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  • 1
    Electronic Resource
    Electronic Resource
    An O .fwdarw. N acyl transfer. An important activation step for a formal nucleophilic substitution in a cyclopropane derivative (1987)
    s.l. : American Chemical Society
    The @journal of organic chemistry 52 (1987), S. 4921-4924 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00231a016
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  • 2
    Electronic Resource
    Electronic Resource
    Thermal cycloelimination of bis(dialkylamino)cyclopropanes to amidines and cycloalkenes (1988)
    s.l. : American Chemical Society
    The @journal of organic chemistry 53 (1988), S. 1806-1808 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00243a040
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  • 3
    Electronic Resource
    Electronic Resource
    Eine Synthese für Cyclopropandiyl-bis-(isopropylidenmalonate) (1987)
    Springer
    Monatshefte für Chemie 118 (1987), S. 1147-1161 
    Details
    ISSN: 1434-4475
    Keywords: Aminocyclopropane derivatives ; Diacyclomethylenecyclopropane intermediates ; Cyclopropanes, nucleophilic substitution at
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reaction of HexahydroazepinobicycloalkylMeldrum's acid7 Ba-7 Bd or PiperidinocyclopropylMeldrum's acid7 Ce withMeldrum's acid (1) generates cyclopropanes possessing two isopropylidene malonate moieties. In the solid state the bicyclic derivatives were found to be dienolic compounds11 a-11 d, whereas the monocyclic system has the tetracarbonyl structure10e. 7a-7d, the starting materials for the synthesis of11 a-11 d, were obtained from1 and O,N-acetal4B or aminal6B.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00811288
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  • 4
    Electronic Resource
    Electronic Resource
    2-Cyclopropyliden-1,3-cycloalkandione als Zwischenstufen einer nukleophilen Substitution am Dreiring (1987)
    Springer
    Monatshefte für Chemie 118 (1987), S. 1039-1056 
    Details
    ISSN: 1434-4475
    Keywords: Aminobicyclo[n. 1.0]alkane derivatives ; 2-Cyclopropylidene-1,3-cycloalkanedione intermediates ; Cyclopropanes, nucleophilic substitution at
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reaction of morpholinobicycloalkyl-dimedone4 C with various CH-acids3 leads to a substitution of theexo-dimedone unit as a consequence of a strong preference of theexo-leaving group in a bicyclic compound of type4 and5, respectively. Dimedone (3 C) as a nucleophile, however, makes theexo substitution unproductive in4 C and allows the displacement of the morpholino moiety leading to12 C. Thus compounds12 C–12 F could be obtained directly from the N,O-acetal1 and the CH-acids3 C–3 F by a twofold substitution, the isolation of the monoalkylated compounds4 not being necessary. Formation of12 C–12 F involves aMichael addition of3 C–3 F to the unstable 2-Cyclopropylidene-1,3-cycloalkanedione intermediates7 C–7 F. Cyclopentanedione3 F as a CH-acid and1 gave the enamine17 F besides12 F. The Hexahydroazepino-N,O-acetal19 in this special case was superior leading exclusively to12 F.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00815330
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  • 5
    Electronic Resource
    Electronic Resource
    Aminocyclopropyl-substituierte CH-Säuren als Substrate der nukleophilen Substitution am Dreiring (1987)
    Springer
    Monatshefte für Chemie 118 (1987), S. 1057-1071 
    Details
    ISSN: 1434-4475
    Keywords: Aminocyclopropane derivatives ; Diacylmethylenecyclopropane intermediates ; Cyclopropanes, nucleophilic substitution at
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Piperidinocyclopropyl-dimedone (9 a),Meldrum's acid (9 b), and barbituric acid (9 c) were synthesized by aminoalkylation of CH-acids8 a–8 c with silyl-N,O-acetal7. In9 a–9 c the piperidino moiety was displaced by interaction with weakly basic carbanions derived from CH-acids8 a–8 g leading to compounds11,14,15, and16. A scrambling of the CH-acid being present in9 and the CH-acid8 added as a nucleophile generally did not take place. This allowed the specific preparation of cyclopropanes possessing two different CH-acidic substituents at the C1 atom. In one special case an exchange reaction of the CH-acidic moieties was observed to a minor extent. The nucleophilic substitution at the dimedone compound9 a was more or less strongly limited by a ring opening reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00815331
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  • 6
    Electronic Resource
    Electronic Resource
    Reaktionen mit Phosphinalkylenen, XXVIII. Neue Synthesemöglichkeiten für α-verzweigte β-Keto-carbonsäureester (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2794-2801 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Alkylidenetriphenylphosphoranes, XXVIII. New Syntheses of α-Branched β-Ketocarboxylic AcidsThe reaction between acyl chlorides 1 and (1-alkoxycarbonylalkylidene)triphenylphosphoranes 2 in a molar ratio of 1:1 gives rise to the formation of phosphonium chlorides 3. The electrolysis of these phosphonium salts leads to the formation of triphenylphosphine and α-branched β-ketocarboxylic acid esters 6. The reaction between 1 and 2 in a molar ratio of 1:2 produces allenic carboxylic acid esters 8, which react with piperidine (9) to form enamines 10. Acidic hydrolysis of the latter compounds also yields the β-ketoesters 6.
