Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Solution Structure of [Me-L-Leu7]Didemnin B Determined by NMR Spectroscopy and Refined by MD Calculation (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 25-47 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several homo- and heteronuclear two-dimensional NMR techniques were used to assign all H- and C-resonances of the two conformers A and B of [7-(N-methyl-L-leucine)]didemnin B. Didemnine is a biologically highly active cytostaticum and immunosuppressivum. The assignment of the aliphatic C-atoms were done by the inverse H,C-COSY with TOCSY transfer which connects complete proton spin systems and represents them on C-atoms. The structure of both conformers (A and B) in (D6)DMSO solution was derived from homo- and heteronuclear couplings (J), temperature dependencies of NH protons, and NOE effects. Distances determined from the latter were used for refinements by restrained MD calculations using the GROMOS program. The solution structure of [Me-L-Leu7]didemnin B (A and B) was compared to that of didemnin B. The backbone structure of the macrocyclic ring and of the linear side-chain moiety are very similar in conformer A and didemnin B, though the Ist1-Hip2 region of the ring is slightly ex tended in conformer A. This may be caused by the influence of the Me-L-Leu7 residue in A and may be responsible for its reduced biological activity in comparison to didemnin B. The more weakly populated conformer B exhibits a βVI turn in the linear side-chain moiety.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730104
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Synthese von cis- und trans-3-PhenoxyprolinHerrn Professor Dr. W. Lüttke zum 60. Geburtstag gewidmet. (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1881-1889 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of cis- and trans-3-Phenoxyproline**Allylic bromination of the 1,2-dehydroproline ester 4 and reaction of the resulting bromoimine 3 with thallium phenolate affords 3-phenoxy-1,2-dehydroproline methyl ester (9). Reduction experiments with 9 and 10 are described, which lead in the most favorable case to a mixture of the corresponding cis/trans-isomeric prolines 11a and 11b in a ratio of 2:3. A “one-pot” procedure starting from 3 is described for the preparation of 7a.
    Notes: Allylbromierung des 1,2-Dehydroprolinesters 4 und Umsetzung des entsprechenden Bromimins 3 mit Thalliumphenolat gibt den 3-Phenoxy-1,2-dehydroprolin-methylester (9). Reduktionsversuche an 9 sowie 10 werden beschrieben und führen im günstigsten Fall zu einer Mischung der entsprechenden cis/trans-isomeren Proline 11a und 11b im Verhältnis 2:3. Ausgehend von 3 wird eine“Eintopf”-Reaktion zur Darstellung von 7a beschrieben.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919791125
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Sequenzierung von Thiazolaminosäuren enthaltenden Cyclopentapeptiden („Dolastatin 3“) durch FAB/MSMS (1986)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1986 (1986), S. 1940-1949 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sequencing of Cyclopeptides Containing Thiazole Amino Acids (“Dolastatin 3”) by Using Fast Atom Bombardment (FAB)/Tandem Mass Spectrometry (MSMS)Unequivocal sequencing of the cyclopeptides cyclo[-LPro-DLeu-L Val-D(gln)Thz-(gly)Thz-] (1) and cyclo[-(gly)Thz-D(gln)Thz-LVal-DLeu-LPro-] (2) can be achieved by combining fast atom bombardment with tandem mass spectrometry methodologies, thus opening a way to elucidate the as yet unknown sequence of dolastatin 3.
    Notes: Die Sequenzen der Cyclopeptide cyclo[-L-Pro-DLeu-L Val-D(gln)Thz-(gly)Thz-] (1) und cyclo[-(gly)Thz-D(gln)Thz-LVal-DLeu-LPro-] (2) lassen sich durch eine Kombination von „Fast-Atom-Bombardment“-(FAB-) und Tandem-Massenspektrometrie in eindeutiger Weise herleiten. Hiermit wird die Möglichkeit eröffnet, die bis jetzt unbekannte Struktur von Dolastatin 3 aufzuklären.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198619861114
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Synthesen von Peptidalkaloiden, 11. Über Aminosäuren und Peptide, 51.  -  Dehydroaminosäuren, 19. Totalsynthese von Hexaacetylcelenamid A (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 1882-1894 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Peptide Alkaloids, 11.  -  Amino Acids and Peptides, 51.  -  Dehydroamino Acids, 19.  -  Total Synthesis of Hexaacetylcelenamide AThe total synthesis of the linear peptide alkaloid hexaacetylcelenamide A (7) is described. Key steps are two condensation reactions with α-dialkylphosphoryl amino acid derivatives 10 to obtain the dehydroamino acid and dehydro peptide derivatives 14 and 17, respectively.
