolic solutions.Potentiometric measurements have been carried out at 25°, using 5 · 10-2MEt4N+ClO4- as support-electrolyte, in order to determine the nature of the species formed upon complexation and their stability constants. The results were confirmed by spectrophotometry, for the cupric complexes of [2.1] and [2.2.2], and the electronic spectra of the different complexes were calculated.Comparison between complexation in aqueous and methanolic solutions have been made: as in water, ML2+ species and sometimes protonated MHL3+ species, with higher stability constants, are present in methanol; but the main difference is the formation of dinuclear complexes M2L4+, between Cu2+ and all ligands except [2.1]. In these complexes the Cu2+ cations cannot be both ‘encaged’ in the ligand cavity because of its small size. The different possible structures are discussed in terms of the stability constants values. The protonation constants values and the existence of the binuclear complexes may indicate a possible conformational change in the complexing ligand on changing the solvent from water to methanol.
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  • 22
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    Helvetica Chimica Acta 62 (1979), S. 1549-1558 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: rac-1,2,10-Trimethoxy-aporphine (14) and rac-2-ethoxy-10,11-dimethoxyaporphine (27) have been synthesized from the 3-phenylphenethylamines 9 and 22 by a new route. The 8-phenyl-3,4-dihydroisoquinolines 11 and 24, the oxo-aporphines 12 and 25 and the rac-nor-aporphines 13 and 26 were obtained as intermediates.
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  • 23
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (6aR)-1,2-(Methylenedioxy)aporphine-10, 11-diol (8) and (6aR)-aporphine-1, 1, 10, 11-tetrol (16) have been prepared from natural (S)-bulbocapnine (4). For both compounds, the partial synthesis included racemic intermediates which have been resolved into their enantiomers. Both compounds 8 and 16 showed dopaminergic activity in rats, although to a lower extent than (R)-apomorphine (1) itself.
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  • 24
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    Helvetica Chimica Acta 62 (1979), S. 1559-1565 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The self-ordered supramolecular structures formed by 5′-guanosine monophosphate (disodium salt) in aqueous solution at pH 7.8 show pronounced interaction with ammonium ions. Rather than competing with potassium ions for the central cavity in hydrogen-bonded guanine tetramers, ammonium ions bring about - in synergism with potassium ions - further aggregation. Glycine appears to destroy the aggregates, by competing with potassium ions for the core positions within the tetramers. Conversely, alanine does not interact significantly with the system. These conclusions follow from analysis, at various concentrations, of the microdynamics and of the mole fractions of sodium ions bound to self-assembled 5′-GMP--, obtained from relaxation rate measurements for the 23Na nucleus, as the 5′-GMP-- counter-ion.
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  • 25
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    Helvetica Chimica Acta 62 (1979), S. 1586-1602 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthetic application of epoxynitrones. II. Syntheses of steroidal α-methylidene-γ-lactonesThis communication describes the application of the epoxynitrone/CF3SO3SiR3 → 1,2-oxazine annelation-reaction [1] to the syntheses of steroidal α-methylidene-γ-lactones from olefines, e.g. 12 → 14a/b → 16a/b → 18a/b → 20 → 22 (Scheme 2).
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  • 26
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Evidence is presented which demonstrates that 13C-NMR. spectroscopy can be used with confidence in evaluating the configuration of R1R2CHOH centers at C(6) and C(8) of iridoid glucosides.
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  • 27
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: XPS. and 1H-NMR. spectra of 1,3-diaryltriazenes complexes of Hg(II)The core binding energies C 1s, N 1s, Hg 4f7/2, Hg 4f5/2 in 7 symmetrical p-substituted 1,3-diphenyltriazenes complexes of Hg(II) have been measured by XPS. Within the limits of experimental error (± 0.2 eV) only one N 1s signal could be detected. This indicates the equivalence of the 3 N-atoms. Invariance of C 1s, N 1s, Hg 4f7/2, Hg 4d5/2 signals with the para substituents on the phenyl ring is explained on the basis of ionic character in the Hg, N bond. These results are corroborated by the 1H-NMR. spectra.
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  • 28
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and reactivity of 3-aryl-1-(3,4-dimethyl-5-isoxazolyl)-triazenes and 4-arylazo-3,4-dimethylisoxazol-5-onesAccording to the experimental conditions and the nature of the substituents on the aromatic ring, aryldiazonium salts react with 5-amino-3,4-dimethylisoxazole (3) leading to either 3-aryl-1 (3,4-dimethyl-5-isoxazolyl)-triazenes (1A) or 4-arylazo-3,4-dimethylisoxazol-5-ones (4). Analyses of the products resulting from thermal decomposition of these triazenes in aromatic substrates and in DMSO and their behaviour in acidic medium show that it is essentially the arylazo form 1B which is reactive.
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  • 29
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    Helvetica Chimica Acta 62 (1979), S. 2282-2284 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The neurotoxin α-kainic acid (7) was synthesized from 1 via the thermal key step 5 → 6 in 41% overall yield.
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  • 30
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    Helvetica Chimica Acta 62 (1979), S. 2276-2281 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereospecific synthesis of 6β,7β-methylene-20-spirox-4-ene-3,21-dioneA stereospecific synthesis of the highly active 6β,7β-methylene-20-spirolactone 4 (Prorenone) is described.
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  • 31
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    Helvetica Chimica Acta 62 (1979), S. 2285-2302 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral 2,2′-polyoxaalkano-9,9′-spirobifluorenesFrom 2,2′-diacetyl-9,9′-spirobifluorene (2), twelve chiral polyethers have been prepared as potential ion- and enantiomer-selective ionophores. The absolute configuration of the polyethers 15-17, 19-22, and 25 has been determined by chemical correlation with vespirenes [11] [29], by circular dichroism, and by X-ray analysis. The circular dichroism of 15-17, 19 and 21 depends on the size of the macrocycle and indicates that the fluorene chromophores of 19 and 21 with 13- and 16-membered rings respectively deviate considerably from orthogonality.
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  • 32
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    Helvetica Chimica Acta 62 (1979), S. 2325-2328 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Favorskii-rearrangement in the presence of 3,4-dimethoxyfuran: preparation of 3,4-dimethoxy 11endo-oxo-tricyclo [4.3.1.12,5]undec-3-en-10-one and any derivativesOn treatment with sodiumhydride of 2-chloro-cyclohexanone in the presence of 3,4-dimethoxyfuran, a possible intermediate of the Favorskii-rearrangement has been trapped as 3,4-dimethoxy-11endo-oxa-tricyclo [4.3.1.12,5]undec-3-en-10-one (3). This new compound contains a highly nucleophilic double bond. It can be cleaved in high yield by ozonolysis to 2exo, 4exo-bis (methoxycarbonyl)-3-oxabicyclo [3.3.1]nonan-9-one (4). Addition of chlorine to 3 occurs in stereoselective exo-cis-manner to the crystalline 3exo, 4exo-dichloro-3endo,4endo-dimethoxy 11endo-oxa-tricyclo [4.3.1.12,5]undecan-10-one (5). Silver ion assisted hydrolysis of 5, followed by thermal treatment of the intermediate hydrates, leads to the red 11endo-oxa-tricyclo [4.3.1.12,5]undecan-3,4, 10-trione (6), and methanolysis to 3,3,4,4-tetramethoxy-11endo-oxa-tricyclo [4.3.1.12,5]undecan-10-one (8). By photolytic decarbonylation, 8 is converted into 3,3,4,4-tetramethoxy-10-oxa-tricyclo-[4.3.12,5.0]decan (9).
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  • 33
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Activated quinones: O- versus C-addition of phenols. New regiospecific syntheses of xanthones, thioxanthones and N-methyl-9-acridonesThe acid catalyzed reaction of phenols with activated quinones, e.g. 2-methoxycarbonyl-1, 4-benzoquinone or 2-acetyl-1, 4-benzoquinone, leads to substituted biphenylderivatives (C, C-addition) as has been previously described [1]. O, C-Addition of phenols has now been achieved by using 2-methoxypyridin or 4-dimethyl-aminopyridin [4] as basic catalysts. The resulting substituted diphenylethers can serve as convenient starting materials for regiospecific syntheses of substituted xanthones, especially for 1, 4-dimethoxyxanthones.Arylthiols and N-methyl-N-arylamines also react readily with activated quinones to give substituted di-aryl-thioethers and N-methyl-N, N-diarylamines respectively; both types of compounds are convenient materials for regiospecific syntheses of substituted thioxanthones and N-methyl-9-acridones.
