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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 1097-1110 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Glycoside Synthesis, IV. Novel Silver Salts in Glycoside SynthesisThe glykosylation of steroid alcohols (e.g. 4, and 9-12, R==OH) with cis-halogenoses in the presence of various silver salts was investigated. In many cases the silver salts of 2-, 3-, and 4-hydroxyalkanoic acids as well as of 1.3- and 1.4-dicarboxylic acids proved to be superior to the commonly used Ag2CO3 or Ag2O. Good yields (5, 7-12) were obtained in cases in which neighbouring group effects within the anion limit the formation of 1-O-acylglycoses in favour of glycoside formation. The reaction takes place most readily in diethyl ether and is well suited for the glycosylation of chemically sensitive alcohols.
    Notes: Bei der Glykosylierung von Steroidalkoholen (u.a. 4 und 9-12, R == OH) mit cis-Halogenosen in Gegenwart verschiedener Silbersalze erwiesen sich die von 2-, 3-und 4-Hydroxy-carbonsäuren sowie von 1.3- und 1.4-Dicarbonsäuren den üblichen Salzen in vielen Fällen als überlegen. Gute Ausbeuten (an 5, 7-12) wurden dann erhalten, wenn im Anion des Silbersalzes durch eine Nachbargruppenbeziehung die Bildung der 1-O-Acyl-glucose zugunsten der Glykosidbidung eingeschränkt ist. Die Reaktion verläuft in Diäthyläther am besten und ist besonders auch zur Glykosylierung von chemisch empfindlichen Alkoholen gut geeignet.
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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: Fragmentation Reactions of Carbonyl Compounds with Electronegative ß-Substituents, XXIII cis- and trans-4.4.8.8-Tetraalkyl-2.6-dioxabicyclo[3.3.0]octanes from 1.6-Bis(tosyloxy)-2.2.5.5-tetraalkyl-3.hexandionesDiketoditosylates 8 and 9a-c are prepared and reduced with NaBH4. 8 yields 16a and a cis-trans mixture of 23; 9a-c afford the tetrahydrofuranols 14a-c and the cis-2.6-dioxabicyclo[3.3.0]octanes 21a-c. 14a-c and 16a react with NaOH in methanol to form the pure trans-compounds 21a-c and 23. Solvolysis of 9a with excess NaOH in methanol leads to the tetrahydrofuranone 13a and to the bicyclo acetal 22a. Solvolysis of 9b with only 2 equivalents of NaOH yields thc intermediate 12, which can be isolated and converted to 13b and 22b.The trispiro compound 27 is isolated as an unexpected side product from the NaBH4-reduction of 9b.
    Notes: Die Diketo-ditosylate 8 und 9a-c werden dargestellt und mit NaBH4 reduziert. 8 liefert 16a und ein cis-trans-23-Gemisch, aus 9a-c werden die Tetrahydrofuranole 14a-c und die cis-2.6-Dioxa-bicyclo[3.3.0]octane 21a-c erhalten. 14a-c und 16a reagieren mit NaOH in Methanol zu den reinen trans-Verbindungen 21a-c und 23. Die Solvolyse von 9a mit überschüssigem NaOH in Methanol führt zu dem Tetrahydrofuranon 13a und dem bicyclischen Acetal 22a. Mit 2 Äquivv. NaOH kann aus 9b die Zwischenstufe 12 isoliert und erneut zu 13b und 22b umgesetzt werden.Als ungewöhnliches Nebenprodukt tritt bei der NaBH4-Reduktion von 9b die Trispiroverbindung 27 auf.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 1387-1399 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Glycoside Synthesis, II. The Reaction of α-Acetobromoglucose with Silver Salts of Hydroxycarboxylic AcidsWhereas the reaction mentioned in the title yields the corresponding 1-O-acyl-2.3.4.6-tetra-O-acetyl-β-D-glucoses (1-4) in the case of simple carboxylic acids, hydroxycarboxylic acids in addition are glucosylated at the hydroxyl group (6b-14b) as well as at the hydroxyl and carboxyl group (6a-13a). The 1-O-acylglucoses of the hydroxycarboxylic acids (5c, 6c, 8c, 13c, 14c) show very different stability depending on the position of the hydroxyl group; the γ- and δ-hydroxycarboxylic acids being the most unstable ones.
