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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 50 (1985), S. 1295-1298 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 129 (1998), S. 1313-1318 
    ISSN: 1434-4475
    Keywords: Keywords. Ethoxymethylene malononitrile; Ethoxymethylene cyanoacetic acid ethylester; 1 ; 4 ; 5-Trisubstituted pyrazoles; 4 ; 5-Disubstituted pyrazoles; Acyl migration; Rearrangement..
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Die Reaktion von Ethoxymethylenmalodinitril und Ethoxymethylencyanessigsäureethylester mit substituierten Hydrazinen zu substituierten 5-Aminopyrazolen wird beschrieben. Der Einfluß unterschiedlicher Substituenten auf mögliche Wanderungen während des Ringschlusses wurde untersucht..
    Notes: Summary.  The reaction of ethoxymethylene malononitrile and ethoxymethylene cyanoacetic acid ethylester with substituted hydrazines to substituted 5-aminopyrazoles is described. The influence of different substituents on possible migrations during the ring closure was studied..
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-4475
    Keywords: Chloroformate ; Chloro(di)thioformate acylation ; 5-Amino-1,2,3,4-thiatriazole ; Trithiadiazapentalenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die durch Pyridine katalysierte Acylierung von 5-Amino-1,2,3,4-thiatriazol mit Chlorameisensäureethylester führt zu 3,5-bis-(ethoxycarbonylamino)-1,2,4-thiadiazolen, während mit Chlorthioameisensäureethylester 2,5-bis(phenoxy)-1,6,6a,Δ4-trithia-3,4-diazapentalene erhalten werden. Ohne Pyridin entsteht bei letzterer Reaktion ein wenig stabiles, aber isolierbares Zwischenprodukt: 2-Phenoxy-1-aza-3,4-dithiolium-5-imid. Die Bis(phenoxy)trithiadiazapentalene reagieren leicht mit nukleophilen Reagenzien und tauschen dabei schrittweise eine oder beide Phenoxygruppen aus.
    Notes: Summary Pyridine catalyzed acylation of 5-amino-1,2,3,4-thiatriazole with chloroformates and chlorothioformates afforded 3,5-bis(ethoxycarbonylamino)-1,2,4-thiadiazoles in the former and 2,5-bis(phenoxy)-1,6,6a,Δ4-trithia-3,4-diazapentalenes in the latter case. An unstable, but isolable intermediate 2-phenoxy-1-aza-3,4-dithiolium-5-imide has been found if the chlorothioformate acylation was performed in acetonitrile in the absence of pyridine. The bis(phenoxy)trithiapentalenes are prone to nucleophilic displacement reactions at positions 2 and 5, exchanging in a stepwise manner one or both phenoxy groups. The structures of the compounds described could be inferred from their1H-NMR13C-NMR, and mass spectra and were corroborated by the comparison with the data of authentic and similar derivatives as well as by chemical means.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 337 (1995), S. 534-537 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Cryptands with 1,3,5-Triazines as Ring Building BlocksThe synthesis and characterization of 10 new cryptands 5a-j, containing two 1,3,5-triazine rings as subunits are described. The general methodology used is based on the aminolysis of cyanuric chloride with α,ω-diamino compounds or diazacrowns.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 335 (1993), S. 585-588 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acyl Migrations on 3(5)-Amino-pyrazole3(5)-Amino-pyrazole 1 form 3 isomeric monoacylation products, 4 diacylation products and 3 triacylation products by reaction with electrophiles like cyanates, isocyanates or carboxylic and chlorides, respectively. Acyl migrations are observed depending on the reaction temperature and the structure of the acyl residue. The structures of the acyl derivatives of 3(5)-amino-pyrazole were characterized by nmr-spectroscopy.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 253-260 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: General Synthesis of 1-Substituted Pyrazolidine-3-ones by Nucleophilic Grignard Addition at Carbonyl-stabilized AzomethiniminesBy means of Grignard compounds in THF the nucleophilic addition of alkyl, aralkyl or aryl groups at the C-6 atom of carbonyl-stabilized azomethinimines 1 is achieved. This new general synthesis gives high yields of 1-substituted pyrazolidine-3-ones 8. The C-6-substitution is proved by unambiguous syntheses and by 1H-n.m.r. C-4-Substituted azomethinimines 1 and Grignard compounds give mixtures of diastereomeric 1-substituted pyrazolidine-3-ones 8, as indicated by their 1H- and 13C-n.m.r. spectra. The Grignard addition is thus shown to proceed not stereospecifically.
