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  • Articles: DFG German National Licenses  (90)
  • Polymer and Materials Science  (37)
  • Life and Medical Sciences  (26)
  • Chemical Engineering  (13)
  • Inorganic Chemistry  (12)
  • Amphibian  (3)
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  • Articles: DFG German National Licenses  (90)
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  • 1
    Electronic Resource
    Electronic Resource
    Formation of the amphibian grey crescent: Effects of colchicine and cytochalasin B (1978)
    Springer
    Development genes and evolution 185 (1978), S. 99-104 
    Details
    ISSN: 1432-041X
    Keywords: Amphibian ; Grey crescent ; Colchicine ; Cytochalasine B
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of colchicine and cytochalasin B on grey crescent formation in frog (Rana pipiens) and toad (Bufo arenarum) eggs were determined. Colchicine prevented the appearance of the grey crescent, but this inhibition was not due to the absence of an aster. Cytochalasin B did not inhibit grey crescent formation, nor did it inhibit certain activation events such as cortical granule breakdown or cortical contraction. Cytochalasin B caused a detachment of the cortex from the cytoplasm and induced the formation of a morphological grey crescent in non-activated eggs. The results suggest that microtubules may play several roles in grey crescent formation and that a change in the attachment of the cortex to the cytoplasm may also be involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848218
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  • 2
    Electronic Resource
    Electronic Resource
    Ultraviolet light inhibits grey crescent formation on the frog egg (1980)
    Springer
    Development genes and evolution 189 (1980), S. 73-76 
    Details
    ISSN: 1432-041X
    Keywords: Ultraviolet irradiation ; Amphibian ; Grey crescent ; Embryology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Work by others has shown that ultraviolet (UV) irradiation of the vegetal half of the uncleaved frog egg causes defects in neural development. We find that the earliest effect of irradiation ofRana pipiens eggs is to prevent grey crescent formation, the first indication of dorso-ventral polarization of the egg. The UV effect on the grey crescent and on neural development shows similarities in timing, dose-responses, and reversal by cold. We suggest that the UV effect on neural morphogenesis may be caused by the inhibition of cortical-cytoplasmic movement involved in grey crescent formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848569
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  • 3
    Electronic Resource
    Electronic Resource
    Heterocyclen mit einem Azaallyl-System, 4. 5H-Dibenz[c,e]azepine mit Donor-Gruppen in 7-Stellung (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2085-2090 
    Details
    ISSN: 0009-2940
    Keywords: 5H-Dibenz[c,e]azepines ; Imidates ; alkyl ; heterocyclic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heterocycles with an Azaallyl System, 4.  -  5H-Dibenz[c,e]azepines with Donor Groups at the 7-Position5H-Dibenz[c,e]azepines substituted with a methoxy (1) or methylthio group (10) at the 7-position have been synthesized from 6,7-dihydro-5H-dibenz[c,e]azepin-5-one (5) by regioselective O- or S-alkylation with methyl trifluoromethansulfonate and subsequent NH-deprotonation. According to the spectroscopic properties the semicyclic 7-membered alkyl imidates exist exclusively in the benzenoid 5H structure.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240934
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  • 4
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Chemie von Isoindolen und Isoindoleninen, XXVII. 2-Alkyl-2H-dibenz[e,g]isoindole: Synthese, Eigenschaften, Reaktionen (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 81-87 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Chemistry of Isoindoles and Isoindolenines, XXVII. - 2-Alkyl-2H-dibenz[e,g]isoindoles; Synthesis, Properties, ReactionsThe tetracyclic hetarenes 6 are easily accessible via the N-oxide route starting with 9,10-bis(bromomethyl)phenanthrene (3) in a three-step procedure. The twofold annelation reduces the diene reactivity of the central 2H-isoindole system. Cycloaddition occurs as well with activated alkynes as with arynes. The hetarenes 6 can be protonated with trifluoroacetic acid and substituted by reaction with arenediazonium tetrafluoroborates.
