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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 182 (1992), S. 262-268 
    ISSN: 0006-291X
    Keywords: [abr] BCS; bovine calf serum ; [abr] IGF-I; insulin-likegrowth factor I ; [abr] IGFBP-1; insulin-like growth factor binding protein-1 ; [abr] INS; insulin ; [abr] PDB; phorbol-12, 13-dibutyrate ; [abr] PKC; protein kinase C ; [abr] PMA; phorbol 12-myristate 13-acetate ; [abr] SDS/ PAGE; sodium dodecyl sulfate polyacrylamide gel ; [abr] kDa; kilodalton
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 182 (1992), S. 262-268 
    ISSN: 0006-291X
    Keywords: [abr] BCS; bovine calf serum ; [abr] IGF-I; insulin-likegrowth factor I ; [abr] IGFBP-1; insulin-like growth factor binding protein-1 ; [abr] INS; insulin ; [abr] PDB; phorbol-12, 13-dibutyrate ; [abr] PKC; protein kinase C ; [abr] PMA; phorbol 12-myristate 13-acetate ; [abr] SDS/ PAGE; sodium dodecyl sulfate polyacrylamide gel ; [abr] kDa; kilodalton
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, VII1) Studies in the Synthesis of the Antibiotics Gliotoxin, Sporidesmin, Aranotin, Chaetocin, and Verticillin, VII1) On the Introduction of Oxygen Functions in Prolyl-proline Anhydride with Lead Tetraacetate: A New Way to Epidithioprolyl-proline AnhydrideOxidation of L-prolyl-L-proline anhydride (1a) with lead tetraacetate affords 3,6-diacetoxy-L-prolyl-D-proline anhydride (2b). Reaction of 2b with ethanethiole yields cis-3,6-bis(ethylthio)prolyl-proline anhydride (3a), with thiolacetic acid :trans-3,6-bis(acetylthio)prolyl-proline anhydride (4b) is formed. Solvolysis with diluted aqueous acid leads to cis-3,6-di-hydroxyprolyl-proline anhydride (5a). By means of the reactions 1a → 2b → 5a a new way to epidithioprolyl-proline anhydride 6 was found.
    Notes: L-Prolyl-L-prolinanhydrid (1a) wird mit Bleitetraacetat zum 3,6-Diacetoxy-L-prolyl-D-prolinanhydrid (2b) oxidiert. 2b bildet mit Äthylmercaptan cis-3, h-Bis(äthylmercapto)prolyl-prolinanhydrid (3a) und mit Thioessigsäure trans-3,6-Bis(acetylmercapto)prolyl-prolin-anhydrid (4b). Durch Solvolyse mit verdünnter wäßriger Säure erhält man cis-3,6-Dihydroxy-prolyl-prolinanhydrid (5a). Durch dic Reaktionsfolge 1a → 2b → 5a ist ein neuer Weg zum Epidithioprolyl-prolinanhydrid 6 gegeben.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 2907-2916 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, XV. Formation of hydroxycyclodipeptides by Cyclization of Pyruvoyl Amino Acids, II. Double Cyclization2-Oxo-5-(pyruvoylamino)valeric methylamide (15) is synthesized via the compounds 10-14. 15 is stable in cristalline form and in chloroform solution, but affords the dihydroxycyclodipeptide 16 in dilute HCl solution by a double cyclization reaction. Further reaction with H2S/ZnCl2 and subsequent dehydrogenation yield the epidithio-cyclodipeptide 17. 1,2-Dehydroproline methylamide (23) is obtained by reaction of 5-azido-2-oxovaleric methylamide (22) with triphenylphosphine.
    Notes: 2-Oxo-5-(pyruvoylamino)valerian-methylamid (15) wird über die Stufen 10-14 aufgebaut. 15, in kristallinem Zustand und in Chloroformlösung stabil, bildet in verdünnter Chlorwasserstoffsäure durch zweifachen Ringschluß das Dihydroxy-cyclodipeptid 16. Reaktion mit H2S/ZnCl2 und folgende Dehydrierung führen von 16 zur Epidithioverbindung 17. 5-Azido2-oxovalerian-methylamid (22) wird mit Hilfe von Triphenylphosphin in 1,2-Dehydroprolinmethylamid (23) umgewandelt.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 921-941 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, XVII. On Dehydroamino Acids, IV. Ring Closure of DehydropeptidesSix- or five-membered cyclic compounds (amino-piperazinediones: 2, 14-19, 21, 24, or imidazolidinones 28, 29) are obtained under basic conditions from dehydropeptides by α-addition of an amide function to the acylaminoacrylic unit. Sterical conditions, scope, and limitations of this cyclisation have been investigated up to the dehydrotetrapeptide amide 20. Formation of six-membered rings is preferred. Five-membered rings only result, if reaction to six-membered rings is excluded either by the structure of the dehydropeptide (no NH-function available) or by its conformation (s-trans amide function). Ring closure to the cyclodipeptides 2a, 14, 15, 18, 19, 21, and 24 proceeds stereoselectively.
