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  • 1
    Electronic Resource
    Electronic Resource
    α-Metalated Isocyanides in Organic Synthesis. New synthetic methods (6) (1974)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 13 (1974), S. 789-804 
    Details
    ISSN: 0570-0833
    Keywords: Isocyanides ; Synthetic methods ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Alkali-metalated isocyanides, which can be obtained from isocyanides and bases, can be used for nucleophilic introduction of (masked) α-aminoalkyl groups. Intramolecular ring-closure may then follow if a nucleophile combines at the electron sextet of the isocyanide carbon. Treatment of α-alkali-metalated isocyanides with electrophilic agents permits rapid and efficient synthesis of, inter alia, 2- and 3-amino alcohols, straight-chain, branched, and β-functional α-amino acids, olefins, vinyl isocyanides, and of a large number of mainly five-, but also six- and seven-membered aza-, diaza-, oxa-aza-, and thia-aza heterocycles.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.197407891
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  • 2
    Electronic Resource
    Electronic Resource
    The Homoaldol Reaction, or How to Overcome Problems of Regio- and Stereo-selectivityMetalated Nitrogen Derivatives of Carbonic Acid in Organic Synthesis, Part 28. - Part 27: [72b].Dedicated to Professor Wolfgang Lüttke on the occasion of his 65th birthday (1984)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 23 (1984), S. 932-948 
    Details
    ISSN: 0570-0833
    Keywords: Homoaldol reaction ; Stereoselectivity ; Synthetic methods ; Regioselectivity ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Even today, there are conspicuous gaps in the register of organic synthetic methods. Thus, numerous types of homoenolate reagents are listed; yet no generally applicable method for the homologue of the aldol addition, viz. the homoaldol addition, is to be found. The methods documented up to 1980 offer only singular solutions, and, moreover, are not stereoselective. The present article gives an overview of the existing possibilities and then describes how the gap can be closed by using a new class of homoenolate reagents: 2-alkenyl esters of N,N-diisopropylcarbamic acid are lithiated and the resulting allyllithium compounds tailored to high regio- and diastereoselectivity in addition reactions to the carbonyl group via metal exchange. Altogether, the homoaldol reactions now offer a general and reliable, highly stereoselective entry to γ-hydroxycarbonyl compounds, whereby the C(β)—C(γ) bond is formed. Furthermore, it is demonstrated how problems associated with the application of allyl anions as synthetic reagents can be solved today.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.198409321
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  • 3
    Electronic Resource
    Electronic Resource
    Metallierte Stickstoff-Derivate der Kohlensäure in der organischen Synthese, X. 2-Alkylthio-2-oxazolin-4-carbonsäureester und ihre baseninduzierte Ringöffnung zu 2-〈N-[(Alkylthio)carbonyl]amino〉acrylsäureestern (1976)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 1843-1849 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metalated Nitrogen Derivatives of Carbonic Acid in Organic Synthesis, XI). - 2-Alkylthio-2-oxazoline-4-carboxylates and their Base-Induced Ring Cleavage to give 2-(N-I(Alkylthio)-carbonyl]amino)acrylates 2)2-Alkylthio-2-oxazoline-4-carboxylic esters 8 are readily obtained by condensation of iso-thiocyanato acetates 1 with carbonyl compounds 3 and subsequent alkylation of anions 4. The oxazolines 8 are cleaved by means of potassium tert-butoxide to yield the 2-(N-[(alkylthio)-carbonyl]amino)acrylic esters 12. This method provides the convenient synthesis of esters of 2,3-didehydro 2-amino acids containing selectively cleavable N-protecting groups of thiourethane type by formation of the central C=C bond.
    Notes: 2-Alkylthio-2-oxazolin-4-carbonsäureester 8 werden im Eintopfverfahren durch Alkylierung der Anionen 4 erhalten, die durch Kondensation von Isothiocyanatoessigsäure-äthylester 1 und Carbonylverbindungen 3 dargestellt werden. Ihre baseninduzierte Ringöffnung durch Kalium-tert-butylat führt zu den 2-〈N-[(Alkylthio)carbonyl]amino)acrylsäureestern 12. Die Methode gestattet die einfache Synthese von 2,3-Didehydro-2-aminosäureestern mit selektiv entfernbaren N-Schutzgruppen vom Thiourethan-Typ unter Aufbau der zentralen C=C-Bindung.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197619761015
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesen mit α-metallierten Isocyaniden, XV1) 4-Äthoxycarbonyl-2-oxazoline und ihre Hydrolyse zu N-Formyl-β-hydroxy-α-aminosäureäthylestern (1972)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 763 (1972), S. 1-16 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with α-Metallated Isocyanides, XV1). - 4-Ethoxycarbonyl-2-oxazolines and their Hydrolysis to Ethylesters of N-Formyl-β-hydroxy-α-amino Acids4-Ethoxycarbonyl-2-oxazolines 1 are formed from ethyl-α-isocyanocarboxylates 6 and carbonyl compounds 8 in a weakly basic enthanolic medium. The course of reaction is discussed. Hydrolysis of 1 leads to the ethyl esters 2 of N-formyl-β-hydroxyamino acids (ethyl esters of α-and β-substituted N-formylserines).
