- Visible-Light-Induced Arene C(sp 2)-H Lactonization Promoted by DDQ and tert -Butyl Nitrite
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A visible-light photocatalytic aerobic oxidative lactonization of arene C(sp 2)-H bonds proceeds in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tert -butyl nitrite (TBN). Under the optimized conditions, a range of 2-arylbenzoic acids is converted into the corresponding benzocoumarin derivatives in moderate to excellent yields. This method is characterized by its atom economy, mild reaction conditions, the use of a green oxidant and metal-free catalysis.
- Chen, Bajin,Hu, Baoxiang,Hu, Xinquan,Jin, Liqun,Li, Meichao,Shen, Zhenlu,Sun, Nan,Wang, Shengpeng,Wang, Yiqing
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supporting information
p. 261 - 266
(2020/02/18)
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- Vitamin Catalysis: Direct, Photocatalytic Synthesis of Benzocoumarins via (-)-Riboflavin-Mediated Electron Transfer
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An operationally simple protocol is disclosed to facilitate entry to benzo-3,4-coumarins directly from biaryl carboxylic acids without the need for substrate prefunctionalization. Complementary to classic lactonization strategies, this disconnection relies on the oxidation competence of photoactivated (-)-riboflavin (vitamin B2) to generate the heterocyclic core via photoinduced single electron transfer. Collectively, the inexpensive nature of the catalyst, ease of execution, and absence of external metal additives are a convincing endorsement for the incorporation of simple vitamins in contemporary catalysis.
- Morack, Tobias,Metternich, Jan B.,Gilmour, Ryan
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supporting information
p. 1316 - 1319
(2018/03/09)
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- Silver-Catalyzed C(sp2)-H Functionalization/C-O Cyclization Reaction at Room Temperature
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Silver-catalyzed C(sp2)-H functionalization/C-O cyclization has been developed. The scalable reaction proceeds at room temperature in an open flask. The present method exhibits good functional-group compatibility because of the mild reaction conditions. Using a AgNO3 catalyst and a (NH4)2S2O8 oxidant in CH2Cl2/H2O solvent, various lactones are obtained in good to excellent yields. A kinetic isotope effect (KIE) study indicates that the reaction may occur via a radical process.
- Dai, Jian-Jun,Xu, Wen-Tao,Wu, Ya-Dong,Zhang, Wen-Man,Gong, Ying,He, Xia-Ping,Zhang, Xin-Qing,Xu, Hua-Jian
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p. 911 - 919
(2015/01/30)
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- Synthesis of fluorenones through rhodium-catalyzed intramolecular acylation of biarylcarboxylic acids
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An efficient approach to the synthesis of fluorenones via the rhodium-catalyzed intramolecular acylation of biarylcarboxylic acids was developed. Using this procedure, fluorenones with various substituents can be synthesized in good to high yields. This work marks the first recorded use of catalytic intramolecular acylation to synthesize fluorenones.
- Fukuyama, Takahide,Maetani, Shinji,Miyagawa, Kazusa,Ryu, Ilhyong
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supporting information
p. 3216 - 3219
(2014/07/08)
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- Pd-catalyzed C-H lactonization for expedient synthesis of biaryl lactones and total synthesis of cannabinol
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A practical Pd(II)/Pd(IV)-catalyzed carboxyl-directed C-H activation/C-O cyclization to construct biaryl lactones has been developed. The synthetic utility of this new reaction was demonstrated in an atom-economical and operationally convenient total synthesis of the natural product cannabinol from commercially available starting materials, with the newly developed method used for two key steps.
- Li, Yan,Ding, Yan-Jun,Wang, Jian-Yong,Su, Yi-Ming,Wang, Xi-Sheng
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supporting information
p. 2574 - 2577
(2013/07/11)
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- General and practical carboxyl-group-directed remote C-H oxygenation reactions of arenes
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Two methods for remote aromatic C-H oxygenation reactions, have been developed. Method1, the Cu-catalyzed oxygenation reaction, is highly efficient for cyclization of electron-neutral and electron-rich biaryl carboxylic acids into 3,4-benzocoumarins. Method2, the K2S2O 8-mediated oxygenation reaction, is more general and practical for cyclization of substrates with electron-donating and -withdrawing groups (see scheme). Copyright
- Wang, Yang,Gulevich, Anton V.,Gevorgyan, Vladimir
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supporting information
p. 15836 - 15840
(2014/04/03)
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- THIOPHENE AND FURAN COMPOUNDS
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The present invention relates to thiophene and furan compounds and their pharmaceutically acceptable salts, and further relates to their use in treating schizophrenia, cognitive deficits associated with schizophrenia, Alzheimer's disease, dementia of the Alzheimer's type, mild cognitive impairment, or depression.
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Page/Page column 73
(2010/02/13)
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- PYRROLE AND PYRAZOLE DERIVATIVES AS POTENTIATORS OF GLUTAMATE RECEPTORS
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The present invention relates to pyrrole and pyrazole compounds of formula (I) and their pharmaceutically acceptable salts, and further relates to their use in treating schizophrenia, cognitive deficits associated with schizophrenia, Alzheimer's disease, dementia of the Alzheimer's type, mild cognitive impairment, or depression. The compounds act as potentiators on glutamate receptors, in particular AMPA and the GluR family.
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Page/Page column 92-93
(2008/06/13)
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- Nonpeptide angiotensin II receptor antagonists. I. Synthesis and biological activity of pyridine derivatives
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Substituted pyridines were synthesized as potential angiotensin II (AII) receptor antagonists. Substitution at the position 2 in the pyridine resulted in potent activity, and the optimal alkyl length was four carbons. The potency further increased with the introduction of a hydroxymethyl group at the position 4. One of the compounds, 2-butyl-6-chloro-4-hydroxymethyl-5-methyl-3-[[2'-(1H-tetrazol-5-yl)bip henyl-4-yl]methyl]pyridine 9 h (KT3-579)is a competitive AII antagonist with a pA2 value of 9.31, and is about 10 times more potent than Du Pont 753. It was found to be an AT1 specific antagonist with an IC50 of 3.09 nM.
- Ueyama,Yanagisawa,Kawai,Sonegawa,Baba,Mochizuki,Kosakai,Tomiyama
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p. 1841 - 1849
(2007/10/02)
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- Biaryl aldehyde
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This invention relates to a method of synthesis of certain substituted carboxylic acids useful in lowering serum triglyceride and total cholesterol levels in mammals (including man) represented by the general formula I: wherein Ar1 is selected from STR1 Ar2 is selected from STR2 and R is selected from C1-5 alkyl, halogen, perhalo-C1-4 alkyl, C1-4 alkoxy, phenyl, C1-4 acyl, C1-6 alkoxycarbonyl, amino or hydroxy.
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