    Notes: Die tetracyclischen Hetarene 6 sind nach dem N-Oxid-Verfahren einfach aus 9,10-Bis(brommethyl)phenanthren (3) präparativ dreistufig zugänglich. Durch die zweifache Anellierung wird die Reaktivität des zentralen 2H-Isoindol-Systems abgeschwächt. Cycloaddition tritt sowohl mit aktivierten Alkinen als auch mit Arinen ein. Die Hetarene 6 sind mit Trifluoressigsäure protonierbar und durch SE-Reaktion mit Arendiazonium-tetrafluoroboraten substituierbar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881210113
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  • 5
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Chemie von Isoindolen und Isoindoleninen, XXVIII. 3-Alkoxy-1H-isoindole  -  Synthesen und Eigenschaften (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 243-252 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Chemistry of Isoindoles and Isoindolenines, XXVIII.  -  3-Alkoxy-1H-isoindoles, Syntheses and Properties3-Alkoxy-1H-isoindoles 1 bearing substituents at the carbocyclic moiety have been synthesized from substituted 2,3-dihydro-1H-isoindol-1-ones 4 by regiospecific O-alkylation to 5 with trialkyloxonium tetrafluoroborates or methyl trifluoromethanesulfonate and subsequent NH deprotonation. According to the spectroscopic properties the semicyclic alkyl imidates 1 exist exclusively in the benzenoid 1H structure; the tautomeric o-quinonoid 2H structure 2 cannot be detected by spectroscopic means.
    Notes: 3-Alkoxy-1H-isoindole 1 mit Substituenten am carbocyclischen Teil wurden aus substituierten 2,3-Dihydro-1H-isoindol-1-onen 4 durch regiospezifische O-Alkylierung mit Trialkyloxonium-tetrafluoroboraten oder Trifluormethansulfonsäure-methylester zu 5 und nachfolgende NH-Deprotonierung synthetisiert. Aufgrund der spektroskopischen Befunde existieren die semicyclischen Imidsäure-alkylester 1 ausschließlich in der benzoiden 1H-Form; die tautomere 2H-Form 2 mit o-chinoider Struktur ist spektroskopisch nicht nachweisbar.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881210209
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  • 6
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Chemie von Isoindolen und Isoindoleninen, XXIX. Reaktionen des 2H-Isoindols mit Maleinimiden: Ein einfaches Herstellungsverfahren für 7-Azabicyclo[2.2.1]heptene (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 927-934 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Chemistry of Isoindoles and Isoindolenines, XXIX.  -  Reactions of 2H-Isoindole with Maleic Imides: A Simple Procedure for the Preparation of 7-Azabicyclo [2.2.1]heptenesSolutions of 2H-isoindole 1 in ether were prepared by a simple procedure and treated with maleic imides 2. 1,3-Cycloaddition reactions lead to the formation of 1:1 adducts 3 with an 7-azabicyclo[2.2.1]heptene frame. The endo isomers 3.1 can thermally be isomerized to the more stable exo isomers 3.2. The constitution and configuration of the 1:1 cycloadducts 3 are established by 1H- and 13C-NMR spectroscopy.
