- Mechanochemical-Cascaded C-N Cross-Coupling and Halogenation Using N-Bromo- And N-Chlorosuccinimide as Bifunctional Reagents
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Exploration of alternative energy sources for chemical transformations has gained significant interest from chemists, and mechanochemistry is one of those sources. Herein, we report the use of N-bromosuccinimides (NBS) and N-chlorosuccinimides (NCS) as bifunctional reagents for a cascaded C-N bond formation and subsequent halogenation reactions. Under the solvent-free mechanochemical (ball-milling) conditions, the synthesis of a wide range of phenanthridinone derivatives from N-methoxy-[1,1′-biphenyl]-2-carboxamides is accomplished. During the reactions, NBS and NCS first assisted the oxidative C-N coupling reaction and subsequently promoted a halogenation reaction. Thus, the role of NBS and NCS was established to be bifunctional. Overall, a mild, solvent-free, convenient, one-pot, and direct synthesis of various bromo- and chloro-substituted phenanthridinone derivatives was achieved.
- Bera, Shyamal Kanti,Mal, Prasenjit
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p. 14144 - 14159
(2021/09/13)
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- SUBSTITUTED HYDANTOINAMIDES AS ADAMTS7 ANTAGONISTS
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The application relates to substituted hydantoinamides of formula (I) as ADAMTS7 antagonists, to processes for their preparation, their use alone or in combination for the treatment or prophylaxis of diseases, in particular of cardiovascular diseases, including atherosclerosis, coronary artery disease (CAD), peripheral vascular disease (PAD), arterial occlusive disease or restenosis after angioplasty. R1 is hydrogen, alkyl, cycloalkyl, heterocycloalkyl, heteroaryl or phenyl; R2 is hydrogen, cyano, halogen, alkylsulfonyl, alkyl, cycloalkyl or alkoxy; R3, R4, R5, R6, R7 and R8 are independently hydrogen, halogen, alkyl or alkoxy; most groups being optionally substituted; with the proviso that at least one of R2, R3, R4 is H; X1, X2, X3, X4, X5 and X6 are independently N or C; with the proviso that in each ring maximal one X is N.
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Page/Page column 221-222
(2021/05/21)
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- Palladium-catalyzed intramolecular aromatic C-H acylation of 2-arylbenzoyl fluorides
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The catalytic intramolecular cyclization of acyl fluorides using a Pd(OAc)2/PCy3 system is described. A wide range of 2-arylbenzoyl fluoride derivatives can be used as fluorenone precursors and the reaction proceeds via an intramolecular coupling between aromatic C-H bonds with acyl C-F bonds. The reaction can be applied to the synthesis of indenofluorenedione derivatives and to the construction of other molecules with fivemembered rings.
- Hayakawa, Kazuki,Ikai, Kana,Ogiwara, Yohei,Sakai, Norio,Sakurai, Yuka
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p. 1882 - 1893
(2021/08/13)
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- Visible-Light-Induced Arene C(sp 2)-H Lactonization Promoted by DDQ and tert -Butyl Nitrite
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A visible-light photocatalytic aerobic oxidative lactonization of arene C(sp 2)-H bonds proceeds in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tert -butyl nitrite (TBN). Under the optimized conditions, a range of 2-arylbenzoic acids is converted into the corresponding benzocoumarin derivatives in moderate to excellent yields. This method is characterized by its atom economy, mild reaction conditions, the use of a green oxidant and metal-free catalysis.
- Chen, Bajin,Hu, Baoxiang,Hu, Xinquan,Jin, Liqun,Li, Meichao,Shen, Zhenlu,Sun, Nan,Wang, Shengpeng,Wang, Yiqing
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supporting information
p. 261 - 266
(2020/02/18)
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- Synthesis and Biological Activity of Novel Succinate Dehydrogenase Inhibitor Derivatives as Potent Fungicide Candidates
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In searching for novel fungicidal leads, the novel bioactive succinate dehydrogenase inhibitor (SDHI) derivatives were designed and synthesized by the inversion of carbonyl and amide groups. Bioassay indicated that compound 5i stood out with a broad spectrum of in vitro activity against five fungi. Its EC50 value (0.73 μg/mL) was comparable to that of boscalid (EC50 of 0.51 μg/mL) and fluxapyroxad (EC50 of 0.19 μg/mL) against Sclerotinia sclerotiorum. For Rhizoctonia cerealis, 5i and 5p with EC50 values of 4.61 and 6.48 μg/mL, respectively, showed significantly higher activity than fluxapyroxad with the EC50 value of 16.99 μg/mL. In vivo fungicidal activity of 5i exhibited an excellent inhibitory rate (100%) against Puccinia sorghi at 50 μg/mL, while the positive control boscalid showed only a 70% inhibitory rate. Moreover, 5i showed promising fungicidal activity with a 60% inhibitory rate against Rhizoctonia solani at 1 μg/mL, which was better than that of boscalid (30%). Compound 5i possessed better in vivo efficacy against P. sorghi and R. solani than boscalid. Molecular docking showed that even the carbonyl oxygen atom of 5i was far from the pyrazole ring. It could also form hydrogen bonds toward the hydroxyl hydrogen and amino hydrogen of TYR58 and TRP173 on SDH, respectively, which consisted of the positive control fluxapyroxad. Fluorescence quenching analysis and SDH enzymatic inhibition studies also validated its mode of action. Our studies showed that 5i was worthy of further investigation as a promising fungicide candidate.