    Notes: Es wird die Totalsynthese des linearen Peptidalkaloids Hexaacetylcelenamid A (7) beschrieben. Schlüsselreaktionen sind zwei Kondensationen mit α-(Dialkylphoshoryl)aminosäurederivaten 10 zum Aufbau der Dehydroaminosäure- und Dehydropeptidderivate 14 bzw. 17.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519850915
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Über Aminosäuren und Peptide, XLVIII Totalsynthese und biomimetische Bildung von Clionamid-Derivaten (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 785-793 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Acids and Peptides, XLVIII. - Total Synthesis and Biomimetic Formation of Clionamide DerivativesThe total synthesis of tetraacetylclionamide (9) from the sponge Cliona celata is described. The (E)-enamide is formed by selenium-oxide elimination. - A biomimetic preparation of N-Boc-O,O′,O''-trimethyldebromoclionamide (13) by decarboxylation of the corresponding dehydro amino acid is demonstrated.
    Notes: Die Totalsynthese von Tetraacetylclionamid (9) aus dem Schwamm Cliona celata wird beschrieben. Das (E)-Enamid wird durch Selenoxid-Eliminierung gebildet. - Eine biomimetische Bildung von N-Boc-O,O′,O′′-trimethyldesbromclionamid (13) durch Decarboxylierung der entsprechenden Dehydroaminosäure wird aufgezeigt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519850414
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    über Aminosäuren und Peptide, 50. Über aktivierte N, N-Dimethylaminosäuren. - Synthese von Enkephalinen mit N,N-Dimethyltyrosin (1985)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1985 (1985), S. 1254-1262 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Acids and Peptides, 50. - Activated N,N-Dimethylamino Acids. - Synthesis of Enkephalines Containing N,N-DimethyltyrosinePeptides of N,N-dimethylamino acids which are hard to obtain by conventional methods of peptide synthesis were prepared by using 3-cyano-4,6-dimethylpyridinethiol esters of N,N-dimethylamino acids. This method was used to synthesize N,N-dimethylenkephalines without epimerisation.
    Notes: Zur Aktivierung von N, N-Dimethylaminosäuren beim Aufbau von N,N-Dimethylpeptiden sind die Ester des 3-Cyan-4,6-dimethyl-2-pyridinthiols allen anderen untersuchten Aminosäurederivaten überlegen. Mit ihrer Hilfe ließen sich N,N-Dimethyl-Enkephaline ohne Epimerisierung aufbauen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198519850615
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Synthesen von Peptidalkaloiden, IX. Über Aminosäuren und Peptide, XLVI. Totalsynthese von Mucronin B (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 1205-1215 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Peptide Alkaloids, IX. - Amino Acids and Peptides, XLVI. - Total Synthesis of Mucronin BThe total synthesis of hte cyclopeptide alkaloid mucronin B (5), an ansapeptide with a 12-membered “handle” is described. Key steps are the preparation of hte N-methylamino acid 16 via phosphonate condensation followed by enantioselective hydrogenation and ring closure of hte linear educts 24a + 24b, which is achieved by catalytic hydrogenation and affords the ring compounds 25a + 25b.