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  • 34
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    Helvetica Chimica Acta 62 (1979), S. 2361-2373 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cob(I)alamin as Catalyst. 5. Communication [1]. Enantioselective Reduction of α,β-Unsaturated Carbonyl DerivativesThe cob(I)alamin-catalyzed reduction of an α,β-unsaturated ethyl ester in aqueous acetic acid produced the (S)-configurated saturated derivative 2 with an enantiomeric excess of 21%. The starting material 1 is not reduced at pH = 7.0 in the presence of catalytic amounts of cob(I)alamin (see Scheme 2). It is shown that the attack of cob(I)alamin and not of cob(II)alamin, also present in Zn/CH3COOH/H2O, accounts for the enantioselective reduction observed. All the (Z)-configurated starting materials 1, 3, 5, 7, 9 and 11 have been transformed to the corresponding (S)-configurated saturated derivatives 2, 4, 6, 8, 10 and 12, respectively. The highest enantiomeric excess revealed to be present in the saturated product 12 (32,7%, S) derived from the (Z)-configurated methyl ketone 11 (see Scheme 3 and Table 1). The reduction of the (E)-configurated starting materials led mainly to racemic products. A saturated product having the (R)-configuration with a rather weak enantiomeric excess (5.9%) has been obtained starting from the (E)-configurated methyl ketone 23 (see Scheme 5 and Table 2). The allylic alcohols 16 and 24 have been reduced to the saturated racemic derivative 17.
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  • 35
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Total Synthesis of Natural α-TocopherolTwo independent syntheses of (S)-6-hydroxy-2,5,7,8-tetramethylchroman-2-yl-methanol (8b), (Scheme 6 resp. 9) as optically active chroman moiety for the preparation of natural vitamin E via (S)-6-acetoxy-2,5,7,8-tetramethylchroman-2-carboaldehyde (2a) (Scheme 1) and a corresponding side chain are described. Both reaction sequences use trimethyl-hydroquinone as starting material; one approach employs an optically active C4 unit (10a) (Schemes 5 and 6) to introduce the required configuration at C(2), the other uses an optically active C5-synthon (11a) (Schemes 8 and 9) to build the optically active chroman unit. The correct configuration and optical purity of the chroman synthesized is established by correlation with optically pure material of known configuration from which natural vitamin E had already been derived [2].
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  • 36
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Azimines. IITeil I, siehe [1]. . Preparation and Thermal Fragmentation of cis- and trans-2,3-Diphenyl-1-phthalimido-2,3-di[15N]-azimine Teilweise vorgetragen in der Versammlung der Schweizerischen Chemischen Gesellschaft am 8./9. Oktober 1976 in Genf und als Autoreferat veröffentlicht [2].cis- and trans-2,3-Diphenyl-1-phthalimido-2,3-di[15N]-azimine (11 and 12) wer synthesized from cis-di[15N]-azobenzene (10) and phthalimido-nitrene (2), the latter generated by lead tetraacetate oxidation of N-aminophthalimide (1). Useful information was obtained from the comparison of several data of 11 and 12 with those of the unmarked diphenyl-azimines 5 and 6 (R = C6H5).The 15N- and 13C-NMR. spectra of 11 and 12 were interpreted to furnish additional evidence for the azimine structure and for the indicated configurations. The IR. spectra permitted identification of two bands in the 1200 to 1450 cm-1 region, probably characteristic for the functionality of diaryl-phthalimido-azimines. Comparison of the mass spectrum of 11/12 with that of the unmarked analogues 5/6 (R = C6H5) permitted the interpretation of the fragmentation path of 1-phthalimidoazimines. The major path may be the purely thermal decomposition to 13 and 7 (R = C6H5), respectively. Two other competing fragmentation paths are discussed.Prolonged thermolysis of 11 at 61° in solution gave 83% of N,N′-diphenyl-N N′-phthaloyl-di[15N]-hydrazine (13) of 98% isotope purity, which means that the imide nitrogen atom and N(1) of the azimine function are removed in this reaction. A mechanism passing through an intermediate cyclic tetrazene 16 is considered.Benzocyclobutenedione (14) added to trans-azobenzene (4, R = C6H5) under the influence of a high pressure lamp in a quarz apparatus to give N,N′-diphenyl-N,N′-phthaloyl-hydrazine (7, R = C6H5). This reaction was found not to take place in the dark, even after prolonged heating in trichloromethane.
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  • 37
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Azimines. I. Synthesis and Stereoisomerism of 2, 3-Diaryl- and 2, 3-Dialkyl-1-phthalimido-aziminesTeilweise vorgetragen in der Versammlung der Schweizerischen Chemischen Gesellschaft in Lausanne am 7./8. Mai 1971 und als Autoreferat veröffentlicht [1].Special examples of a new class of compounds, the open-chain azimines (1), have been prepared and their properties examined.Addition of phthalimido-nitrene (4), generated by lead tetraacetate oxidation of N-aminophthalimide (3), to cis- and trans-azobenzene (6 and 5), -azo-p-toluene (8 and 7), and to trans-azomethane (9), -azoethane (10) and -azo-α-phenylethane (11) afforded the separable cis- and trans-isomers of 2, 3-diphenyl- (12 and 13), 2, 3-di-p-toyl- (14 and 15), 2, 3-dimethyl- (16 and 17), 2, 3-diethyl- (18 and 19) and 2, 3-di-(α-phenylethyl)-1-phthalimido-azimines (20 and 21) in different ratios (see Scheme 1).The constitution of the nitrene azo compound adducts as azimines was derived from their properties, especially from the conjugation effect (visible in the UV. spectra) of the aryl-substituted compounds and from the non-equivalence (shown by the 1H-NMR. spectra) of the substituents on the two nitrogen atoms derived from the azo compounds. This evidence excluded the triaziridine 22 and an alternative azimine constitution 23 for the adducts.Of the two stereoisomers obtained for each of the azimines, the aryl-substituted examples 12/13 and 14/15 were readily interconverted by warming in solution, the cis-isomers 12 and 14 exceeding the trans-isomers 13 and 15 in the equilibrium. The dialkyl-azimines appear to be configurationally more stable, since interconversion of the dimethyl-azimines 16 and 17 was not possible under the same conditions, and also not before another thermal reaction took place (see below).The identification of the N(2)-N(3) bond as the stereogenic center, i.e. that the stereoisomerism of the azimines is due to the difference in relative position at N(2) and N(3) of the substituents derived from the azo compounds, as well as a configurational assignment was possible in the aryl-substituted examples on the basis of the UV. spectroscopic comparison of the isomeric azimines with the corresponding stereoisomeric azoxy compounds: The cis-azimines 12 and 14 showed absorptions similar to those of cis-azoxybenzene and cis-azoxy-p-toluene, and the trans-azimines 13 and 15 showed absorptions similar to those of the respective trans-azoxy compounds. With respect to the configuration of the alkyl-substituted azimines, it was observed that the isomers 17 and 19, which from their formation and chromatographic behaviour are likely to be the trans-isomers, show a visible coupling (∽ 1 Hz) between the two H (α)'s in the 1H-NMR. spectrum, whereas the dimethyl isomer 16 (cis) does not exhibit such a coupling.Thermal treatment of four azimines, namely 12, 14, 16 and 17, in solution for a longer time afforded the corresponding N, N′-disubstituted N, N′-phthaloyl-hydrazines 27, 28 and 29. The order of velocity of this fragmentation with nitrogen extrusion was 12/13 ≍ 14/15 〉 16(cis) 〉 17(trans).
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  • 38
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    Helvetica Chimica Acta 60 (1977), S. 874-881 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 6-chloro-2-cyclohexenones 3, 6 and 11, and the 5-chloro-2-cyclopentenone 15 were newly synthesized. The results obtained with compounds 3 and 15 in photocycloadditions to olefins show that the oxetane vs. cyclobutane product ratio is reduced by the substitution of florine by chlorine in the α′ -position of the enone. No oxetanes are formed in the intramolecular photocycloaddition of 6. Compound 11 does not photoadd to olefins. The newly synthesized 2-chloro-3-cyclohexenones 8 and 9 are also photostable towards light of λ=366 nm, but π-π*-excitation (λ=254 nm) in pentane leads to the formation of 4,4-dimethylcyclohexanone (29).