- Yang, Dongyan,Zhao, Bin,Fan, Zhijin,Yu, Bin,Zhang, Nailou,Li, Zhengming,Zhu, Yilin,Zhou, Jinghui,Kalinina, Tatiana A.,Glukhareva, Tatiana V.
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p. 13185 - 13194
(2019/12/02)
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- Vitamin Catalysis: Direct, Photocatalytic Synthesis of Benzocoumarins via (-)-Riboflavin-Mediated Electron Transfer
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An operationally simple protocol is disclosed to facilitate entry to benzo-3,4-coumarins directly from biaryl carboxylic acids without the need for substrate prefunctionalization. Complementary to classic lactonization strategies, this disconnection relies on the oxidation competence of photoactivated (-)-riboflavin (vitamin B2) to generate the heterocyclic core via photoinduced single electron transfer. Collectively, the inexpensive nature of the catalyst, ease of execution, and absence of external metal additives are a convincing endorsement for the incorporation of simple vitamins in contemporary catalysis.
- Morack, Tobias,Metternich, Jan B.,Gilmour, Ryan
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supporting information
p. 1316 - 1319
(2018/03/09)
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- Iodobenzene-Catalyzed Synthesis of Phenanthridinones via Oxidative C-H Amidation
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We report a novel synthesis of phenanthridinones from N-methoxybenzamides using an oxidative C-H amidation reaction at room temperature in open air with modest to excellent yields. This method demonstrated unprecedented substrate scope. In particular, it solved the long-standing challenge in the synthesis of phenanthridinones with sterically demanding substitutions.
- Liang, Dongdong,Yu, Wenbo,Nguyen, Nam,Deschamps, Jeffrey R.,Imler, Gregory H.,Li, Yue,MacKerell, Alexander D.,Jiang, Chao,Xue, Fengtian
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p. 3589 - 3596
(2017/04/11)
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- A reusable heterogeneous catalyst without leaking palladium for highly-efficient Suzuki-Miyaura reaction in pure water under air
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Herein, we report a heterogenous catalyst (Pd@FSM) by immobilization of a novel Pd2+ sensor as promoter over mesoporous silica. Pd@FSM with a high palladium loading of ca. 11 mg g-1 exhibited superior catalytic activity for Suzuki-Miyaura cross-couplings and a catalyst loading of 0.05 mol% is typically sufficient to achieve excellent reaction yields. Notably, the reaction is typically carried out in water without removing atmospheric oxygen. The catalyst is conveniently recycled and remains highly active even after being recycled 5 times. During this process, loss of palladium from the solid support of the catalyst is negligible. Furthermore, the catalyst can be stored in air for at least three months without loss of its catalytic activity. This work provides a new approach to developing heterogeneous palladium catalysts by combing materials and fluorescent sensors.
- Cai, Qi,Liang, Gaosheng,Xu, Yufang,Qian, Xuhong,Zhu, Weiping
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p. 60996 - 61000
(2016/07/12)
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- Electronic effects on the substitution reactions of benzhydrols and fluorenyl alcohols. Determination of mechanism and effects of antiaromaticity
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A range of substituted benzhydrols and fluorenols were prepared and subjected to acid catalysed methanolysis. Analysis of the rates of each of these processes showed correlation with Hammett σ+ parameters as is consistent with the significant build-up of positive charge adjacent to the ring. In combination with the similarity of the electronic susceptibility of the processes, these data suggest that both reactions proceed through a unimolecular rate-determining step. This shows that the effect of fusion of the phenyl systems (and hence potentially introducing an antiaromatic carbocation intermediate) is only to slow the rate of reaction rather than change the mechanism of the process.
- George, Stephen R. D.,Elton, Timothy E.,Harper, Jason B.