    Notes: An das C-6-Atom carbonylstabilisierter Azomethinimine 1 lassen sich Alkyl-, Aralkyl- oder Arylreste mit Hilfe von Grignard-Verbindungen in THF nucleophil addieren. Diese neue, allgemeine Synthese 1-substituierter Pyrazolidone-(3) 8 verläuft mit hoher Ausbeute. Die C-6-Substitution wird durch eindeutige Synthesen und NMR-spektroskopisch bewiesen. Die Grignard-Addition verläuft, wie an der NMR-spektroskopisch nachgewiesenen Bildung von diastereomeren 1-substituierten Pyrazolidonen-(3) 8 aus C-4-substituierten 1 gezeigt wird, nicht stereospezifisch.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structure and Reactivity of Heterosubstituted Nitriles. 24. Kinetics and Mechanism of the Reaction of o-Phenylen diamine with Aryl CyanatesThe second and third order rate constants for the reaction of o-phenylene diamine with aryl cyanates to 2-amino benzimidazole phenylester imide in water/dioxane have been determined by i.r. measurements. The reaction proceeds through a bimolecular and a trimolecular mechanism simultaneously. In the slow step of the bimolecular process an electrophilic attack of the aryl cyanate on o-phenylene diamine takes place in a seven membered cyclic transition state. The slow step of the trimolecular mechanism consists of a nucleophilic attack of the diamine on a phenole aryl cyanate associate by a six membered cyclic transition state. The final products of both reactions are formed by successive fast reactions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acylation of Heterocycles with Carbonic Acid Derivatives. I. Kinetics and Mechanism of the Reaction of 2-Aminobenzimidazoles with Aryl CyanatesThe second order rate constants for the reaction of 2-amino-benzimidazoles (2-ABI) with aryl cyanates forming 2-amino-benzimidazole aryl ester imide 3 have been determined in dependence on substituent effects by u. v. measurements. The results are interpreted by a six-membered cyclic transition state in which the electrophilic attack of the cyanate on the endocyclic N atom is catalyzed by an H bridge interaction of the exocyclic amino group of 2-ABI with the OCN group.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 329 (1987), S. 409-416 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On Alkylation and Acylation of 5-Hydrazino-1,2,3,4-thiatriazole Derivatives5-Hydrazino-1,2,3,4-thiatriazole reacts with oxo carboxylic acids to give highly unstable 5-carboxyalkylidene-hydrazino-1,2,3,4-thiatriazoles (2). The more stable 5-alkylidenehydrazino-1,2,3,4-thiatriazoles (3) may be alkylated; the thiatriazole system is retained. On action of activated nitriles or isocyanates 1,2,4-thiadiazole (6) or 1,2,4-thiadiazoline derivatives (7) are formed with nitrogen evolution. At temperatures above 40°C, the described thiatriazoles decomposed to give undefinable components.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 316 (1974), S. 886-894 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Aryliden-pyrazolidon-(3)-azomethinimine 5 lagern sich in protonischen Lösungsmitteln quantitativ in 1-substituierte 3-Hydroxy-pyrazole 2 um. Damit steht erstmalig eine einfache allgemeine Synthese für 2 zur Verfügung. IR- und 1H-NMR-Parameter, deren Signifikanz durch eindeutig synthetisierte 1-substituierte 3-Hydroxy-pyrazole 2 belegt ist, beweisen die Struktur der 3-Hydoxy-pyrazole 2.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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