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  • 39
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    Helvetica Chimica Acta 60 (1977), S. 867-873 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polynuclear Cobalt Complexes. II. Preparation and Structure of [(tren) (NH3)Co(O2)Co(NH3) (tren)](SCN)4 · 2H2OThe title compound is obtained on oxygenation of [Co(tren)(H2O)2]2+ in 6M aqueous ammonia or by ligand exchange starting from [(NH3)5Co(O2)Co(NH3)5]-(NO3)4. An X-ray structure determination was made. The substance forms monoclinic crystals, space group P21/c, lattice constants a=10,135, b=8,473, c=19,484 Å, β=108,58°, with two formula units in the cell. The final R is 0,066. The binuclear cation has a center of symmetry, so the Co—O—O—Co unit is planar; the Co—O—O angle is 111,5°. The tertiary nitrogen atoms of both chelate groups are cis to the O2 bridge, as found in doubly bridged [(tren)Co(O2,OH)Co(tren)](ClO4)3 · 3H2O.On acidification in solution, the singly bridged cation [(tren) (NH3)CoO2Co(NH3)(tren)]4+ (a) loses the bound O2 completely. But unlike the doubly bridged cation b, the rate of dissociation of a is independent of pH (Fig. 5). At higher pH (8-10) bridging a→b (Fig. 2) occurs. Both reactions must have the same rate determining step, the first order rate constants being of the order of 2 · 10-3 s-1 (25°, 0,35M KCl).
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    Helvetica Chimica Acta 60 (1977), S. 881-887 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Following the intraperitoneal administration of high doses of 14C- and 3H- labelled retinoic acid (1) to rats, three major metabolites and the intact compound were isolated from the feces in microgram amounts by use of column, thin-layer and high-pressure liquid chromatography. Their structures were elucidated by mass spectrometry and Fourier Transform 1H-NMR. spectroscopy as 2 (all-trans-4-oxoretinoic acid), 3 (7-trans-9-cis-11-trans-13-trans-5′-hydroxy-retinoic acid).Hydroxylation of the 5-methyl group of the cyclohexene ring, oxidation of the cyclohexene ring in position 4 and cis-trans isomerisation of the nonatetraenoic acid side chain were the reactions, which produced these products from retinoic acid. The metabolites 2 and 4 each accounted for about 4% of the radioactivity administered. The metabolite 3 and the parent compound accounted for about 16% and 17% of the dose, respectively.
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  • 41
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    Helvetica Chimica Acta 60 (1977), S. 892-895 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel types of acetylenic sugarsThe coupling, following Cadiot's procedure, of a 6-bromo-5,6-dideoxy-1,2-O-isopropylidène-3-O-methyl-α-D-xylo-hex-5-yno-1, 4-furanose (1) with phenylacetylene, 2-propyn-1-ol or terminal acetylenic sugars gave with excellent yields the expected diynes (an enediyne when the terminal acetylene was the 3,5, 6-trideoxy-1,2-O-isopropylidene-α-D-glycero-hex-3-en-5-yno-1,4-furanose 7). The chloro analogue 8 of 1 on treatment with lithium thiophenate gave the corresponding phenylthio-acetylenic sugar 9. An acetylene was also formed by reacting the gem-difluoro-olefinic sugar 10 with butyllithium whereas the same olefinic sugar and its 3-O-benzyl analogue 11 gave only a gem-fluoro-arylthio-olefinic sugar (13-15) as a mixture of the Z and E isomers (Z/E 〉 4) when treated with the conjugate base of an arylmercaptan.
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  • 42
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some more examples of stable free radicals of carbohydrate heterocyclic derivatives2-Glycosyl-4,4,5,5-tetramethylimidazoline- 3-oxide-1-oxyls and 2-glycosyl-4,4,5,5-tetramethylimidazoline 1-oxyls have been prepared in nine carbohydrate series, which proves the generality of the method. The hyperfine coupling constant between the free electron and the α-proton of the glycosyl group is never very large (0-2.3 G) but a correlation between its value and the structure of the aglycone has been noted. Free radicals of that type, stable in aqueous solutions, are potentially interesting for biological studies.
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  • 43
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Interpretation of the chemical and spectral (IR., UV., 1H- and 13C-NMR.) properties of the antitumor antibiotic hedamycin (C41H50N2O11) suggests that the molecule contains a methyl substituted 1-hydroxyanthraquinone nucleus, an α, β-unsaturated ketone, two sugar-like tetrahydropyran rings (4 and 8) and an aliphatic chain 2, presumably with an epoxy group (see the Scheme).
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  • 44
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    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 60 (1977), S. 907-921 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Halogenated pyridines and 1,8-naphthyridines. VI.The principle of the synthesis of 3-halomethyl-2,6-dichloro-pyridines has been extended to compounds with side chains of more than one carbon atom in the 3-position. Feasible synthetic routes are outlined starting from cheap, commercially available α-methylideneglutaronitrile and trichloroalkyl functional compounds which yield the intermediate 1,3,5-trisubstituted alkanes. These are cyclized by aqueous mineral acid or by hydrogen bromide in an organic solvent to 2-substituted glutarimids or hexahydronaphthyridinones, depending on the mode of cyclization. The final aromatization provides a simple route to pyridines or 1, 8-naphthyridines.
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  • 45
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Proton catalysed [1,2]-H-shift in the rearrangement of 6,7-diphenyl-5,6-dihydropterine (I) to 6,7-diphenyl-7,8-dihydropterine (III)The arrangement from I to the thermodynamically more stable III undergoes through a acid catalysed [1,2]-H-shift (intramolecular 6,7-hydride rearrangement) (see Scheme 1).
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  • 46
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structure of the antibiotic hedamycin (1) has been solved by direct method and refined by least squares techniques to R = 0.091 for 2289 of 2643 independent reflexions. Crystals of C41H50N2O11 are orthorhombic, space group P212121 with lattice parameters a = 24.239 (12), b = 21.440 (10), c = 7.369 (4) Å, Z = 4. The structural features of hedamycin derived earlier by chemical and spectroscopical means are confirmed. Optical rotation and circular dichroism indicate that hedamycin (1) has the absolute configuration of the related antibiotic kidamycin (3). The conformation of ring F is a chair form with the aryl substituent almost axial. The bioxirane part of the antibiotic is in a synclinal conformation.
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  • 47
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Chirality of (5R, 6R)-5,6-Dihydro-β, ψ-carotene-5,6-diol, (5R, 6R, 6′R)-5,6-Dihydro-β, ε-carotene-5,6-diol, (5S, 6R)-5,6-Epoxy-5,6-dihydro-β,ψ-carotene and (5S, 6R, 6′R)-5,6-Epoxy-5,6-dihydro-β,ε-caroteneWittig-condensation of optically active azafrinal (1) with the phosphoranes 3 and 6 derived from all-(E)-ψ-ionol (2) and (+)-(R)-α-ionol (5) leads to the crystalline and optically active carotenoid diols 4 and 7, respectively. The latter behave much more like carotene hydrocarbons despite the presence of two hydroxylfunctions. Conversion to the optically active epoxides 8 and 9, respectively, is smoothly achieved by reaction with the sulfurane reagent of Martin [3]. These syntheses establish the absolute configurations of the title compounds since that of azafrin is known [2].
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  • 48
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    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2517-2524 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ESR. and ENDOR. studies are reported for the radical anions of 1,2-diphenylcyclopentene (3) and its di(pe+deuteriophenyl)-derivative (3-D10). Comparison of the coupling constants of the phenyl protons in 3\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}. with the analogous values for the radical anions of 1,2-diphenyl substituted cyclopropene (1) and cyclobutene (2) reveals regular changes in the sequence 1\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, 2\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, 3\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}, which are caused by an increasing twist of the phenyl groups about the C(1), C(1′)- and C(2), C(1″)-bonds linking them to the ethylene fragment. Such a twist is shown to be also responsible for the large difference in the coupling constants of the methylene β-protons in 3\documentclass{article}\pagestyle{empty}\begin{document}$ ^{\ominus \atop \dot{}} $\end{document}. (0.659 and 0.293 mT). It is suggested that - in order to minimize the losses caused by this twist in the π-delocalization energy - the 2 pz-axes at the centres 1 and 2 deviate from a perpendicular orientation to the mean plane of the cyclopentene ring. A deviation by 19° from such an orientation is required to account for the observed β-proton coupling constants in terms of their conventional cos2-dependence on the dihedral angles θ.