    Notes: Während die im Titel genannte Reaktion bei einfachen Carbonsäuren fast ausschließlich zu den entsprechenden 1-O-Acyl-2.3.4.6-tetra-O-acetyl-β-D-glucosen (1-4) führte, lieferten Hydroxycarbonsäuren zusätzlich die an der Hydroxylgruppe glucosylierten Produkte (6b bis 14b) und die an Hydroxyl- und Carboxylgruppe glucosylierten Derivate (6a-13a). Die 1-O-Acyl-glucosen der Hydroxycarbonsäuren (5c, 6c, 8c, 13c, 14c) weisen in Abhängigkeit von der Stellung der Hydroxylgruppe eine sehr unterschiedliche Stabilität auf: die der γ- und δ-Hydroxysäuren sind infolge ihrer Lactonisierungstendenz am instabilsten.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 3230-3239 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Molecular und Crystal Structure of 3,3-Bis(methoxycarbonyl)-4-phenyl-1-pyrazoline-N-(tetracarbonyliron)The single crystal x-ray analysis of the title compound (cell data: a= 10.113 (2), b = 27.548 (7), c = 6.938 (2) Å, β = 99.53 (2)°, P21/c, Z = 4) shows the 1-pyrazoline derivative to be linked through a σ-bond to the apical position of a Fe(CO)4 residue. The geometry of the ligand is not altered upon complexation.
    Notes: Die Röntgenstrukturanalyse der Titelverbindung (Zelldaten: a = 10.113 (2), b = 27.548 (7), c = 6.938 (2) Å, β = 99.53 (2)σ, P21/c, Z = 4) beweist die σ-Komplexbildung zwischen einem 1-Pyrazolin-Derivat und einem Übergangsmetall. Der Ligand ist überraschenderweise in apikaler Position an einen trigonal-bipyramidalen Fe(CO)4-Rest gebunden. Die Geometrie des Liganden ändert sich durch die Komplexierung nicht wesentlich.
    Additional Material: 4 Ill.
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  • 5
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentation Reactions of Carbonyl Compounds with Electronegative Substituents in the β-Position, XXIV. 4,7-Dimethyl-2,9-dioxatricyclo[5.3.0.04,10]decane from 3,6-Bis(iodomethyl)- and 3,6-Bis(p-tolyl-sulfonyloxymethyl)-3,6-dimethyl-1,2-cyclohexanedione3,6-Dimethyl-1,2-cyclohexanedione (7) reacts with CH2O to give the di-aldol 9 (14), which is tosylated to yield 10. The diiodide 11 is prepared from 10 by treatment with NaI in diethylketone. Solvolysic of 10 or 11 with NaOH/CH3OH leads in good yields to the tricyclic diacetal 16. Reduction of 10 or 11 with NaBH4/C2H5OH affords as the main product the bicyclic compound 18 or 22, respectively; the tricyclic compound 15 is obtained only in low yield. 15 is prepared in quantitative yield from 18 by reaction with NaOH in DMSO or by CrO3-oxidation to 25 followed by NaBH4 reduction.
    Notes: Durch Umsetzung von 3,6-Dimethyl-1,2-cyclohexandion (7) mit CH2O wird das Di-aldol 9 (14) dargestellt, das zu 10 tosyliert wird. 10 liefert mit NaJ in Diäthylketon das Dijodid 11. Die Umsetzung von 10 bzw. 11 mit NaOH/CH3OH führt in guten Ausbeuten zum tricyclischen Di-acetal 16. Die Reduktion von 10 bzw. 11 mit NaBH4/C2H5OH liefert dagegen nur in geringer Ausbeute die entsprechende tricyclische Verbindung 15, als Hauptprodukt wird jeweils die bicyclische Verbindung 18 bzw. 22 isoliert. Aus 18 kann durch Reaktion mit NaOH in DMSO oder durch CrO3-Oxidation zu 25 und anschließende NaBH4-Reduktion in fast quantitativer Ausbeute 15 erhalten werden.
