89781-40-8Relevant academic research and scientific papers
Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers
De Bruin, Bas,De Zwart, Felix J.,Li, Zirui,Mathew, Simon,Wolzak, Lukas A.,Zhou, Minghui
, p. 20501 - 20512 (2021/12/03)
The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
Copper-Catalyzed N-O Cleavage of α,β-Unsaturated Ketoxime Acetates toward Structurally Diverse Pyridines
Ding, Xiaojuan,Duan, Jindian,Fang, Zheng,Guo, Kai,Li, Zhenjiang,Mao, Yiyang,Rong, Binsen,Xu, Gaochen,Zhang, Lei,Zhu, Ning
, p. 2532 - 2542 (2020/03/13)
The copper-catalyzed [4 + 2] annulation of α,β-unsaturated ketoxime acetates with 1,3-dicarbonyl compounds for the synthesis of three classes of structurally diverse pyridines has been developed. This method employs 1,3-dicarbonyl compounds as C2 synthons and enables the synthesis of multifunctionalized pyridines with diverse electron-withdrawing groups in moderate to good yields. The mechanistic investigation suggests that the reactions proceed through an ionic pathway.
A robust multifunctional ligand-controlled palladium-catalyzed carbonylation reaction in water
Gao, Pei-Sen,Zhang, Kan,Yang, Ming-Ming,Xu, Shan,Sun, Hua-Ming,Zhang, Jin-Lei,Gao, Zi-Wei,Zhang, Wei-Qiang,Xu, Li-Wen
supporting information, p. 5074 - 5077 (2018/05/26)
A novel, hydrophilic and recyclable methoxypolyethylene glycol (PEG)-modulated s-triazine-based multifunctional Schiff base/N,P-ligand L9 was prepared and used in Pd-catalyzed Heck-type carbonylative coupling reactions, affording diverse chalcone derivatives and 1,4-dicarbonyl esters in good yields.
Enantioselective NHC-catalysed redox [4+2]-hetero-Diels-Alder reactions using α-aroyloxyaldehydes and unsaturated ketoesters
Taylor, James E.,Davies, Alyn T.,Douglas, James J.,Churchill, Gwydion,Smith, Andrew D.
, p. 355 - 366 (2017/02/15)
N-Heterocyclic carbene (NHC)-catalysed redox [4+2]-hetero-Diels-Alder reactions of α-aroyloxyaldehydes with either β,γ-unsaturated α-ketoesters or α,β-unsaturated γ-ketoesters generates substituted syn-dihydropyranones in good yield with excellent enantioselectivity (up to >99:1 er). The product diastereoselectivity is markedly dependent upon the nature of the unsaturated enone substituent. The presence of either electron-neutral or electron-rich aryl substituents gives excellent diastereoselectivity (up to >99:5 dr), while electron-deficient aryl substituents give reduced diastereoselectivity. In these cases, the syn-dihydropyranone products are more susceptible to base-promoted epimerisation at the C(4)-position under the reaction conditions, accounting for the lower diastereoselectivity obtained.
Substrate-Controlled, One-Pot Synthesis: Access to Chiral Chroman-2-one and Polycyclic Derivatives
Sun, Xue-Li,Chen, Ying-Han,Zhu, Dan-Yang,Zhang, Yan,Liu, Yan-Kai
supporting information, p. 864 - 867 (2016/03/04)
Based on the appropriate choice of electrophiles, one-pot, multicomponent, enantioselective domino reactions have been realized which contain a five-step sequence and provide highly efficient access to potentially bioactive chroman-2-one derivatives as a single diastereoisomer with excellent enantioselectivities and in high yields. This new strategy could significantly improve the previous protocol by directly starting from commercial 2-hydroxybenzaldehydes rather than preformed lactols, which have to be synthesized in several additional steps. (Chemical Equation Presented).
Synthesis of 1,5-benzodiazepine derivatives using p-toluenesulfonic acid as catalyst
Wang, Shasha,Hu, Lijuan,Cheng, Suyan,Wang, Lanzhi
, p. 419 - 424 (2015/01/30)
A series of substituted ethyl 4-oxo-4-phenylbut-2-enoates were prepared and reacted with substituted o-phenylenediamine, undergone Michael addition reactions and cyclodehydration to provide novel 4-phenyl-2,3-dihydro-1,5-benzodiazepine-2-carboxylate derivatives with excellent yields. The synthetic protocol fulfilled many green-chemical requirements by using simple catalyst p-toluenesulfonic acid as activator and ethanol as solvent at room temperature.