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  • 49
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sorelline and Hobartine, Two New Indole Alkaloids from Aristotelia peduncularis (LABILL.) HOOK. F.From Aristotelia peduncularis (LABILL.) HOOK. F. two new indole alkaloids, sorelline (1) and hobartine (2), have been isolated. Their structures were elucidated on the basis of spectroscopic data (the formulae represent their relative configurations). The alkaloids 1 and 2 have closely related structures with a monosubstituted indole moiety and an unrearranged monoterpene unit in the aliphatic part.
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  • 50
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and configuration of some spiro [indan-2,2′-pyrrolidine] and spiro [pyrrolidine-2,2′-tetraline] derivativesCatalytic hydrogenation of the nitrosoindan and nitrosotetralin derivatives 8 yielded trans-1-hydroxy-spiro [indan-2,2′-pyrrolidin]-5′-one (9) and trans-1′-hydroxy-spiro [pyrrolidine-2,2′-tetralin]-5-one (10) respectively, whilst the corresponding cis compounds 12 and 15 were prepared via the chlorides 11 and 14.The configurations of 10 and 13 were determined by X-Ray analysis.
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  • 51
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of valencepolaromeric ketenes of mesoionic heterocyles with 3-dimethylamino-2H-azirinesReactions of the 3-dimethylamino-2H-azirines 1a and 1b with the mesoionic oxazole 5 and the mesoionic dithiole 6 in acetonitrile at room temperature yield the 1:1 adducts 11, 12, 19 and 20, respectively (Schemes 5 and 8). These products can be formulated as adducts of the aminoazirines and the ketenes 5a and 6a, which are valence polaromeric forms of the mesoionic heterocycles 5 and 6 (Scheme 2).The structure of the adducts has been elucidated by spectral data and their comparison with the data of (Z)-11, the structure of which has been established by X-ray [19]. Oxidation of the 1:1 adducts with KMnO4 in a two-phase system yields 4-dimethylamino-3-oxazolin-2-ones (cf. Scheme 6) by clevage of the exocyclic C,C-double bond. A mechanism for the formation of the adducts is given in Scheme 9: Nucleophilic attack of 1 on the ketene leads to a primary adduct of type a, which undergoes clevage of the former N(1), C(2)-azirine bond to give adducts of type 11 or 19. The N(1), C(2)-ring opening of 1a in the reaction with ketenes contrasts with the N(1), C(3)-opening of 1a in the addition with, for instance, isothiocyanates. These different ring openings are explained by the difference in nucleophilicity of the heteroatoms X and Y in a′ (Scheme 10).
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  • 52
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spironaphthalen-2-ones 2, 10 and 18 were prepared by N-bromosuccinimide (NBS) oxidation of 1, 9 and 17 respectively, whereas spironaphthalen-1-ones 24 and 25 were obtained by treating 23 with NBS.The stereoisomeric reduction products 29, 30 and 32 obtained from 24 and 25, gave the pentacyclic compound 33 on treatment with polyphosphoric acid.
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  • 53
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyclopeptide antibiotics from Aspergillus species. Structure of echinocandins C and DThe echinocandins B, C and D are antifungal antibiotics produced by a strain of Aspergillus rugulosus. All three metabolites are closely related representing cyclic oligopeptides composed of six amino acids and a linolic acid residue in an amide linkage. The complete structure of echinocandin B (1) has recently been established by X-ray analysis. Structural assignments to the new minor metabolites C and D have now been made by hydrolytic and oxidative cleavage reactions, formation of N-acyl-α-aminoethers as well as by chemical correlations and extensive NMR. examinations. Echinocandin C (2), C52H81N7O15, contains 3-hydroxyhomotyrosine in the place of 3, 4-dihydroxyhomotyrosine present in 1. Echinocandin D (3), C52H81N7O13, differs in two amino acids: 3, 4-dihyroxyhomotyrosine and 4, 5-dihydroxyornithine, unusual units of 1 being replaced by 3-hydroxyhomotyrosine and ornithine.
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  • 54
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Compounds 2, 5 and 9 represent the first examples of isolable dichlorooxiranes formed by formal addition of dichloro carbene to a carbonyl group under phase transfer conditions. On heating, 2, 5 and 9 rearrange into α-chloroacid chlorides 3, 6 and 10, respectively.
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  • 55
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aminoisoxazoles C-nucleosidesUpon treatment with bromocyanomethylenetriphenylphosphorane, a series of aldehydosugar derivatives gave in good to excellent yields the corresponding terminal gem-bromocyanoenoses 3, 7-10 and 16. Reacted with hydroxylamine, these unsaturated sugars led to the expected [3] 5-amino-3-glycosylisoxazoles 4, 11, 12 and 17, whereas using hydroxyurea as a binucleophile they gave the corresponding 3-amino-5-glycosylisoxazoles 13 and 14 as previously described in other series [3]. The major interest of these compounds rests in their being close analogs (or enantiomers of analogs) of important biological compounds as f.e. AICAR.
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  • 56
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Irradiation of 4-Allylated 2,6-Dimethylanilines in Methanol4-Allyl-, 4-(1′-methylallyl)-, 4-(2′-butenyl)-, and 4-(1′,1′-dimethylallyl)-2,6-dimethylaniline (14-17; cf. Scheme 3) were obtained by the acid catalysed, thermal rearrangement of the corresponding N-allylated anilines in good yields. Aniline 14, when irradiated with a high pressure mercury lamp through quartz in methanol, yielded as main product 4-(2′-methoxypropyl)-2,6-dimethylaniline (22; cf. Scheme 4) and, in addition, 2,6-dimethyl-4-propylaniline (18) and 4-cyclopropyl-2,6-dimethylaniline (23). The analogous products, namely erythro- and threo-4-(2′-methoxy-1′-methylpropyl)-2,6-dimethylaniline (erythro- and threo-24), 2,6-dimethyl-4-(1′-methylpropyl)aniline (19), trans- and cis-2,6-dimethyl-4-(2′-methylcyclopropyl)aniline (trans- and cis-25), as well as small amounts of 4-ethyl-2,6-dimethylaniline (26), were formed by irradiation of 15 in methanol (cf. Scheme 5). When this photoreaction was carried out in O-deuteriomethanol, erythro- and threo-24 showed an up-take of one deuterium atom in the side chain. The mass spectra of erythro- and threo-24 revealed that in 50% of the molecules the deuterium was located at the methyl group at C(1′) and in the other 50% at the methyl group at C(2′) (cf. Scheme 6). This is a good indication that the methanol addition products arise from methanolysis of intermediate spiro[2.5]octa-4,7-dien-6-imines (cf. Scheme 7). This assumption is further supported by the photoreaction of 17 in methanol (cf. Scheme 8) which led to the formation of 4-(2′-methoxy-1′,2′-dimethylpropyl)-2,6-dimethylaniline (28) as main product. The occurrence of a rearranged side chain in 28 can again be explained by the intervention of a spirodienimine 31 (cf. Scheme 9). In comparison with 14, 15 and 17, the 2′-butenylaniline 16 reacted only sluggishly on irradiation in methanol (cf. Scheme 10). It is suggested that all photoproducts - except for the cyclopropyl derivatives which are formed presumably via a triplet di-π-methane rearrangement - arise from an intramolecular singlet electron-donor-acceptor complex between the aniline and ethylene chromophor of the side chain. Protonation of this complex at C(3′) or C(2′) will lead to diradicals (e.g. 33 and 34, respectively, in Scheme 11). The diradicals of type 33 undergo ring closure to the corresponding spirodienimine intermediates (e.g. 31) whereas the diradicals of type 34 take up two hydrogen atoms to yield the photo-hydrogenated compounds (e.g. 21) or undergo to a minor extent fragmentation to side chain degraded products (e.g. 30; see also footnote 7).-Irradiation of 4-ally-2,6-dimethylaniline (14) in benzene or cyclohexane yielded the corresponding azo compound 38 (cf. Scheme 12), whereas its N,N-dimethyl derivative 41 was transformed into the cyclopropyl derivative 42. The allyl moiety in 14 is not necessary for the formation of azo compounds since 2,4,6-trimethylaniline (39) exhibited the same type of photoreaction in benzene solution.
