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  • 1
    Electronic Resource
    Electronic Resource
    Mechanistic studies on the Reactions of Cis-Diaquobis (Biguanide)Chromium(III) ion with 2,2′-dipyridyl and 1,10-phenanthroline (1976)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 424 (1976), S. 93-96 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Untersuchungen der Mechanismen der Reaktionen des cis-Diaquobis(biguanid)-Chrom(III)-Ions mit 2.2′-Dipyridyl und 1.10-PhenanthrolinKinetische Untersuchungen in wäßriger Lösung über den Austausch der Wasser-Liganden im cis-[Cr(BigH)2(OH2)2]3+ (BigH = Biguanid, C2H7N5) durch 2.2′-Dipyridyl bzw. 1.10-Phenanthrolin (phen) unter Bildung von [Cr(BigH)2(AA)]3+ (AA = dipy bzw. phen) wurden spektralphotometrisch durchgeführt.
    Notes: Kinetic studies in aqueous solution on the replacement of the aqua ligands in cis-[Cr(BigH)2(OH2)2]3+ (BigH = biguanide, C2H7N5) by 2,2′-dipyridyl (dipy) and 1,10-phenanthroline (phen) forming [Cr(BigH)2(AA)]3+ (AA = dipy or phen) have been made spectrophotometrically. In both the cases the reaction proceeds by a path purely first-order with respect to the ligand. From the values of the rate constant at four different temperatures, values of the activation parameters, ΔH≠ and ΔS≠, have been evaluated for each system. The results are consistent with a mechanism involving outer-sphere association of the reactants followed by transformation of the outer-sphere complex in a dissociative process.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19764240114
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  • 2
    Electronic Resource
    Electronic Resource
    Über Pterinchemie 52. Mittelung [1] Eine eindeutige Synthese isomerenfreier Pteroyl-γ-L-glutamyl-γ-L-glutamyl-L-glutaminsäure (1975)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 58 (1975), S. 1374-1379 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new and unequivocal synthesis of pteroyl-γ-L-glutamyl-γ-L-glutamyl-L-glutamic acid free of isomers is described. A melt of N(2′)-acetyl-6-formylpterine and tetramethyl-N-(p-amino-benzoyl)-γ-L-glutamyl-γ-L-glutamyl-L-glutamatewas quantitatively converted to the corresponding azomethin IX. NaBH4-reduction followed by basic hydrolysis of acetyl and methylester groups gives pure pteroyl-γ-L-glutamyl-γ-L-glutamyl-L-glutamic acid in good yield.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19750580516
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  • 3
    Electronic Resource
    Electronic Resource
    Über Pterinchemie. 54. Mitteilung [1]. Eine allgemeine Methode zur Synthese von Folsäure, Folsäurekonjugaten und FolsäureanalogenTeilweise von P. K. Sengupta anlässlich des 5 Internationalen Pteridin-Symposiums in Konstanz, BRD (14.-18. April 1975) vorgetragen. (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 242-247 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A general method for synthesis of folic acid, its conjugates and analogues.A new and general method for the synthesis of folic acid, folic acid conjugates and folic acid analogues is described. The key step, i.e. the condensation of N(2′)-acetyl-6-formyl-pterine (I: R1 = COCH3) with aminoaryl derivatives II, is achieved by refluxing in absolute ethanol to afford the azomethines III. NaBH4-reduction followed by basic hydrolysis gives pure V products in high yield, free from 7-isomers.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590127
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  • 4
    Electronic Resource
    Electronic Resource
    Über Pterinchemie. 62. Mitteilung. Protonenkatalysierte [1,2]-H-Verschiebung bei der Umlagerung von 6,7-Diphenyl-5,6-dihydropterin zu 6,7-Diphenyl-7,8-dihydropterin (1977)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 60 (1977), S. 922-924 
    Details
    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).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19770600322
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  • 5
    Electronic Resource
    Electronic Resource
    Über Pterinchemie. 73. Mitteilung [1]. Zum Verlauf der katalytischen Reduktion von 7-Methylpterin (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 395-401 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Pathway of the Catalytic Reduction of 7-MethylpterinThe catalytic hydrogenation of 7-methylpterin (VII) in a neutral solution occurs first by the reduction of the 7,8-double bond (thermodynamically-controlled reaction) followed by the reduction of the 5,6-double bond. On the contrary, in an acidic medium like CF3COOH, the 5,6-double bond is reduced first (kinetically-controlled reaction). The dihydro-intermediate then undergoes a [1,2]-H-rearrangement leading to the formation of the thermodynamically more stable 7-methyl-7,8-dihydropterin (XV) which on further reduction gives 7-methyl-5,6,7,8-tetrahydropterin (VIII). The catalytic reduction of 7-methyl-7,8-dihydropterin (XV) with deuterium gives stereoselectively a sole product with D at C(6) in the equatorial position.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19800630209