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  • 6
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fragmentation Reactions of Carbonyl Compounds with Electronegative β-Substituents, XXII. cis- and trans-4.4.8.8-Tetramethyl-2.6-dioxabicyclo[3.3.0]octane from 1.6-Bis(tosyloxy)-2.2.5.5-tetramethyl-3.4-hexanedioneTreatment of 1.6-bis(tosyloxy)-2.2.5.5-tetramethyl-3.4-hexanedione (5) with NaBH4, NaOH/CH3OH and CH3MgJ leads to 2.6-dioxabicyclo[3.3.0]octanes c-7, t-7, 8, and 10. In addition the tetrahydrofuran derivatives 12, 13, and E-18 are isolated, which are considered to be intermediates. 12 and E-18 can be converted to 8 and t-7 respectively by NaOH/CH3OH. The hitherto unknown trans-2.6-dioxabicyclo[3.3.0]octane skeleton is proved. The mechanistic intermediates 11 and E-18 are prepared independently by NaBH4-reduction of monotosylate 4 to 6 and E-17, followed by tosylation. Treatment of 11 with NaBH4 affords a mixture of c/t-7 and E-18 having the same composition as that obtained from 5. Reduction of 12 gives 9.
    Notes: Die Umsetzung von 1.6-Bis-tosyloxy-2.2.5.5-tetramethyl-hexandion-(3.4) (5) mit NaBH4, NaOH/CH3OH und CH3MgJ führt zu den 2.6-Dioxa-bicyclo[3.3.0]octanen c-7, t-7, 8 und 10. Daneben werden jeweils die Tetrahydrofuran-Derivate 12, 13 und E-18 isoliert, die als Zwischenstufen anzusehen sind. 12 und E-18 können separat wiederum mit NaOH/CH3OH zu 8 bzw. t-7 umgesetzt werden. Das bisher nicht bekannte trans-2.6-Dioxa-bicyclo[3.3.0]octan-Gerüst ist bewiesen. Die vom Mechanismus postulierten Zwischenstufen 11 und E-18 werden unabhängig durch NaBH4-Reduktion des Monotosylats 4 zu 6 und E-17 und anschließende Tosylierung erhalten. Aus 11 wird mit NaBH4 ein Gemisch aus c/t-7 und E-18 gleicher Zusammensetzung wie aus 5 erhalten. NaBH4-Reduktion von 12 führt zu 9.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 3706-3715 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Molecular Structure of two Complexes with Dimethylphosphonium-bis(methylide) as LigandsThe X-ray analyses of one isomeric form (1) of the compound dinickel-tetrakis[dimethylphosphonium-bis(methylide)] and of dimethylbis(trimethylphosphine)cobalt(III)-[dimethylphosphonium-bis(methylide)] (2) were carried out and the results are discussed. Both compounds contain the new ligand dimethylphosphonium-bis(methylide). In the nickel compound the ligand bridges two nickel atoms and also acts as a chelating ligand.
    Notes: Es werden die Röntgenstrukturanalysen einer isomeren Form (1) des Dinickel-tetrakis[dimethylphosphonium-bis(methylids)] (a = 11.8445(6), b = 10.7782(8), c = 9.3078(6) Å, β = 99.672(6)°, R = 0.037) sowie des Dimethylbis(trimethylphosphin)kobalt(III)-[dimethyl-phosphonium-bis(methylids)] (2) (a = 9.0217(11), b = 11.767(2), c = 9.0769(9) Å, β = 109.12(1)°, R = 0.062) vorgestellt und die gefundenen Bindungsverhältnisse diskutiert. In beiden Verbindungen tritt der neuartige Ligand Dimethylphosphonium-bis(methylid) auf, wobei er in der Nickelverbindung sowohl als Chelat-Ligand wie auch als verbrückender Ligand beobachtet wird.
    Additional Material: 7 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 2305-2310 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Oxygen absorption is a widely used test for measuring polymer stability and antioxidant effectiveness. Commonly, periodic measurements are made using a mercury buret to measure the rate at which oxygen is taken up by the polymer. We designed and built a safe, dependable apparatus that continuously monitors the reaction of a hydrocarbon polymer with oxygen. The instrument operates by recording the frequency with which small, known volumes of oxygen are introduced into the sample tube to maintain a preestablished pressure in the tube. No operator time is required during the test. The instrument readings are readily converted to standard oxygen absorption curves.
    Additional Material: 6 Ill.
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  • 9
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 83 (1971), S. 250-251 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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