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  • 57
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    Helvetica Chimica Acta 62 (1979), S. 2661-2672 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conjugated cyclic divinyl ketones containing fifteen and seventeen membered rings have been prepared in a single step by condensation of 1,3-bis (dimethylphosphono)-2-propanone (10) with the dialdehydes 14, 17, 20, and 42 in the presence of hydrogencarbonate in aqueous t-butyl alcohol at reflux without using high dilution techniques. The more highly unsaturated aldehydes give better yields and ketones 34 and 36, or mixtures of the two, were transformed to muscone (1) and Exaltone® by standard procedures. Civetone (2) was prepared by hydrogenation of 43 in pyridine solution. Dienone 29 appears to be the first α, β-unsaturated ketone in which one of the β-vinyl proton resonates at higher field than the corresponding α-proton.
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  • 58
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mechanism of the Photochemical Addition of Methanol to 2-Allylated AnilinesWe studied in methanol the photoreaction of the 2-allylated anilines, given in Scheme 3 (cf. also [1]). Irradiation of N-methyl-2-(1′-methylallyl)aniline (15) with a high pressure mercury lamp yielded trans- and cis-1,2,3-trimethylindoline (trans- and (cis-34) as well as erythro- and threo-2-(2′-methoxy-1′-methylpropyl)-N-methylaniline (erythro- and threo-35; Scheme 7). When the corresponding aniline d3-15, specifically deuterated in the 1′-methyl group, was irradiated in methanol, a mixture of trans- and cis-d3-34, and of erythro- and threo-d3-35 was obtained. Successive dehydrogenation of the mixture of cis/trans-d3-34 by Pd/C in boiling xylene and by MnO2 in boiling benzene lead to the corresponding indole d3-36 (cf. Scheme 9), the 1H- and 2H-NMR. spectra of which showed that both cis-d3- and trans-d3-34 had bound the deuterium labeled methyl group exclusively at C(3). The 1H- and 2H-NMR. analyses of the separated methanol addition products revealed that erythro-d3-35 contained the deuterium label to at least 95% in the methyl group at C(1′), and threo-d3-35 to 50% in CH3—C(1′) and to 50% in CH3—C(2′) (cf. Scheme 9). To confirm these results 2-(1′-ethylallyl)aniline (16) was irradiated in methanol, whereby a complex mixture of at least 6 products was obtained (cf. Scheme 11). Two products were identified as trans- and cis-3-ethyl-2-methylindoline (trans- and cis-37). The four other products represented erythro- and threo-2-(1′-ethyl-2′-methoxypropyl)aniline (erythro- and threo-39) as major components, and erythro- and threo-2-(2′-methoxy-1′-methylbutyl)aniline (erythro- and threo-40). These results clearly demonstrate that the methanol addition products must arise from spirodienimine intermediates of the type of trans-9 and cis-11 (R1 = CD3 or C2H5, R2 = CH3 or H; Scheme 2) which are opened solvolytically with inversion of configuration by methanol. Thus, cis-11 (R1 = CD3, R2 = CH3) must lead to a 1:1 mixture of threo-13 and threo-14 (i.e.) a 1:1 distribution of the deuterium labelled methyl group between C(1′) and C(2′) in threo-35) The formation of erythro-d3-35 with at least 95% of the deuterium label in the methyl group at C(1′) indicates that trans-9 (R1 = CD3, R2 = CH3) reacts with methanol regioselectively (〉 95%) at the C(2), C(3) bond. Similarly, the formation of the methanol addition products in the photoreaction of 16 (Scheme 11) can be explained. Since the indolines, formed in both photoreactions, show no alteration in the position of the subsituent at C(1′) with respect to the starting material we suppose that the diradical 7 (R1 = CD3 or C2H5, R2 = CH3 or H; Scheme 2) is a common intermediate which undergoes competetive 1.3 and 1.5 ring closure yielding the spirodienimines and the indolines.This conception is supported by irradiation experiments with N, 3,5-trimethyl-2-(1′-methylally)aniline (17) and 2-(2′-cyclohexenyl)-N-methylaniline (18) in methanol. In the former case the formation of spirodienimines is hindered by the methyl group at C(3) for steric reasons, thus leading to a ratio of the indoline to the methoxy compounds of about 6.3 as compared with ca. 1.0 for 15 (cf. Scheme 12). On the other hand, no methoxy compounds could be detected in the reaction mixture of 18 (cf. Scheme 13) which indicates that in this case the 1.3 ring closure cannot compete with the 1.5 cyclization in the corresponding cyclic diradical of the type 7 (R1-C(1′)-C(2′) is part of a six-membered ring; Scheme 2).We suppose that the diradicals of type 7 are formed by proton transfer in an intramolecular electron-donor-acceptor (EDA) complex arising from the excited single state of the aniline chromophor and the allylic side chain. This idea is supported by the fluorescence specta of 2-allylated N-methylanilines (cf. Fig.1-4) which show pronounced differences with respect to the corresponding 2-alkylated anilines. Furthermore, the anilines 18 and 20 when irradiated in methanol in the presence of an excess of trans-1,3-pentadiene undergo preferentially an intermolecular addition to the diene, thus yielding the N-(1′-methyl-2′-butenyl)anilines 52 and 51, respectively (Scheme 15), i.e. as one would expect the diene with its low lying LUMO is a better partner for an EDA complex than the double bond of the allylic side chain.
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  • 59
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    Helvetica Chimica Acta 62 (1979), S. 2673-2680 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new strategy for the synthesis of muscone (1) using the OH-assisted Prins reaction for macrocyclic ring closure has been developed. The monoacetal 4 of (Z,E)-4,8-dodecadienedial (3), easily obtainable from (Z,E,E)-1,5,9-cyclododecatriene (2), is treated with methallylmagnesium chloride, and the resulting C16-precursor 5 is subjected to acid-catalyzed cyclization in dilute (≤1%) solutions. This results in formation of the bicyclic dihydropyran derivatives 6 which directly yield muscone (1) on heating with a noble metal catalyst saturated with hydrogen. The five-step pathway proceeds with readily available starting materials in conventional steps and excellent overall yield (∼40%). This new principle of macrocyclic ring formation has also been used successfully for the preparation of 3-methylcyclotridecanone (34) and should be generally applicable for other suitable ring systems.
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  • 60
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    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 62 (1979), S. 2681-2694 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A synthesis of (6 R, 7 R)-7-acylamino-2-oxocephem-4-carboxylic acids from penicillins is reported based on the formation of the 2-oxocephem system in an intramolecular Wittig condensation. An interesting steric effect of the acylamino grouping on the course of this key step was used to advantage. Some physical and biological properties of this new type of Δ3-cephem are described.
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  • 61
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chiral aminoethers 1-4, accessible from tartaric acid, are tested as complexing ligands in organolithium reactions. The tetramine 4 turns out to cause highest inductions [see Table 2 and Equations (1)-(4)].
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  • 62
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    Helvetica Chimica Acta 63 (1980), S. 658-663 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Routes to 1H- and 2H-PyrrolesA synthesis of 1H-pyrroles is described starting with pyridine analogues of chalcones and involving the reaction of acetic anhydride with 1-pyrroline-1-oxides. Another route leads from 1-pyrrolines to 2 H-pyrroles via bromination with N-bromosuccinimide and subsequent dehydrobromination in dimethylformamide.
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  • 63
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diglycosyl Derivatives. Preliminary communicationNovel types of diglycosyl compounds, some of them bearing a resemblance to natural di- or tri-saccharides are described: a diglycosyldiyne (1), a diglycosylthiophene (2), a diglycosylaziridine (3), a diglycosyldioxolane (4), as well as six C,N-diglycosylnitrones, 9b-9f and 14. These C,N-diglycosylnitrones, on treatment with an acetylenic Grignard reagent, led to the expected acetylenic diglycosyl-hydroxylamine 11, whereas diglycosylisoxazolines (f. ex. 10) were obtained when these nitrones underwent 1,3-dipolar cycloaddition to acetylenic compounds.