    Notes: Lösungen des 2H-Isoindols 1 in Ether werden nach einem einfachen Verfahren hergestellt und mit Maleinimiden 2 umgesetzt. 1,3-Cycloadditionsreaktionen führen zu 1:1-Addukten 3 mit der Struktur von 7-Azabicyclo[2.2.1]heptenen. Die endo-Isomeren 3.1 lassen sich thermisch in die stabileren exo-Isomeren 3.2 umlagern. Konstitution und Konfiguration der 1:1-Cycloaddukte 3 werden durch die 1H- und 13C-NMR-Spektren begründet.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881210517
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  • 7
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Chemie von Isoindolen und Isoindoleninen, XXXVII. Symmetrisch substituierte 2-Alkyl-2H-isoindole (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1719-1727 
    Details
    ISSN: 0009-2940
    Keywords: Isoindoles, symmetrically substituted ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies on the Chemistry of Isoindoles and Isoindolenines, XXXVII1) - Symmetrically Substituted 2-Alkyl-2H-isoindoles2-Alkyl-Rn-2H-isoindoles (1; Rn=4,5,6,7-tetramethyl, 4,5,6,7-tetrachloro) have been prepared efficiently by the N-oxide route and characterized by spectroscopic means.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230823
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  • 8
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Chemie von Isoindolen und Isoindoleninen, XXXI. 4,5,6,7-Tetrachlor- und 4,5,6,7-Tetrabrom-2H-isoindol (1988)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1827-1832 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Chemistry of Isoindoles and Isoindolenines, XXXI. 4,5,6,7-Tetrachloro- and 4,5,6,7-Tetrabromo-2H-isoindolesThe crystalline 2H-isoindoles 4b are synthesized starting with substituted 2-methylsulfonyl-2,3-dihydro-1H-isoindoles 3 by base-induced elimination of methanesulfinic acid. Compared with the parent compound, a considerable thermal stabilization and chemical deactivation is caused by the halogen atoms at the carbocyclic system. The spectroscopic properties of the o-quinonoid hetarenes 4b have been investigated.
    Notes: Die kristallinen 2H-Isoindole 4b werden aus substituierten 2-Methylsulfonyl-2,3-dihydro-1H-isoindolen 3 durch Basen-induzierte Eliminierung von Methansulfinsäure synthetisiert. Die Halogenatome am carbocyclischen System bewirken - verglichen mit dem Grundkörper - eine beträchtliche thermische Stabilisierung und chemische Desaktivierung. Die spektroskopischen Eigenschaften der o-chinoiden Hetarene 4b wurden untersucht.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19881211022
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  • 9
    Electronic Resource
    Electronic Resource
    Struktur und Reaktivität von isoanellierten heterocyclischen Systemen mit 4n;-π- und (4n + 2)-π-Elektronen, XVIII. Benzo[c]thiophene mit symmetrischer Struktur: Modifizierte und optimierte Herstellung nach der S-Oxid-Route (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 645-654 
    Details
    ISSN: 0009-2940
    Keywords: Benzo[c]thiophenes ; preparation by the S-oxide route ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structure and Reactivity of Isoannullated Heterocyclic Systems with 4n;-π and (4n + 2)-π Electrons, XVIII. - Benzo[c]thiophenes with Symmetric Structure: Modified and Optimized Preparation by the S-Oxide RouteBenzo[c]thiophenes (15) with symmetric structure have been prepared efficiently from 1,3-dihydrobenzo[c]thiophene 2-oxides (9) by reaction with aluminium oxide, by O-acylation with trifluoroacetic anhydride, or O-alkylation with methyl trifluoromethanesulfonate. The aromatization of the S-oxides 9 is achieved by O-functionalization, subsequent elimination, and consecutive deprotonation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240332
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  • 10
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Chemie von Isoindolen und Isoindoleninen, XXXIX. Reaktionen von 2-Alkyl-4,5,6,7-Rn-2H-isoindolen (Rn=tetramethyl, tetrachlor) mit aktivierten C=C-Dienophilen (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 183-189 
    Details
    ISSN: 0009-2940
    Keywords: 2H-Isoindoles, 2-alkyl-, reactions with C=C dienophiles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies on the Chemistry of Isoindoles and Isoindolenines, XXXIX.  -  Reactions of 2-Alkyl-4,5,6,7-Rn-2H-isoindoles (Rn=tetramethyl, tetrachloro) with Activated C=C DienophilesSubstituted 2H-Isoindoles 2 react with maleic imides in absolute ether. Cycloaddition in 1,3-position leads to the formation of 1:1 adducts. The ratio between endo isomers 4 and exo isomers 5 depends on the substituents and the solvents. In the case of steric hindrance the Diels-Alder addition can be induced by Lewis acids. In the presence of oxygen-substituted 4,5,6,7-tetrachloro-2-methylisoindolin-1-ones 7 are formed as minor products.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250130
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