    Notes: Dehydropeptide bilden in alkalischer Lösung durch α-Addition einer Amidgruppe an das Acylaminoacrylsäuresystem sechs- oder fünfgliedrige Ringe (Amino-piperazindione: 2, 14-19, 21, 24 bzw. Imidazolidinone: 28, 29). Reaktionsbedingungen, räumlicher Ablauf und Grenzen der Cyclisierung wurden bis zum Ringschluß des Dehydrotetrapeptidamids 20 untersucht. Der Sechsring wird bevorzugt. Ein Fünfring bildet sich nur dann, wenn die Cycloaddition zum Sechsring infolge der Struktur (keine NH-Funktion zur Addition) oder der Konformation (s-trans-Fixierung einer Amidbindung) des Dehydropeptids nicht möglich ist. Der Ringschluß zu den Cyclodipeptiden 2a, 14, 15, 18, 19, 21 und 24 verläuft stereoselektiv.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 3722-3723 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies in the Synthesis of the Antibiotics Gliotoxin, Sporidesmin, Aranotin, and Chaetocin, IV. Preparation of Epidithio-L-prolyl-L-proline AnhydrideRepeated research of the electrophilic introduction of sulfur functions into the -3 and 6-positions of 2.5-dioxopiperazines leads to the preparation of the amorphous epioligothio-L-prolyl-L-proline anhydride (7). The latter could be reduced and consequently dehydrogenated forming epidithio-L-prolyl-L-proline anhydride (8) which corresponds in conformation and configuration to the naturally occurring antiviral antibiotics.
    Notes: Erneute Untersuchung der elektrophilen Einführung von Schwefelfunktionen in den Dioxopiperazinkern führte zur Synthese eines amorphen Epioligothio-L-prolyl-L-prolinanhydrids (7). Aus diesem wurde durch Reduktion und folgende Dehydrierung Epidithio-L-prolyl-L-prolinanhydrid (8) gebildet, das in der Konformation und Konfiguration den natürlichen antiviralen Antibiotika entspricht.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Amino Acids and Peptides, VI. Studies in the Synthesis of the Antibiotics Gliotoxin, Sporidesmin, Aranotin, Chaetocin, and Verticillin, VI. Nucleophilic Introduction of Sulfur Functions via Sulfones and Hydroxy Derivatives of Cyclic Dipeptides (Dioxopiperazines)2,3-Dehydroprolyl-proline anhydride (6) and 2,3-dehydroprolyl-2-3-dehydroproline anhydride (2) are prepared by elimination of methanethiol from cis-3-(methylthio)prolyl-proline anhydride (5a) and cis- or trans-3,6-bis(methylthio)prolyl-proline anhydride (1a, 1b). Oxidation of the sulfides (5a, 1a, 1b) affords the corresponding sulfones (10a) and hydroperoxides (12a, 14b). 12a and 14b are reduced to the hydroxides 13a and 15b. Sulfones and hydroxides undergo nucleophilic displacement reactions with sulfur functions. In this way it is possible to convert the mixture of the isomeric sulfides 1a and 1b to racemic epidithioprolyl-proline anhydride (20). The steric course of these nucleophilic reactions is examined. Retention of configuration is observed in displacement reactions involving only one asymmetric carbon of cis-prolyl-proline anhydride. Reactions involving both asymmetric carbons yield the thermodynamically more stable isomer (ld or ll + dd).