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  • 64
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    Helvetica Chimica Acta 62 (1979), S. 882-893 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cob(I)alamin as Catalyst. 4. Communication. Reduction of α,β-Unsaturated NitrilesUsing catalytic amounts of cob (I)alamin and an excess of metallic zinc as source of electrons 1-naphthonitril (5) has been reduced to (1-naphthyl)methylamin (6) and in small amounts to (1-naphthyl)methanol (7) and (1,2,3,4-tetrahydro-1-naphthyl)methanol (8) (5 ½ h, CH3COOH/H2O; s. Scheme 3). Starting from cyclododecylideneacetonitrile (15) similar conditions (68 h, CH3COOH/H2O) produced the amines 16-19 as well as the nitrogen free saturated aldehyde 20, the corresponding allylic alcohol 21 and the saturated derivative 22 (s. Scheme 6). It is deduced that the first attack of cob (I)alamin on an α,β-unsaturated nitrile might occur on both the nitrile dipole as well as on the carbon atom in β-position. Cob (I)alamin in aqueous acetic acid saturates the isolated double bonds in allylic alcohols and amines. In a slow reaction the two different aromatic rings of (1-naphthyl)methanol (7) have been reduced giving the corresponding tetrahydronaphthalene derivatives 8 and 12, and in one case the production of the octahydroderivative 14 has been observed in a low yield (s. Scheme 5).
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  • 65
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    Helvetica Chimica Acta 63 (1980), S. 681-681 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 66
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compound 1 is a further example of an olefinic alcohol that undergoes ether formation under basic conditions (→ 3) although the double bond is not activated by an electron-attracting group. This unusual reactivity is due to steric compression, which is increased in the 10-methyl analogue 2. This forms the corresponding ether 7 at a much higher rate. - In a deuteriated medium, base-catalysed cyclization of 1 gives the exo-deuteriated ether 6, corresponding to trans-addition. - An X-ray structure analysis of 4, the p-nitrobenzoate of 1, is presented.
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  • 67
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The wavelength range of the CD. spectra of some cyclohexapeptides containing different sequences of glycine, L- and D-alanine is extended down to 170 nm. This allows a relatively complete recording of the (n - π*) and (π° - π*) Cotton effects. Some striking spectral changes are observed on going from one molecule to another. The relative influence of L- and D-alanyl residues is discussed: Some spectra may be qualitatively related to each other by considering the effect of an L-residue at position q in the ring to cancel partially with the effect of a D-residue at position q ± 3. Assuming these cyclopeptides to occur in a hydrogen-bonded pleated sheet structure, certain dominant changes in the spectra are interpreted as reflecting a transition of the overall backbone conformation from one which is closer to the (optically inactive) symmetry Ci to another which is closer to the (optically active) symmetry C2. An attempt is made to relate the influence of L- and D-substituents within hairpin bends of the pleated sheet structure to an amide sector rule.
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  • 68
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lincomycin analogues. I. Chain-extensions of [1,2:3,4]-di-O-isopropylidene-α-D-galacto-hexodialdo-1,5-pyranoseThe title aldehydosugar 1 treated with Wittig reagents led in good to excellent yields to the unsaturated sugar derivatives 3-7 and 10-15, 8 having been prepared by condensation of 1 with malonic acid. The configuration (Z or E) of each compound obtained has been established by 1H-NMR. These chain-extensions constitute the first synthetic step towards the preparation of lincomycin analogues.
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  • 69
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photochemistry of optical active λ, δ-epoxy-enones. Racemization and cyclization of (-)-4-methylidene-5,6-epoxy-5,6-dihydro-β-ionone and of (-)-4-oxo-5,6-epoxy-5,6-dihydro-β-iononeUV.-irradiation (λ ≥ 347 nm as well as λ = 254 nm) converts the conjugated λ, δ-epoxy-enones (-)-2 and (-)-4 by cleavage of the C,C-oxirane bond to an intermediate ketonium ylide f which cyclizes giving the racemic starting materials. The degree of racemization depends on the length of the irradiation time.The formation of the optical active products (-)-3 and (+)-5 in these irradiations gives evidence, that the photocyclization of (-)-2 und (-)-4, respectively, is a one step reaction of a state g.
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  • 70
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photoinduced cleavage of the C,C-oxirane bond of γ, δ-epoxy-enones: UV.-irradiation of 4-methylidene-5,6-epoxy-5,6-dihydro-β-iononeOn 1n, π*-excitation (λ ≥ 347 nm, pentane) 5 gives the isomeric bicyclic ether 10 in 75% yield (s. Scheme 2). In methanol the photoconversion of 5 to 10 is strongly reduced (12%) in favour of the formation of the methanol adduct 11 (43%). On photolysis in aqueous acetonitrile 5 is converted to the bicyclic ether 10 (9%), the dihydrofurane 12 (18%) as well as to the triketones 13A and 13B (7%), and 14 (23%).On 1π, π*-excitation (λ = 254 nm) in pentane no 10 is formed, but 5 isomerizes to the tricyclic cyclopropyl compound 16 (59%), the allenic product 17 (10%), and the cyclopropene compound 18 (12%; s. Scheme 3). Photolysis in methanol furnishes 11 (63%), and 18 (4%), but no tricyclic cyclopropyl compound 16. In a secondary photoreaction (λ = 254 nm) the dihydrofurane 12 is isomerized to the bicyclic cyclopropyl compound 20.Evidence is given that the products 11 and 13 are formed by solvent addition to an intermediate ketonium ylide b (s. Scheme 12). The presence of b is further proven by the formation of 12, a product of an electrocyclization of b. On photofragmentation of b carbenoids d and e are presumably formed (s. Scheme 14). 1,2-Hydrogen shift in d yields the allene derivative 17, and cyclization of d gives the cyclopropene compound 18. On the other hand, e cyclizes to the non isolated cyclopropene compound 69 which is transformed to 16 by an intramolecular [4 + 2]-cycloaddition.The present investigation shows that the photochemistry of 5 is determined by photoinduced C,C-bond cleavage of the oxirane ring. This is in sharp contrast to the photochemistry of conjugated γ, δ-epoxy-enones without the additional double bond in ε, ζ-position, where selective photocleavage of the C(λ), O-bond is observed.
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  • 71
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    Helvetica Chimica Acta 62 (1979) 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 72
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantioselective 1,2-addition of Li-, Mg-, Zn-, and Cu-organic compounds and of Li-enolates to carbonyl derivatives in the chiral medium DDBDDB = 1,4-Dimethylamino-2,3-dimethoxybutan (= 2,3-Dimethoxy-N,N,N′,N′-tetramethyl-1,4-butandiamin).The (+)-enantiomer of the methoxyamine DDB is used as a chiral cosolvent in the title reactions. As evident from the results listed in the table, enantiotopic faces are generally differentiated with preferences ranging from 55:45 to 60:40.
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  • 73
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    Helvetica Chimica Acta 62 (1979), S. 1736-1744 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of twenty substituents R on the solvolysis rates and products of tertiary chlorides R - CH2CH2C(CH3)2Cl (7) has been studied. H, CH3, (CH3)2NCH2, ClCH2, Cl, CN and NO2 exert an inductive effect only, as the good correlation of the rates with the corresponding inductive substituent constants σIq shows. Bulkier alkyl groups, i.e. isopropyl and t-butyl, lower the rate due to a Baker-Nathan effect, while the n-electron donors CH3S, CH3O, HO and (CH3)2N and the σ-electron donors (CH3)3Sn and HOCH2 cause rate increases based on σIq constants. These accelerations are attributed to C,C-hyperconjugative and inductomeric effects which arise in the transition state for ionization. A comparison of the reactivity of the acyclic chlorides 7 and the corresponding 1-R-substituted 3-bromoadamantanes 1a shows that polar substituent effects are more strongly transmitted in the rigid bicyclic compounds 1a than in the flexible acyclic compounds 7.
