AbstractDer Begriff „Thermochromie”︁T leitet sich aus den griechischen Bezeichnungen für Wärme („thermos”︁) und Farbe („chroma”︁) ab. Bezeichnet wird damit das Auftreten reversibler Farbänderungen von Stoffen in Abhängigkeit von der Temperatur. Entsprechende Erscheinungen sind im Bereich der Anorganischen Chemie schon seit langem bekannt. Ein klassisches Beispiel ist der rote Rubin, der sich beim Erhitzen grün färbt und beim Abkühlen wieder rot wird. Aber auch wenn man gerade keinen Rubin zur Hand hat, lassen sich thermochrome Effekte z.B. beim Zinkoxid (in der Kälte weiß, in der Hitze gelb) oder, wie vor einiger Zeit beschrieben, beim Kupfer(I)oxid (in der Kälte rot, in der Hitze schwarz) beobachten [1].Aber auch im Bereich der Organischen Chemie hat es bereits gegen Ende des 19. Jahrhunderts erste Beobachtungen und Untersuchungen zu thermochromen Erscheinungen im Zusammenhang mit der Entdeckung von Flüssigkristallen durch Reinitzer und Lehmann sowie deren maßgebliche Klassifikation und Beschreibung durch Friedel gegeben (nach [2]). Interessanterweise waren alle drei keine Chemiker, sondern Lehmann und Friedel Physiker und Reinitzer Botaniker. Abgesehen von dem akademischen Interesse an diesen Stoffen dauerte es allerdings bis in die 50er und 60er Jahre des vergangenen Jahrhunderts, bis eine intensive Forschung auf dem Gebiet der Flüssigkristalle im Hinblick auf eine Anwendung deren thermochromer, vor allem aber ihrer elektrooptischen Eigenschaften einsetzte. Aus unserer heutigen Gesellschaft sind z.B. LCD‐Displays oder seit neuestem LCD‐Fernseher kaum noch wegzudenken.

Monoalkylations of different nucleophilic azoles were investigated with the electron-deficient trans-3,3,3-trifluoro-1-nitropropene (1) as alkylating reagent without addition of any catalyst. In each case, the bonding of the alkene at the azole occurs regioselectively at the trifluoromethyl-substituted C atom of the alkene, whereas the azoles react at different positions depending on the electron density of the heterocycles. Thus, 1-methyl-pyrrole (2) reacted with 1 under C-C bond formation giving the two regioisomers 2-(1-trifluoromethyl-2-nitroethyl)-1-methyl-pyrrole (3) (major product) and 3-(1-trifluoromethyl-2-nitroethyl)-1-methyl-pyrrole (4). The less nucleophilic pyrazole (5), 1,2,4-triazole (7), 3-bromo-1,2,4-triazole (9), and 3,5-dibromo-1,2,4-triazole (12) gave exclusively the corresponding N-alkyl azoles 1- (1-trifluoromethyl-2-nitroethyl )-pyrazole (6), 1-(1-trifluoromethyl-2-nitroethyl) -1,2,4-triazole (8), 3-bromo-1- (1-trifluoromethyl-2-nitroethyl)-1,2,4-triazole (10)/5-bromo-1-(1-trifluoromethyl-2-nitroethyl)-1,2,4-triazole (11), and 3,5-dibromo-1-(1-trifluoromethyl-2-nitroethyl)-1,2,4-triazole (13), respectively. The enantiomeric pairs of the chiral monoalkyl-azoles could not be separated. Moreover, we used trans-3,3,3-trifluoro-1-nitropropene (1) as a dienophile in Diels-Alder cycloadditions with cyclopentadiene (14), cyclohexa-1,3-diene (16), and furan (18). Two diastereomeric products (15A/15B, 17A/17B, and 19A/19B), which could not be separated by column chromatography, are formed from each diene. All compounds were characterized by 1H, 13C, and 19F NMR data.

