Article
Chemistry, Multidisciplinary
Mohamed Abd-Elsabour, Hytham F. Assaf, Ahmed M. Abo-Bakr, Abdulrahman G. Alhamzani, Mortaga M. Abou-Krisha, Aamal A. Al-Mutairi, Hesham M. Alsoghier
Summary: In this study, a green-electrochemical synthesis was used to oxidize catechol to o-benzoquinone, resulting in the successful synthesis of a novel heterocyclic triazinone functionalized with hydroxyl and amide groups.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Applied
Long Chen, Xiao-Yan Liu, Jing Zhang, Li Duan, Zhong Wen, Hai-Liang Ni
Summary: The one-pot phospha-Michael addition/5-exo-dig cyclization/isomerization reaction catalyzed by relay Cu(I)/Brønsted base successfully synthesized C3-phosphorylated indoles from in situ generated aza-alkynyl o-quinone methides (N-o-AQMs) and P(O)-compounds. The study demonstrated that the 1,4-conjugate addition adduct from N-o-AQMs could undergo further cyclization with the tethered alkyne moiety to afford N-heterocyclic compounds.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Ganesh Shivayogappa Sorabad, Ding-Yah Yang
Summary: A facile and regioselective Lewis acid-catalyzed cascade annulation of o-hydroxyphenyl propargyl amines with 4-hydroxycoumarin to afford furano[3,2-c]coumarin and pyrano[3,2-c]coumarin derivatives is reported. The reaction proceeds through the conjugate addition of 4-hydroxycoumarin to the in situ-generated alkynyl o-quinone methide followed by intramolecular 5-exo-dig and 6-endo-dig annulation to form furano[3,2-c]coumarins and pyrano[3,2-c]coumarins, respectively. The prepared o-hydroxyl substituted pyrano[3,2-c]coumarins can be easily transformed into the corresponding coumarin-derived dioxabicycles by acid-mediated cyclization.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Chandan Gharui, Chandrakanta Parida, Subhas Chandra Pan
Summary: An organocatalytic asymmetric addition reaction of aromatic alpha-cyanoketones to in situ-generated o-quinone methides was successfully developed, leading to the synthesis of 3,4-dihydrocoumarin and tetrasubstituted chroman products. The desired products were obtained with high enantio- and diastereoselectivities under 10 mol % catalyst.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Rupashri Dash, Sudhir Kumar Hota, Sandip Murarka
Summary: We describe an efficient higher order conjugate addition reaction of azauracils to substituted para-quinone methides (p-QMs) mediated by triethylamine, forming previously unknown diarylmethane scaffolds through C-N bond formation. This protocol offers mild conditions, high atom economy, broad scope, and allows convenient access to biologically relevant new chemical entities (NCEs) consisting of p-QM and azauracil hybrids in good to excellent yields.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Multidisciplinary
Fiona Sprang, Jana Klein, Siegfried R. Waldvogel
Summary: A novel electrosynthetic protocol is reported for the direct conversion of 4-hydroxybenzaldehydes to valuable benzoquinones. The transformation is conducted through anodic oxidation, minimizing waste by eliminating terminal oxidants and redox mediators. Graphite serves as a metal-free anode material. A wide range of substituents, including halogens, are tolerated in this electrochemical protocol, with quinones selectively obtained in up to 99% yield. The compatibility of the protocol with electrochemical flow synthesis is demonstrated, and its application to lignosulfonate yields quinones in up to 7.6 wt%.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Organic
Qinfang Yan, Yi Jiang, Xianheng Song, Guoqing Lu, Qianzhong Zhang, Zhibo Du, Albert S. C. Chan, Yong Zou
Summary: A facile and practical approach for the synthesis of natural coumestans and derivatives starting from 2',4'-dihydroxyl-3-arylcoumarins has been developed. The process involves a sequential intramolecular dehydrogenation/oxa-Michael reaction efficiently promoted by 1,8-diazabicyclo[5.4.0]undec-7-ene at 40 degrees C under metal- and ligand-free conditions with good functional group compatibility.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Sajjad Ahmed, Mohammad Yaqoob Bhat, Feroze Hussain, Qazi Naveed Ahmed
Summary: In this study, the activation of diphenyl phosphite by BF3/BF4(-) resulted in the formation of thionium ions from aldehydes and thiophenols. These reactive species then reacted with in situ generated phenol, leading to the synthesis of diarylmethyl thioethers. It was found that the addition of external phenol in the reaction yielded unsymmetrical gem-diarylmethyl thioethers in good yields.
