69622-40-8Relevant academic research and scientific papers
DFT-Guided Phosphoric-Acid-Catalyzed Atroposelective Arene Functionalization of Nitrosonaphthalene
Ding, Wei-Yi,Yu, Peiyuan,An, Qian-Jin,Bay, Katherine L.,Xiang, Shao-Hua,Li, Shaoyu,Chen, Ying,Houk,Tan, Bin
, p. 2046 - 2059 (2020/07/13)
Guided by computational design, Tan and colleagues disclose a chiral phosphoric-acid-catalyzed asymmetric functionalization of naphthalenes with nitroso as the activating and directing group. This nucleophilic aromatic substitution reaction allows divergent access to two types of axially chiral arylindole frameworks with wide substrate generality under excellent enantiocontrol and, more importantly, offers a facile approach to the privileged NOBIN (2-amino-2′-hydroxy-1,1′-binaphthyl) structures. DFT calculations illustrate the plausible reaction pathway and provide additional insights into the origins of enantioselectivity.Functionalization of arenes represents the most efficient approach for constructing a core backbone of important aryl compounds. Compared with the well-developed electrophilic aromatic substitution and transition-metal-catalyzed C–H activation, nucleophilic aromatic substitution remains challenging because of the lack of a convenient route for rapid conversion of the σH adduct to other stable and versatile intermediates in situ. Guided by computational design, we were able to realize asymmetric nucleophilic aromatic substitution by introducing a nitroso group on naphthalene via chiral phosphoric acid catalysis. This strategy enables efficient construction of atropisomeric indole-naphthalenes and indole-anilines with excellent stereocontrol. Density functional theory (DFT) calculations provide further insights into the origins of enantioselectivity and the reaction mechanisms. The successful application in the synthesis of NOBINs (2-amino-2′-hydroxy-1,1′-binaphthyl) extends the utility of this strategy.Highly efficient conversion of inexpensive and readily available arene materials into high-value-added chiral molecules is of great importance in modern synthetic chemistry given the enormous potential of such structures in functional materials, pharmaceuticals, and other relevant chemical industries. Organocatalytic nucleophilic aromatic substitution enabled by an azo group offers an effective approach to enantioselective functionalization of naphthalene C–H bonds featuring an intramolecular oxidation of an unstabilized σH adduct. Premised on density functional theory (DFT) calculations, nitroso has emerged as another promising activating and oxidative group, whose synthetic potential is substantiated in the atroposelective synthesis of several groups of representative biaryl atropisomers processed by a chiral phosphoric acid catalyst. The success of this reaction explicitly exemplifies the ability of computational tools to streamline organic synthesis with intensified robustness in the disclosed strategy.
Palladium-Catalyzed C–C Ring Closure in α-Chloromethylimines: Synthesis of 1H-Indoles
Bellezza, Delia,Noverges, Bárbara,Fasano, Francesco,Sarmiento, Jeymy T.,Medio-Simón, Mercedes,Asensio, Gregorio
, p. 1229 - 1235 (2019/01/04)
The C-C ring closure of α-chloromethyl alkyl or aryl N-aryl imines catalyzed with 1 to 10 % Pd(OAc)2/P(p-tolyl)3 afford efficiently 2-aryl- and 2-alkyl-1H-indoles. The heterocyclization reaction involves the initial formation of [2-(arylimino)ethyl]palladium(II) chloride complexes with subsequent C-H activation of the aromatic amine ring. Readily or commercially available α-chloromethyl-aryl or -alkyl ketones are used as the precursors. Functionalized indoles at the benzene ring are obtained when the imines are derived from substituted anilines.
Inhibition of cytosolic phospholipase A2α: Hit to lead optimization
McKew, John C.,Foley, Megan A.,Thakker, Paresh,Behnke, Mark L.,Lovering, Frank E.,Sum, Fuk-Wah,Tam, Steve,Wu, Kun,Shen, Marina W. H.,Zhang, Wen,Gonzalez, Mario,Liu, Shanghao,Mahadevan, Anu,Sard, Howard,Khor, Soo Peang,Clark, James D.
, p. 135 - 158 (2007/10/03)
Compound 1 was previously reported to be a potent inhibitor of cPLA 2α in both artificial monomeric substrate and cell-based assays. However, 1 was inactive in whole blood assays previously used to characterize cyclooxygenase and lipoxygenase inhibitors. The IC50 of 1 increased dramatically with cell number or lipid/detergent concentration. In an attempt to insert an electrophilic ketone between the indole and benzole acid moieties, we discovered that increasing the distance between the two moieties gave a compound with activity in the GLU (7-hydroxycoumarinyl-γ- linolenate) micelle assay, which contains lipid and detergent. Extensive structure-activity relationship work around this lead identified a potent pharmacophore for cPLA2α inhibition. The IC50s between the GLU micelle and rat whole blood assays correlated highly. No correlation was found for other parameters, including lipophilicity or acidity of the required acid functionality. Compounds 25, 39, and 94 emerged as potent, selective inhibitors of cPLA2α and represent well-validated starting points for further optimization.
Carbonylation of various organolithium reagents. A novel approach to heterocycles via intramolecular trapping of aromatic acyllithiums
Smith, Keith,El-Hiti, Gamal A.,Pritchard, Gareth J.,Hamilton, Anna
, p. 2299 - 2303 (2007/10/03)
Doubly lithiated N-pivaloylanilines react smoothly with carbon monoxide at 0°C to give 3-tert-butyl-3-hydroxy-2,3-dihydroindol-2-ones in good yields. Similarly, carbonylation of doubly lithiated 4-pivaloylamino- and 2-pivaloylaminopyridines at 0°C affords the corresponding 5-aza- and 7-aza-3-tert-butyl-3-hydroxy-2,3-dihydroindol-2-ones, respectively, in good yields. However, carbonylation of doubly lithiated N-pivaloyl-o-toluidines takes a different course due to direct intramolecular cyclisation of the dilithio reagents to afford 2-tert-butylindoles without uptake of carbon monoxide.
