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  • 1
    Electronic Resource
    Electronic Resource
    Synthese, Reaktionen und NMR-Spektren von 2-Brom-3-oxo-1-alkenyl- und 3-Oxo-1-alkinyl-phosphonsäure-dialkylestern (1984)
    Springer
    Monatshefte für Chemie 115 (1984), S. 493-508 
    Details
    ISSN: 1434-4475
    Keywords: Acyl-substituted pyrazolylphosphonates ; 2-Bromo-3-oxo-1-alkenylphosphonates13C-NMR-spectra, Configurational assignment ofβ-discubstituted vinylphosphonates ; 3-Oxo-1-alkenylphosphonates ; 3-Oxo-1-alkinyl-phosphonates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Dialkyl (E)-3-oxo-1-alkenylphosphonates (1), on reaction with bromine and subsequent HBr-elimination, yield the isomeric β-bromovinyl derivatives (Z)-3 and (E)-3 and the alkinylphosphonates4. β-Bromovinyl compounds3 can also be obtained by reaction of1 withNBS in aqueous solution. The configuration of the β-disubstituted vinylcompounds is assigned from their13C-NMR spectra. Both bromovinyl compounds3 and alkinylderivatives4 are used for regioselective syntheses of acylsubstituted pyrazolylphosphonates5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00810011
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  • 2
    Electronic Resource
    Electronic Resource
    Stereochemical dependence of13C-shift and31P-13C-coupling in 3-substituted bicyclo[2.2.1]hept-5-en-2-yl- and bicyclo[2.2.2]oct-5-en-2-yl-phosphonates (1982)
    Springer
    Monatshefte für Chemie 113 (1982), S. 1321-1327 
    Details
    ISSN: 1434-4475
    Keywords: Bicyclo[2.2.1]hept-5-en-2-ylphosphonates ; Bicyclo[2.2.2.]oct-5-en-2-ylphosphonates ; 13C-Shifts ; 31P-13C-Coupling constants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Der sterische Einfluß auf13C-Verschiebungen und31P-13C Kopplungskonstanten wurde an Phosphonaten mit starrer Struktur untersucht.
    Notes: Abstract Steric influences operating on13C-shifts and31P-13C-coupling constants have been investigated on phosphonates with a rigid framework.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00808747
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  • 3
    Electronic Resource
    Electronic Resource
    Cyclisierungsreaktionen von Diazoalkenyl-phosphonsäureestern Synthese von Pyrazolyl- und 2,3-Benzodiazepinylphosphonsäureestern (1984)
    Springer
    Monatshefte für Chemie 115 (1984), S. 629-646 
    Details
    ISSN: 1434-4475
    Keywords: Benzo-2,3-diazepinyl-phosphonates ; 1,5- and 1,7-Cyclisation ; Diazo-alkenylphosphonates ; Oxo-alkenylphosphonates ; Pyrazolylphosphonates ; Tosylhydrazones of oxo-alkenylphosphonates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Tosylhydrazones3 and4 of dialkyl 3-oxo-1-alkenylphosphonates1 and 1-oxo-2-alkenylphosphonates2, respectively, react with aqueous sodium carbonate to give the pyrazoles7 in excellent yields. Under analogous conditions the tosylhydrazone9 of diethylo-vinylbenzoyl phosphonate (8) affords diethyl 2-hydroxy-1-indanyl phosphonate (10). Upon thermolysis of the sodium salt12 generated from9 in anhydrousD M E, one obtains, depending on the reaction conditions, either the 1-H-benzodiazepinyl derivative14 or its 5H-isomer15. At room temperature the diazo compound13 cyclizes slowly to give14, which can be isomerized to15 by action of base.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00799172
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  • 4
    Electronic Resource
    Electronic Resource
    Ein einfacher Weg zu α-substituierten (E)-3-Oxo-1-alkenylphosphonsäureestern (1985)
    Springer
    Monatshefte für Chemie 116 (1985), S. 77-86 
    Details
    ISSN: 1434-4475
    Keywords: Wittig-reaction of dialkyl acylphosphonates, with 2-oxo alkylidene triphenylphosphoranes ; E-β-acylvinylphosphonates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract α-Substituted dialkyl (E)-β-acylvinylphosphonates [R 2CO-CH=C(R 1)-P(O)(OR′)2,3], are easily obtained in good yields byWittig-reaction of dialkyl acylphosphonates1 [R 1CO-P(O)(OR′)2,R 1=alkyl or aryl) with 2-oxoalkylidene triphenylphosphoranes2 [R 2CO-CH=PPh 3,R 2=alkyl, O-alkyl and CH2 X (X=Br, OMe, CO2 Et)].
