- Enantioselective Lewis Acid Catalyzed ortho Photocycloaddition of Olefins to Phenanthrene-9-carboxaldehydes
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Visible-light irradiation (λ=457 nm) enabled the enantioselective ortho photocycloaddition of olefins to phenanthrene-9-carboxaldehydes (15 examples, 46–93 % yield, 82–98 % ee). A chiral oxazaborolidine Lewis acid (20 mol %) was employed as the catalyst. It operates by coordination to the aldehyde inducing a bathochromic absorption shift beyond the nπ* absorption of the uncomplexed aldehyde. At long wavelengths the Lewis acid complex is exclusively excited; within the complex, one enantiotopic face of the aromatic aldehyde is efficiently shielded. Lewis acid coordination also alters the type selectivity and the simple diastereoselectivity of the photocycloaddition.
- Stegbauer, Simone,Jandl, Christian,Bach, Thorsten
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p. 14593 - 14596
(2018/10/15)
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- Synthesis of smart bimetallic nano-Cu/Ag@SiO2 for clean oxidation of alcohols
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Here, we have demonstrated the synthesis and characterization of silica supported bimetallic copper/silver nanoparticles (Cu/Ag@SiO2 NPs) and their application in the clean oxidation of benzoins/benzyl alcohols in the presence of tert-butyl hydroperoxide as a mild oxidant. All the reactions were very fast (4 h) and high yielding (95-99%), and the Cu/Ag@SiO2 NPs were very stable under the reaction conditions. The catalyst was recovered simply by filtration and reused eight times without loss of its catalytic performance.
- Saha, Arijit,Payra, Soumen,Banerjee, Subhash
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supporting information
p. 13377 - 13381
(2017/11/27)
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- Palladium-Catalyzed Ring-Forming Aminoalkenylation of Alkenes with Aldehydes Initiated by Intramolecular Aminopalladation
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A palladium-catalyzed aminopalladation reaction followed by nucleophilic addition with aldehydes and dehydration is described. This direct and operationally simple procedure provides a rapid and reliable approach to a wide range of functionalized tetrahydroisoquinolines with high selectivity. Mechanistic studies disclosed that the nucleophilic addition, performed via a highly ordered transition-state, is the turnover-limiting step in which the inherent β-hydride elimination of the key Csp3?Pd species was controlled by the confined conformation and the nucleophilicity of the Csp3?Pd bond was enhanced by the strong electron-donating effect of the nitrogen atom.
- Hu, Yue,Xie, Yinjun,Shen, Zhiqiang,Huang, Hanmin
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supporting information
p. 2473 - 2477
(2017/02/23)
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- Fe(III)-catalyzed trityl benzyl ether formation and disproportionation cascade reactions to yield benzaldehydes
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During investigating water-compatible Lewis acids catalyzed etherifications using alcohols as alkylating reagents directly, we developed Fe(III)-catalyzed trityl benzyl ether formations irradiated by microwave. Then an in situ trityl benzyl ether formation and disproportionation cascade reaction was achieved to yield the benzaldehyde products with good functional group tolerances under neat conditions at relative higher temperatures. The substituent effects of the substrates on the etherification and disproportionation were explored by changing the substitutions on benzyl alcohols and triarylmethanols using chemical kinetic plots methods and the mechanism of the transformation was studied by crossover experiments. The etherification and disproportionation cascade process could be conveniently scaled up in laboratory without losing much efficiency.
- Wang, Xiaoyu,Du, Chuan,Shi, Hui,Pang, Yadong,Jin, Shengfei,Hou, Yuqian,Wang, Yanshi,Peng, Xiaoshi,Xiao, Jianyong,Liu, Yang,Liu, Yongxiang,Cheng, Maosheng
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p. 6744 - 6748
(2015/08/24)
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- LOXOPROFEN DERIVATIVE AND PHARMACEUTICAL PREPARATION CONTAINING THE SAME
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There is provided a novel loxoprofen derivative that has no side effect such as a gastrointestinal disorder and also has excellent anti-inflammatory and analgesic effects and is represented by the following formula (I) or (II): (wherein R1 and
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Page/Page column 3-4
(2012/02/01)
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- Properties and synthesis of 2-{2-fluoro (or bromo)-4-[(2-oxocyclopentyl) methyl]phenyl}propanoic acid: Nonsteroidal anti-inflammatory drugs with low membrane permeabilizing and gastric lesion-producing activities
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We previously proposed that membrane permeabilization activity of NSAIDs is involved in NSAID-induced gastric lesions. We here synthesized derivatives of loxoprofen that have lower membrane permeabilization activity than other NSAIDs. Compared to loxoprofen, the derivatives 10a and 10b have lower membrane permeabilization activity and their oral administration produced fewer gastric lesions but showed an equivalent anti-inflammatory effect. These results suggest that 10a and 10b are likely to be therapeutically beneficial as safer NSAIDs.