    Notes: Es wird die Totalsynthese des Cyclopeptidalkaloids Mucronin B (5), eines Ansapeptids mit 12gliedrigem Henkel, beschrieben. Charakteristische Stufen sind der Aufbau der N-Methylaminosäure 16, durch Phosphonat-Kondensation mit enantioselektiver Hydrierung und der hydrierende Ringschluß des linearen Edukts 24a + 24b zum Cyclus 25a + 25b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198419840616
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Über Aminosäuren und Peptide, 63. Peptidsynthese durch N- oder O-Aktivierung von Aminosäuren mit 1,2-Dihydro-4,6-dimethyl-2-thioxo-3-pyridincarbonitril - Synthese des Cyclosporin-8 - 11 - Tetrapeptid-Segments (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 935-942 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Acids and Peptides, 63. - Peptide Synthesis via N- or O-Activation of Amino Acids with 1,2-Dihydro-4,6-dimethyl-2-thioxo-3-pyridinecarbonitrile. - Synthesis of the 8-11 Tetrapeptide Sequence of CyclosporinPeptides and N-methyl peptides have been prepared in high yields and nearly free of racemisation via N-activation (Scheme 1) or O-activation (Scheme 2) of N-acylamino acids and N-acyl-N-methylamino acids, respectively, by 1,2-dihydro-4,6-dimethyl-2-thioxo-3-pyridinecarbonitrile. - The difficultly accessible tetrapeptide Z-(R)-Ala-MeLeu-MeLeu-MeVal-Ot Bu (9) with the 8-11 sequence of the immunosuppressive undecacyclopeptide cyclosporin is synthesize by this method in 61% yield and free of racemisation.
    Notes: Peptide und N-Methylpeptide werden in guter Ausbeute und nahezu racemisierungsfrei aufgebaut über N-Aktivierung (Schema 1) oder O-Aktivierung (Schema 2) von N-Acylaminosäuren bzw. N-Acyl-N-methylaminosäuren mit 1,2-Dihydro-4,6-dimethyl-2-thioxo-3-pyridincarbonitril. Das schwierig zugängliche Tetrapeptid Z-(R)-Ala-MeLeu-MeLeu-MeVal-Ot Bu (9) mit der 8-11-Sequenz des immunosuppressiven Undecacyclopeptids Cyclosporin wird mit dieser Methode in 61% Ausbeute racemisierungsfrei hergestellt.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870851
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Synthesen von Peptidalkaloiden, VI. über Aminosäuren und Peptide, XXXVII. Totalsynthese von 9,10-Dihydrozizyphin G (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 2153-2162 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Peptide Alkaloids, VI1a).  -  Amino Acids and Peptides, XXXVII1b).  -  Total Synthesis of 9,10-Dihydrozizyphine G9,10-Dihydrozizyphine G (2a) was synthesized according to the reaction sequence 3a → 4a → 5a → 6a → 7a → 8a → 9a → 2a by ring formation at the phenylethylamine nitrogen atom and by the sequence 3a → 10a → 11a → 12a → 2a forming the ring at the proline nitrogen. The last method was more advantageous. The ring closures were achieved by catalytic hydrogenation of the pentafluorophenyl esters of ω-Z-amino acids.
    Notes: 9,10-Dihydrozizyphin G (2a) wurde auf dem Wege 3a → 4a → 5a → 6a → 7a → 8a → 9a → 2a durch Ringschluß am Phenylethylaminstickstoff (C) und über die Sequenz 3a → 10a → 11a → 12a → 2a durch Ringbildung am Prolinstickstoff synthetisiert. Der letzte Weg erwies sich als günstiger. Die Ringschlüsse wurden mittels katalytischer Hydrierung der ω-Z-Aminosäure-penta-fluorphenylester erreicht.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821206
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Synthesen von Peptidalkaloiden, VII. Über Aminosäuren und Peptide, XXXVIII. Totalsynthese der 10,11-Dihydrozizphine A und B (1983)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 1459-1467 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of peptide Alkaloids, VII. - Amino Acids and Peptides, XXXVIII. - Total Synthesis of the 10, 11-Dihydrozizyphines A and BThe 10,11-dihydrozizyphines A (13a) and B (15a) were synthesized. The cyclopeptide ring closure reactions were accomplished by catalytic hydrogenation of the linear ω-amino acid pentafluorophenyl ester 8a.
    Notes: Die 10,11-Dihydrozizyphine A (13a) und B (15a) wurden synthetisiert. Der Cyclopeptidringschluß wurde durch katalytische Hydrierung des linearen ω-Z-Aminosäure-pentafluorphenylesters 8a erreicht.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198319830902
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...