108934-20-9Relevant academic research and scientific papers
Palladium-on-Carbon-Catalyzed Coupling of Nitroarenes with Phenol: Biaryl Ether Synthesis and Evidence of an Oxidative-Addition-Promoted Mechanism
Begum, Tahshina,Mondal, Manoj,Borpuzari, Manash Protim,Kar, Rahul,Gogoi, Pradip K.,Bora, Utpal
, p. 3244 - 3248 (2017)
Nucleophilic substitution in nitroarenes to form biaryl ethers is of fundamental importance in organic synthesis. Under non-catalytic conditions, this can occur if highly activated nitroarenes are used or if the nucleophile is activated by a strong stoichiometric base. We established a new method involving the use of a ligand-free palladium-on-carbon (Pd/C) catalyst for the cross-coupling of activated nitroarenes with relatively non-nucleophilic phenol derivatives, including naphthol, in the absence of harsh bases. Control experiments, hot filtration, the three-phase test, and inductively coupled plasma atomic emission spectroscopy analysis revealed that the catalysis proceeded through an usual oxidative addition step of the nitroarene to Pd/C, which resulted in the release of active palladium particles having extremely high catalytic activity. DFT calculations revealed the origin of the selectivity of the activated nitroarenes.
Trialkylammonium salt degradation: Implications for methylation and cross-coupling
Assante, Michele,Baillie, Sharon E.,Juba, Vanessa,Leach, Andrew G.,McKinney, David,Reid, Marc,Washington, Jack B.,Yan, Chunhui
, p. 6949 - 6963 (2021/06/02)
Trialkylammonium (most notably N,N,N-trimethylanilinium) salts are known to display dual reactivity through both the aryl group and the N-methyl groups. These salts have thus been widely applied in cross-coupling, aryl etherification, fluorine radiolabelling, phase-transfer catalysis, supramolecular recognition, polymer design, and (more recently) methylation. However, their application as electrophilic methylating reagents remains somewhat underexplored, and an understanding of their arylation versus methylation reactivities is lacking. This study presents a mechanistic degradation analysis of N,N,N-trimethylanilinium salts and highlights the implications for synthetic applications of this important class of salts. Kinetic degradation studies, in both solid and solution phases, have delivered insights into the physical and chemical parameters affecting anilinium salt stability. 1H NMR kinetic analysis of salt degradation has evidenced thermal degradation to methyl iodide and the parent aniline, consistent with a closed-shell SN2-centred degradative pathway, and methyl iodide being the key reactive species in applied methylation procedures. Furthermore, the effect of halide and non-nucleophilic counterions on salt degradation has been investigated, along with deuterium isotope and solvent effects. New mechanistic insights have enabled the investigation of the use of trimethylanilinium salts in O-methylation and in improved cross-coupling strategies. Finally, detailed computational studies have helped highlight limitations in the current state-of-the-art of solvation modelling of reaction in which the bulk medium undergoes experimentally observable changes over the reaction timecourse. This journal is
Lipophilic tail modifications of 2-(hydroxymethyl)pyrrolidine scaffold reveal dual sphingosine kinase 1 and 2 inhibitors
Li, Hao,Sibley, Christopher D.,Kharel, Yugesh,Huang, Tao,Brown, Anne M.,Wonilowicz, Laura G.,Bevan, David R.,Lynch, Kevin R.,Santos, Webster L.
, (2021/01/07)
The sphingosine 1-phosphate (S1P) signaling pathway is an attractive target for pharmacological manipulation due to its involvement in cancer progression and immune cell chemotaxis. The synthesis of S1P is catalyzed by the action of sphingosine kinase 1 or 2 (SphK1 or SphK2) on sphingosine and ATP. While potent and selective inhibitors of SphK1 or SphK2 have been reported, development of potent dual SphK1/SphK2 inhibitors are still needed. Towards this end, we report the structure–activity relationship profiling of 2-(hydroxymethyl)pyrrolidine-based inhibitors with 22d being the most potent dual SphK1/SphK2 inhibitor (SphK1 Ki = 0.679 μM, SphK2 Ki = 0.951 μM) reported in this series. 22d inhibited the growth of engineered Saccharomyces cerevisiae and decreased S1P levels in histiocytic lymphoma myeloid cell line (U937 cells), demonstrating inhibition of SphK1 and 2 in vitro. Molecular modeling studies of 22d docked inside the Sph binding pocket of both SphK1 and SphK2 indicate essential hydrogen bond between the 2-(hydroxymethyl)pyrrolidine head to interact with aspartic acid and serine residues near the ATP binding pocket, which provide the basis for dual inhibition. In addition, the dodecyl tail adopts a “J-shape” conformation found in crystal structure of sphingosine bound to SphK1. Collectively, these studies provide insight into the intermolecular interactions in the SphK1 and 2 active sites to achieve maximal dual inhibitory activity.
Pyrimidine onium compound and application thereof
-
Paragraph 0264-0267, (2019/10/23)
The invention relates to a pyrimidine onium compound, nitride oxides, salt of the nitride oxides and a composition comprising the compound. The invention further relates to an application of the compound to plant pest control.