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supporting information
p. 10745 - 10750
(2015/11/17)
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- Silver-Catalyzed C(sp2)-H Functionalization/C-O Cyclization Reaction at Room Temperature
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Silver-catalyzed C(sp2)-H functionalization/C-O cyclization has been developed. The scalable reaction proceeds at room temperature in an open flask. The present method exhibits good functional-group compatibility because of the mild reaction conditions. Using a AgNO3 catalyst and a (NH4)2S2O8 oxidant in CH2Cl2/H2O solvent, various lactones are obtained in good to excellent yields. A kinetic isotope effect (KIE) study indicates that the reaction may occur via a radical process.
- Dai, Jian-Jun,Xu, Wen-Tao,Wu, Ya-Dong,Zhang, Wen-Man,Gong, Ying,He, Xia-Ping,Zhang, Xin-Qing,Xu, Hua-Jian
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p. 911 - 919
(2015/01/30)
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- Photocatalytic Dehydrogenative Lactonization of 2-Arylbenzoic Acids
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A metal-free dehydrogenative lactonization of 2-arylbenzoic acids at room temperature was developed. This work illustrates the first application of visible-light photoredox catalysis in the preparation of benzo-3,4-coumarins, an important structural motif in bioactive molecules. The combination of photocatalyst [Acr+-Mes] with (NH4)2S2O8 as a terminal oxidant provides an economical and environmentally benign entry to different substituted benzocoumarins. Preliminary mechanistic studies suggest that this reaction most likely occurs through a homolytic aromatic substitution pathway.
- Ramirez, Nieves P.,Bosque, Irene,Gonzalez-Gomez, Jose C.
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supporting information
p. 4550 - 4553
(2015/09/28)
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- Synthesis of fluorenones through rhodium-catalyzed intramolecular acylation of biarylcarboxylic acids
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An efficient approach to the synthesis of fluorenones via the rhodium-catalyzed intramolecular acylation of biarylcarboxylic acids was developed. Using this procedure, fluorenones with various substituents can be synthesized in good to high yields. This work marks the first recorded use of catalytic intramolecular acylation to synthesize fluorenones.
- Fukuyama, Takahide,Maetani, Shinji,Miyagawa, Kazusa,Ryu, Ilhyong
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supporting information
p. 3216 - 3219
(2014/07/08)
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- Efficient cobalt-catalyzed formation of unsymmetrical biaryl compounds and its application in the synthesis of a sartan intermediate
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(Chemical Equation Presented) No prior preparation of the organometallic reagent is required in a cobalt-catalyzed coupling of two different aryl halides under mild conditions (see scheme). A broad spectrum of valuable biaryl compounds can be prepared in this way. Not only may a variety of reactive substituents be present, but heteroaryl halides and aryl triflates are also suitable substrates. DMF = N,N-dimethylformamide, FG = functional group.
- Amatore, Muriel,Gosmini, Corinne
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supporting information; experimental part
p. 2089 - 2092
(2009/02/06)
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- A water-compatible, highly active and reusable PEG-coated mesoporous silica-supported palladium complex and its application in Suzuki coupling reactions
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A highly active heterogeneous palladium catalyst was prepared from coated mesoporous materials which contain a layer of readily available PEG with a labile coordinating ability for palladium. The aqueous suspension of the catalyst may be reused several times by simple extraction of the aqueous reaction mixture with ether to remove the product. The Royal Society of Chemistry 2006.
- Yang, Qing,Ma, Shengming,Li, Jixue,Xiao, Fengshou,Xiong, Hai
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p. 2495 - 2497
(2008/09/16)
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- Diaminoindanes as microsomal triglyceride transfer protein inhibitors
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The synthesis and biological activities of biarylamide-substituted diaminoindanes as microsomal triglyceride transfer protein (MTP) inhibitors are described. One of the more potent compounds, 8aR, inhibited both the secretion of apoB from Hep G2 cells and the MTP-mediated transfer of triglycerides between synthetic acceptor and donor liposomes with IC50 values of 0.7 and 70 nM, respectively. In normolipidemic rats and dogs, oral administration of 8aR dose-dependently reduced both plasma triglycerides and total cholesterol. Moreover, in rats and dogs, 8aR also prevented the postprandial rise in plasma triglycerides following a bolus administration of a fat load. Because MTP inhibitors decrease very low density lipoprotein assembly in the liver, the potential for hepatic lipid accumulation was evaluated. In normolipidemic rats, hepatic cholesterol and triglyceride contents were dose-dependently increased by 8aR. However, hepatic lipid accumulation resulted in negligible change in total liver weight and was reversible after withdrawal of the compound.
- Ksander,DeJesus,Yuan,Fink,Moskal,Carlson,Kukkola,Bilci,Wallace,Neubert,Feldman,Mogelesky,Poirier,Jeune,Steele,Wasvery,Stephan,Cahill,Webb,Navarrete,Lee,Gibson,Alexander,Sharif,Hospattankar
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p. 4677 - 4687
(2007/10/03)
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