    Notes: Die 4-Äthoxycarbonyl-2-oxazoline 1 entstehen aus den α-Isocyan-alkancarbonsäureäthylestern 6 und den Carbonylverbindungen 8 in schwach basischem äthanolischem Medium. Der Reaktionsverlauf wird diskutiert. Die Hydrolyse von 1 in Gegenwart von Triäthylamin liefert die N-Formyl-β-hydroxy-aminosäureäthylester (α-und β-substituierte N-Formyl-serinäthylester) 2, die durch Erwärmen mit 6 n HCl in die β-Hydroxy-aminosäuren 3 überzuführen sind.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19727630102
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesen mit α-metallierten Isocyaniden, XVI1) β-Substituierte α-Formylamino-acrylsäureäthylester aus α-metallierten Isocyanessigestern und Carbonylverbindungen (Formylaminomethylenierung von Carbonylverbindungen) (1973)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 766 (1973), S. 116-129 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis with α-Metalated Isocyanides, XVI1). - β-Substituted α-Formylaminoacrylic Esters form α-Metalated Isocyanoacetic Esters and Carbonyl Compounds (Formylaminomethylenation of Carbonyl Compounds)The α-metalated isocyanoacetic esters 7, prepared from isocyanoacetic esters 10 and butyllithium, potassium tert-butoxide or sodium hydride in tetrahydrofuran, react with the carb only compounds to the β-substituted α-formylaminoacrylic esters 8 or 9 (formylamino-methylenation of carbonyl compounds). The course of this new reaction is discussed. - The α-formylaminoacrylic esters 8 and 9 can also be obtained from alkyl 2-oxazoline-4-carboxylates of type 18 by base induced ring opening. - The reaction of isocyanoacetic esters 10 with benzaldehyde or acetophenone in ethanol in the presence of sodium ethoxide or in tetrahydrofuran in the presence of excess sodium hydroxide gives N-formyl-β-phenylserine (25a) or N-formyl-β-phenylthreonine (25b), respectively.
    Notes: Die α-metallierten Isocyanessigsäureester 7, dargestellt aus Isocyanessigsäureestern 10 mit Butyllithium bzw. Kalium-tert.-butanolat oder Natriumhydrid, reagieren in Tetrahydrofuran mit den Carbonylverbindungen 2 in einem Zug zu den β-substituierten α-Formylamino-acrylestern 8 oder 9 (Formylaminomethylenierung von Carbonylverbindungen). Der Verlauf dieser neuartigen Reaktion wird diskutiert. - Die α-Formylaminoacrylester 8 und 9 sind auch aus 2-Oxazolin-4-carbonsäure-alkylestern (vom Typ 18) durch baseninduzierte Ringöffnung zu erhalten. - Bei der Umsetzung von Isocyanestern 10 mit Benzaldehyd oder Acetophenon in Äthanol in Gegenwart von Natriumäthylat oder in Tetrahydrofuran mit überschüss. Natriumhydroxid entstehen N-Formyl-β-phenylserin (25a) bzw. N-Formyl-β-phenylthreonin (25b).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.19727660113
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesen mit α-metallierten Isocyaniden, XVIII1) 1-Amino-cyclopropancarbonsäuren über 1-Isocyan-cyclopropancarbonsäure-äthylester (1973)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1973 (1973), S. 611-618 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with α-Metalated Isocyanides, XVIII1). - 1-Aminocyclopropane-1-carboxylic Acids Via Ethyl 1-Isocyanocyclopropane-1-carboxylates2-Substituted ethyl 1-isocyanocyclopropane-1-carboxylates are obtained from dimethylsulfoxonium methylid (5) and β-substituted ethyl α-isocyanoacrylates (8). These are accessible from ethyl formylaminoacrylates (3). The 2-unsubstituted compound 10a is obtained by cycloalkylation of ethyl isocyanoacetate either with 1,2-dibromoethane or 2-chloroethyl tosylate in presence of sodium hydride. - The compounds 10 can be converted to ethyl 1-aminocyclopropane-1-carboxylates or their derivatives 11, 12 and 6 by acid or alkaline hydrolysis.