A 2,2′-bipyridine-palladacycle catalyzed the coupling of arylboronic acids with nitroarenes
Peng, Dongpo,Yu, Ajuan,Wang, Hailei,Wu, Yangjie,Chang, Junbiao
, p. 6884 - 6889 (2013/07/26)
A novel palladium-catalyzed protocol for the synthesis of diaryl ethers derivatives has been developed. In the presence of 2,2′-bipyridine- cyclopalladated ferrocenylimine complex (Cat. Ic), diaryl ethers were selectively generated by adjusting reaction parameters through the coupling of arylboronic acids and nitroarenes with yields ranging from poor to good. The efficiency of this reaction was demonstrated by its compatibility with a range of groups. Moreover, the rigorous exclusion of air or moisture was not required in these transformations.
First palladium-catalyzed denitrated coupling reaction of nitroarenes with phenols
Wang, Hailei,Yu, Ajuan,Cao, Aijuan,Chang, Junbiao,Wu, Yangjie
, p. 611 - 614 (2013/10/21)
The first palladium-catalyzed protocol for the denitrated coupling reaction of nitroarenes with phenols has been developed, achieving unsymmetrical diaryl ethers in moderate to excellent yields. The cyclopalladated ferrocenylimine (catalyst Ic) exhibited highly catalytic activity for this transformation with low catalyst loading (0.75 mol%) and short reaction time (2 h). The efficiency of this reaction was demonstrated by its compatibility with a range of groups. Moreover, the rigorous exclusion of air or moisture was not required in these transformations. Copyright
5-Aryl thiazolidine-2,4-diones: Discovery of PPAR dual α/γ agonists as antidiabetic agents
Desai, Ranjit C.,Han, Wei,Metzger, Edward J.,Bergman, Jeffrey P.,Gratale, Dominick F.,MacNaul, Karen L.,Berger, Joel P.,Doebber, Thomas W.,Leung, Kwan,Moller, David E.,Heck, James V.,Sahoo, Soumya P.
, p. 2795 - 2798 (2007/10/03)
A novel series of 5-aryl thiazolidine-2,4-diones based dual PPARα/γ agonists was identified. A number of highly potent and orally bioavailable analogues were synthesized. Efficacy study results of some of these analogues in the db/db mice model of type 2 diabetes showed them superior to rosiglitazone in correcting hyperglycemia and hypertriglyceridemia.
2-substituted phenyl-benzimidazole antibacterial agents
-
, (2008/06/13)
The invention relates to benzimidazole antibacterial compounds of the Formula I: STR1 as described herein, pharmaceutical compositions containing the compounds, and methods for their production and use. These compounds are effective in inhibiting the action of a bacterial histidine protein kinase and are useful as anti-infective agents against a variety of bacterial organisms, including organisms which are resistant to other known antibiotics.
(Aryloxy)aryl semicarbazones and related compounds: A novel class of anticonvulsant agents possessing high activity in the maximal electroshock screen
Dimmock, Jonathan R.,Puthucode, Ramanan N.,Smith, Jennifer M.,Hetherington, Mark,Quail, J. Wilson,Pugazhenthi, Uma,Lechler, Terry,Stables, James P.
, p. 3984 - 3997 (2007/10/03)
A number of (aryloxy)aryl semicarbazones and related compounds were synthesized and evaluated far anticonvulsant activities. After intraperitoneal injection to mice, the semicarbazones were examined in the maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ), and neurotoxicity (NT) screens. The results indicated that greater protection was obtained in the MES test than the scPTZ screen. Quantitation of approximately one-third of the compounds revealed an average protection index (PI, i.e. TD50/ED50) of approximately 9. After oral administration to rats, a number of compounds displayed significant potencies in the MES screen (ED50 of 1-5 mg/kg) accompanied by very high protection indices. In fact over half the compounds had PI figures of greater than 100, and two were in excess of 300. The compounds were essentially inactive in the scPTZ and NT screens after oral administration to rats. Various compounds displayed greater potencies and PI figures in the mouse intraperitoneal and rat oral screens than three reference clinically used drugs. The data generated supported a binding site hypothesis. Quantitative structure-activity relationships indicated a number of physicochemical parameters which contributed to activity in the MES screen. X-ray crystallography of five compounds suggested the importance of certain interatomic distances and bond angles for activity in the mouse and rat MES screens.
A convenient method for the preparation of 4-aryloxyphenols
Yeager,Schissel
, p. 63 - 68 (2007/10/02)
A convenient method for the preparation of 4-aryloxyphenols via the homologation of preformed phenols is described. Condensation of various 4-substituted phenols with either 4-fluorobenzaldehyde (8) or 4-fluoroacetophenone (9) yielded the corresponding 4-aryl-oxybenzaldehydes, 10, and acetophenones, 11, in 70-93% yield. Baeyer-Villiger oxidation of these materials with 3-chloroperoxybenzoic acid (MCPBA) yielded the corresponding 4-formyloxy and 4-acetoxyphenyl ethers which were hydrolyzed without purification to the desired 4-aryloxyphenols 12 in 72-94% yield. Both 4-fluorobenzaldehyde (8) and 4-fluoroacetophenone (9) are synthetically equivalent to the a4 umpoled synthon 6. Extension of this methodology of the preparation of 4,4'-[arylbis(oxy)]bisphenols from aromatic diols is also described. Condensation of various aromatic diols with 8 or 9 yielded the corresponding 4,4'-[arylbis(oxy)]bisbenzaldehydes 15 and acetophenones 16 in 71-89% yield. Baeyer-Villiger oxidation of these compounds with MCPBA yielded the desired 4,4'-[arylbis(oxy)]bisphenyl bisformates 17 and bisacetates 18 in 67-84% yield. Hydrolysis of these compounds afforded the desired 4,4'-[arylbis(oxy)bisphenols 19 in 70-91% yield.
