Mechanistic study of the addition reaction of TeCl4 to alkynes: Participation of TeCl3 centered-radical

The mechanism of the addition reaction of TeCl₄ to alkynes was indirectly established by the detection of TeCl₃ centered radicals using EPR spin trapping, ESI-MS and ESI-MS/MS characterization.     

Rhythmische Abscheidung von Stearinsäure aus alkoholischer und ätherischer Lösung

Kurze Zusammenfassung Stearins?ure scheidet sich aus hei?er alkoholischer L?sung (100 g in 70 ccm) und aus ges?ttigter ?therischer L?sung in Form von konzentrischen Ringen aus. Ein Versuch, diese Bildung zu erkl?ren, nimmt das Wechselspiel zwischen fortschreitender Abkühlung und freiwerdender Kristallisationsw?rme als ma?gebend an.     

Über Propanal-2-Methyl-2-Brom

Ohne Zusammenfassung     

Die Funksche Integralgleichung der Kugelflächen-funktionen und ihre Übertragung auf die Überkugel

Ohne Zusammenfassung     

Complex and unpredictable Cardano

This purely recreational paper is about one of the most colorful characters of the Italian Renaissance, Girolamo Cardano, and the discovery of two basic ingredients of quantum theory, probability and complex numbers.     

Kinetik der Verseifung des Benzolsulfosäuremethylesters

Ohne ZusammenfassungIch fühle mich verpflichtet, am Schlusse dieser Arbeit Herrn Prof. Wegscheider für die mir zu teil gewordene Unterstützung wärmstens zu danken.     

Insight into the mechanism of three component condensation leading to aminomethylenebisphosphonates

Three-component reaction of a primary amine, diethyl phosphite and triethyl orthoformate followed by acid hydrolysis of the adduct provides N-substituted aminomethylenebisphosphonic acids in good yields. Being extremely versatile, it is commonly utilized for preparation of compounds possessing potential antiosteoporotic, antibacterial, anticancer, antiparasitic or herbicidal activity. However, the mechanism of the reaction remains unknown. p-Nitroaniline has been found an interesting tool to shed light on this matter. Its use allowed to separate and identify four intermediates, both non-phosphorus and phosphorus containing, and subsequently suggest the mechanism of the whole process. The acquired knowledge was helpful in explanation the route and the final product structure obtained for more complex reaction proceeding with the use of 4-aminopyridine. Additional alkylation of the pyridine nitrogen atom, leading to unexpected N-(1-alkylpyridinium-4-amino)methylenebisphosphonic acids was unambiguously proved.