216443-25-3Relevant academic research and scientific papers
Gold Catalysts Can Generate Nitrone Intermediates from a Nitrosoarene/Alkene Mixture, Enabling Two Distinct Catalytic Reactions: A Nitroso-Activated Cycloheptatriene/Benzylidene Rearrangement
Cheng, Mu-Jeng,Kardile, Rahul Dadabhau,Kuo, Tung-Chun,Liu, Rai-Shung,More, Sayaji Arjun
, p. 5506 - 5511 (2021/07/31)
Gold-catalyzed reactions of cycloheptatrienes with nitrosoarenes yield nitrone derivatives efficiently. This reaction sequence enables us to develop gold-catalyzed aerobic oxidations of cycloheptatrienes to afford benzaldehyde derivatives using CuCl and nitrosoarenes as co-catalysts (10-30 mol %). Our density functional theory calculations support a novel nitroso-activated rearrangement, tropylium → benzylidene. With the same nitrosoarenes, we developed their gold-catalyzed [2 + 2 + 1]-annulations between nitrosobenzene and two enol ethers to yield 5-alkoxyisoxazolidines using 1,4-cyclohexadienes as hydrogen donors.
COMPOUNDS OF PHOSPHINANES AND AZAPHOSPHINANES, A PROCESS FOR THEIR PREPARATION AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM
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Paragraph 0314; 0315; 0316, (2018/02/27)
Compounds of formula (I) wherein: Ak1 represents an alkyl chain, X represents —(CH2)m—, —CH(R)—, —N(R)—, —CH2—N(R)—, —N(R)—CH2— or —CH2—N(R)—CH2—, m and R are as defined in the description, R1 and R2 each represent H when X represents —(CH2)m—, —CH(R)—, —N(R)—, —CH2—N(R)— or —N(R)—CH2—, or together form a bond when X represents —CH2—N(R)—CH2—, R3 represents NH2, Cy-NH2, Cy-Ak3-NH2 or piperidin-4-yl, Cy and Ak3 are as defined in the description, R4 and R5, which may be identical or different, each represent H or F, their optical isomers, and addition salts thereof with a pharmaceutically acceptable acid. Medicinal products containing the same which are useful in treating conditions requiring a TAFIa inhibitor.
Synthesis of dibenzopyranones and pyrazolobenzopyranones through copper(0)/Selectfluor system-catalyzed double C[sbnd]H activation/oxygen insertion of 2-arylbenzaldehydes and 5-arylpyrazole-4-carbaldehydes
Zhang, Jian,Shi, Dongdong,Zhang, Haifeng,Xu, Zheng,Bao, Hanyang,Jin, Hongwei,Liu, Yunkui
, p. 154 - 163 (2016/12/23)
A mild and efficient protocol for the synthesis of dibenzopyranones and pyrazolobenzopyranones was developed involving a copper(0)/Selectfluor system-catalyzed double C[sbnd]H activation/oxygen insertion of 2-arylbenzaldehydes and 5-arylpyrazole-4-carbaldehydes. Preliminary mechanistic studies suggest that both water and dioxygen act as the oxygen source in the formation of pyranone scaffolds.
Chromium-Catalyzed, Regioselective Cross-Coupling of C-O Bonds by Using Organic Bromides as Reactants
Tang, Jinghua,Luo, Meiming,Zeng, Xiaoming
, p. 2577 - 2580 (2017/09/28)
We report a chromium-catalyzed cross-coupling of C-O bonds with widely accessible organic bromides as reactants for the preparation of ortho -arylated or -alkylated aromatic aldehydes at room temperature. The use of metallic magnesium is essential for the reaction to occur, giving it an advantage over previous reactions involving Grignard reagents that have to be prepared separately from organic halides before the coupling.
Low-Valent, High-Spin Chromium-Catalyzed Cleavage of Aromatic Carbon-Nitrogen Bonds at Room Temperature: A Combined Experimental and Theoretical Study
Cong, Xuefeng,Fan, Fei,Ma, Pengchen,Luo, Meiming,Chen, Hui,Zeng, Xiaoming
, p. 15182 - 15190 (2017/10/31)
The cleavage of aromatic carbon-nitrogen bonds catalyzed by transition metals is of high synthetic interest because such bonds are common in organic chemistry. However, few metal catalysts can be used to selectively break C(aryl)-N bonds in electronically neutral molecules. We report here the first low-valent, high-spin chromium-catalyzed cleavage of C(aryl)-N bonds in electronically neutral aniline derivatives at room temperature. By using simple and inexpensive chromium(II) chloride as precatalyst, accompanied by an imino auxiliary, the selective arylative and alkylative C-C coupling of C(aryl)-N bonds can be achieved. Crossover experiments indicate that a low-valent chromium species, formed in situ by reduction of CrCl2 with Grignard reagent, is responsible for the catalytic cleavage of C(aryl)-N bonds. DFT calculations show that facile insertion of the C(aryl)-N bond by chromium(0) can take place in a high-spin quintet (S = 2) ground state, whereas the lower-spin singlet (S = 0) and triplet (S = 1) states are inaccessible in energy. It was found that both donation of the sole paired d electrons in the d6 shell of high-spin chromium(0) to the antibonding orbital of the C(aryl)-N bond and the nitrogen ligating interaction to the metal center with its lone pair play important roles in the cleavage of the C(aryl)-N bond by the zerovalent chromium species.