- Yamakawa, Naoki,Suemasu, Shintaro,Matoyama, Masaaki,Kimoto, Ayumi,Takeda, Miho,Tanaka, Ken-Ichiro,Ishihara, Tomoaki,Katsu, Takashi,Okamoto, Yoshinari,Otsuka, Masami,Mizushima, Tohru
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scheme or table
p. 7879 - 7882
(2011/02/22)
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- Structure elucidation and enantioselective total synthesis of the HMG-CoA reductase inhibitors FR901512 and FR901516
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The enantioselective total synthesis of the potent HMGCoA reductase inhibitors FR901512 (1) and FR901516 (2) is reviewed. FR901512 was prepared in 15 steps from commercially available compound via 2 in 16.3% overall yield (89% average yield). This study validated the applicability and reliability of the catalytic asymmetric Nozaki-Hiyama reactions that were developed by us. These reactions enabled the concise, efficient, and protecting-group-free enantioselective total syntheses of these new statins.
- Inoue, Masahiro,Nakada, Masahisa
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scheme or table
p. 3694 - 3707
(2010/03/30)
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- DIAGNOSTIC AND REMEDY FOR DISEASE CAUSED BY AMYLOID AGGREGATION AND/OR DEPOSITION
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To provide a diagnostic drug which binds specifically to an amyloid aggregate and/or an amyloid deposit, to thereby realize imaging and quantification of a disease caused by amyloid aggregation and/or deposition. The invention provides a compound represented by formula (1) : (wherein X1 represents an optionally substituted bicyclic heterocyclic group; X2 represents a hydrogen atom, a halogen atom, or a chelate-forming group; ring A represents a benzene ring or a pyridine ring; and ring B represents an optionally substituted 5-membered aromatic heterocyclic group which is bonded to the benzene ring or the pyridine ring via a carbon atom of ring B), a salt thereof, a solvate of any of these, or a transition metal coordination compound of any of these, and a diagnostic, preventive, or therapeutic drug containing the same.
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Page/Page column 28
(2008/12/07)
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- Haloarenes in the Duff reaction under high pressures 2. Formylation and amidomethylation of haloarenes in trifluoroacetic acid
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Reactions of haloarenes with urotropine in CF3COOH at elevated temperatures and high pressures give the corresponding aromatic aldehydes and/or N-(haloarylmethyl)trifluoroacetamides.The yields of the products and their ratio depend on electronic properties of substituents in the aromatic ring.The reaction carried out in a mixture of CF3COOH and (CF3CO)2O affords only amides. - Keywords: haloarenes; Duff reaction; high pressure; haloarenecarbaldehydes; N-(haloarylmethyl)trifluoroacetamides.
- Sedishev, I. P.,Agafonov, N. E.,Kutin, A. A.,Zhulin, V. M.
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p. 2127 - 2130
(2007/10/03)
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- Synthesis of 2,7-Dimethylanthracene by a Route Which is Potentially a General One
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A synthetic route to specifically substituted anthracenes was attempted by using a selectively substituted o-bromobenzaldehyde derivative as the precursor. 2,7-Dimethylanthracene was successfully prepared.H 9 and H 10 in 2,7-dimethylanthracene were readily assigned by n.O.e. experiments.
- Lai, Yee-Hing,Peck, Thian-Guan
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p. 2067 - 2071
(2007/10/02)
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- Pesticides
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A compound of formula I: STR1 in which formula: D represents hydrogen or a cyano group; X represents halogen; A represents an alkyl group (typically a C1 -C6 alkyl group); n is 0 to 4; RCOO. represents a residue of an acid RCO2 H, which acid, or an ester-forming derivative of which acid, on reaction with α-cyano-3-phenoxybenzyl alcohol or an ester-forming derivative thereof, gives rise to an α-cyano-3-phenoxybenzyl ester having pesticidal properties.
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