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  • 1
    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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  • 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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