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  • 1
    Electronic Resource
    Electronic Resource
    MO-LCAO Calculations of Polymethines (1975)
    Springer
    Theoretical chemistry accounts 36 (1975), S. 351-355 
    Details
    ISSN: 1432-2234
    Keywords: Polymethines ; Streptopolymethines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Idealized polymethines are defined as conjugated chain molecules with complete bond equilization and charge alternation. A constant π-bond order along the chain with N atoms has been derived for three types of polymethines which differ by the nature of the heteroatomic end groups. Corresponding to the number of π-electrons they are termined (N + 1)π-, Nπ- or (N − 1)π-polymethines. This classification embraces closed shell as well as open shell systems. The relations for the energy eigenvalues, coefficients and derived quantities have been obtained in closed form. The results for the different classes of polymethines are strongly related. Their molecular properties should be similar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00549699
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  • 2
    Electronic Resource
    Electronic Resource
    MO-LCAO-Berechnungen an schwefelhaltigen π-Elektronensystemen (1968)
    Springer
    Theoretical chemistry accounts 12 (1968), S. 319-324 
    Details
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mercaptosubstituierte Ionen von Schwefelheterocyclen, die iso-π-elektronisch mit dem Mercaptotropyliumion sind, zeigen mehrere charakteristische Absorptionsmaxima im Ultravioletten, die sich mehr oder weniger von den Absorptionen der unsubstituierten Heterocyclen unterscheiden. Diese Verbindungen werden durch Protonierung iso-π-elektronischer Thiotropene erhalten. Halbempirische SCF-LCI-Rechnungen mit früher abgeleiteten Parametern geben die experimentellen Ergebnisse gut wieder. Der Einfluß einer Methylsubstitution am exocyclischen Schwefel läßt sich durch eine Änderung des Parameters U s abschätzen.
    Abstract: Résumé Des thiotropones isolélectroniques π sont par protonation converties en ions mercapto-substitués des hétérocycles correspondants. Ces ions présentent différents maxima d'absorption caractéristiques dans le spectre U.V. Des calculs semi-empiriques SCF-LCI, utilisant des paramètres précédemment obtenus, reflètent d'une manière satisfaisante les résultats expérimentaux. Par un ajustement convenable du paramètre U s il est possible d'estimer l'influence de la substitution méthylique sur l'atome de soufre exocyclique.
    Notes: Abstract Iso-π-electronic thiotropones are converted by means of protonisation into mercaptosubstituted ions of the analogous heterocycles. These ions show various characteristic absorption maxima in the UV-region. Semiempirical SCF-LCI-calculations using parameters derived formerly reflect the experimental results satisfactory. By appropriate adjustment of the parameter U s it is possible to estimate the influence of methyl substitution on the exocyclic sulfur atom.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00527548
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation and properties of 2-Dialkylamino-5-haloacetyl-thiazoles and 4-(2-Dialkylamino-5-thiazolyl)-thiazolesPresented in part at the third conference on iminium salts, Stimpfach-Rechenberg (Germany), September 17-19, 1997 (1998)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 340 (1998), S. 375-380 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By the reaction of N-acylthioureas 7 with 1,3-dichloroacetone 9 2-dialkylamino-5-chloroacetyl-thiazoles 11 are available. These compounds react with thioureas or arylthioamides under heterocyclisation to give bis-(2-dialkylamino-5-thiazolyl)-ketones 13, 2-aryl-4-(2-dialkylamino-5-thiazolyl)-thiazoles 14, or 2-dialkylamino-4-(2-dialkylamino-5-thiazolyl)-thiazoles 15, resp., from which the last-mentioned compound exhibit a high reactivity towards several electrophilic reagents. Thus, deeply colored cyanovinyl, arylazo, and arylmethine substituted bisthiazole dyes 17, 18, and 19, resp., have been formed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19983400413
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  • 4
    Electronic Resource
    Electronic Resource
    Darstellung und Charakterisierung N-Disubstituierter 2-Amino-4-chlor-thiazol-5-aldehyde und ihrer Dicyanmethylen-Derivate (1996)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 338 (1996), S. 51-54 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation and Characterisation of N-Disubstituted 2-Amino-4-chloro-5-formyl-thiazoles and Their Dicyanmethylene DerivativesIn contrast to N-disubstituted 3-hydroxy-anilines 5 which react with the Vilsmeier reagent to N-substituted 4-amino-salicylaldehydes 7 their heteroanalogous N-disubstituted 2-amino-4-hydroxy-thiazoles 6 react with the same reagent to N-substituted 2-amino-4-chloro-thiazole-5-aldehydes 12 via their corresponding iminium salts precursors 11. Both types of compounds can be transformed, in analogy to other 2-amino-thiazole-5-aldehydes, by reaction with malodinitrile 13 into stable N-substituted 2-amino-4-chloro-5-(2,2-dicyano-ethenyl)-thiazoles 14.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19963380108
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  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and Spectroscopic Characterization of New NIR Absorbing (2-Thienyl)- and (4-Dialkylaminoaryl)-substituted Croconic Acid Dyes (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 935-939 
    Details
    ISSN: 0170-2041
    Keywords: Croconic acid ; Dyes ; Thiophenes ; Calculations, PPP ; Near infrared (NIR) absorbing dyes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By condensation of croconic acid (7) with 2-(dialkylamino)-thiophenes 6a-d and with 3-(dialkylamino)phenols 9a-c the deeply colored, sparingly soluble croconic acid dyes (“croconines”) 8a-d and 10a-c, respectively, have been prepared. These croconines have been characterized by UV/Vis, IR, and 1H-NMR spectrometry. They exhibit strong electronic absorption bands in the near infrared (NIR) region (λmax ≈ 750-850 nm; cf. Table 1).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301149
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  • 6
    Electronic Resource
    Electronic Resource
    Oxidation von Thioamiden; eine einfache Synthese von neuartigen 3,5-Diaryl-1,2,4-dithiazoliumsalzen (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 1005-1012 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidation of Thioamides; a Simple Synthesis of Novel 3,5-Diaryl-1,2,4-dithiazolium SaltsArylthioamides 1 and their N-aminomethylene or N-hydroxymethylene derivatives 5 or 6, respectively, can be oxidized to give novel 3,5-diaryldithiazolium salts 3 in acidic medium. The salts 3 react with ammonia or secondary amines to give 3,5-diaryl-1,2,4-thiadiazoles 2 or N2-thioacylamidines 17, respectively. These results permit discussion of the known mechanism of oxidation of thioamides from a new point of view.