    Notes: Säurechloride 1 und [1-Alkoxycarbonyl-alkyliden]-triphenylphosphorane 2 reagieren im Molverhältnis 1:1 zu Phosphoniumsalzen 3, deren Elektrolyse neben Triphenylphosphin α-verzweigte β-Keto-carbonsäureester 6 ergibt. Setzt man die aus 1 und 2 im Molverhältnis 1:2 entstehenden 8 mit Piperidin (9) um, so erhält man Enamine 10, bei deren saurer Hydrolyse ebenfalls die Verbindungen 6 entstehen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030912
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  • 7
    Electronic Resource
    Electronic Resource
    Konfigurationszuordnung bei größeren Bicyclo[n.1.0]alkylaminen: Der Hexahydro-1-azepinyl-Rest als „Stereoindikator“ (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2900-2909 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Assignment of Configuration of Larger Bicyclo[n.1.0]alkyl Amines: The Hexahydro-1-azepinyl Residue as „Stereo Indicator“The temperature dependency of the 1H NMR spectra of the hexahydro-1-azepinylbicyclo[9.1.0]-dodecanes 3a  -  f is investigated. The ΔG≠-values of the hexahydroazepine dynamics permit an easy assignment of the endo-amino configuration in 3a  -  f. Starting from 3a, which is synthesized via the enaminosulfonium salt 7, the derivatives 3b  -  f are obtained by nucleophilic substitutions. Normally the cis-configuration of the bicyclo system is not changed during these reactions. However, reaction of the cis-compound 3a with hexahydroazepine leads either to a cis-aminal 3e or to a trans-aminal 4e depending on the conditions of the reaction.
    Notes: Die aus der Temperaturabhängigkeit der 1H-NMR-Spektren der Hexahydro-1-azepinylbicyclo [9.1.0]dodecan-Derivate 3a  -  f ermittelten ΔG≠-Werte der Hexahydroazepinyl-Dynamik ermöglichen eine einfache Festlegung der endo-Amino-Konfiguration. Die Verbindungen 3b  -  f werden aus 3a über eine Folge nucleophiler Substitutionen erhalten; 3a ist über das Enaminsulfonium-Salz 7 zugänglich. Normalerweise bleibt die cis-Konfiguration des Bicyclosystems bei den Substitutionen erhalten. Jedoch führt die Umsetzung der cis-Verbindung 3a mit Hexahydroazepin  -  abhängig von den Reaktionsbedingungen  -  zu einem cis-Aminal 3e oder einem trans-Aminal 4e.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170911
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  • 8
    Electronic Resource
    Electronic Resource
    Reaktionen mit Aminobicyclo[n.1.0]alkanen, I. Thermolyse von Aminobicyclo[n.1.0]alkanen mit einem Dimedonrest (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2910-2927 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Aminobicyclo[n.1.0]alkanes, I Thermolysis of Aminobicyclo[n.1.0]alkanes with a Dimedone MoietyFrom the bicyclic aminals 4 and dimedone (5) derivatives 6 are obtained, which give different types of products upon thermolysis depending on the ring size of the bicyclus. The bicycloheptane and -octane compounds 6b, c lead to diacylated enamines 8b, c by protonation of the cyclo-propane ring. Contrarily, an elimination of morpholine takes place in 6a, d, e containing a bicyclohexane, -undecane, or -dodecane ring. There are formed derivatives with an exo-methylenefuran unit, which has a Z-configuration in 17a and an E-configuration in 16d, e. 16e the product of a kinetically controlled reaction, rearranges via the Z-isomer 17e to give the furan 18e by heating in morpholine. A methylenebicyclo[n.1.0]alkane 14 is discussed to be an intermediate in the formation of 16d, e and 17a, respectively.
