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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 1563-1566 
    ISSN: 0947-3440
    Keywords: 1-Hydroxypyrazoles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxidation of sodium pyrazolate with dibenzoyl peroxide is the first direct route to 1-hydroxypyrazole (2a). The reaction may be also applied to substituted pyrazoles.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Directed Synthesis of Sulfinato-O and -S Complexes of Some Transition Metals, XVII. The Coordination Chemical Behaviour of the Silver Sulfinates RSO2Ag towards TriphenylphosphineThe remarkably stable complexes of the type (RSO2)Ag(PPh3)n (n = 1 (2), 2 (3), 3 (4) are obtained by the stepwise addition of triphenylphosphine to the silver sulfinates RSO2Ag (1). According to the i. r. spectra, the compounds 2 (coordination number (cn) = 2) and 4 (cn = 4) contain a sulfinato-O linkage, in the compounds 3 (cn = 4), however, a sulfinato-O,O′ linkage is present. The bonding of the RSO2- ligand via “hard” oxygen to the “soft” silver(I) ion is due to its weak π-donor ability.
    Notes: Durch schrittweise Addition von Triphenylphosphin an die Silbersulfinate RSO2Ag (1) werden die bemerkenswert stabilen Komplexe des Typs (RSO2)Ag(PPh3)n (n = 1 (2), 2 (3), 3 (4) erhalten. Den IR-Spektren zufolge liegt in den Verbindungen 2 (Koordinationszahl (KZ) = 2) und 4 (KZ = 4) eine Sulfinato-O-, in den Verbindungen 3 (KZ = 4) dagegen eine Sulfinato-O,O′-Verknüpfung vor. Die Bindung des RSO2--Liganden über den „harten“ Sauerstoff an das „weiche“ Silber(I)-Ion ist auf dessen geringe π-Donorfähigkeit zurückzuführen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 463-467 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Directed Synthesis of Sulfinato-O and -S Complexes of Some Transition Metals, XIV Sulfinato-O,S Complexes of Palladium(II) and Rhodium(III)The directed preparation of the sulfinato-O,S complexes {R(O)OS}nM (2a, b; 5a, b) was successful for the first time by elimination of coordinated water from the sulfinato-S complexes {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] by 2,2-dimethoxypropane. The O,S-linkage is unequivocally shown from their chemical behaviour and the i. r. spectra. The criteria necessary for the formation of sulfinato-O,S complexes are discussed.
    Notes: Durch Abspaltung von koordiniertem Wasser aus den Sulfinato-S-Komplexen {RS(O)2}nM(OH2)n [n = 2, M = Pd (1a, b); n = 3, M = Rh (4a, b)] mit 2,2-Dimethoxypropan gelang erstmals die gezielte Darstellung der Sulfinato-O,S-Komplexe {R(O)OS}nM (2a, b; 5a, b). Die O,S-Verknüpfung ergibt sich eindeutig aus dem chemischen Verhalten und den IR-Spektren. Die für die Bildung von Sulfinato-O,S-Komplexen notwendigen Kriterien werden diskutiert.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 833-840 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Directed Synthesis of Sulfinato-O and -S Complexes of Some Transition Metals, XV. The Coordination Chemical Behaviour of the RSO2- Ligand in Silver(I) ComplexesThe preparation and characterization of the silver sulfinates RSO2Ag (1) (R = CH3 (a), C6H5 (b), p-CH3C6H4 (c)) are described extensively for the first time and their behaviour towards the N-heterocycles pyridine, 2,2′-bipyridine and 1,10-phenanthroline is investigated. Starting from 1 one obtains with these ligands without exception the temperature and light sensitive sulfinato-O complexes 2-4. Only in the case of (C6H5S(O)2)Ag(bipy) the unstable sulfinato-S complex 5 which is irreversibly transformed to its linkage isomer 3b can be isolated. The i. r. spectra are discussed in detail. The investigations show the HSAB model to be only of limited application to d10 ions.
    Notes: Die Darstellung und Charakterisierung der Silbersulfinate RSO2Ag (1) (R = CH3 (a), C6H5 (b), p-CH3C6H4 (c) werden erstmals ausführlich beschrieben und ihr Verhalten gegenüber den N-Heterocyclen Pyridin, 2,2′-Bipyridyl und 1,10-Phenanthrolin untersucht. Ausgehend von 1 erhält man mit diesen Liganden die durchweg temperatur- und lichtempfindlichen Sulfinato-O-Komplexe 2-4. Nur im Falle von (C6H5S(O)2)Ag(bipy) läßt sich der labile Sulfinato-S-Komplex 5 isolieren, welcher irreversibel in sein Bindungsisomeres 3b übergeführt werden kann. Die IR-Spektren werden diskutiert. Die Untersuchungen zeigen, daß das HSAB-Modell bei d10-Ionen nur beschränkt anwendbar ist.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 765 (1973), S. 47-54 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Isomerisation of 1,4-Epoxy-2,3-dibromomethylene-1,2,3,4-tetrahydronaphthaleneAddition of dibromocarbene to 1,4-epoxy-1,4-dihydronaphthalene (1) yields the exo-adduct 2. On heating in methanol/HCl 2 rearranges to the allyl bromide 4a and to its methoxy derivative 4b. Furthermore 2-bromonaphthalene (5) was obtained. Reduction of 4a with lithium aluminium hydride leads to the bromo-olefine 6 and to the olefine 7. Reduction of 6 with Na/NH3 yields 5,6,7,8-tetrahydro-9H-benzocyclohepten-9-ol (10). Treatment with 70% perchloric or 56% sulfuric acid results in the formation of the benztropylium salts 9.