Article
Chemistry, Multidisciplinary
Yong-Chao Ming, Xue-Jiao Lv, Ying-Han Chen, Yan-Kai Liu
Summary: A highly selective cascade process is demonstrated based on enantioselective iminium-catalyzed conjugate addition of 2-hydroxycinnamaldehydes and 2-oxocarboxylic esters. Normal cinnamaldehydes do not show reactivity under the same reaction conditions. Bridged bicyclic ketals are synthesized, bearing stereocenters on both the bridge carbon and bridgehead ketal carbon.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Jianmin Zhou, Zhi-Yuan Ma, Chantale Shonhe, Su-Hui Ji, Yun-Rui Cai
Summary: The study presents a TEMPO-catalyzed electrosynthetic method for the dehydrogenative cyclocondensation of o-aminophenols to access pharmaceutically valuable 2-aminophenoxazinones. The method is mild, sustainable, and does not require stoichiometric oxidants, providing a new approach for the synthesis of bioactive compounds with improved structural diversity. Mechanistic studies show that electrochemically generated TEMPO+ enables the oxidative radical homo-dimerization of o-aminophenols.
Article
Medicine, Research & Experimental
Pengxiao Li, Yazhong Ma, Ke Wang, Xiaohan Shi, Jie Yang, Guoyun Liu
Summary: The cytotoxicity of para-quinone methides (p-QMs) derivatives was investigated against cancer cells, and it was found that substituents in the ortho-position of the phenyl ring significantly enhanced the cytotoxicity. Further studies revealed that this cytotoxicity originated from the ability of p-QMs derivatives to generate ROS, leading to disruption of redox balance and induction of apoptosis.
BIOMEDICINE & PHARMACOTHERAPY
(2022)
Article
Chemistry, Applied
Laura A. Bryant, Kenneth Shankland, Hannah E. Straker, Callum D. Johnston, Nicholas R. Lees, Alexander J. A. Cobb
Summary: The article describes a rare organocatalytic intramolecular cyclization of resorcinols with a high enantioselectivity using a specific organocatalyst. The obtained bicyclic resorcinols show excellent utility in the synthesis of cannabinoid-like compounds, and exhibit anticonvulsant activity.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Organic
Jianli Zheng, Yingqian Xu, Shaorui Song, Ling Huang, Dongdong Cao, Aiguo Zhong, Jianguo Yang, Dingben Chen
Summary: The photoredox-catalyzed 1,6-difluoromethylation of 3-methyl-4-nitro-5-styrylisoxazole with HCF2SO2Na has been developed, yielding structurally diverse difluoromethylated products. The di-, tri-, and monofluoromethylation were compared, showing the highest yield for difluoromethylation. DFT calculations revealed the nucleophilicity of CF2H radical and the lowest transition state activation energy in the difluoromethylation reaction.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Nanoscience & Nanotechnology
Juyeon Lee, June Sung Lim, Gyeonghye Yim, Hongje Jang, Sang Hoon Joo, Young Jin Sa
Summary: In this study, it was found that the type and concentration of cations in the electrolyte have a significant influence on the activity of oxygen-doped carbons for the 2e(-) oxygen reduction reaction. Specifically, carbon materials exhibited cation-dependent activity trends in alkaline media.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Dimitri Berne, Sebastien Lemouzy, Pascale Guiffrey, Sylvain Caillol, Vincent Ladmiral, Eric Manoury, Rinaldo Poli, Eric Leclerc
Summary: This study describes a spontaneous (uncatalyzed) Michael addition of thiols to alpha-trifluoromethyl acrylates and its efficient application in the preparation of a thermoset. Mechanistic investigation reveals a probable solvent-assisted proton transfer in the rate-determining step and a considerable lowering of the energy barrier induced by the CF3 group in the addition of arene- and alkanethiols to tert-butyl trifluoromethyl acrylate in polar aprotic solvents.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
