Thiazolochinoline, I. Im Thiazolkern Substituierte Thiazolo[4.5‐b]Chinoline

Abstract

Die Oxydation des 2‐Mercapto‐thiazolo[4.5‐b]chinolins wird untersucht und die große Reaktivität der Sulfogruppe der Thiazolo[4.5‐b]chinolyl‐(2)‐sulfonsäure festgestellt. Durch Substitution der Sulfogruppe wird Reihe von Derivaten des Thiazolo[4.5‐b]chinolins dargestellt.

TiCl4‐Mediated Dealkylative Cyclization of Arylidene‐azol‐ones

“…Taken, that the reaction is operating only with sulfur derivatives such as thiazolidinediones and thiohydantoins, local aromaticity of the heterocyclic moiety may be playing the key role in such facilitated isomerization. After the isomerization intramolecular nucleophilic attack and cyclization furnish the tricyclic core B and after condensation – final product C [10] …”

“…[7] Thus, only 2,3-diamino derivatives are readily available, which gives rise only to imidazo [4,5b]pyridines. Alternative azolo [4,5-b]pyridines are accessed differently with the pyridine ring construction step usually performed late in synthesis, after the creation of a fivemembered heterocyclic fragment, [5,6,8,9,10] or via unique oxidative ring contraction of 5-deazaflavin derivatives. [11,12] In this view, access to differently substituted azolo [4,5-b]pyridines, especially for medicinal chemistry purposes, lacks generality.…”

Facile Condensation of 2‐Aminobenzaldehydes into Azolo[4,5‐b]Quinolones

“…[8,9] The synthesis of such compounds is typically multistep and complicated. [10][11][12] Therefore, there is a demand for general and straightforward methods for their creation is in demand. Recently, we have discovered a reaction 2-amino-arylidenethiazolidin-2,4-diones with titanium tetrachloride, which leads to the formation of thiazolo [4,5-b]quinolin-2(4H)-ones through desalkylation on nitrogen atom followed by condensation (Scheme 2).…”