106263-53-0Relevant articles and documents
A one-pot copper(II)-catalyzed tandem synthesis of 2-substituted pyrrolo[1,2-b]pyridazin-4(1H)-ones
Tan, Cun,Xiang, Haoyue,He, Qian,Yang, Chunhao
, p. 3656 - 3660 (2015)
A one-pot copper(II)-catalyzed tandem synthesis of 2-substituted pyrrolo[1,2-b]pyridazin-4(1H)-ones from N-aminopyrroles was developed. This tandem reaction involves a Conrad-Limpach-type reaction, including the thermal condensation of N-aminopyrroles with the carbonyl group of β-oxo esters followed by the cyclization of Schiff base intermediates. Compared to the traditional Conrad-Limpach quinoline synthesis, we herein successfully applied copper(II) as a catalyst in this transformation to furnish 2-substituted pyrrolo[1,2-b]pyridazin-4(1H)-ones for the first time. Most of the substrates bearing electron-donating (EDG) and electron-withdrawing (EWG) groups worked well with this procedure. The corresponding products could be converted directly into diverse pyrrolo[1,2-b]pyridazine for drug discovery and materials science. A copper(II)-catalyzed tandem synthesis of 2-substituted pyrrolo[1,2-b]pyridazin-4(1H)-ones from N-aminopyrroles was developed, and the corresponding products could be converted directly into diverse pyrrolo[1,2-b]pyridazine for drug discovery and materials science.
An efficient route for the synthesis of N-(1H-benzo[d]imidazol-2-yl)benzamide derivatives promoted by CBr4 in one pot
Li, Songhua,Li, Yunyi,Ma, Chen,Xie, Caixia
, (2020)
A metal-free one-pot method for the synthesis of N-(1H-benzo[d]imidazol-2-yl)benzamide derivatives was proposed mediated by CBr4. The reaction went through ring formation and opening processes with only two protons leaving and the thermodynamically favorable products were selectively formed in moderate to good yields.
Ligand steric and electronic effects on β-ketiminato neutral nickel(II) olefin polymerization catalysts
Song, Dong-Po,Shi, Xin-Cui,Wang, Yong-Xia,Yang, Ji-Xing,Li, Yue-Sheng
, p. 966 - 975 (2012)
A series of novel neutral nickel complexes 3a-g and 4a-d bearing the β-ketiminato ligands [(2,6-iPr2C6H 3)N=CHCHC(R)O]Ni(R′)(L) (for 3a-g, R′ = Me, L = Py, and R = tBu (3a), Ph (3b), 1-naphthyl (3c), 9-anthryl (3d), PhNMe 2(p) (3e), PhOMe(p) (3f), PhCF3(p) (3g); for 4a-d, R′ = Ph, L = PPh3, and tBu (4a), Ph (4b), 1-naphthyl (4c), 9-anthryl (4d)) have been synthesized and characterized. The molecular structures of 3b-d,f,g and 4a,c were further confirmed by X-ray crystallographic analysis. These complexes were employed in ethylene polymerization to systematically investigate ligand steric and electronic effects on the catalytic properties, including activity, molecular weight (MW), and branching number of the polyethylene obtained. The complexes bearing more bulky ligands showed higher activities and produced more branched polyethylene. Electron-deficient ligands were found to increase the catalytic activity, decrease the MW, and enhance the branching content of the polyethylene. In addition, phosphine NiII-Ph complexes 4a-d proved to be more active than the corresponding pyridine NiII-Me complexes 3a-d, probably due to the easier dissociation of PPh3 relative to a pyridine from a nickel center.
Annulation-retro-Claisen cascade of bifunctional peroxides for the synthesis of lactone natural products
Hu, Lin,Li, Jialin,Li, Xuemin,Xu, Qianlan
, p. 274 - 277 (2022/01/03)
A new and highly efficient annulation-retro-Claisen cascade, which involves the [4 + 1] or [5 + 1] annulation of α-benzoylacetates with bielectrophilic peroxides and a subsequent debenzoylation process under mild basic conditions, has been developed for the rapid construction of valuable tetrahydrofuran- and dihydropyran-2-carboxylates in good yields. By employing the new reaction, the unified total synthesis of γ- and δ-lactone natural products such as (±)-tanikolide, (±)-goniothalamins, (±)-7-epi-goniodiol, and (±)-plakolide A has been accomplished in 4-7 steps.
Electrochemical Oxidative Cyclization: Synthesis of Polysubstituted Pyrrole from Enamines
Chen, Zhiwei,Shi, Guang,Tang, Wei,Sun, Jie,Wang, Wenxing
supporting information, p. 951 - 955 (2021/02/03)
A conceptually novel method for the preparation of pyrrole is described by electrochemical-oxidation-induced intermolecular annulation via enamines. In a simple undivided cell, based on a sodium acetate-facilitated, polysubstituted pyrrole derivations has been facilely synthesized under external oxidant-free condition. This electrosynthetic approach providing an environmentally benign protocol for C?C bond cross-coupling and oxidative annulation, which features unparalleled broad scope of substrates and practicality.