    Notes: Die Addition von Dibromcarben an 1.4-Epoxy-1.4-dihydronaphthalin (1) führt zum exo-Addukt 2. Durch Erhitzen mit methanolischer Salzsäure lagert sich 2 in das Allylbromid 4a und in das entsprechende Methoxyderivat 4b um. Als 3. Reaktionsprodukt entsteht 2-Bromnaphthalin (5). Aus 4a werden durch Reduktion mit Lithiumaluminiumhydrid das Bromolefin 6 und das Olefin 7 erhalten. Mit Natrium in flüssigem Ammoniak wird 6 zu 5.6.7.8-Tetrahydro-9H-benzocyclohepten-9-ol (10) reduziert. 7 geht bei Behandlung mit 70 proz. Perchlorsäure oder 65 proz. Schwefelsäure in die entsprechenden Benzotropylium-Salze 9 über.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 766 (1973), S. 58-72 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Ureidoalkylation with Trivalent Phosphorus Compoundsα-Hydroxyalkyl or α-alkoxyalkyl compounds of acyclic or cyclic ureas and thioureas react in the presence of equivalent amounts of acids via α-ureidoalkylcarboniumimonium ions (A) with triphenylphosphine to α-ureidoalkyltriphenylphosphonium salts of type B. Corresponding reactions with phosphorus trihalides lead to α-ureidoalkylphosphonic dihalides of type C. α-Haloalkylureas and trialkyl phosphites give dialkyl α-ureidoalkylphosphonates of type D, which are also formed by condensation of α-hydroxyalkyl- or α-alkoxyalkylureas with dialkyl phosphites.
    Notes: Durch Reaktion von α-Hydroxyalkyl- oder α-Alkoxyalkyl-Verbindungen acyclischer oder cyclischer Harnstoffe und Thioharnstoffe entstehen in Gegenwart von äquivalenten Säuremengen über α-Ureidoalkyl-carbonium-imonium-Ionen (A) mit Triphenylphosphin α-Ureidoalkyl-triphenylphosphonium-Salze vom Typ B. Entsprechende Umsetzungen mit Phosphortrihalogeniden führen zu α-Ureidoalkyl-phosphonsäuredihalogeniden vom Typ C. α-Halogenalkyl-harnstoffe reagieren mit Trialkylphosphiten unter Bildung von α-Ureidoalkyl-phosphonsäuredialkylestern des Typ D, die auch durch Kondensation von α-Hydroxyalkyl-oder α-Alkoxyalkyl-harnstoffen mit Dialkylphosphiten zugänglich sind.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 726 (1969), S. 188-200 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: p-Xylylenes*). Valence Tautomerism of Unsaturated SystemsIn the dehalogenation of 7a the saturated solvent containing tetramer 9a is isolated instead of the expected quinoid p-xylylene 8a. If energy is applied to the system (heat or mechanical pressure), compound 9a is cleaved to a slight extent and turns blue both in the solid state and in solution. In solution the monomeric fraction occurs mainly as the quinoid p-xylylene 8a; however, the paramagnetism of the blue violet crystals suggests that the twisted biradicals 10a are formed. By suitable substitution of the dibromide 7a it can be shown that the remarkable behaviour of p-xylylene 8a is due, in the main, to the steric hindrance of the hydrogen atoms on C-1 and C-2′ together with the tendency of the quinoid system to aromatize.
    Notes: Bei der Enthalogenierung von 7a wird anstelle des erwarteten chinoiden p-Xylylens 8a das gesättigte solvenshaltige Tetramere 9a isoliert. Durch Energiezufuhr (Erhitzen oder mechanischer Druck) wird 9a sowohl in festem Zustand als auch in Lösung in geringem Umfang unter Blauviolettfärbung gespalten. Während in Lösung die monomeren Bruchstücke vorwiegend als chinoides p-Xylylen 8a vorliegen, spricht der Paramagnetismus der blauvioletten Kristalle dafür, daß hier verdrillte Biradikale 10a gebildet werden. Durch geeignete Substitution des Dibromids 7a läßt sich zeigen, daß das bemerkenswerte Verhalten des p-Xylylens 8a wesentlich auf die sterische Hinderung der Wasserstoff-Atome an C-1 und C-2′ im Zusammenwirken mit der Aromatisierungstendenz des chinoiden Systems zurückzuführen ist.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 761 (1972), S. 20-24 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition Products of 1,4-Epoxy-1,4-dihydronaphthalene and N-MethylisoindoleAddition of 1,4-epoxy-1,4-dihydronaphthalene (1) to N-methylisoindole yields the exo/exo-and exo/endo-isomers 3a and 3b. The configuration of the isomers is determined by NMR-spectroscopy. Only the exo/endo-product 3b can be quaternized by methyl iodide. The structure of the adducts 3a and 3b is confirmed by oxidation of the mixture of 3a and 3b to naphthacene-5,12-quinone (7).
    Notes: Durch Addition von 1.4-Epoxy-1.4-dihydro-naphthalin (1) an N-Methyl-isoindol (2) werden die exo/exo- und exo/endo-Isomeren 3a und 3b erhalten. Die Konfigurationszuordnung erfolgt durch die 1H-NMR-Spektren. Nur das exo/endo-Isomere 3b läßt sich mit Methyljodid zu 4 quaternieren. Der Strukturbeweis für das Grundgerüst der Addukte 3a und 3b wird durch Oxidation des Isomerengemisches zum Naphthacen-5.12-chinon (7) erbracht.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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