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  • 74
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The intramolecular and dimensionless equilibrium constant, K′, for the equilibrium between open and aromatic-ring stacked isomers of ternary complexes formed between adenosine 5′-triphosphate, inosine 5′-triphosphate, or uridine 5′-triphosphate, Mg2+ or Zn2+, and L-tryptophanate, 2,2′-bipyridyl (bipy), or 1,10-phenanthroline (phen) have been estimated by 1H-NMR. shift measurements in D2O (I = 0.1M, NaNO3; 27°). The approximate equilibrium constants K′ are ≥ 20, ≥ 20, 1.2, 0.9, 0.7, 0.5, and 0.3 for the ternary complexes Zn (phen) (ATP)2-, Mg (phen) (ATP)2-, Zn (bipy) (ATP)2-, Zn (bipy) (ITP)2-, Zn (bipy) (UTP)2-, Zn (trp) (ATO) 3-, and Mg (trp) (ATP)3-, respectively. The percentages of the stacked isomers decrease in the order Zn (phen) (ATP)2- (≥ 95%) ≫ Zn (bipy) (ATP)2- (55%) 〉 Zn (bipy) (ITP)2- (48%) 〉 Zn (bipy) (UTP)2- (∼ 40%), which coincides with the order of stability of the binary metal-free adducts (phen) (ATP)4- 〉 (bipy) (ATP)4- ≃ (bipy) (ITP)4- 〉 (bipy) (UTP)4-; the corresponding stability constants are KABA = 28.2 ± 4.7, 8.1 ± 2.6, 8.8 ± 1.8, and ∼ 1 (M-1), respectively (D2O; I = 0.1 M, NaNO3; 27°): these series reflect the decreasing size of the aromatic-ring systems forming the stacks. The indole moiety of tryptophan resembles 2,2′-bipyridyl rather than 1,10-phenanthroline and K(trp)(ATP)(trp) = 6.2 ± 1.8 M-1 for (trp) (ATP)4-. Implications with respect to the stability of ternary complexes, and to biological systems are indicated briefly.
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  • 75
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    Helvetica Chimica Acta 62 (1979), S. 1763-1769 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structural Modifications of Vitamin D3. Synthesis and Properties of the SO2-Adducts with (5Z)- and (5E)-Vitamin D3Treatment of (5Z)- and (5E)-vitamin D3 (4) with sulfur dioxide yields each quantitatively the cyclic sulfones 1a and 1b. Thermally induced elimination of sulfur dioxide leads to either isotachysterol3 (3) alone or mixtures of isotachysterol3 (3) and isovitamin D3 (2). On the other hand the extrusion of SO2 can be brought about by means of KOH/CH3OH or on an alumina surface affording (5E)-vitamin D3 (4). On treatment with CD3UD/tBuOK/D2O 1a and 1b are transformed (5E)-6, 19, 19′-trideuteriovitamin D3 (4a).
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  • 76
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (E)-3α-Acetoxy-5, 10-seco-1(10)-cholesten-5-one (3) was synthesized by fragmentation of 3α-acetoxy-5α-cholestan-5-ol (1) using the photochemical version [3] of the lead tetraacetate reaction [4], and transformed into the corresponding 3-oxo-compound (5). Two conformations (A2α and B1α) were deduced for the 10-membered ring of 3 by analysis of the 1H- and 13C-NMR. spectra in toluene. The major conformation (A2α) corresponds to that found in the solid state by X-ray analysis. According to its NMR. spectra in toluene, the medium-sized ring of the diketone 5 exists also predominantly in two conformations, the major one being analogous to A1β (the solid-state conformation of the 3β-acetoxy isomer (9) [1]) and the minor one to A2α (see above). The stereochemistry of the acidcatalyzed and thermal cyclisations of 3 as well as of the corresponding 5-oxime is discussed in terms of conformational factors.
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  • 77
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    Helvetica Chimica Acta 62 (1979), S. 1016-1024 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structures of PdCl2[(-)-DIOP], PtCl2[(-)-DIOP] and of NiCl2-[(-)-DIOP] have been determined by X-ray analysis and refined by least-squares methods [(-)-DIOP=(-)-2,2-dimethyl-4,5-bis(diphenylphosphinomethyl)-1,3-dioxolane]. The coordination around the nickel atom is tetrahedral, the coordination around palladium and platinum is square planar. The unit cell of the palladium complex contains two non-equivalent molecules with different conformations of the seven-membered chelate ring involving the metal and the two phosphorus atoms. PtCl2[(-)-DIOP] is isostructural with the corresponding palladium complex.
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  • 78
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H-NMR. Spectroscopic Determination of Enantiomeric Purities of Allenic Esters Using Optically Active Europium Shift ReagentsThe racemic allenic methyl esters 3--7 and the racemic allenic diesters 8--10 (cf. Scheme 2) in 1,1,2-trichloro-1,2,2-trifluoroethane (TCFE) and CCl4 in the presence of optically active tris[3-(heptafluorobutyryl)-(+)-camphorato]europium(III) (Eu(hfc)3) have induced unlike 1H-NMR. shift differences (ΔΔδ) for the protons of the methoxycarbonyl groups of their enantiomers. In some allenic esters the shift reagent causes additional separation of resonance signals; thus, further substituents on the allenic framework may be differentiated in the racemic mixture. This finding provides a widely applicable method for the determination of absolute enantiomeric purities of allenic esters and their corresponding acids. Accordingly we found for optically pure (+)-(S)-2-methyl-2,3-pentadienoic acid ((+)-(S)-13; cf. Fig. 2) a calculated [α]58920 value of + 73.3 ± 1.8°. Finally, the substituent effects on ΔΔδ-values (cf. Table 1--3) are discussed.
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  • 79
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    Topics: Chemistry and Pharmacology
    Notes: Stereospecific Fragmentations in the Mass Spectra of Cyclohexanediamines and Bis(aminomethyl)cyclohexanesThe mass spectral behaviour, especially loss of NH3, of the six isomeric cyclohexanediamines 1--3 (cis and trans each, Scheme 1) as well as of the six isomeric bis(aminomethyl)cyclohexanes 4--6 (cis and trans each, Scheme 6) has been investigated. The cis- and trans-compounds of the 1,2-isomers 1 and 4 show very similar spectra, because of the ease of ring cleavage at C(1)--C(2) and the similar geometrical relations in all ring conformations. The cis- and trans-compounds of both the 1,3- and 1,4-isomers 2, 3, 5 and 6 show striking differences in their mass spectra due to stereospecific elimination of NH3 from the molecular ion.
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  • 80
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 81
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    Topics: Chemistry and Pharmacology
    Notes: The Mass Spectral Decomposition of Isomeric Diacetamido-cyclohexanes, their N-Phenethyl-Derivatives and Bis(acetamidomethyl)cyclohexanesIn the mass spectra of the six isomeric diacetamidocyclohexanes 2--4 (cis and trans each, Scheme 2) as well as of the six isomeric bis(acetamidomethyl)cyclohexanes 6--8 (cis and trans each, Scheme 5) are clear differences between the constitutional isomers, whereas cis/trans isomers show very similar spectra. The lack of stereospecific fragmentations is explained by loss of configurational integrity of the molecular ion before fragmentation.However, the mass spectral fragmentation of epimeric diamidocyclohexanes becomes very stereospecific by the introduction of a phenethyl group on one of the nitrogen atoms: this group avoids epimerization of the molecular ion prior to fragmentation. In the N-phenethyl derivatives 10, 11, 13 and 14 (Scheme 8) the typical fragmentations of the cis-isomer after loss of ·C7H7 from the molecular ion are the elimination of CH2CO by formation of cyclic ions, and the loss of p-toluenesulfonic acid or benzoic acid, respectively, with subsequent elimination of CH3CN (Scheme 9). In the trans-isomer the typical fragmentations are the loss of the side chain bearing a tertiary nitrogen atom, and the elimination of the tosyl or benzoyl radical, respectively, with subsequent loss of CH3CONH2 (Scheme 10).
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  • 82
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    Topics: Chemistry and Pharmacology
    Notes: The potentiometric study of the complexation of Cu2+ with 1,4,7-triazacyclononane (1), 1,4,8-triazacyclodecane (2) 1,5,9-triazacyclododecane (3) has shown that CuL, CuL2 and (CuLOH)2 are the main species present in solution. Their stabilities (Table 1) and their absorption spectra (Table 2) indicate facial coordination of the cyclic triamines in a distorted octahedral geometry.The formation and dissociation kinetics have been measured by stopped-flow techniques. The formation in acetate buffer can be described by the reaction of Cu2+ and CuAcO+ with the monoprotonated species of the ligand. The bimolecular rate constants for these complexations (Table 3) decrease when the ring size increases. In contrast the dissociation induced by acid is only little affected by the ring size. Thus for these complexes the rate of formation and not that of the dissociation determines the overall stability.
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  • 83
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    Helvetica Chimica Acta 62 (1979), S. 1096-1097 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The absolute configuration of the title compound, a minor constituent of civet, is shown to be S,S.