Construction of isoxazolone-fused phenanthridinesviaRh-catalyzed cascade C-H activation/cyclization of 3-arylisoxazolones with cyclic 2-diazo-1,3-diketones
Hu, Wangcheng,He, Xinwei,Zhou, Tongtong,Zuo, Youpeng,Zhang, Shiwen,Yang, Tingting,Shang, Yongjia
supporting information, p. 552 - 556 (2021/02/06)
A Rh(iii)-catalyzed cascade C-H activation/intramolecular cyclization of 3-aryl-5-isoxazolones with cyclic 2-diazo-1,3-diketones was described, leading to the formation of isoxazolo[2,3-f]phenanthridine skeletons. The protocol features the simultaneous one-pot formation of two new C-C/C-N bonds and one heterocycle in moderate-to-good yields with good functional group compatibility. It is amenable to large-scale synthesis and further transformation.
Sulfur-controlled and rhodium-catalyzed formal (3 + 3) transannulation of thioacyl carbenes with alk-2-enals and mechanistic insights
Wu, Qiuyue,Dong, Ziyang,Xu, Jiaxi,Yang, Zhanhui
supporting information, p. 3173 - 3180 (2021/04/21)
A rhodium-catalyzed denitrogenative formal (3 + 3) transannulation of 1,2,3-thiadiazoles with alk-2-enals is achieved, producing 2,3-dihydrothiopyran-4-ones in moderate to excellent yields. An inverse KIE of 0.49 is obtained, suggesting the reversibility of the oxidative addition of thioacyl Rh(i) carbenes to alk-2-enals. The late-stage structural modifications of steroid compounds are realized. Moreover, our studies show that thioacyl carbenes have different reactivities to those of α-oxo and α-imino carbenes, and highlight the importance of heteroatoms in deciding the reactivities of heterovinyl carbenes.
Synthesis of Dithiolethiones and Identification of Potential Neuroprotective Agents via Activation of Nrf2-Driven Antioxidant Enzymes
Bai, Feifei,Fang, Jianguo,Song, Zi-Long,Zhang, Baoxin
, p. 2214 - 2231 (2020/03/06)
Oxidative stress is implicated in the pathogenesis of a wide variety of neurodegenerative disorders, and accordingly, dietary supplement of exogenous antioxidants or/and upregulation of the endogenous antioxidant defense system are promising for therapeutic intervention or chemoprevention of neurodegenerative diseases. Nrf2, a master regulator of the cellular antioxidant machinery, cardinally participates in the transcription of cytoprotective genes against oxidative/electrophilic stresses. Herein, we report the synthesis of 59 structurally diverse dithiolethiones and evaluation of their neuroprotection against 6-hydroxydopamine-or H2O2-induced oxidative damages in PC12 cells, a neuron-like rat pheochromocytoma cell line. Initial screening identified compounds 10 and 11 having low cytotoxicity but conferring remarkable protection on PC12 cells from oxidative-mediated damages. Further studies demonstrated that both compounds upregulated a battery of antioxidant genes as well as corresponding genes' products. Significantly, silence of Nrf2 expression abolishes cytoprotection of 10 and 11, indicating targeting Nrf2 activation is pivotal for their cellular functions. Taken together, the two lead compounds discovered here with potent neuroprotective functions against oxidative stress via Nrf2 activation merit further development as therapeutic or chemopreventive candidates for neurodegenerative disorders.
Modular Tuning of Electrophilic Reactivity of Iridium Nitrenoids for the Intermolecular Selective α-Amidation of β-Keto Esters
Lee, Minhan,Jung, Hoimin,Kim, Dongwook,Park, Jung-Woo,Chang, Sukbok
supporting information, p. 11999 - 12004 (2020/08/06)
We report herein an Ir-catalyzed intermolecular amino group transfer to β-keto esters (amides) to access α-aminocarbonyl products with excellent chemoselectivity. The key strategy was to engineer electrophilicity of the putative Ir-nitrenoids by tuning electronic property of the κ2-N,O chelating ligands, thus facilitating nucleophilic addition of enol π-bonds of 1,3-dicarbonyl substrates.
Radical Aza-Cyclization of α-Imino-oxy Acids for Synthesis of Alkene-Containing N-Heterocycles via Dual Cobaloxime and Photoredox Catalysis
Tu, Jia-Lin,Liu, Jia-Li,Tang, Wan,Su, Ma,Liu, Feng
supporting information, p. 1222 - 1226 (2020/02/15)
Nitrogen-containing heterocycles are prevalent in both naturally and synthetically bioactive molecules. We report herein an unprecedented protocol for radical aza-cyclization of α-imino-oxy acids with pendant alkenes via synergistic photoredox and cobaloxime catalysis. With or without alkenes as the intermolecular cross-coupling partners, the transformation provides a variety of corresponding alkene-containing dihydropyrrole products in satisfactory yields. In the presence of external alkenes, the tandem reaction generates E-selective coupling products with excellent chemo- and stereoselectivity.
