249608-62-6Relevant academic research and scientific papers
Synthesis of Carbazoles and Carbazole-Containing Heterocycles via Rhodium-Catalyzed Tandem Carbonylative Benzannulations
Song, Wangze,Li, Xiaoxun,Yang, Ka,Zhao, Xian-Liang,Glazier, Daniel A.,Xi, Bao-Min,Tang, Weiping
, p. 2930 - 2942 (2016/04/26)
Polycyclic aromatic compounds are important constituents of pharmaceuticals and other materials. We have developed a series of Rh-catalyzed tandem carbonylative benzannulations for the synthesis of tri-, tetra-, and pentacyclic heterocycles from different types of aryl propargylic alcohols. These tandem reactions provide efficient access to highly substituted carbazoles, furocarbazoles, pyrrolocarbazoles, thiophenocarbazoles, and indolocarbazoles. While tricyclic heterocycles could be derived from vinyl aryl propargylic alcohols, tetra- and pentacyclic heterocycles were synthesized from diaryl propargylic alcohols. The tandem carbonylative benzannulation is initiated by a π-acidic rhodium(I) catalyst-mediated nucleophilic addition to alkyne to generate a key metal-carbene intermediate, which is then trapped by carbon monoxide to form a ketene species for 6π electrocyclization. Overall, three bonds and two rings are formed in all of these tandem carbonylative benzannulation reactions.
Synthesis of new pyrrolobenzazepines via Pictet-Spengler cyclization
Gracia, Stéphanie,Schulz, Jürgen,Pellet-Rostaing, Stéphane,Lemaire, Marc
scheme or table, p. 1852 - 1856 (2009/04/07)
A new six-step divergent strategy was developed allowing access to pyrrolobenzazepine structures from pyrrole. This strategy was based on a regioselective Friedel-Crafts acylation followed by a Pictet-Spengler cyclization. Georg Thieme Verlag Stuttgart.
Reduction of 2- and 3-acylpyrroles. A new synthesis of the pyrrolo[1,2-b]cinnolin-10-one ring system from 1-(4-methylphenyl)sulfonyl-1H-pyrrole
Kimbaris, Athanasios,Varvounis, George
, p. 9675 - 9682 (2007/10/03)
Reduction of (2-nitrophenyl)(1H-pyrrol-2-yl)methanone 4 with zinc and ammonium chloride gave 5,10-dihydro-pyrrolo[1,2-b]cinnolin-10-one 5 and (2-hydroxylaminophenyl)(1H-pyrrol-2-yl)methanone 6 whereas reduction of 4 with zinc and sodium hydroxide gave only 5. Reaction of (2-nitrophenyl)(1H-pyrrol-3-yl)methanone 10 with zinc and ammonium chloride or zinc and sodium hydroxide afforded (2-nitrosophenyl)(1H-pyrrol-3-yl)methanone 11 and 2-aminophenyl)(1H-pyrrol-3-yl)methanone 12 or 12 as a single product, respectively. Sodium borohydride reduction of (2-nitrophenyl)(1-methyl-1H-pyrrol-2-yl)methanone 13 or (2-nitrophenyl)(1-methyl-1H-3-pyrrolyl)methanone 19 gave a mixture of the corresponding alcohols 15 or 21 and nitroso-ketones 18 or 22. Reduction of alcohols 15 or 21 with zinc and sodium hydroxide afforded nitroso-ketones 18 or 22, respectively. (C) 2000 Elsevier Science Ltd.