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  • 84
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    Helvetica Chimica Acta 62 (1979), S. 1640-1644 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 22,23-methano-24-nor-cholest-5-en-3β-ol and comparison with cystosterol22,23-Methano-24-nor-cholest-5-en-3β-ol, a novel cyclopropane-containing sterol was synthesized from stigmasterol and found to be different from the isomeric, naturally occurring marine sterol cystosterol.
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  • 85
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    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the spin-labeled uridine and 2′-deoxyridine analogues RUGT 2, DUGT 3, l-RUGT 4, and l-DUGT 5 is described. DUGT 3 showed some activity against the leukemia P388 cell line.
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  • 86
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    Helvetica Chimica Acta 62 (1979), S. 1688-1688 
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    Keywords: Chemistry ; Organic Chemistry
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  • 87
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    Helvetica Chimica Acta 62 (1979), S. 1682-1687 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The unique stabilization of the ester link in dialkyl succinyl succinates is explained and a facile route to known as well as to hitherto inaccessible succinyl succinates is suggested. New representatives of this series are described.
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  • 88
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    Helvetica Chimica Acta 62 (1979), S. 1689-1690 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 89
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    Helvetica Chimica Acta 62 (1979), S. 1689-1700 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of ethylene oxidation by air over a supported silver catalyst were investigated in the temperature range 490-620 K. The reaction network was found to be triangular. Under virtually constant oxygen partial pressure (0.2 bar), the following rate relationships, (in mol g-1s-1) were found: (formulae in curved brackets denote partial pressures) where R is expressed in J · mol-1 · K-1.The given rate expressions are discussed in the framework of earlier kinetic investigations.
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  • 90
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    Topics: Chemistry and Pharmacology
    Notes: Enantioselective 1,4-additions of organometallic compounds to conjugated systems in the chiral medium DDBDDB = 1,4-Dimethylamino-2,3-dimethoxybutan (= 2,3-Dimethoxy-N,N,N′,N′-tetramethyl-1,4-butandiamin).The chiral methoxyamine DDB is used as a cosolvent to add achiral Li-, Cu-, and Zn-organic compounds enantioselectively to prochiral β-carbon atoms of α, β-unsaturated aldehydes, ketones, nitro compounds and ketene-thioacetals (Tables 1 and 2). The selectivity generally ranges from 55:45 to 63:27, in one case (9b) an enantiomeric excess of 43% was obtained.
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  • 91
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    Helvetica Chimica Acta 62 (1979), S. 1745-1752 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The study of 16, 17, 18, 19, 28, 29-hexahydrorifamycin S by 1H-NMR. spectroscopy using INDOR at 100 MHz and homodecoupling at 270 MHz has shown that the conformation of the ansa fragment C(20)-C(27) and the position of this fragment relative to the naphthoquinone chromophore are practically the same as those of rifamycin S. This finding rules out the hypothesis that the lower activity of the hydrogenated rifamycins could be due to a different conformation.
    Additional Material: 1 Ill.
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  • 92
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrazolo[1,5-a]indolesTreatment of 1-(2-heteroaroyl or aroyl-phenyl)-pyrazoles (3) with potassium hydroxide in 95% ethanol or with sodium ethanolate in ethanol produces a novel ring closure to new 4-hydroxy-4-(4-heteroaryl or aryl)-4H-pyrazolo [1,5-a]indoles 5 and 6 (Table 1). A 2, 3, or 4-pyridyl at position 4 is easily reduced yielding the 4-(2, 3, or 4-piperidyl)-derivatives 7 and 8 (Table 2). Water is split off from these piperidyl-derivatives 7 or 8 to give the piperidylidene derivatives 9 or 10 (Table 3) which may be considered as heterocyclic analogues to known tricyclic psychopharmaceuticals with antidepressant or neuroleptic activities.
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  • 93
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure and configuration of gilmaniellin, a metabolite of Gilmaniella humicola BARRON, has been shown to be 2 by X-ray analysis. By comparison of spectral data structure 1 has been assigned to dechlorogilmaniellin.
    Additional Material: 3 Ill.
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  • 94
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaktionen von 1,3,5,7-Tetramethyl-anti-tricyclo[5.1.0.03,5]octan-2,6-diolen und deren 4,4,8,8-Tetrachlor- und 4,8-Dichlorderivaten mit DiphosphortetrajodidEs wurden die P2I4-Reaktionen mit 1,3,5,7-Tetramethyl-anti-tricyclo[5.1.0.03,5]-octan-2,6-diolen (3/6), mit dem 4,8-Dichlorderivat 4 und mit den 4,4,8,8-Tetrachlorderivaten 5/7 untersucht. Dabei entstanden die Styrolderivate 9 und 12, die anti-Bishomobenzolderivate 8 und 11, ein Homotropylidenderivat 10, ein Cyclo-octatetraenderivat 13 und ein 9-Oxabicyclo[4.2.1]nona-2,4,7-trienderivat 15. Die Ausbeuten lagen zwischen 1 und 10%. Die Bildung aller dieser Produkte liess sich unter der Annahme der primären Umwandlung einer oder beider Hydroxylgruppen in Abgangsgruppen X oder X und Y (wahrscheinlich X=Y=I) mechanistisch deuten. Die Reaktion der Deschlorderivate 3/6 lieferte nach Substitution beider Hydroxyl-gruppen durch X und Y: (a) unter Abspaltung von HX und HY das Styrolderivat 9 (Schema 2) und (b) unter Abspaltung von XY das Homotropylidenderivat 10 (Schema 3a) und das Bishomobenzolderivat 8 (Schema 3b). Die Reaktion des 4,8-Dichlor-derivates 4 lieferte nach Substitution beider Hydroxylgruppen durch X und Y: (a) unter Abspaltung von HX und HY das Styrolderivat 12 (Schema 2), und (b) unter Abspaltung von XY das Bishomobenzolderivat 11 (Schema 3b). Die Reaktion mit den 4,4,8,8-Tetrachlorderivaten 5/7 lieferte: (a) nach Substitution beider Hydroxyl-gruppen durch X und Y unter Abspaltung von XCl und YCl das Cyclooctatetraen-derivat 13 (Schema 4), und (b) nach Substitution nur einer Hydroxylgruppe durch X unter Abspaltung von XCl und HCl das bicyclische Derivat 15 (Schema 5). Alle diese Reaktionen sind zusätzlich zu den angegebenen Fragmentierungen und Eliminierungen noch teilweise von Umlagerungen des Kohlenstoffgerüstes begleitet.Die thermische Umlagerung von 1,5-Dichlor-2,4,6,8-tetramethyl-cycloocta-1,3,5,7-tetraen (13) in das Styrolderivat 12 wurde in Abhängigkeit der Lösungs-mittelpolarität untersucht und mit der analogen thermischen Umlagerung von Brom-cyclooctatetraen und Chlor-cyclooctatetraen verglichen.
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  • 95
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Leaf-gland Pigments: Coleons S and T from Plectranthus caninus ROTH (Labiatae), New Hydroquinones of the Abietane Series with a Diosphenol/trans-A/B-6,7-Diketone Structure.Coleons S and T were isolated from the more polar fractions from extracts of the above mentioned plant. Coleon S, C20H26O6, has been shown to have structure 1a, and coleon T, C20H26O6, structure 2.
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  • 96
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 60 (1977), S. 1452-1455 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On a Synthesis of the angular Di(cyclobuteno)benzolIn the course of our studies aimed at better understanding the Mills-Nixon effect, we have also prepared the angular di(cyclobuteno)benzene (1), the synthesis of which has been recently described by another group [3]. Our completely different and essentially simpler synthetic approach will be pointed out. A special pyrolysis apparatus is designed.
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  • 97
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A substitute for the Darzens glycidic ester synthesis for converting unsaturated ketones or aldehydes into the homologated β,γ- or α,β-unsaturated aldehydes employing sulfur ylides is described. The carbonyl group is converted into the unsaturated oxirane which is then rearranged to the new aldehyde. High yields of isomerically pure aldehydes are available by this method and the process is of practical importance in the conversion of β-ionone into the β-C14-aldehyde, a key intermediate in the Isler synthesis of vitamin A. The efficient preparation of α- and β-cyclocitral by the novel process is also described.
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  • 98
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 60 (1977), S. 1455-1455 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 99
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 60 (1977), S. 1456-1458 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 60 (1977) 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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