Enantioselective conjugate addition of aliphatic thiols to divergently activated electron poor alkenes and dienes
Kowalczyk, Rafa?,Wierzba, Aleksandra J.,Boratyński, Przemys?aw J.,Ba?kowicz, Julia
supporting information, p. 5834 - 5842 (2015/03/30)
Divergently activated double bonds in electron poor 4-oxo-butenoates and (2E,4E)-6-oxo-2,4-dienoates underwent stereoselective and regioselective addition of mercaptans catalyzed by simple Cinchona alkaloids. Application of quinine and quinidine afforded both enantiomers of the 1,4-adducts with respect to the ketone carbonyl group in ees of up to 80%. Single recrystallization of some adducts resulted in further enrichment of up to 99%ee.
CuI-catalyzed aerobic oxidative α-aminaton cyclization of ketones to access aryl or alkenyl-substituted imidazoheterocycles
Zhang, Yuhong,Zhang, Yuanfei,Chen, Zhengkai,Wu, Wenliang,Su, Weiping
supporting information, p. 12494 - 12504 (2014/01/17)
CuI-catalyzed aerobic oxidative synthesis of imidazoheterocycles has been achieved. Four hydrogen atoms were removed in one step. This protocol was compatible with a broad range of functional groups, and it has been also successfully extended to unsaturated ketones, bringing about the formation of alkenyl-substituted imidazoheterocycles, which were difficult to prepare by previous means. Preliminary mechanistic studies indicated that this reaction was most likely to proceed through a catalytic Ortoleva-King reaction. By using this method, the marketed drug Zolimidine could be prepared with 90% yield on a gram scale from commercially available materials.
Structure-activity relationship, cytotoxicity and mode of action of 2-ester-substituted 1,5-benzothiazepines as potent antifungal agents
Kang, Wang,Du, Xingqiong,Wang, Lanzhi,Hu, Lijuan,Dong, Yuhuan,Bian, Yanqing,Li, Yuan
, p. 1305 - 1314 (2013/11/06)
Our studies examined the structural features responsible for the antifungal activity of 2-ethoxycarbonyl-1,5-benzothiazepine (7a). Three series of 1,5-benzothiazepine derivatives were synthesized and screened for their antifungal activity. The results suggested that the ethoxycarbonyl group at the 2 position and the imine moiety on the seven-membered ring are essential for activity. The most potent of the synthesized analogues (7a, 7b) were further studied by evaluating their cytotoxicity and mode of action (for 7a). The results showed that compounds 7a and 7b were relatively safe for BV2 cells, but compound 7a interfered with Cryptococcus neoformans cell wall integrity by increasing the chitinase activity. Therefore, compound 7a was considered safe as an antifungal agent for animal cells. Three series of 1,5-benzothiazepine derivatives were synthesized and their antifungal activities were evaluated to determine the structure-activity relationships with respect to the antifungal activity of 2-ester-substituted 1,5-benzothiazepines. The effective antifungal compounds 7a and 7b were further studied for their antifungal activity, cytotoxicity and mechanism of action (for compound 7a). The results provided important information about this class of benzothiazepines. Copyright
Flow chemistry synthesis of zolpidem, alpidem and other GABAA agonists and their biological evaluation through the use of in-line frontal affinity chromatography
Guetzoyan, Lucie,Nikbin, Nikzad,Baxendale, Ian R.,Ley, Steven V.
, p. 764 - 769 (2013/03/14)
The flow of information between chemical and biological research can present a bottleneck in pharmaceutical research. Tools that bridge these disciplines and aid information exchange have therefore clear value. Over the last few years, both synthetic chemistry and biological screening have benefited from automation, and a seamless chemistry-biology interface is now possible. We report here on the use of flow processes to perform synthesis and biological evaluation in an integrated manner. As proof of concept, a flow synthesis of a series of imidazo[1,2-a]pyridines, including zolpidem and alpidem, was developed and connected to a Frontal Affinity Chromatography screening assay to investigate their interaction with Human Serum Albumin (HSA). The Royal Society of Chemistry 2013.