    Notes: Zusammenfassung α-Substituierte β-Acylvinylphosphonate3 mitE-Konfiguration [R 2CO-CH=C(R 1)-P(O)(OR′)2], werden in guten Ausbeuten durchWittig-Reaktion von Acylphosphonsäureestern1 [R 1CO-P(O)(OR′)2,R 1=Alkyl oder Aryl] mit (2-Oxoalkyliden)triphenylphosphoranen2 [R 2CO-CH=PPh 3,R 2=Alkyl, O-Alkyl oder CH2 X (X=Br, OMe, CO2 Et)] erhalten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00798281
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  • 5
    Electronic Resource
    Electronic Resource
    Ein einfacher Weg zu D-Apio-β-D-furanosyl- und 2′-Desoxyapio-β-D-furanosylnucleosiden (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 551-558 
    Details
    ISSN: 0947-3440
    Keywords: Apionucleosides ; Nucleosides ; Antiviral agents ; Tris(trimethylsilyl)silane ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Convenient Route to D-Apio-β-D-furanosyl- and 2′-Deoxyapio-β-D-furanosyl Nucleosides2,3-O-Isopropylidene-D-apio-β-D-furanose (1), available in 40% overall yield by modified literature procedures, is acylated regioselectively to the new 3′-O-benzoyl-derivative 2. This is converted to the anomeric triacetates 4 (β-4; α-4 = 1.8:1) by cleavage of the isopropylidene protecting group from 2 followed by peracetylation. Reaction of compounds 4 with silylated nucleobases and subsequent deprotection gives the D-apio-β-D-furanosyl nucleosides 8-10 in good yields. Regioselective hydrazinolysis of the protected nucleosides 5 and 6 affords the 2′-hydroxy-derivatives 11 and 12, respectively, which are converted to the 2′-deoxyapio-β-D-furanosyl nucleosides 17 and 18, respectively, via deoxygenation of the corresponding thionocarbonates 13 and 14 with tris(trimethylsilyl)silane and subsequent deprotection. The 2′-deoxyapio-β-D-furanosyl cytosine 20 is prepared from the 2′-deoxyapio-β-D-furanosyl uracil derivative 16.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199519950375
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  • 6
    Electronic Resource
    Electronic Resource
    Ein einfacher Weg zu 3′-Desoxy-α-L- und 3′-Desoxy-β-D-apionucleosiden (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 559-565 
    Details
    ISSN: 0947-3440
    Keywords: Apionucleosides ; Nucleosides ; Antiviral agents ; Branched nucleosides ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Convenient Route to 3′-Deoxy-α-L- and 3′-Deoxy-β-D-apionucleosidesThe cyclic thionocarbonate 3, easily available in three steps from 3′-O-benzoyl-2,3-O-isopropylidene-D-apio-β-D-furanose (1), is deoxygenated with n-Bu3SnH to yield the 3′-deoxy epimers 4 [methyl 3-C-(benzoyloxymethyl)-3-deoxy-α-L-threo-tetrofuranoside] and 6 [methyl 3-C-(benzoyloxymethyl)-3-deoxy-β-D-erythro-tetrofuranoside]. These are separated by chromatography and further converted to the 3′-deoxy-α-L-apionucleosides 11-13, and the 3′-deoxy-β-D-apionucleosides 17-19, respectively.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199519950376
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  • 7
    Electronic Resource
    Electronic Resource
    N,O Highly Regio- and Stereoselective Alkylation of Nucleophilic Glycine Equivalents with Carbonates of Allylic α-Hydroxyphosphonates: A Convenient Route to Racemic 2-Amino-5-phosphono-4-pentenoic Acids (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1437-1445 
    Details
    ISSN: 0947-3440
    Keywords: Phosphonate-substituted allylic carbonates ; Allylic alkylation, palladium(0)-catalyzed ; Glycine equivalents ; Regioselectivity ; Stereoselectivity ; Alkylations ; Palladium ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Palladium(0)-catalyzed allylic alkylation of diethyl (acetyl-amino)malonate (6), ethyl (diphenylmethyleneamino)acetate (7), and (diphenylmethyleneamino)acetonitrile (8), respectively, with the acrolein-derived 1-dialkoxyphosphinyl-substituted carbonates 5 provides the γ-substituted vinylphosphonates 9-11 in very good yields and with high regioselectivity. The stereochemical outcome is dependent on the mode of nucleophilic activation of the glycine equivalents 6-8: When the reactions are performed in the presence of N,O-bis(trimethylsilyl)acetamide (BSA) the (Z) isomers (Z)-9-(Z)-11 are highly favoured, while in the absence of any additional activation of the nucleophiles the corresponding (E) isomers predominate. In the latter case, upon alkylation of the Schiff base derivatives 7 and 8, up to 30% of the α-substitution products 12 and 13, respectively, are isolated as by-products. The vinylphosphonates 9-11 are easily converted to the racemic 2-amino-5-phosphono-4-pentenoic acids (Z)-3 and (E)-3, and to the saturated analogue 1.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970722
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  • 8
    Electronic Resource
    Electronic Resource
    Syntheseversuche in der Reihe der 3.6-Epidithio-2.5-dioxo-piperazin-Antibiotika Gliotoxin, Sporidesmin, Aranotin und Chaetocin, IV. Synthese des Epidithio-L-prolyl-L-prolinanhydrids (1972)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 635-641 
    Details
    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
    URL: http://dx.doi.org/10.1002/cber.19721050229
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  • 9
    Electronic Resource
    Electronic Resource
    Über Aminosäuren und Peptide, VII1) Syntheseversuche in der Reihe der 3,6-Epidithio-2,5-dioxopiperazin-Antibiotika Gliotoxin, Sporidesmin, Aranotin, Chaetocin und Verticillin, VII1) Über die Einführung von Sauerstoffunktionen in Prolyl-prolinanhydrid mit Bleitetraacetat: Ein neuer Weg zum Epidisulfid des Prolyl-prolinanhydrids (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 396-398 
    Details
    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
    URL: http://dx.doi.org/10.1002/cber.19731060205
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  • 10
    Electronic Resource
    Electronic Resource
    Über Aminosäuren und Peptide, XV. Hydroxylsubstituierte Cyclodipeptide durch Ringschluß von Pyruvoylaminosäureamiden, II Zweifacher Ringschluß (1975)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 2907-2916 
    Details
    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
    URL: http://dx.doi.org/10.1002/cber.19751080910
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