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Zeitschrift für ChemieVolume 22, Issue 11 p. 411-412 Kurze Originalmitteilungen Zur Struktur und innermolekularen Beweglichkeit von 1,3-Diazabutadienen† Manfred Michalik, Manfred Michalik Sektion Chemie der Wilhelm-Pieck-Universität Rostock, DDR-25 Rostock, Buchbinderstr. 9Search for more papers by this authorRainer Evers, Rainer Evers Sektion Chemie der Wilhelm-Pieck-Universität Rostock, DDR-25 Rostock, Buchbinderstr. 9Search for more papers by this author Manfred Michalik, Manfred Michalik Sektion Chemie der Wilhelm-Pieck-Universität Rostock, DDR-25 Rostock, Buchbinderstr. 9Search for more papers by this authorRainer Evers, Rainer Evers Sektion Chemie der Wilhelm-Pieck-Universität Rostock, DDR-25 Rostock, Buchbinderstr. 9Search for more papers by this author First published: November 1982 https://doi.org/10.1002/zfch.19820221112Citations: 1 † N-Cyano-amidino-dithiocarbimidsäurediester AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume22, Issue11November 1982Pages 411-412 RelatedInformation

Chemischer InformationsdienstVolume 12, Issue 9 Heterocyclic Compounds ChemInform Abstract: STRUCTURE AND REACTIVITY OF ACTIVATED C:N DOUBLE BONDS; 5. SYNTHESIS OF SUBSTITUTED 1,3,4-THIADIAZOLES R. EVERS, R. EVERSSearch for more papers by this authorE. FISCHER, E. FISCHERSearch for more papers by this authorM. PULKENAT, M. PULKENATSearch for more papers by this author R. EVERS, R. EVERSSearch for more papers by this authorE. FISCHER, E. FISCHERSearch for more papers by this authorM. PULKENAT, M. PULKENATSearch for more papers by this author First published: March 3, 1981 https://doi.org/10.1002/chin.198109241Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume12, Issue9March 3, 1981 RelatedInformation

Zeitschrift für ChemieVolume 21, Issue 10 p. 358-360 Kurze Originalmitteilungen Struktur und Reaktionsverhalten aktivierter CN-Doppelbindungen;† Synthese von substituierten Guanyl-isothioharnstoffen Rainer Evers, Rainer Evers Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this author Rainer Evers, Rainer Evers Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this author First published: Oktober 1981 https://doi.org/10.1002/zfch.19810211011Citations: 4 † 7. Mitteilung; 6. Mitteilung siehe [1] AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume21, Issue10Oktober 1981Pages 358-360 RelatedInformation

Zeitschrift für ChemieVolume 20, Issue 11 p. 412-413 Kurze Originalmitteilung Zum Reaktionsverhalten der Thio-bis-formamidine†Versuche zur Synthese von Pyrimidino[4,5-d]pyrimidinderivaten Rainer Evers, Rainer Evers Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this authorEberhard Fischer, Eberhard Fischer Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this author Rainer Evers, Rainer Evers Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this authorEberhard Fischer, Eberhard Fischer Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this author First published: November 1980 https://doi.org/10.1002/zfch.19800201105Citations: 4 † 7. Mitteilung; 6. Mitteilung siehe [1] AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume20, Issue11November 1980Pages 412-413 RelatedInformation

Zeitschrift für ChemieVolume 20, Issue 10 p. 369-370 Kurze Originalmitteilungen Zum Reaktionsverhalten der Thio-bis-formamidine†Darstellung einiger 2-Isothioureido-4-ureido-1,3,5-triazine Rainer Evers, Rainer Evers Wilhelm-Pieck-Universität Rostock, Sektion Chemie DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this author Rainer Evers, Rainer Evers Wilhelm-Pieck-Universität Rostock, Sektion Chemie DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this author First published: Oktober 1980 https://doi.org/10.1002/zfch.19800201004Citations: 2 † 6. Mitteilung; 5. Mitteilung siehe [1] AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume20, Issue10Oktober 1980Pages 369-370 RelatedInformation

