98015-07-7Relevant academic research and scientific papers
Phosphine-Catalyzed Intramolecular Vinylogous Aldol Reaction of α-Substituted Enones
Mondal, Atanu,Satpathi, Bishnupada,Ramasastry
supporting information, p. 256 - 261 (2022/01/04)
We demonstrate the first phosphine-catalyzed intramolecular vinylogous aldol reaction (IVAR) of α-substituted enones. This strategy provides access to various pentannulated (hetero)arenes and dibenzocycloheptanones incorporated with two contiguous stereocenters, one of which is an all-carbon quaternary center. The scope of this work is further broadened through elaborations of the IVAR adducts to (i) benzannulated nine-membered carbocyclic systems, (ii) interesting classes of 1,3-dienes, 1,3,5-trienes, and 1-yn-3,5-dienes, and (iii) the analogs of echinolactone D and russujaponol F.
Cobalt-Catalyzed Chemoselective Transfer Hydrogenative Cyclization Cascade of Enone-Tethered Aldehydes
Ma, Shuang-Shuang,Jiang, Biao-Ling,Yu, Zheng-Kun,Zhang, Suo-Jiang,Xu, Bao-Hua
supporting information, p. 3873 - 3878 (2021/05/26)
The ligand-free Co-catalyzed chemoselective reductive cyclization cascade of enone-tethered aldehydes with i-PrOH as the environmentally benign hydrogen surrogate is developed by this study. Mechanistic studies disclosed that such a protocol is initiated
Copper-Catalyzed Tandem Cross-Coupling and Alkynylogous Aldol Reaction: Access to Chiral Exocyclic α-Allenols
Xu, Guangyang,Wang, Zhen,Shao, Ying,Sun, Jiangtao
supporting information, p. 5175 - 5179 (2021/07/19)
An enantioselective copper-catalyzed tandem cross-coupling/alkynylogous aldol reaction has been developed. The tetrasubstituted allenoates containing both central and axial chirality have been obtained in moderate to good yields and excellent enantio-and
Palladium-Catalzyed Atroposelective 16-Membered Macrocyclization: Total Synthesis of Isoplagiochin D?
Xi, Junwei,Gu, Zhenhua
supporting information, p. 1081 - 1085 (2020/07/06)
Isoplagiochin D is a ring-strained macrocyclic bisbibenzylis, which showed stable axial chirality in one biaryl structure, and semistable axial chirality in the other biaryl moiety. We reported here an unprecedented example for the catalytically asymmetri
Chiral phosphine nitrogen phosphine ligand and chiral metal organic coordination complex and application
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Paragraph 0075-0077, (2020/07/02)
The invention discloses a chiral phosphine nitrogen phosphine ligand and chiral metal organic coordination complex and application. The chiral tridentate phosphine nitrogen phosphine ligand is shown as a formula (I), and the chiral metal organic coordination complex is shown as a formula (II), wherein the chiral metal organic coordination complex shown as the formula (II) is used as a homogeneouscatalyst to be applied to preparation of phenylalanine derivatives with high optical activity. The novel chiral nitrogen-phosphine ligand synthesized by taking cheap amino acid as a chiral source is applied to asymmetric hydrogenation reaction, and a chiral product with relatively high yield can be obtained with relatively low catalytic dosage, relatively short reaction time and relatively mild reaction conditions.
Catalytic Synthesis of 8-Membered Ring Compounds via Cobalt(III)-Carbene Radicals
Lankelma, Marianne,Zhou, Minghui,de Bruin, Bas,van der Vlugt, Jarl Ivar
supporting information, p. 11073 - 11079 (2020/04/29)
The metalloradical activation of o-aryl aldehydes with tosylhydrazide and a cobalt(II) porphyrin catalyst produces cobalt(III)-carbene radical intermediates, providing a new and powerful strategy for the synthesis of medium-sized ring structures. Herein we make use of the intrinsic radical-type reactivity of cobalt(III)-carbene radical intermediates in the [CoII(TPP)]-catalyzed (TPP=tetraphenylporphyrin) synthesis of two types of 8-membered ring compounds; novel dibenzocyclooctenes and unprecedented monobenzocyclooctadienes. The method was successfully applied to afford a variety of 8-membered ring compounds in good yields and with excellent substituent tolerance. Density functional theory (DFT) calculations and experimental results suggest that the reactions proceed via hydrogen atom transfer from the bis-allylic/benzallylic C?H bond to the carbene radical, followed by two divergent processes for ring-closure to the two different types of 8-membered ring products. While the dibenzocyclooctenes are most likely formed by dissociation of o-quinodimethanes (o-QDMs) which undergo a non-catalyzed 8π-cyclization, DFT calculations suggest that ring-closure to the monobenzocyclooctadienes involves a radical-rebound step in the coordination sphere of cobalt. The latter mechanism implies that unprecedented enantioselective ring-closure reactions to chiral monobenzocyclooctadienes should be possible, as was confirmed for reactions mediated by a chiral cobalt-porphyrin catalyst.