    Notes: 2,3-Dehydroprolyl-prolinanhydrid (6) und 2,3-Dehydroprolyl-2,3-dehydroprolinanhydrid (2) werden durch Eliminierung von Methylmercaptan aus cis-3-(Methylmercapto)prolyl-prolinanhydrid (5a) und cis- oder trans-3,6-Bis(methylmercapto)prolyl-prolinanhydrid (1a, 1b) hergestellt. Oxidation der Thioäther (5a, 1a, 1b) liefert die entsprechenden Sulfone (10a) bzw. Hydroperoxide (12a, 14b). Letztere werden zu den Hydroxiden (13a, 15b) reduziert. Sulfone und Hydroxide sind nucleophilen Substitutionsreaktionen durch Schwefelfunktionen zugänglich. Auf diese Weise ist es möglich, das Isomerengemisch 1a + 1b in racemisches Epidisulfid 20 umzuwandeln. Die Stereochemie dieser nucleophilen Reaktionen wird untersucht: Bei nucleophilen Reaktionen an nur einem der asymmetrischen Kohlenstoffatome des cis-Prolyl-prolinanhydrids bleibt die Konfiguration erhalten, bei Reaktionen an beiden asymmetrischen Kohlenstoffatomen wird das thermodynamisch stabilere Isomere (ld oder ll + dd) gebildet.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies in the Synthesis of the Antibiotics Gliotoxin, Sporidesmin, Aranotin, Chaetocin, and Verticillin, V. Preparation of Epitrithio- and Epitetrathio-L-prolyl-L-proline Anhydridecis-3.6-Dimercapto-L-prolyl-L-proline anhydride (5) was prepared in crystalline and pure form by reduction of 3.6-epidithio-L-prolyl-L-proline anhydride (2) using sodium borohydride. Treatment of the dimercaptan with SCl2 and S2Cl2 affords epitrithio- (6) and epitetrathio-L-prolyl-L-proline anhydride (4), respectively.
    Notes: Reines und kristallines cis-3.6-Dimercapto-L-prolyl-L-prolinanhydrid (5) ließ sich durch Boranatreduktion aus 3.6-Epidithio-L-prolyl-L-prolinanhydrid (2) gewinnen. Mit SCl2 und S2Cl2 bildete das Dimercaptan Epitrithio- (6) bzw. Epitetrathio-L-prolyl-L-prolinanhydrid (4).
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3034-3047 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Dialkyl Hetaryl- and Hetarylvinylphosphonates from Dialkyl 2-Bromo-1-oxoalkyl-and 4-Bromo-3-oxo-1-alkenylphosphonatesDialkyl 3-oxo-1-alkenylphosphonates 1 react with NBS to give the (bromoacyl)vinyl derivatives 2. Reacting acylphosphonates 3 with bromine, the α-bromoacyl compounds 4 are obtained. The latter yield thiazolylphosphonates 7 and 8 with thioacetamide and thiourea, respectively, indolizinylphosphonates 15 with ethyl α-pyridylacetate, imidazo[1,2-a]pyridinyl derivatives 16 with 2-aminopyridine, and imidazo[1,2-a]pyrimidinyl compounds 17 and 18 with 2-aminopyrimidine and 2-amino-4,6-dimethylpyrimidine, respectively. - Starting with the vinyl compounds 2 the vinylogous thiazoles 9 and 10, indolizines 19, imidazo[1,2-a]pyridines 20, and imidazo[1,2-a]-pyrimidines 21 are obtained by the same method. Condensation with cytosine affords the imidazo[1,2-c]pyrimidines 24.
    Notes: 3-Oxo-1-alkenylphosphonate 1 werden mit NBS zu den (Bromacyl)vinyl-Derivaten 2, Acylphosphonsäureester 3 mit Brom zu den α-Bromacylphosphonaten 4 umgesetzt. Letztere reagieren mit Thioacetamid und Thioharnstoff zu den Thiazolylphosphonaten 7 bzw. 8, mit 2-Pyridylessigester zu den Indolizinylphosphonaten 15, mit 2-Aminopyridin zu den Imidazo[1,2-a]pyridinylphosphonaten 16, mit 2-Aminopyrimidin bzw. 2-Amino-4,6-dimethylpyrimidin zu den Imidazo-[1,2-a]pyrimidinyl-Systemen 17 bzw. 18. - Aus den 4-Brom-3-oxoalkenylphosphonaten 2 werden nach dem gleichen Reaktionsprinzip entsprechende vinyloge Thiazole 9 und 10, Indolizine 19, Imidazo[1,2-a]pyrimidine 20 und Imidazo[1,2-a]pyrimidine 21 erhalten. Kondensation mit Cytosin liefert die Imidazo[1,2-c]pyrimidine 24.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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