- Exploring Tandem Ruthenium-Catalyzed Hydrogen Transfer and SNAr Chemistry
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A hydrogen-transfer strategy for the catalytic functionalization of benzylic alcohols via electronic arene activation, accessing a diverse range of bespoke diaryl ethers and aryl amines in excellent isolated yields (38 examples, 70% average yield), is reported. Taking advantage of the hydrogen-transfer approach, the oxidation level of the functionalized products can be selected by judicious choice of simple and inexpensive additives.
- Polidano, Kurt,Reed-Berendt, Benjamin G.,Basset, Ana?s,Watson, Andrew J. A.,Williams, Jonathan M. J.,Morrill, Louis C.
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p. 6716 - 6719
(2017/12/26)
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- Copper mediated formation of carbon-heteroatom bonds using organoboron reagents and ultrasound
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This report summarizes research efforts focused on copper acetate mediated reactions to form new carbon-heteroatom bonds using organoboron reagents under ultrasound irradiation. The method involves the application of ultrasound irradiation to the Chan-Evans-Lam reaction to achieve O-arylation of phenols, N-arylation of anilines and indoles, and S-arylation of thiols. Ultrasound irradiation was found to decrease reaction times from 72 hours to 4 hours while improving the product yields an average of 20%.1 Representative C-O, C-N, and C-S coupling reactions were successfully scaled-up from the milligram to gram levels while maintaining good product yields offering potential applications in industrial processes.
- Musolino, Bryan J.,Kabalka, George W.
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p. 271 - 297
(2015/03/04)
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- Ligand-free copper-catalyzed O-arylation of nitroarenes with phenols
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The first example of ligand-free copper-catalyzed O-arylation of nitroarenes with phenols was developed, achieving unsymmetrical diaryl ethers in moderate to excellent yields. This arylation proceeded smoothly without promotion of the ligands, and displayed great functional group compatibility. Thus, the method represents a new, facile, and cost-effective approach to access unsymmetrical diaryl ethers.
- Chen, Jiuxi,Wang, Xingyong,Zheng, Xingwang,Ding, Jinchang,Liu, Miaochang,Wu, Huayue
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supporting information
p. 8905 - 8907
(2012/10/29)
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- The coupling of arylboronic acids with nitroarenes catalyzed by rhodium
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The coupling of arylboronic acids with electron-deficient nitroarenes was realized for the first time by using a rhodium(I) catalyst under an air atmosphere, achieving unsymmetrical diaryl ethers with yields ranging from poor to good. From a deuterium labeling experiment, the oxygen atom is derived from ambient water. The efficiency of this reaction was demonstrated by its compatibility with fluoro, bromo, chloro, and trifluoromethyl groups.
- Zheng, Xingwang,Ding, Jinchang,Chen, Jiuxi,Gao, Wenxiao,Liu, Miaochang,Wu, Huayue
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supporting information; experimental part
p. 1726 - 1729
(2011/05/06)
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- Amino-pyridines as inhibitors of beta-secretase
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The present invention provides an amino-pyridine compound of formula I The present invention also provides methods for the use thereof to inhibit β-secretase (BACE) and treat β-amyloid deposits and neurofibrillary tangles.
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Page/Page column 22
(2008/06/13)
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- C-5-disubstituted barbiturates as potential molecular probes for noninvasive matrix metalloproteinase imaging
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Studies have demonstrated a positive correlation between inflammation, metastasis, or atherosclerosis and the unbalanced or culminated expression of matrix metalloproteinases (MMPs). The molecular imaging of locally upregulated MMP activity in vivo is a c
- Breyholz, Hans-J?rg,Sch?fers, Michael,Wagner, Stefan,H?ltke, Carsten,Faust, Andreas,Rabeneck, Helmut,Levkau, Bodo,Schober, Otmar,Kopka, Klaus
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p. 3400 - 3409
(2007/10/03)
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- Cytotoxic and anticonvulsant aryloxyaryl Mannich bases and related compounds
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A series of 1-(4-aryloxyphenyl)-3-diethylamino-1-propanone hydrochlorides 3a-3e and related compounds 3f, 3g and 4a-4d were synthesised. In addition, a group of 4-(4-aryloxyphenyl)-3-(4-aryloxyphenylcarbonyl)-1-ethyl-4-piperidinol hydrochlorides 6a-6e were prepared which incorporated most of the structural features of 3a-3e. All of these compounds displayed cytotoxic properties towards murine L1210 cells as well as human Molt 4/C8 and CEM T-lymphocytes. A number of these compounds possessed noteworthy potencies towards seven human colon cancer cell lines. Some correlations were noted between the IC 50 values generated in the different screens and the σ, π and molar refractivity constants of the aryl substituents as well as with the volumes and solvent accessible surface areas of various basic groups. Molecular modelling of representative compounds revealed structural features, which may have contributed to the varying potencies noted. In general, the compounds in series 6 were well tolerated when administered to mice. Anticonvulsant properties were demonstrated by a number of compounds in the maximal electroshock (MES) screen when administered intraperitoneally to mice while 4c and 6e afforded protection in the MES test when given orally to rats.
- Vashishtha, Sarvesh C.,Zello, Gordon A.,Nienaber, Kurt H.,Balzarini, Jan,De Clercq, Erik,Stables, James P.,Dimmock, Jonathan R.
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- (Aryloxy)aryl semicarbazones and related compounds: A novel class of anticonvulsant agents possessing high activity in the maximal electroshock screen
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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.
- Dimmock, Jonathan R.,Puthucode, Ramanan N.,Smith, Jennifer M.,Hetherington, Mark,Quail, J. Wilson,Pugazhenthi, Uma,Lechler, Terry,Stables, James P.
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p. 3984 - 3997
(2007/10/03)
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- A convenient method for the preparation of 4-aryloxyphenols
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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.
- Yeager,Schissel
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