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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 71 (1999), S. 199-206 
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Nanofiltration Membranes for Separation Problems in Organic Solutions.Nanofiltration based on rejection and flux features intermediate between those ultrafiltration and reverse osmosis is one of the technically and scientifically interesting membrane processes with a great future. Moreover, most commercial available nanofiltration membranes are only suitable for separation processes in aqueous solutions. A small number of composite membranes with a highly cross-linked selective layer show a technically interesting resistance towards organic solvents, such as ketones, esters, ethers or alcohols. The present article describes such nanofiltration membranes used for separation of low molecular weight chemical compounds from polar or nonpolar solvents, but also for the removal of organic compound from aqueous solutions. Methods of manufacturing and modifying such solvent stable composite membranes are shown, as are the conditioning of membranes and examples of industrial application.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 1562-1567 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chain elongation of the deoxy-nitroribose 6 by a Michael addition to the vinyl-phosphonate 7 followed by a solvolysis gave the heptulosephosphonate 11 (87%). From 11, the key intermediates 15 and 16 (77%) were obtained by a highly diastereoselective reduction, followed by detritylation, periodate cleavage, and silylation. Methoxycarbonylation of 15 and 16 gave 17 and 18 which were converted into methyl shikimate (21; 79%) by intramolecular olefination and partial deprotection. Similarly, phosphonoylation of 16 gave 22 (99%) which was transformed into the diethyl phosphashikimate 2 (53% from 6).
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 988-996 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pseudolactones 6 and 12 were prepared in a straightforward way from methyl α-D-glucopyranoside and methyl α-D-mannopyranoside, respectively. The pseudolactone 6 reacted with tert-butyl lithioacetate to give the protected, trihydroxylated cyclohexenone carboxylate 7 (51 %). The sterically hindered, L-ribo-configurated pseudolactone 12 reacted with diethyl ethylphosphonate and dimethyl methylphosphonate to give the protected trihydroxycyclohexenones 17 (49 %) and 18 (62 %), respectively. The hydroxymethylated cyclohexenone 21 was obtained from 18 by treatment with Me2AlSPh and then formaldehyde, oxidation of the product 19, and elimination. Deprotection of 21 gave 2, identical with KD16-Ul. Esterification of 2 gave 1, identical with the title compound. Alternatively, 1 was obtained in higher yields by esterification of 21, followed by deprotection of the hydroxy groups. This synthesis gave 1 and 2 from methyl α-D-mannopyranoside in an overall yield of 18 and 20 %, respectively, confirming their absolute configuration.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 67 (1984), S. 730-738 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of the 83%-trans-13CH3-labelled 1,6-dienoate 7 with Et2AlCl at-78° provided in high yield the ene product 9 containing 83% 13C localized in the olefinic C(8)-methylene group. Accordingly, H-transfer occurs exclusively from the trans-methyl group of 7, consistent with a concerted ene process 7 9 thereby ruling out an intermediate cation 8 (Scheme 4).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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