Palladium salt and functional reduced graphene oxide complex: in situ preparation of a generally applicable catalyst for C-C coupling reactions
Wang, Sheng,Hu, Donghua,Hua, Wenwen,Gu, Jiangjiang,Zhang, Qiuhong,Jia, Xudong,Xi, Kai
, p. 53935 - 53939 (2015/06/30)
A novel Pd catalyst was designed by affording Pd2+ salt on the surface of functional reduced graphene oxide (FRGO), providing a new cheap and stable in situ prepared palladium catalyst for C-C coupling reactions, including the Heck reaction, Suzuki reaction, C-H bond functionalization reactions of thiophenes, and terminal alkyne C-H activation and homocoupling.
Catalytic oxidative cyclization of 2′-arylbenzaldehyde oxime ethers under photoinduced electron transfer conditions
Hofstra, Julie L.,Grassbaugh, Brittany R.,Tran, Quan M.,Armada, Nicholas R.,De Lijser, H. J. Peter
, p. 256 - 265 (2016/09/09)
A series of 2′-arylbenzaldehyde oxime ethers were synthesized and shown to generate the corresponding phenanthridines upon irradiation in the presence of 9,10-dicyanoanthracene in acetonitrile. Mechanistic studies suggest that the oxidative cyclization reaction sequence is initiated by an electron transfer step followed by nucleophilic attack of the aryl ring onto the nitrogen of the oxime ether. A concave downward Hammett plot is presumably the result of a change in charge distribution in the radical cation species with strongly electron-donating substituents that yields a less electrophilic nitrogen atom and a decreased amount of cyclized product. The reaction is selective (no nitrile byproduct is formed unlike other photochemical reactions involving aldoxime ethers) as well as regiospecific when using 2′-aryl groups with metasubstituents, making this reaction a useful alternative for preparing substituted phenanthridines.
Regio- and Chemoselective Kumada-Tamao-Corriu Reaction of Aryl Alkyl Ethers Catalyzed by Chromium under Mild Conditions
Cong, Xuefeng,Tang, Huarong,Zeng, Xiaoming
supporting information, p. 14367 - 14372 (2015/12/01)
Acting as an environmentally benign synthetic tool, the cross-coupling reactions with aryl ethers via C-O bond activation have attracted broad interest. However, the functionalizations of C-O bonds are mainly limited to nickel catalysis, and selectivity has long been a prominent challenge when several C-O bonds are present in the one molecule. We report here the first chromium-catalyzed selective cross-coupling reactions of aryl ethers with Grignard reagents by the cleavage of C-O(alkyl) bonds. Diverse transformations were achieved using simple, inexpensive chromium(II) precatalyst combining imino auxiliary at room temperature. It offers a new avenue for buildup functionalized aromatic aldehydes with high efficiency and selectivity.
Atom-economic threefold cross-couplings of triarylbismuth reagents with 2-halobenzaldehydes and pot-economic in situ Wittig functionalizations with phosphonium salts
Rao, Maddali L. N.,Dhanorkar, Ritesh J.
, p. 63792 - 63806 (2015/02/19)
In this paper we report an efficient pot-economic methodology for the synthesis of ortho-olefinated biaryls. This has been achieved through an atom-economic threefold cross-coupling of triarylbismuth reagents with 2-halobenzaldehydes followed by pot-economic in situ Wittig olefination. The overall process is a pot-economic straightforward synthesis of ortho-olefinated biaryls from 2-halobenzaldehydes, triarylbismuth reagents and phosphonium salts. This pot-economic approach was applied to the formal synthesis of medicinally important Eupomatilone-6.
Discovery of aryl-biphenyl-2-ylmethylpiperazines as novel scaffolds for 5-HT7 ligands and role of the aromatic substituents in binding to the target receptor
Kim, Youngjae,Kim, Jeeyeon,Tae, Jinsung,Roth, Bryan L.,Rhim, Hyewhon,Keum, Gyochang,Nam, Ghilsoo,Choo, Hyunah
, p. 2568 - 2576 (2013/06/26)
It has been reported that 5-HT7 receptors are promising targets of depression and neuropathic pain. 5-HT7 receptor antagonists have exhibited antidepressant-like profiles, while agonists have represented potential therapeutics for pain. In the course of our ongoing efforts to discover novel 5-HT7 modulators, we designed an arylpiperazine scaffold with a substituted biphenyl-2-ylmethyl group. A series of biphenyl-2-yl-arylpiperazinylmethanes were then prepared, which showed a broad spectrum of binding affinities to the 5-HT7 receptor depending upon the substituents attached to the biphenyl and aryl functionalities. Among those synthesized compounds, the compounds 1-24 and 1-26 showed the best binding affinities to the 5-HT7 receptor with Ki values of 43.0 and 46.0 nM, respectively. Structure-activity relationship study in conjunction with molecular docking study proposed that the 5-HT7 receptor might have two distinctive hydrophobic binding sites, one specific for aromatic 2-OCH3 substituents within the arylpiperazine and the other for biphenyl methoxy group.