    Notes: Aus den bicyclischen Aminalen 4, und Dimedon (5) werden Derivate 6 erhalten, die in Abhängigkeit von der Ringgröße des Bicyclus unterschiedliche Thermolyseprodukte ergeben. Die Bicycloheptan- und -octanverbindungen 6b, c, führen unter Protonierung des Cyclopropanrings zu Diacylenaminen 8b, c. Eine Eliminierung von Morpholin wird dagegen bei 6a, d, e mit einem Bicyclohexan-, -undecan- bzw. -dodecan-Ring beobachtet. Dabei entstehen Verbindungen mit einem exo-Methylenfuran-Strukturelement, das bei 17a in der Z- und bei 16d, e in der E-Konfiguration vorliegt. 16e, das kinetisch kontrollierte Reaktionsprodukt, kann durch Erhitzen in Morpholin über das Z-Isomere 17e zum Furan 18e umgelagert werden. Die Beteiligung einer Methylenbicyclo-[n.1.0]alkan-Zwischenstufe 14 beim Entstehen von 16d, e bzw. 17a wird diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170912
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  • 9
    Electronic Resource
    Electronic Resource
    Die Stevens-Umlagerung von N1-Sulfoniumsalzen des Hydantoins (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 1136-1146 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Stevens Rearrangement of N1-Sulfonium Salts of HydantoinIn chloroform at - 25° C, N1-chlorohydantoins 3 or 4 react with methyl alkyl sulfides 5 to give N-sulfonium salts 6. With tertiary amines above 0°C the salts 6 undergo a rearrangement with formation of the instabile imidates 16, which are changed into the isomers 19 by heating. The slow rearrangement of 6 is supposed to be caused by the formation of the imide anion 8. Alkylation of 8 yields N-sulfonium salts 10 which are easily rearranged to the imidates 12 by tertiary amines.
    Notes: N1-Chlorhydantoine 3 bzw. 4 und Methyl-alkyl-sulfide 5 reagieren in Chloroform bei -25°C zu N-Sulfoniumchloriden 6. Bei der Einwirkung von tertiären Aminen auf 6 erhält man erst oberhalb von 0° C eine Stevens-Umlagerung zu den instabilen Imidaten 16, die beim Erwärmen in die isomeren Verbindungen 19 übergehen. Die langsame Umlagerung von 6 wird auf die Bildung des Anions 8 zurückgeführt. Durch Alkylierung von 8 entstehen N-Sulfoniumsalze 10, die mit tertiären Aminen spezifisch in die Imidate 12 umgelagert werden können.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110331
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  • 10
    Electronic Resource
    Electronic Resource
    Die Stevens-Umlagerung an N1,N3-Disulfoniumsalzen des Hydantoins (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 1147-1159 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Stevens Rearrangement of N1,N3-Disulfonium Salts of HydantoinUpon treatment with tertiary amines, the reaction products 6 from the N1,N3-dichlorohydantoin 5 and methyl alkyl or methyl aryl sulfides 4 give a Stevens rearrangement with formation of bisalkylthio- or -arylthiomethylated hydantoins. Though five isomers are possible, a strongly selective formation of only two isomers 9 and 10 occurs. As byproducts the N1-monosulfonium salt 1 of hydantoin and chloromethyl alkyl or chloromethyl aryl sulfides 19 are obtained. The course of the reaction is followed by 1H NMR spectroscopy. The structures of intermediates of the rearrangement are determined.
    Notes: Die Reaktionsprodukte 6 aus dem N1,N3-Dichlorhydantoin 5 und Methyl-alkyl- bzw. Methylaryl-sulfiden 4 geben bei der Einwirkung von tertiären Aminen eine Stevens-Umlagerung zu bisalkylthio- bzw. -arylthio-methylierten Hydantoinen. Obwohl fünf Isomere dieser Verbindungen möglich sind, erfolgt eine stark selektive Bildung von nur zwei Isomeren 9 und 10. Als Nebenprodukte erhält man ein N1-Monosulfoniumsalz 1 des Hydantoins und Chlormethyl-alkyl- bzw. -aryl-sulfide 19. Der Reaktionsablauf wird 1H-NMR-spektroskopisch verfolgt. Die Strukturen von Zwischenstufen der Umlagerung werden aufgeklärt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110332
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