Structure-Activity Relationship Study Enables the Discovery of a Novel Berberine Analogue as the RXRα Activator to Inhibit Colon Cancer
Xu, Beibei,Jiang, Xunjin,Xiong, Jing,Lan, Jun,Tian, Yuan,Zhong, Linhai,Wang, Xinquan,Xu, Ning,Cao, Hanwei,Zhang, Wenqing,Zhang, Hao,Hong, Xiaoting,Zhan, Yan-Yan,Zhang, Yandong,Hu, Tianhui
, p. 5841 - 5855 (2020/07/03)
We reported recently that berberine (Ber), a traditional oriental medicine to treat gastroenteritis, binds and activates retinoid X receptor α (RXRα) for suppressing the growth of colon cancer cells. Here, we extended our studies based on the binding mode of Ber with RXRα by design, synthesis, and biological evaluation of a focused library of 15 novel Ber analogues. Among them, 3,9-dimethoxy-5,6-dihydroisoquinolino[3,2-a]isoquinolin-7-ium chloride (B-12) was identified as the optimal RXRα activator. More efficiently than Ber, B-12 bound and altered the conformation of RXRα/LBD, thereby suppressing the Wnt/β-catenin pathway and colon cancer cell growth via RXRα mediation. In addition, B-12 not only preserved Ber's tumor selectivity but also greatly improved its bioavailability. Remarkably, in mice, B-12 did not show obvious side effects including hypertriglyceridemia as other RXRα agonists or induce hepatorenal toxicity. Together, our study describes an approach for the rational design of Ber-derived RXRα activators as novel effective antineoplastic agents for colon cancer.
Synthesis and in vitro evaluation of diverse heterocyclic diphenolic compounds as inhibitors of DYRK1A
Zhou, Qingqing,Reekie, Tristan A.,Abbassi, Ramzi H.,Indurthi Venkata, Dinesh,Font, Josep S.,Ryan, Renae M.,Munoz, Lenka,Kassiou, Michael
, p. 5852 - 5869 (2018/11/10)
Dual-specificity tyrosine phosphorylation-related kinase 1A (DYRK1A) is a dual-specificity protein kinase that catalyses phosphorylation and autophosphorylation. Higher DYRK1A expression correlates with cancer, in particular glioblastoma present within the brain. We report here the synthesis and biological evaluation of new heterocyclic diphenolic derivatives designed as novel DYRK1A inhibitors. The generation of these heterocycles such as benzimidazole, imidazole, naphthyridine, pyrazole-pyridines, bipyridine, and triazolopyrazines was made based on the structural modification of the lead DANDY and tested for their ability to inhibit DYRK1A. None of these derivatives showed significant DYRK1A inhibition but provide valuable knowledge around the importance of the 7-azaindole moiety. These data will be of use for developing further structure-activity relationship studies to improve the selective inhibition of DYRK1A.
Assessment of the regioselectivity in the condensation reaction of unsymmetrical o-phthaldialdehydes with alanine
D'Hollander, Agathe C.A.,Westwood, Nicholas J.
supporting information, p. 224 - 239 (2017/12/08)
One approach for the synthesis of isoindolinones, a privileged bioactive heterocyclic core structure, involves a condensation reaction of o-phthaldialdehydes with a suitable nitrogen-containing nucleophile. This fascinating reaction is revisited here in the context of the use of o-phthaldialdehydes that contain additional substituents in the aromatic ring leading to a detailed analysis of the regioselectivity of the reaction. Eleven monosubstituted o-phthaldialdehydes were synthesised and reacted with alanine. The regioselectivity observed across the eleven substrates led to the design of a disubstituted substrate that reacted with very high control. A gram-scale reaction followed by esterification gave one major regioisomer in high yield. In addition, the regioselectivity observed on reaction of two novel monodeuterated substrates led to an increased mechanistic understanding.
Catalytic Dibenzocyclooctene Synthesis via Cobalt(III)–Carbene Radical and ortho-Quinodimethane Intermediates
te Grotenhuis, Colet,van den Heuvel, Naudin,van der Vlugt, Jarl Ivar,de Bruin, Bas
supporting information, p. 140 - 145 (2017/12/13)
The metalloradical activation of ortho-benzallylaryl N-tosyl hydrazones with [Co(TPP)] (TPP=tetraphenylporphyrin) as the catalyst enabled the controlled exploitation of the single-electron reactivity of the redox non-innocent carbene intermediate. This method offers a novel route to prepare eight-membered rings, using base metal catalysis to construct a series of unique dibenzocyclooctenes through selective Ccarbene?Caryl cyclization. The desired eight-membered-ring products were obtained in good to excellent yields. A large variety of aromatic substituents are tolerated. The proposed reaction mechanism involves intramolecular hydrogen atom transfer (HAT) to CoIII–carbene radical intermediates followed by dissociation of an ortho-quinodimethane that undergoes 8π cyclization. The mechanism is supported by DFT calculations, and the presence of radical-type intermediates was confirmed by trapping experiments.
