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  • Articles  (15)
  • Articles: DFG German National Licenses  (15)
  • 1985-1989  (15)
  • 1
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The year-round mooring station WS-1 is located at 62°26.5' S, 34°45.5' W, in a water depth of 3,880 m. This station is covered by sea ice for about 70% of the year (〉9 on ice-cover scale (ICS); see refs 1 and 2). We developed an automated Parflux Mk 5-25 time-series sediment trap3 at 863 ...
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 567-572 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrylium Compounds. 33. 2-Dialkylamino-2H-thiopyrans from 2,4,6-Triaryl-thiopyrylium Salts2,4,6-Triaryl-thiopyrylium salts 7 react with dialkylamines in diethyl ether to give stable crystalline 2-dialkylamino-2H-thiopyrans 8, the structure of which is in accordance with their u.v., n.m.r. and mass spectra. The chemical properties of 8 parallel those of structurally analogous 2-alkoxy- and 2-dialkylamino-2H-pyrans and 2-alkoxy-2H-thiopyrans. Thus, on heating 2-dimethylamino-2,4,6-triphenyl-2H-thiopyran (8a) with methanol the corresponding 2-methoxy-2H-thiopyran 9 is formed. Nitromethane and ethyl cyanoacetate give rise to ring transformations yielding 1,3,5-triphenyl benzene (10) and 2,4,6-benzonitrile (11), respectively. From 8a electrophiles (e.g. mineral acids, methyl iodide, benzoyl chloride) regenerate the initial thiopyrylium system by taking over the dialkylamino group.
    Additional Material: 2 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 651-655 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Phosphorus Compounds. XV. Studies on the Reactivity of Selected Vinyl Phosphates
    Additional Material: 1 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 327 (1985), S. 151-155 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrylium Compounds. XXVI. Comparative U.V./Vis. Studies on 3-Methyl-2,4,6-triarylpyrylium Perchlorates
    Additional Material: 2 Tab.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 327 (1985), S. 529-535 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrylium Compounds. XXVIII. Specifically Deuterated Carbo- and heterocycles via 2,4,6-Triaryl[3,5-2H2]pyrylium SaltsOn heating with catalytic amounts of bases(e.g. triethyl amine) in deuterated alcohols such as methan[2H]ol or ethan[2H]ol pseudobases of 2, 4, 6-triarylpyrylium salts 1 undergo fast1H/2H isotopic exchange reaction affording 1, 3, 5-triaryl[2, 4, 4-2H3]pent-2-ene-1,5-diones which with [2H] perchloric acid give highly deuterated 2, 4, 6-triaryl-[3, 5-2H] pyrylium perchlorates 8. These salts are obtainable also directly from 1 through a one-pot procedure by ring opening of the latter with deuterium oxide under the above-mentioned1H/2H isotopic exchange conditions followed by recyclization of the formed 1, 3, 5-triaryl[2, 4, 4-2H3]pent-2-ene-1, 5-diones with [2H]ClO4. Ring transformations of 2, 4, 6-triphenyl[3, 5-2H2]pyrylium perchlorate (8a) to 2, 4, 6-triphenyl[3, 5-2H2]nitrobenzene (9) 2, 4, 6-triphenyl[3, 5-2H2]pyridine (10), 1, 2, 4, 6-tetraphenyl[3, 5-2H2]pyrydinium perchlorate(11), 2, 4, 6-triphencyl[3, 5-2H2]thiopyrylium perchlorate(12), 2-benzoyl-3, 5-diphenyl[4-2H]furan (13), and 3, 5, 7-triphenyl-[4, 4, 6-2H3]4H-1, 2-diazepin (14) demonstrate the usability of pyrylium salts of type 8 as starting materials for syntheses of specifically deuterated carbo- and hetrocycles.
    Additional Material: 1 Tab.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 329 (1987), S. 499-510 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrylium Compounds. 36. Substituted Benzoic Acid Esters from 2,4,6-Triarylpyrylium Salts and α-Ketocarboxylic Acid Esters2,4,6-Triarylpyrylium salts 1 react with α-ketocarboxylic acid esters 2 in the presence of two equivalents of an appropriate condensing agent (e.g. dialkylamine salts of weak acids, triethylamine/acetic acid, or sodium acetate) to give 2-aroyl-3,5-diarylbenzoic acid esters 3. However, using only one equivalent of the condensing agent, the formation of 3,5-diarylbenzoic acid esters 5 predominates. Alkaline saponification of the new esters 3 and 5 yields the corresponding substituted benzoic acids 4 and 6, respectively. - I.r., u.v., n.m.r. and mass spectroscopic data of the novel products 3-6 are reported.