Zeitschrift für ChemieVolume 20, Issue 8 p. 294-295 Kurze Originalmitteilungen Zur Struktur der N-Cyano-guanyl-imido-dithiokohlensäurediester† Rainer Evers, Rainer Evers Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this authorManfred Michalik, Manfred Michalik Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this author Rainer Evers, Rainer Evers Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this authorManfred Michalik, Manfred Michalik Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this author First published: August 1980 https://doi.org/10.1002/zfch.19800200806Citations: 5 † 2. Mitteilung über Struktur und Reaktionsverhalten aktivierter CN-Doppelbindungen; 1. Mitteilung vgl. [1] AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume20, Issue8August 1980Pages 294-295 RelatedInformation

Zeitschrift für ChemieVolume 20, Issue 10 p. 371-372 Kurze Originalmitteilung Struktur und Reaktionsverhalten aktivierter CN-Doppelbindungen† Rainer Evers, Rainer Evers Wilhelm-Pieck-Universität Rostock, Sektion Chemie, DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this authorEberhard Fischer, Eberhard Fischer Wilhelm-Pieck-Universität Rostock, Sektion Chemie, DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this authorMarianne Pulkenat, Marianne Pulkenat Wilhelm-Pieck-Universität Rostock, Sektion Chemie, DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this author Rainer Evers, Rainer Evers Wilhelm-Pieck-Universität Rostock, Sektion Chemie, DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this authorEberhard Fischer, Eberhard Fischer Wilhelm-Pieck-Universität Rostock, Sektion Chemie, DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this authorMarianne Pulkenat, Marianne Pulkenat Wilhelm-Pieck-Universität Rostock, Sektion Chemie, DDR-2500 Rostock, Buchbinderstr. 9Search for more papers by this author First published: Oktober 1980 https://doi.org/10.1002/zfch.19800201006Citations: 4 † 4. Mitteilung; 3. Mitteilung siehe [1] AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume20, Issue10Oktober 1980Pages 371-372 RelatedInformation

Zeitschrift für ChemieVolume 20, Issue 11 p. 413-414 Kurze Originalmitteilung Struktur und Reaktionsverhalten aktivierter C-N-Doppelbindungen†Synthese substituierter 1,3,4-Thiadiazole Rainer Evers, Rainer Evers Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this authorEberhard Fischer, Eberhard Fischer Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this authorMarianne Pulkenat, Marianne Pulkenat Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this author Rainer Evers, Rainer Evers Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this authorEberhard Fischer, Eberhard Fischer Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this authorMarianne Pulkenat, Marianne Pulkenat Sektion Chemie, Wilhelm-Pieck-Universität Rostock, DDR-2500 Rostock, Buchbinderstraße 9Search for more papers by this author First published: November 1980 https://doi.org/10.1002/zfch.19800201106Citations: 7 † 5. Mitteilung; 4. Mitteilung siehe [1] AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume20, Issue11November 1980Pages 413-414 RelatedInformation