    Notes: Arylthioamide 1 und ihre N-Aminomethylen- oder N-Hydroxymethylen-Derivate 5 bzw. 6 können im sauren Medium zu neuartigen 3,5-Diaryl-1,2,4-dithiazoliumsalzen 3 oxidiert werden. Diese Salze 3 gehen mit Ammoniak oder sekundären Aminen in 3,5-Diaryl-1,2,4-thiadiazole 2 bzw. N2-Thioacylamidine 17 über. Die erhaltenen Ergebnisse gestatten neue Rückschlüsse auf den bereits wiederholt untersuchten Reaktionsablauf der Oxidation von Thioamiden.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719770614
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  • 7
    Electronic Resource
    Electronic Resource
    Phenothiazinyl-substituierte Cyanine  -  Modellverbindungen für molekulare SchalterDiese Arbeit wurde von der Deutschen Forschungsgemeinschaft und vom Fonds der Chemischen Industrie gefördert. T. J. J. M. dankt dem Freistaat Bayern für die Gewährung eines Stipendiums zur Förderung des künstlerischen und wissenschaftlichen Nachwuchses. Wir danken Herrn Dr. A. Lerf. Hahn-Meitner-Institut, Garching, für die Durchführung der Leitfähigkeitsmessung. (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 106 (1994), S. 581-584 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19941060510
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  • 8
    Electronic Resource
    Electronic Resource
    Preparation and Characterization of Bridged Naphthoxazinium Salts (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 923-930 
    Details
    ISSN: 1434-193X
    Keywords: Bridged benzo[a]phenoxazinium salts ; Diazo compounds ; Cyclocondensation ; Absorption ; Fluorescence ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -By condensation of bridged 4-arylazo-substituted 3-hydroxyanilines 18 and bridged or unbridged 4-arylazo-substituted 1-naphthylamines 19-23 with bridged 1-naphthylamines 15-17 and 3-aminophenols 14, respectively, in the presence of perchloric acid, bridged naphthoxazinium perchlorates 24-30 have been prepared. The spectral properties of the products have been compared with those of the bridged phenoxazinium salt 31 as well as with data for some unbridged analogues.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    On the formation and solvolysis of 4-aryl-2,2-difluoro-6-methyl-1,3,2-(2H)-dioxaborines (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 8 (1997), S. 147-155 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The condensation of aryl methyl ketones 6 with acetic anhydride 4a in the presence of the boron trifluoride-acetic acid adduct 7 gives rise to the formation of 4-aryl-2,2-difluoro-6-methyl-1,3,2-(2H)-dioxaborines 8 in satisfactory yields. The stable 4-aryl-2,2-difluoro-6-methyl-1,3,2-(2H)-dioxaborines 8 can be transformed by hydrolysis into the corresponding aroylacetones 9. The reaction was optimized so as to avoid the formation of by-products, such as 2,4-diaryl-6-methylpyrylium tetrafluoroborates 11 or self-condensation products. © 1997 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    On the Oxidation of Bridged 1-Naphthylamine and Aniline Derivatives - Formation of Substituted Quinoline and Benzo[c,d]indole DerivativesDedicated to Professor Waldemar Adam on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 2363-2370 
    Details
    ISSN: 0947-3440
    Keywords: Benzo[h]quinolines ; Benzo[i,j]quinolizinium salts ; Bridged benzidine derivatives ; Bridged diphenoquinone diiminium salts ; Benzo[c,d]indoles ; C—C coupling ; Dehydrogenations ; Nitrogen heterocycles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bridged aniline or 1-naphthylamine derivatives 8-10 react with nitrous acid in the presence of perchloric acid to give the bridged diphenoquinone diiminium salts 12·2 HClO4, 17·2 HClO4, 19·2 HClO4 and 23. The same products are obtained from these substrates upon their reaction with hydrogen peroxide. Upon treatment of the bridged diphenoquinone diiminium salts 12·2 HClO4 and 23 with base, a disproportionation reaction occurs resulting in the formation of the corresponding benzidine derivatives 13 and 26 and, following a multistep process, the quinoline derivatives 15 and 25 are obtained. Analogously, the 1,2-dihydrobenzo[c,d]indole hydroperchlorate 10·HClO4 is transformed into the bridged benzidine derivative 21 and the bis(benzo[c,d]indol-6-yl) hydroperchlorate 20·HClO4. Furthermore, as a result of an oxidation process initiated by the protonated species of the corresponding indaminium salts, condensation of N,N-dimethyl-4-nitrosoaniline (27) with the bridged aniline or naphthylamine derivatives 8a-8c leads to the N′-(6-quinolyl)-substituted N,N-dimethylbenzoquinone bis(iminium) salts 29a-28c rather than the corresponding indaminium salts 28a-28c.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719971127
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