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  • 6
    Electronic Resource
    Electronic Resource
    Über Pterinchemie. 74. Mitteilung73. Mitt. s. [1].. Zum Verlauf der katalytischen Reduktion von 6-Methylpterin (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1754-1758 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Pathway of the Catalytic Reduction of 6-MethylpterinThe catalytic hydrogenation of 6-methylpterin (I) in neutral or weekly acidic solution begins, as for the 7-methylpterin, by the thermodynamically controlled reduction of the 7,8-double bond. It is not possible to say, according to our experiments, which double bound, either the 5,6 or the 7,8, is first reduced in strongly acidic solution. However, a 5,8-reduction can be excluded.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19800630646
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  • 7
    Electronic Resource
    Electronic Resource
    Studien über Dehydrogenierung, II (1939)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 152 (1939), S. 9-19 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19391520102
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  • 8
    Electronic Resource
    Electronic Resource
    Studien über Dehydrogenierung, I (1938)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 151 (1938), S. 82-96 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19381510204
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  • 9
    Electronic Resource
    Electronic Resource
    Monohydroxytrifluoroborates and double fluoroborates (1970)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 379 (1970), S. 106-111 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Es wird die Darstellung von Hydroxotrifluoroboraten von Rb, Cs, (CH3)4N+, Nitron, Ni2+, Ni(py)42+ und Co(NH3)63+ beschrieben. Darüber hinaus wurden neuartige 1 : 1-Doppelsalze aus Tetrafluoro- und Hydroxotrifluoroborat erhalten. Von einigen dieser Salze werden Röntgenpulver- und IR-Daten mitgeteilt.
    Notes: The preparation of monohydroxotrifluoroborates of rubidium, cesium, tetramethylammonium, nitron, nickel, tetrapyridine nickel and hexammine cobalt(III) is described. Besides, a new series of double salts, comprising one mole tetrafluoroborate and one mole of monohydroxotrifluoroborate of the same cation, are described. The X-ray and IR-spectra of some of these salts are reported.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19703790118
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  • 10
    Electronic Resource
    Electronic Resource
    Complex Carbonates of Chromium(III) (1974)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 404 (1974), S. 81-86 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Komplex-Carbonate des Chrom(III)Durch Mischen von Cr(III)-Lösungen mit Lösungen von (NH4)2Co3 oder KHCO3 werden tieffarbige Lösungen und mit NaHCO3 ein Niederschlag erhalten. Das Spektrum von Cr(NO3)3 (violett) gelöst in 35proz. KHCO3-Lösung zeigt Absorptionsmaxima bei 430 und 580 nm, wogegen Cr(NO3)3 (violett) Absorptionsmaxima bei 410 und 575 nm hat. Die Lösung von Cr(III) in 20proz. KHCO3-Lösung wurde durch Ionenaustausch untersucht. Die Komplex-Carbonate des Chroms (Formeln siehe Abstract) wurden dargestellt und thermogravimetrisch untersucht sowie die IR-Spektren aufgenommen und Bandenzuordnungen vorgenommen.
    Notes: On adding chromium(III) solution to solutions of (NH4)2CO3 or KHCO3, deep coloured solutions are obtained, whereas, in the case of NaHCO3 a precipitate is obtained. The spectrum of chromium(III) nitrate (violet) dissolved in KHCO3 (35%) solution shows maximum absorbances at 430 and 580nm, whereas the spectrum for chromium(III) nitrate (violet) shows maximum absorbances at 410 and 575 nm. The chromium(III) solution dissolved KHCO3 (20%) is studied by ion exchange method. The complex carbonates of chromium (III), viz., (i) (NH4)2[Cr2(OH)4(CO3)2] · H2O, - (ii) K7[Cr4(OH)9(CO3)5] · 6 H2O, - (iii) Na3[Cr2(OH)5(CO3)2] · 4 H2O, - (iv) NH4[Co(NH3)6] [Cr3(OH)7(CO3)3] · 4 H2O, and (v) K6[Co(NH3)6]2[Cr2(OH)4(CO3)3]3 are isolated and studied by thermogravimetry. The infrared spectra of these compounds are recorded and probable band assignments made.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19744040107
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