- Organocatalyst in Direct C(sp2)-H Arylation of Unactivated Arenes: [1-(2-Hydroxyethyl)-piperazine]-Catalyzed Inter-/Intra-molecular C-H Bond Activation
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This article describes the identification of 1-(2-hydroxyethyl)-piperazine as a new, cost-effective, highly efficient organocatalyst, which promotes both inter- A nd intra-molecular direct C(sp2)-H arylations of unactivated arenes in the presence of potassium tert-butoxide. While the inter-molecular C-H arylation of unactivated benzenes with aryl halides (Ar-X; X = I, Br, Cl) toward biaryl syntheses underwent smoothly in the presence of only 10 mol percent organocatalyst, the intra-molecular C-H arylation catalytic system composed of 40 mol percent each of the catalyst and the additive (4-dimethylaminopyridine (DMAP)). The novel catalyst was also able to perform both inter- A nd intra-molecular direct arylations simultaneously in a single pot. The mechanistic studies confirmed the involvement of aryl radical anions and proceeded via a single-electron-transfer (SET) mechanism. The large substrate scope, high functional group tolerance, competition experiments, gram-scale synthesis, and kinetic studies further highlight the importance and versatile nature of the methodology as well as the compatibility of the new catalyst. To the best of our knowledge, this is the first report on any organocatalyst that reported detailed investigations of both inter- A nd intra-molecular direct C(sp2)-H arylations of unactivated arenes in a single representation.
- Yadav, Lalit,Tiwari, Mohit K.,Shyamlal, Bharti Rajesh Kumar,Chaudhary, Sandeep
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p. 8121 - 8141
(2020/07/16)
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- Ligand-Enabled Gold-Catalyzed C(sp2)-N Cross-Coupling Reactions of Aryl Iodides with Amines
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The first example of ancillary (P,N)-ligand-enabled gold-catalyzed C-N cross-coupling reactions of aryl iodides with amines is reported. The high generality of the reaction in de novo synthesis, late-stage modifications, and cascade processes to access functionalized indolinones and carbazoles underscores the synthetic potential of the presented strategy. Monitoring the reaction with ESI-HRMS and NMR provided strong evidence for the in situ formation of putative high valent Au(III) intermediates.
- Akram, Manjur O.,Das, Avishek,Chakrabarty, Indradweep,Patil, Nitin T.
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supporting information
p. 8101 - 8105
(2019/10/11)
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- Synthesis and antibacterial activity of 5-methylphenanthridium derivatives as FtsZ inhibitors
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5-Methylphenanthridium derivatives were designed, synthesized and evaluated for their in vitro antibacterial activity and cell division inhibitory activity against various Gram-positive and -negative bacteria. Among them, compounds 5A2, 5B1, 5B2, 5B3, 5C1 and 5C2 displayed the best on-target antibacterial activity with an MIC value of 4?μg/mL against B. subtilis ATCC9372 and S. pyogenes PS, showing over 2-fold better activity than sanguinarine. The SARs showed that the 5-methylphenanthridium derivatives with the alkyl side chains at the 2-postion, especially the straight alkyl side chains exerted better on-target antibacterial activity.
- Liu, Fang,Venter, Henrietta,Bi, Fangchao,Semple, Susan J.,Liu, Jingru,Jin, Chaobin,Ma, Shutao
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supporting information
p. 3399 - 3402
(2017/07/07)
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- Practical Synthesis of Phenanthridinones by Palladium-Catalyzed One-Pot C-C and C-N Coupling Reaction: Extending the Substrate Scope to o-Chlorobenzamides
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A highly efficient construction of phenanthridinone derivatives from o-halobenzamides was developed by using a phosphine-free palladium catalyst in N,N-dimethylacetamide. The domino reaction proceeds through a sequential C-C and C-N bond-formation process in one pot. This protocol exhibits broad substrate scope and affords a series of phenanthridinones in up to 93 % yield. Importantly, the protocol could also be applied for the less reactive o-chlorobenzamides. The approach constitutes the first example of the synthesis of phenanthridinones from this kind of substrate. Moreover, the success of a gram-scale reaction demonstrated that this operationally simple process is scalable.
- Liu, Hailong,Han, Weibiao,Li, Chun,Ma, Zhiyong,Li, Ruixiang,Zheng, Xueli,Fu, Haiyan,Chen, Hua
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supporting information
p. 389 - 393
(2016/02/18)
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- Structure-activity relationship-guided development of retinoic acid receptor-related orphan receptor gamma (RORγ)-selective inverse agonists with a phenanthridin-6(5H)-one skeleton from a liver X receptor ligand
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Retinoic acid receptor-related orphan receptors (RORs), which belong to the nuclear receptor superfamily, regulate many physiological processes, including hepatic gluconeogenesis, lipid metabolism, immune function and circadian rhythm. Since RORs resemble liver X receptors (LXRs) in the fold structure of their ligand-binding domains, we speculated that ROR-mediated transcription might be modulated by LXR ligands, in line with the multi-template hypothesis. Therefore, we screened our LXR ligand library for compounds with ROR ligand activity and identified a novel ROR ligand with a phenanthridin-6(5H)-one skeleton. Structure-activity relationship studies aimed at separating ROR inverse agonistic activity from LXR-agonistic activity enabled us to develop a series of ROR inverse agonists based on the phenanthridin-6(5H)-one skeleton, including a RORγ-selective inverse agonist.
- Nishiyama, Yuko,Nakamura, Masahiko,Misawa, Takashi,Nakagomi, Madoka,Makishima, Makoto,Ishikawa, Minoru,Hashimoto, Yuichi
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p. 2799 - 2808
(2014/05/06)
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- Direct arylation under catalysis of an oxime-derived palladacycle: Search for a phosphane-free method
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A phosphane-free method for the direct arylation of benzothiazole by employing oxime-derived palladacycle 1 as a catalyst was developed. The new catalyst system can be used for 2-arylations by using aryl bromides and iodides. In addition, this method is especially suitable for the intramolecular direct coupling of bromo-and iodoamides, as well aschloroamides, to achieve a rapid synthesis of benzo[c]phenanthridine alkaloids. Direct arylation reactions under catalysis of an oxime-derived palladacycle were investigated. This phosphane-free method is applicable for the 2-arylation of benzothiazole and is especially suitable for the intramolecular direct coupling of bromo-and iodoamides, as well as chloroamides, to achieve rapid synthesis of benzo[c]phenanthridine alkaloids. Copyright
- Zhang, Guofu,Zhao, Xiaobao,Yan, Yunbing,Ding, Chengrong
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supporting information; experimental part
p. 669 - 672
(2012/03/27)
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- Structural development studies of anti-hepatitis C virus agents with a phenanthridinone skeleton
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A phenanthridinone skeleton was derived from our previous researches on thalidomide and retinoids as a multi-template for generation of anti-viral lead compounds. Structural development studies focusing on anti-hepatitis C virus activity afforded 5-butyl-2-(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)phenanthridin-6(5H)-one (10) and 5-butylbenzo[b]phenanthridin-6(5H)-one (39), which showed EC50 values of approximately 3.7 and 3.2 μM, respectively.
- Nakamura, Masahiko,Aoyama, Atsushi,Salim, Mohammed T.A.,Okamoto, Mika,Baba, Masanori,Miyachi, Hiroyuki,Hashimoto, Yuichi,Aoyama, Hiroshi
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scheme or table
p. 2402 - 2411
(2010/06/20)
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