    Notes: Die 2-substituierten 1-Isocyan-cyclopropancarbonsäure-äthylester 10 erhält man aus Dimethylsulfoxonium-methylid (5) und den β-substituierten α-Isocyan-acrylsäure-äthylestern 8. Die Verbindungen 8 sind ihrerseits aus den α-Formylamino-acrylsäure-äthylestern 3 zugänglich. Die am C-2 unsubstituierte Verbindung 10a ist durch Cycloalkylierung von Isocyanessigsäure-äthylester mit 1,2-Dibromäthan oder 2-Chloräthyl-tosylat in Gegenwart von Natriumhydrid zu gewinnen. - Die Verbindungen 10 können durch saure oder basische Hydrolyse in 1-Amino-cyclopropancarbonsäuren oder deren Derivate 11, 12 und 6 umgewandelt werden.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197319730410
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  • 7
    Electronic Resource
    Electronic Resource
    α-Isothiocyanatoacrylsäureester, III. Ringschlüsse bei der Addition von Nucleophilen an α-Isothiocyanatoacrylsäureester (1976)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 1997-2006 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Isothiocyanatoacrylic Esters, III . - Ring Formations by Addition of Nucleophiles to Isothiocyanatoacrylic EstersPrimary alkanethiols, dialkylamines, and alkanols add by the aid of base to the hetero-cumulene group of u-isothiocyanatoacrylates 1 to yield thiourethanes 5 or 12 and thioureas 8, respectively. These cyclize on heating (catalyzed by base or acid) across the conjugated C=C bond to give 2-alkylthio-, 2-alkoxy-, or 2-dialkylamino-2-thiazoline-4-carboxylic esters 6, 13, or 9. With primary amines ring closure of the non isolable adducts 15 occurs across the carbonyl group and yields 3-alkyl- or 3-aryl-5-alkylidene-2-thiohydantoins 16.
    Notes: Primäre Alkanthiole, Dialkylamine und Alkanole addieren sich unter dem Einfluß von Basen an die Heterokumulen-Gruppe von α-Isothiocyanatoacrylsäureestern 1 zu den Thiourethanen 5 bzw. 12 oder Thioharnstoffen 8, welche beim Erwärmen (basen- oder säurekatalysiert) über die konjugierte C=C-Bindung zu 2-Alkylthio-, 2-Alkoxy- bzw. 2-Dialkylamino-2-thiazolin-4-carbonsäureestern 6, 13 oder 9 cyclisieren. Mit primären Aminen erfolgt der Ringschluß der (nichtfaßbaren) Addukte 15 über die Estercarbonyl-Gruppe und führt zu 3-Alkyl- oder 3-Aryl-5-alkyliden-2-thiohydantoinen 16.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197619761108
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  • 8
    Electronic Resource
    Electronic Resource
    Metallierte Stickstoff-Derivate der Kohlensäure in der organischen Synthese,XI. α-Isothiocyanatoacrylsäureester, II. Zur Synthese von α-Isothiocyanatoacrylsäureestern aus Isothiocyanatoessigsäureestern und Carbonylverbindungen (1976)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1976 (1976), S. 1850-1861 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metalated Nitrogen Derivatives of Carbonic Acid in Organic Synthesis, XI').- α-Isothiocyanatoacrylates, II.- Synthesis of α-Isothiocyanatoacrylates from Isothiocyanatoacetates and Carbonyl Compounds3,3-Dialkyl-substituted a-isothiocyanatoacrylates 1 a- e are prepared in a one pot reaktion starting from ethyl or methyl isothiocyanatoacetate (4a or 4b) and ketones: base-induced condensation yields the alkali salts 6 of 2-thioxo-4-oxazolidinecarboxylic esters 7, which are phosphorylated by diphenyl phosphorochloridate (16) to give 3-phosphoryloxazolidines 17. Subsequent base-induced ring cleavage of 20 (potassium tert-butoxide at -70°C) gives N-(O,O'-diphenylphosphoryl)-N-vinylmonothiocarbamidates 18, which on warming up to room temperature decompose into 1 and potassium diphenyl phosphate. In analogous manner but after transformation of 18 to α-[N-(O,O'-diphenylphosphoryl)amino]acrylic esters 19 via 20 3-aryl and 3-monoalkyl acrylates 1f - o are obtained. - Some of the intermediate phosphorous compounds 17 and 19 are described.