    Additional Material: 9 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 359-372 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pyrylium Compounds. 31. Reaction of 3-Alkyl-2,4,6-triarylpyrylium Salts with 1,3-Diketonates: A Method for the Preparation of 3-Acylsubstituted BenzophenonesReaction of 3-alkyl-2,4,6-triarylpyrylium salts with 1,3-diketones in the presence of one equivalent of triethylamine or potassium tert-butoxide does not lead  -  as originally suspected  -  to the primary adducts of 2H-pyran structure 6, but to the open-chain valence isomers 7. Treatment of the latter with one equivalent of tert-butoxide in tert-butyl alcohol gives the same 3-alkyl-2,4,6-triarylacetophenones 9 which are obtained directly from 5, 1,3-diketones and two equivalents of potassium tert-butoxide. However, on treating 7 with aqueous ethanolic sodium hydroxide 3-acylsubstituted benzophenones 10 are formed in good yields. The reaction sequence 5→7→10 can also be performed through a one-pot-procedure.  -  The i.r., u.v., n.m.r. and mass spectroscopic data of the novel products 7, 9, and 10 are reported.
    Notes: No abstract.
    Additional Material: 6 Tab.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 327 (1985), S. 983-997 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrylium Compounds. 30. C-Alkylation of 1,3,5-Triaryl-pentene-1,5-dione Enolates: A Simple Approach to 3-Alkylsubstituted 2,4,6-Triarylpyrylium Salts1,3,5-Triaryl-pentene-1,5-dione enolates (10), obtainable in crystalline form from 2,4,6-triarylpyrylium pseudobases (9) and sodium methoxide in benzene/ether, react in dipolar aprotonic solvents (e.g. DMSO, DMF) with various types of alkyl iodides to give C-alkylation products (11) which afford 3-substituted 2,4,6-triarylpyrylium salts (12) on treatment with perchloric acid. This reaction sequence proved to be a convenient synthetic route to pyrylium salts (12) having 3-oriented substituents such as normal or branched alkyl groups CnH2n+1 (e.g.n = 1-5), isotopically modified alkyl groups (e.g. C[2H3], C2[2H5]), allyl type substituents (e.g. CH2=CHCH2, MeCH=CHCH2, CH2, CH2=CMeCH2) or benzyl groups (e. g. PhCH2, 4-Br—C6H4CH2). Bifunctional alkylating agents (e.g. 1,4-diiodobutane, o-xylylenediiodide) resulted in a novel type of bispyrylium salts (14) with 3,3′-linkage. The pyrylium salts obtained were characterized by their 1H-n.m.r. and u.v. spectra as well as, in most cases, by transformation into the corresponding pyridine derivatives (13) and bispyridines (15) respectively.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 327 (1985), S. 775-788 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrylium Compounds. XXIX. Substituted Benzophenones from 2,4,6-Triarylpyrylium Salts and Methyl(ene) KetonesIn the presence of piperidine acetate (or similar salts of certain dialkylamines), 2,4,6-triarylpyrylium perchlorates 5 react with methyl(ene) ketones 6 to give benzophenones 7, the structure of which was proved by spectroscopic methods as well as by independent synthesis. Besides acetone and other acyclic ketones (e. g. alkyl methyl ketones, phenylacetone, desoxybenzoin, dibenzyl ketone) cyclic ketones (e. g. cyclopentanone, cyclohexanone, cycloheptanone, acenaphthenone) can also be used as ketone component 6; acetophenones react differently leading to hydrocarbons of the 1,3,5-triarylbenzene type 15. The varying efficiency of the diverse amine salts and the mode of incorporation of the unsymmetrically substituted ketones suggest the intermediate formation of enamines 10 as crucial step of the ring transformations observed. This assumption is supported by isolation of the iminium salt 18 on reacting 3,5-dimethyl-2,4,6-triphenylpyrylium perchlorate (16) with acetone/piperidine acetate.
    Additional Material: 1 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 330 (1988), S. 35-43 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrylium Compounds. 38. About the Ring Transformation of 2,4,6-Triarylthiopyrylium Salts by Acetic Acid Anhydride to Arylbenzenes and Thiobenzophenones2,4,6-Triarylthiopyrylium salts 5 react in the presence of an appropriate condensing agent (sodium acetate, carbonate, methoxide, tert-butoxide or potassium acetate) with acetic acid anhydride to yield arylbenzenes 3 and thiobenzophenones 6. This ring transformation represents the first example of the conversion of the moiety into the thiocarbonyl group Under the same conditions 3,5-dimethyl-2,4,6-triphenylthiopyrylium perchlorate (13) forms via [1,5]-sigmatropic rearrangement the thiobenzophenone 15. The structure of the new compounds 6 was proved by spectroscopic methods as well as by degradation reactions. Thus, hydrogen peroxide converts 6a to the known benzophenone 4. Alkaline saponification gives the 2-hydroxy-benzophenone 8, whereas heating with hydrochloric acid causes a selective cleavage of the acetoxy group to the 2-hydroxy-thiobenzophenone 7.
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