- Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers
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The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
- De Bruin, Bas,De Zwart, Felix J.,Li, Zirui,Mathew, Simon,Wolzak, Lukas A.,Zhou, Minghui
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supporting information
p. 20501 - 20512
(2021/12/03)
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- KRAS inhibitor compound
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The invention provides a compound with a structure as shown in a formula II as described in the specification or pharmaceutically acceptable salt, ester, isomer, solvate, prodrug or isotope marker thereof. The KRAS G12C inhibitor compound provided by the invention has a relatively good inhibition effect on KRAS mutation, and can be used for preventing and/or treating KRAS G12C mediated diseases.
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Paragraph 0075-0077; 0100-0101
(2020/07/24)
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- An electrocatalytic route for transformation of biomass-derived furfural into 5-hydroxy-2(5H)-furanone
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Development of efficient strategies for biomass valorization is a highly attractive topic. Herein, we conducted the first work on electrocatalytic oxidation of renewable furfural to produce the key bioactive intermediate 5-hydroxy-2(5H)-furanone (HFO). It was demonstrated that using H2O as the oxygen source and metal chalcogenides (CuS, ZnS, PbS, etc.) as electrocatalysts, the reaction could proceed efficiently, and the CuS nanosheets prepared in this work showed the best performance and provided high HFO selectivity (83.6%) and high conversion (70.2%) of furfural. In addition, the CuS electrocatalyst showed long-term stability. Mechanism investigation showed that furfural was oxidized to HFO via multistep reactions, including C-C cleavage, subsequent ring opening and oxidation, and intramolecular isomerization.
- Wu, Haoran,Song, Jinliang,Liu, Huizhen,Xie, Zhenbing,Xie, Chao,Hu, Yue,Huang, Xin,Hua, Manli,Han, Buxing
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p. 4692 - 4698
(2019/05/14)
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- Furan-2-carbaldehydes as C1 building blocks for the synthesis of quinazolin-4(3: H)-ones via ligand-free photocatalytic C-C bond cleavage
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Furan-2-carbaldehydes, as biomass-derived chemicals, are used as efficient green C1 building blocks to synthesize bioactive quinazolin-4(3H)-ones by ligand-free photocatalytic C-C bond cleavage. Notably, protection of hydroxyl, carboxyl, amide, or secondary amino groups is not required. Mechanistic studies suggest that conjugated N,O-tridentate copper complexes act as novel photoinitiators under visible light.
- Yu, Wenjia,Zhang, Xianwei,Qin, Bingjie,Wang, Qiyang,Ren, Xuhong,He, Xinhua
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p. 2449 - 2454
(2018/06/11)
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- DEOXYDEHYDRATION OF SUGAR DERIVATIVES
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The disclosure provides methods for deoxydehydration of sugar-based derivatives using hydrogen gas as a reducing agent.
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Paragraph 0034; 0107
(2017/09/09)
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- Synthesis, properties and singlet oxygen generation of thiazolidinone double bond linked porphyrin at meso and β-position
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Meso and β-substituted free base and zinc metallated thiazolidinone-porphyrin conjugates were synthesized by one pot four component Knoevenagel condensation by utilizing substituted amines, carbon disulfide, ethyl chloroacetate and porphyrin aldehydes. These newly synthesized conjugates were characterized by IR, 1H NMR, 13C NMR, UV-Vis, fluorescence and HRMS spectroscopy. The singlet oxygen generation behaviors of these porphyrin conjugates were studied and it was observed that these porphyrin conjugates followed type II singlet oxygen. Fluorescence and singlet oxygen quantum yields among meso-substituted (mono-, di, tetra) and β-substituted conjugates were examined. The photocatalytic photooxidation of naphthols and furan by using these new organic photocatalysts were further analysed and it was observed that meso-tetra substituted (Zn3a) and β-substituted (Zn6a) porphyrins are much efficient for generation of singlet oxygen and for photocatalytic photooxidation.
- Ahmad, Sohail,Yadav, Kumar Karitkey,Narang, Uma,Bhattacharya, Soumee,Singh, Sarangthem Joychandra,Chauhan
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p. 36090 - 36095
(2016/05/19)
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- LIGNIN OXIDATION AND PRODUCTS THEREOF
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Provided herein is a method of oxidizing lignin. Further disclosed herein are aromatic and non-aromatic compounds obtained from oxidized lignin.
