- Transition-Metal-Free Synthesis of Acridones via Base-Mediated Intramolecular Oxidative C?H Amination
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Intramolecular oxidative C?H amination of 2-aminobenzophenones was achieved in the presence of potassium tert-butoxide and dimethyl sulfoxide. A series of functionalized acridones were prepared in moderate to excellent yields in a mild, efficient, and transition-metal-free manner. (Figure presented.).
- Wei, Wen-Tao,Sheng, Jian-Fei,Miao, Hui,Luo, Xiang,Song, Xian-Heng,Yan, Ming,Zou, Yong
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p. 2101 - 2106
(2018/06/14)
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- PhI(OAc)2-mediated intramolecular oxidative aryl-aldehyde C sp 2-C sp 2 bond formation: Metal-free synthesis of acridone derivatives
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A metal-free protocol for direct aryl-aldehyde Csp2-Csp 2 bond formation via a PhI(OAc)2-mediated intramolecular cross-dehydrogenative coupling (CDC) of various 2-(N-arylamino)aldehydes was developed. The novel methodology requires no need of preactivation of the aldehyde group, is applicable to a large variety of functionalized substrates, and most of all provides a convenient approach to the construction of biologically important acridone derivatives.
- Zheng, Zisheng,Dian, Longyang,Yuan, Yucheng,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
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p. 7451 - 7458
(2014/09/17)
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- Sc(OTf)3-catalyzed dehydrogenative cyclization for synthesis of N-methylacridones
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A novel method has been developed for the synthesis of substituted N-methylacridones from 2-(N-methyl-N-phenylamino)benzaldehydes via dehydrogenative cyclization. This transformation involves two primary processes: the aldehyde first coordinates with Sc(OTf)3 and induces the aromatic electrophilic substitution (SEAr) reaction to form the active intermediate N-methyl-acridin-9-ol, which is then quickly oxidized in situ to afford the acridones. Furthermore, the procedure involved is both environmental friendly and atom efficient; H2O is the only byproduct in this reaction.
- Li, Xi-An,Wang, Hong-Li,Yang, Shang-Dong
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p. 1794 - 1797
(2013/05/23)
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- Synthesis of 10-methylacridin-9(10H)-ones through Cu-Catalyzed Intramolecular Oxidative C(sp2)-H Amination of 2-(Methylamino) benzophenones
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An efficient synthesis of a diverse set of 10-methylacridin-9(10H)-ones from 2-(methylamino)benzophenones has been developed. The reaction proceeds though Cu-catalyzed intramolecular aromatic C-H amination by using O2 as the sole oxidant to provide the desired products in moderate to good yields. In addition, 2-allylamino- and 2-(benzylamino)benzophenones as well as unprotected substrates can also undergo the C-H amination reaction to deliver the corresponding cyclization products smoothly. Preliminary mechanistic studies suggest that C-H activation is involved in a rate-limiting step. An efficient synthesis of a diverse set of 10-methylacridin-9(10H)-ones from 2-(methylamino)benzophenones has been developed. The reaction proceeds through Cu-catalyzed intramolecular aromatic C-H amination by using O2 as the oxidant. Mechanistic studies suggest that a rate-limiting C-H activation step is involved in the C-N bond-formation process.
- Huang, Jinbo,Wan, Congqing,Xu, Ming-Fang,Zhu, Qiang
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supporting information
p. 1876 - 1880
(2013/04/24)
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- Copper-catalyzed intramolecular oxidative C-H functionalization and C-N formation of 2-aminobenzophenones: Unusual pseudo-1,2-shift of the substituent on the aryl ring
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A good move: A copper-catalyzed intramolecular oxidative C-H functionalization of 2-aminobenzophenone affords two regioisomeric acridones (see scheme). The reaction involves an unusual pseudo-1,2-migration of R 2 group(s) on the arene ring (bpy=2,2-bipyridine, DMAc=dimethylacetimide). Copyright
- Huang, Pang-Chi,Parthasarathy, Kanniyappan,Cheng, Chien-Hong
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supporting information
p. 460 - 464
(2013/02/23)
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- The Chemistry of 2H-3,1-Benzoxazine-2,4(1H)-dione (Isatoic Anhydride). 21. A Mild Process For The Preparation of 10-Alkyl-9-acridanones And It's Application To The Synthesis of Acridone Alkaloids
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10-Substituted-9-acridanones are readily prepared by the reaction of the corresponding isatoic anhydride with the lithium enolate of 2-cyclohexen-1-one.The initially formed product, the 1,2-dihydroacridone need not be purified but can be aromatized directly with DDQ to the desired acridone.This methodology is applicable to the synthesis of acridone natural products.Two alkaloids, 1,2,3-trimethoxy-10-methylacridone (9) and evoxanthine (10), were prepared from 4,5,6-trimethoxy-N-methylisatoic anhydride and 6-methoxy-4,5-methylenedioxy-N-methylisatoic anhydride respectively.In these trioxygenated systems, palladium-on-charcoal must be used to aromatize the penultimate intermediate.
- Coppola, Gary M.,Schuster, Herbert F.
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p. 957 - 964
(2007/10/02)
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