    Notes: 3,3-Dialkylsubstituierte α-Isothiocyanatoacrylsäureester 1 a- e werden irn Eintopfverfahren, ausgehend von Isothiocyanatoessigsäure-äthylester oder -methylester 4a bzw. 4 b und Ketonen dargestellt: Basische Kondensation führt zu den Alkalisalzen 6 der 2-Thioxo-4-oxazolidin-carbonsäureester 7, die nach Phosphorylierung zu 3-(O,O'-Diphenylphosphoryl)oxazolidinen 17 durch baseninduzierte Ringöffnung (Kalium-tert-butylat, -70°C) in N-(O.O'-Diphenyl-phosphoryl)-N-vinylmonothiocarbamidate 18 übergeführt werden; diese zerfallen beim Erwärmen auf 20°C in 1 und Kalium-O,O'-diphenylphosphat. Analog - jedoch nach Überführung von 18 in 2-[N-(O,O;'-Diphenylphosphoryl)amino]acrylsäureester 19 und Dithiocarboxylierung zu den Dithiocarbamidaten20 - werden die 3-aryl- sowie 3-monoalkylsubstituierten Acrylester 1f - o synthetisiert. Einige der Phosphorverbindungen 17 und 19 werden charakterisiert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197619761016
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  • 9
    Electronic Resource
    Electronic Resource
    Studien zur β-Lactam-Synthese, IV. Synthese von 3-[Bis(alkylthio)methylenamino]-2-azetidinonen durch Säurechlorid-Imin-ReaktionHerrn Professor Dr. W. Lüttke mit herzlichen Glückwünschen zum 60. Geburtstag gewidmet. (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 2076-2088 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies in β-Lactam-Synthesis, IV.  -  Synthesis of 3-[Bis(alkylthio)methyleneamino]-2-azetidinones by Acid Chloride-Imine ReactionHerrn Professor Dr. W. Lüttke mit herzlichen Glückwünschen zum 60. Geburtstag gewidmet.The acid chlorides 10, prepared from N-[bis(alkylthio)methylene]glycine esters 8 via potassium carboxylates 9 or 15 were treated with imines 11a or 11b and with the thioimidates 11c or 21 in presence of triethylamine. From N-benzhydrylideneaniline (11a) moderate yields up to 70% of N-protected 3-amino-1,4,4-triphenyl-2-azetidinones 12 or 16 are obtained, whereas yields from N-benzylideneaniline 11b or from the thioimidates 11c or 21 range from only 1 to 10%. The imidazolidinones 17 and 18, isolated from the reaction of 11b and acid chlorides 10, afford some evidence for the intermediates involved. - Further, deprotection of the amino group in 12a and methylation of 12c to give the persubstituted β-lactam 25 (via an enolate 24) are reported.
    Notes: Die aus den N-[Bis(alkylthio)methylenglycinestern 8 über die Kaliumcarboxylate 9 oder 15 dargestellten Säurechloride 10 wurden mit den Iminen 11a und 11b sowie mit den Thioimidsäure-S-alkylestern 11c und 21 in Gegenwart von Triethylamin umgesetzt. Während mit N-Benzhydrylidenanilin (11a) die N-geschützten 3-Amino-1,4,4-triphenyl-2-azetidinone 12 bzw. 16 in teilweise guten Ausbeuten entstehen, liegen die Ausbeuten mit N-Benzylidenanilin 11b sowie mit 11c und 21 nur zwischen 1 und 10%. Die bei der Umsetzung mit 11b isolierten Imidazolidinone 17 und 18 geben Hinweise auf den Reaktionsweg. - Die Entfernung der Amino-Schutzgruppe in 12a, sowie die Methylierung von 12c zum persubstituierten β-Lactam 25 (über das Enolat 24) werden beschrieben.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919791218
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  • 10
    Electronic Resource
    Electronic Resource
    Metallierte Stickstoffderivate der Kohlensäure in der organischen Synthese, XVI. Die Synthese von 2-Alkylimino- und 2-Arylimino-1,3-oxathiolanen aus lithiierten Imidodithiokohlensäure-S,S′-dialkylestern und Carbonylverbindungen (1980)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 1765-1778 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metalated Nitrogen Derivatives of Carbonic Acid in Organic Synthesis, XVI.  -  Synthesis of 2-Alkylimino- and 2-Arylimino-1,3-oxathiolanes from Lithiated S,S′-Dialkyl Imidodithiocarbonates and Carbonyl CompoundsS,S′-Dialkyl N-(methyl)-, N-(phenyl)-, or N-(cyclopropyl)imidodithiocarbonates 5 were deprotonated by means of lithium diisopropylamide. The resulting α-thio-substituted lithium alkanides 6, which are stabilized by chelatization, were trapped as trimethylsilanes 7. Reaction of 6 with aldehydes or ketones yields the title compounds 20 via adducts 18 and loss of methanethiolate.
    Notes: N-(Methyl)-, N-(Phenyl)- oder N-(Cyclopropyl)imidodithiokohlensäure-S,S′-dialkylester 5 wurden mit Lithiumdiisopropylamid deprotoniert zu den Chelat-stabilisierten α-Thiolithiumalkaniden 6, welche als Silane 7 nachgewiesen wurden. Die Umsetzung von 6 mit Aldehyden und Ketonen liefert über die Addukte 18 unter Abspaltung von Methanthiolat die Titelverbindungen 20.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198019801116
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