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Page/Page column 79-80
(2012/06/16)
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- Highly efficient continuous flow reactions using singlet oxygen as a "Green" reagent
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Described is a new method for the efficient in situ production of singlet oxygen in a simple continuous flow photochemical reactor. The extremely large interfacial area generated by running the biphasic mixture in a narrow channel at a high flow rate ensures high throughput as well as fast and efficient oxidation of various alkenes, 1,3-dienes, and thioethers on a preparative scale.
- Levesque, Francois,Seeberger, Peter H.
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supporting information; experimental part
p. 5008 - 5011
(2011/12/04)
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- Allylic Oxidations Catalyzed by Dirhodium Catalysts under Aqueous Conditions
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The present invention relates to compositions and methods for achieving the efficient allylic oxidation of organic molecules, especially olefins and steroids, under aqueous conditions. The invention concerns the use of dirhodium (II,II) “paddlewheel complexes, and in particular, dirhodium carboximate and tert-butyl hydroperoxide as catalysts for the reaction. The use of aqueous conditions is particularly advantageous in the allylic oxidation of 7-keto steroids, which could not be effectively oxidized using anhydrous methods, and in extending allylic oxidation to enamides and enol ethers.
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Page/Page column 12; 23
(2009/04/24)
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- Synthetic approaches to either homochiral or achiral derivatives of 3-hydroxy-2(5H)-furanone (isotetronic acid)
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Several title compounds were synthesized according to new methods based either on the use of D-ribonolactone as a chiral precursor or on the cyclization of 2,4-dioxopentanoic acid as a suitable achiral precursor. Base-induced elimination and subsequent acid-promoted ring contraction is an efficient protocol for the preparation of isotetronic acids from 2-O-alkyl-3,4-O-benzylidene-D-ribono-1,5-lactone derivatives.
- Bigorra, Joaquim,Font, Josep,De Echagueen, Cristina Ochoa,Ortuno, Rosa M.
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p. 6717 - 6728
(2007/10/02)
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- Stereoselective intermolecular radical additions to amide-substituted alkenes
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The free-radical addition of carbon radicals to two alkenes substituted with chiral pyrrolidine amides has been studied. The two alkenes studied were both amides of 2,5-dimethylpyrrolidine, available as either the R,R or S,S enantiomer from D- or L-alanine. One alkene studied was the unsymmetrical monoamide derived from 4-oxo-2-pentenoic acid (1), while the other substrate examined was the diamide of fumaric acid, 2. Hexyl, cyclohexyl, and tert-butyl radical addition to the amide of 4-oxo-2-pentenoic acid (1) gave approximately equal amounts of addition at the carbonyl and amide ends of the alkene. The two stereoisomeric products formed from addition at the carbonyl end were formed in nearly 1:1 product ratio while the products formed by addition at the amide end were formed in ratios as high as 40:1 (tert-butyl addition at 0 °C). Addition of cyclohexyl or tert-butyl radical to the fumaric diamide gives essentially only one stereoisomer, (diastereomeric ratio 50:1 and 80:1 at room temperature). This approach provides the highest reported stereoselectivity for radical addition to an acyclic chiral alkene. Furthermore, a rationale for the diastereoselectivity is presented that suggests that the amide selectivity is steric in origin and will be general.
- Porter, Ned A.,Scott, Daniel M.,Rosenstein, Ian J.,Giese, Bernd,Veit, Andreas,Zeitz, Heinz Georg
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p. 1791 - 1799
(2007/10/02)
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- SYNTHESIS AND SOME TRANSFORMATIONS OF VINYL β-ACETYL- AND β-BENZOYLACRYLATES
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Vinyl β-acetyl- and β-benzoylacrylates were obtained by transvinylation with vinyl acetate in the presence of the catalyst Hg(OCOCH3)2.BF3.O(C2H5)2.It was shown that the reactions with bromine, mercuric acetates, and butyl hydrosulfide at the vinyloxy group are regioselective.
- Komarova, L. I.,Zhuravlev, S. V.,Sal'nikova, L. V.
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p. 1422 - 1425
(2007/10/02)
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