Zeitschrift für ChemieVolume 19, Issue 7 p. 250-251 Kurze Originalmitteilungen Zum Reaktionsverhalten der Thio-bis-formamidine;† Synthese von funktionalisierten 2-Isothioureido-6-alkyl-mercapto-pyrimidinen Rainer Evers, Rainer Evers Wilhelm-Pieck-Universität Rostock, Sektion Chemie, 25 Rostock, Buchbinderstr. 9Search for more papers by this author Rainer Evers, Rainer Evers Wilhelm-Pieck-Universität Rostock, Sektion Chemie, 25 Rostock, Buchbinderstr. 9Search for more papers by this author First published: Juli 1979 https://doi.org/10.1002/zfch.19790190704Citations: 9 † 4. Mitteilung, 3. Mitteilung vgl. [1] AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Literatur 1 Als 1., 2. und 3. Mitteilung gelten: Google Scholar Evers, R; Fischer, E.: Z. Chem. 16 (1976) 101; 10.1002/j.0044-2402.1976.tb00064.x CASWeb of Science®Google Scholar Evers, R; Rembarz, G; Fischer, E.: Z. Chem. 16 (1976) 15; 10.1002/j.0044-2402.1976.tb00004.x CASWeb of Science®Google Scholar Evers, R; Fischer, E; Rembarz, G.: J. prakt. Chem. 319 (1977) 713 10.1002/prac.19773190503 CASWeb of Science®Google Scholar 2 Evers, R; Fischer, E; Rembarz, G.: J. prakt. Chem. 319 (1977) 713 10.1002/prac.19773190503 CASWeb of Science®Google Scholar 3 DDR-Pat. 103004, Evers, R.; Rembarz, G.; Fischer, E. Google Scholar 4 Peseke, K.: Rostock, Univ., Dissertation B 1976 Google Scholar 5 Kast, H.: Stuttgart, Univ., Dissertation 1966 Google Scholar 6 Peseke, K.: Z. Chem. 16 (1976) 16 10.1002/j.0044-2402.1976.tb00005.x CASWeb of Science®Google Scholar 7 Gompper, R; Töpfl, W.: Chem. Ber. 95 (1962) 2881 10.1002/cber.19620951208 CASWeb of Science®Google Scholar Citing Literature Volume19, Issue7Juli 1979Pages 250-251 ReferencesRelatedInformation

AbstractBei der Umsetzung der N,N′‐Diaryl‐thioharnstoffe (I) mit Cyanamid (II) und HCl im Molverhältnis 1:1 22 färben sich die Lösungen sofort gelb, und eine unterschiedliche Menge farbloser Kristalle scheidet sich ab, die als das Thio‐bis‐formamidinsalz (VI) identifiziert werden.

Zeitschrift für ChemieVolume 16, Issue 1 p. 15-16 Kurze Originalmitteilungen Über Reaktionen des Cyanamids mit N1,N-Diarylthioharnstoffen Rainer Evers, Sektion Chemie, Universität Rostock, 25 Rostock, Buchbinderstr. 9Search for more papers by this authorEberhard Fischer, Sektion Chemie, Universität Rostock, 25 Rostock, Buchbinderstr. 9Search for more papers by this author Rainer Evers, Sektion Chemie, Universität Rostock, 25 Rostock, Buchbinderstr. 9Search for more papers by this authorEberhard Fischer, Sektion Chemie, Universität Rostock, 25 Rostock, Buchbinderstr. 9Search for more papers by this author First published: 01 January 1976 https://doi.org/10.1002/j.0044-2402.1976.tb00004.xCitations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume16, Issue1Januar 1976Pages 15-16 RelatedInformation

Zeitschrift für ChemieVolume 16, Issue 3 p. 101-102 Kurze Originalmitteilungen Darstellung substituierter Thio-bis-formamidine Rainer Evers, Universität Rostock, Sektion Chemie, DDR-25 RostockSearch for more papers by this authorGerhard Rembarz, Universität Rostock, Sektion Chemie, DDR-25 RostockSearch for more papers by this authorEberhard Fischer, Universität Rostock, Sektion Chemie, DDR-25 RostockSearch for more papers by this author Rainer Evers, Universität Rostock, Sektion Chemie, DDR-25 RostockSearch for more papers by this authorGerhard Rembarz, Universität Rostock, Sektion Chemie, DDR-25 RostockSearch for more papers by this authorEberhard Fischer, Universität Rostock, Sektion Chemie, DDR-25 RostockSearch for more papers by this author First published: 01 March 1976 https://doi.org/10.1002/j.0044-2402.1976.tb00064.xCitations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume16, Issue3März 1976Pages 101-102 RelatedInformation

The reaction of dicyanimide with symmetrical disubstituted thioureas in absolute alcohol in presence of hydrogen chloride gives in good yields derivatives of the 1.3.5-thiadiazine.

N,N-disubstituted thioureas react with dicyanimide in a simple reaction to form derivatives of the 4H-1.3.5-thiadiazine. The N,N-dimethyl-, N,N-diethyl- and N,N-di-n-propyl-thiourea react under formation of derivatives of S, S'-bis-guanyl-diisodithiobiuret.