A synthesis of the tricyclic pyrroloquinoline core of martinelline

Five‐Membered Heterocycles: Pyrrole and Related Systems

“…More efficient radical C2 arylations of pyrroles having an electron-withdrawing substituent at the nitrogen atom have been afforded using anilines in the presence of amyl nitrite in warm acetic acid [437]. Intramolecular radical arylations involving pyrroles are useful tools for the construction of more complex systems, such as the tricyclic derivative 288, which was derived from the precursor 289 by exposure thereof to tributyltin hydride in the presence of AIBN in refluxing toluene [438,439]. Related cyclization reactions may also produce spiropyrrolidinyloxindoles, depending on the properties of the pyrrole protecting group [440].…”

Modern Developments in Aryl Radical Chemistry

“…Although the addition of aryl radicals is more efficient to many heterocycles than to most substituted benzenes, the formation of the desired heterobiaryls can significantly be hindered in the rearomatization step [137][138][139][140]. Two examples from recent studies on Pschorr-type cyclizations on nitrogen-containing heterocycles are shown in Schemes 29 and 30 [141][142][143].…”

Fused quinoline heterocycles VII: synthesis of new isoxazolo[3',4':4,5]pyrrolo(or thieno)[2,3-c]quinoline ring systems

“…4 They are also known for their antibiotic activity against both Gram-positive and Gram-negative bacteria. 5 A number of synthetic analogues in a different oxidation states also have valuable biological properties, as an example 7-chloro-3-methyl-1H-pyrrolo[3,2-c]quinoline-4-carboxylic acid was found to be a relatively potent and selective inhibitor of kynurenine-3-hydroxylase. 6 Moreover, some of the sulfurcontaining fused quinolines and particularly thienoquinolines have recently drawn much attention due to their considerable biological and pharmacological activities.…”