890791-51-2Relevant academic research and scientific papers
Aryl grignard reagents in chemodivergent N-and C-arylations: Concise access to two families of tetracyclic fused carbazoles from 6-nitroquinolines
Sanchez, Juan Domingo,Egris, Riccardo,Perumal, Subbu,Villacampa, Mercedes,Menendez, J. Carlos
experimental part, p. 2375 - 2385 (2012/05/19)
The reaction between aryl Grignard compounds and 5-methoxy-6-nitroquinoline derivatives in THF was found to proceed in a chemodivergent mode that depended on the functional groups present in the heterocyclic ring. Thus, the reactions that started from carbostyril derivatives afforded 6-(arylamino)carbostyrils as the major products, whereas those that started with 2-alkoxyquinolines gave exclusively 5-arylquinolines. Both types of products were transformed into tetracyclic fused linear or angular carbazole systems by using palladium-promoted oxidative coupling or Cadogan reactions, respectively. In the course of this work, an unprecedented oxidative demethylation by palladium acetate of 1,4-dimethoxybenzene systems to the corresponding quinones was discovered. The reaction between aryl Grignard compounds and 5-methoxy-6-nitroquinoline derivatives in THF proceeded in a chemodivergent mode that depended on the electron-withdrawing or electron-releasing nature of the functional groups present in the heterocyclic ring to give N-arylation or C 5-arylation products, respectively.
Synthesis of pyrido[3,2-b]carbazolequinones involving N-arylation of 5,8-dimethoxy-6-nitroquinolines by aryl grignard reagents and a new one-pot, palladium-promoted oxidative coupline-oxidative demethylation sequence
Sánchez, Juan Domingo,Avenda?o, Carmen,Menéndez, J. Carlos
experimental part, p. 1371 - 1375 (2009/04/06)
The reaction between a 5,8-dimethyxy-6-nitrocarbostyril derivative and arylmagnesium bromides gave 6-arylaminocarbostyrils as the major products. Their subsequent treatment with palladium acetate in refluxing acetic acid gave linear pyrido[3,2-b]carbazolequinones in one step, involving the unprecedented oxidative demethylation of 1,4-dimethoxybenzene systems to the corresponding quinones by palladium acetate. A palladium-calalyzed oxidative functionalization of an unactivated C-H bond was also observed. Georg Thieme Verlag Stuttgart.
