Herstellung und Reaktionsverhalten eines schwefelverbrückten Bischinolons

Abstract

1Synthesis and Properties of a Sulfur-bridged Bisquinolone Starting with the tosylated enaminone 5, the novel quinolone derivatives 3, 8, 9, and 10 were formed by reactions with acetic acid, sulfuryl chloride, and thionyl bromide, respectively. Alkylation of the sulfur-bridged bisquinolone 8 yields the N-substituted quinolones 11 and 12. Dehydratisation of 8 leads to the novel heterocyclic system 13. Reaction of 8 with P0Cl3 affords the 4-chloroquinoline derivative 14, from which the sulfoxide 15 can be obtained. The quinoline 14 reacts with thiourea to give the isothiuronium salt 16. Compound 16 is converted into the dithiino bisquinoline 18 either by heating or via the thione 17 by H2S elimination.Enaminone 56*7). Die dabei freigesetzte Bromwasserstoffsaure begiinstigt eine Cyclisierung zu 7 unter Dimethylaminabspaltung.Neben Verbindung 7 fdlt das 3,6-Dibromchinolon lo8) in Abhiingigkeit von der Reinheit des Thionylbromids in mehr oder weniger hohen Ausb. an. GemaB der Zerfallsgleichung des Thionylbromids (GI. 1) ist fur diese Brornierungsreaktion der hohe Bromanteil verantwortlich.Aus Verbindung 7 kann das angestrebte schwefelverbriickte Bischinolon 8 mit Pyridin freigesetzt werden.DaB Substanz 8 eine 4-Chinolonstruktur besitzt, wird durch ein Resonanzsignal bei 175 ppm im '3C-NMR-Spektrum, das nur einem Carbonylkohlenstoff zugeordnet werden kann, bewiesen.

Selective Electrochemical Halogenation of Functionalized Quinolone

“…Jiang developed an electrochemically induced tandem reaction for selective N1-alkylation and C3-halogenation of indoles in 2019. Quinolones are nitrogenous heterocyclic compounds with a wide range of pharmacological effects and biological activity, such as anticancer, antimalarial, antioxidant, and anti-inflammatory effects; they are one of the most important structural scaffolds known to inhibit bacterial growth. – However, organic electrochemistry papers of quinolone derivatives have rarely been reported at present. , As far as we know, electrochemical methods to construct carbon–halogen bonds using quinolones as substrates have never been reported. Thus, we report herein the C3–H halogenation reaction of quinolones under electrochemical conditions (Scheme c, this work).…”