- Helicity induction in hydrogen-bonding-driven zinc porphyrin foldamers by chiral C60-incorporating histidines
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(Chemical Equation Presented) High chiral amplification is exhibited by a new series of zinc porphyrin appended, hydrogen-bonded foldamers on binding with C60-incorporating chiral histidines as a result of the cooperation of two discrete noncovalent interactions: zinc porphyrin/ imidazole coordination and zinc porphyrin/C6 π-π stacking (see picture).
- Hou, Jun-Li,Yi, Hui-Ping,Shao, Xue-Bin,Li, Chuang,Wu, Zong-Quan,Jiang, Xi-Kui,Wu, Li-Zhu,Tung, Chen-Ho,Li, Zhan-Ting
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Read Online
- A tautomeric ligand enables directed C-H hydroxylation with molecular oxygen
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Hydroxylation of aryl carbon-hydrogen bonds with transition metal catalysts has proven challenging when oxygen is used as the oxidant. Here, we report a palladium complex bearing a bidentate pyridine/ pyridone ligand that efficiently catalyzes this reaction at ring positions adjacent to carboxylic acids. Infrared, x-ray, and computational analysis support a possible role of ligand tautomerization from monoanionic (L,X) to neutral (L,L) coordination in the catalytic cycle of aerobic carbon-hydrogen hydroxylation reaction. The conventional site selectivity dictated by heterocycles is overturned by this catalyst, thus allowing late-stage modification of compounds of pharmaceutical interest at previously inaccessible sites.
- Li, Zhen,Wang, Zhen,Chekshin, Nikita,Qian, Shaoqun,Qiao, Jennifer X.,Cheng, Peter T.,Yeung, Kap-Sun,Ewing, William R.,Yu, Jin-Quan
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p. 1452 - 1457
(2021/06/30)
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- Magnetic nano-structured cobalt-cobalt oxide/nitrogen-doped carbon material as an efficient catalyst for aerobic oxidation of p-cresols
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Efficient aerobic oxidation has been developed for the selective preparation of a sequence of valuable p-hydroxybenzaldehydes from corresponding p-cresols, using a new magnetically separable catalyst of nano-structured cobalt-cobalt oxide/nitrogen-doped carbon (CoOx@CN) material. CoOx@CN showed high activity for the 2-methoxy-4-cresol oxidation to vanillin, giving great yield (90%) and with good turnover number (210), as well as other p-cresols in good to great yields. The catalytic performance was investigated and related to the structural, chemical and magnetic properties which determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). The effects of base to substrate molar ratio, catalyst concentration, temperature, and solvent on the conversion and selectivity patterns also have been studied. The investigation revealed that remarkable catalytic properties of CoOx@CN could be ascribed to the active species cobalt oxide, doped nitrogen and porous carbon with large surface area. The size of the catalyst is a key factor for catalyst performance. The ferromagnetic property of catalyst enables to recycle easily by an external magnetic field and reuse six successive times without significant activity loss.
- Liang, Cheng,Li, Xuefeng,Su, Diefeng,Ma, Qiyi,Mao, Jianyong,Chen, Zhirong,Wang, Yong,Yao, Jia,Li, Haoran
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p. 121 - 131
(2018/05/22)
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- Regioselective Enzymatic Carboxylation of Bioactive (Poly)phenols
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In order to extend the applicability of the regioselective enzymatic carboxylation of phenols, the substrate scope of o-benzoic acid (de)carboxylases has been investigated towards complex molecules with an emphasis on flavouring agents and polyphenols possessing antioxidant properties. o-Hydroxycarboxylic acid products were obtained with perfect regioselectivity, in moderate to excellent yields. The applicability of this method was proven by the regioselective bio-carboxylation of resveratrol on a preparative scale with 95% yield. (Figure presented.).
- Plasch, Katharina,Resch, Verena,Hitce, Julien,Pop?oński, Jaros?aw,Faber, Kurt,Glueck, Silvia M.
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p. 959 - 965
(2017/03/27)
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- Synthesis of salicylaldehydes from phenols via copper-mediated duff reaction
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A copper-mediated Duff reaction for ortho-selective formylation of phenols has been developed. In the presence of copper species, significant improvements of yield and ortho-selectivity of the Duff formylation were achieved, which provides an easy access to salicylaldehydes from phenols.
- Fu, Xue-Wen,Pu, Wen-Chen,Zhang, Guo-Lin,Wang, Chun
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p. 8147 - 8158
(2015/02/19)
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- Synthesis and fluorescence properties of benzoxazole-1,4-dihydropyridine dyads achieved by a multicomponent reaction
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Photoactive 2-(2′-hydroxyphenyl)benzoxazole-1,4-dihydropyridine (HBO-DHP) dyads were obtained by a multicomponent one-pot Hantzsch synthesis using a fluorescent aldehyde, a 1,3-dicarbonylic compound and ammonium acetate. The key step in this synthetic methodology was the synthesis of the formyl benzoxazole derivative through a Duff-modified functionalization protocol. UV-Vis absorption and fluorescence emission spectroscopies were also applied to better understand the photophysics of these compounds. The three novel fluorescent compounds were obtained in moderate yields as stable solids with absorption in the UV region and emission in the blue-green region. Preliminary results indicate that after excitation both HBO and DHP fluorophores behave independently in the HBO-DHP structure. the Partner Organisations 2014.
- Affeldt, Ricardo Ferreira,De Amorim Borges, Ant?nio César,Russowsky, Dennis,Severo Rodembusch, Fabiano
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supporting information
p. 4607 - 4614
(2014/11/07)
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- SPIRO-SUBSTITUTED OXINDOLE DERIVATIVES HAVING AMPK ACTIVITY
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The present invention relates to compounds of formula (I), which have valuable pharmacological properties, in particular are activators of AMPK and which are therefore useful in the treatment of certain disorders that can be prevented or treated by activation of this receptor. The compounds are suitable for treatment and prevention of diseases which can be influenced by this receptor, such as metabolic diseases, in particular diabetes type 2.
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Page/Page column 114
(2015/01/07)
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- OLEFIN SUBSTITUTED OXINDOLES HAVING AMPK ACTIVITY
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The present invention relates to compounds of formula (I), which have valuable pharmacological properties, in particular are activators of AMPK and which are therefore useful in the treatment of certain disorders that can be prevented or treated by activation of this receptor. The compounds are suitable for treatment and prevention of diseases which can be influenced by this receptor, such as metabolic diseases, in particular diabetes type 2.
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Page/Page column 108
(2015/01/07)
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- Efficient Co(OAc)2-catalyzed aerobic oxidation of EWG-substituted 4-cresols to access 4-hydroxybenzaldehydes
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We reported an efficient ligand-free Co(OAc)2·4H 2O/NaOH/O2/ethylene glycol reaction system that enables selective aerobic oxidation of a wide range of substrates covering 2,6-di-EWG-, 2,3,6-tri-EWG-, 2-EWG-, and 2-EWG-6-EDG-substituted 4-cresols into the corresponding 4-hydroxybenzaldehydes. Based on the experimental investigations and well-defined p-benzoquinone methides, a plausible reaction mechanism was proposed. Considering the simplicity of the procedure and importance of the products, the methodology was expected to become a favorable and practical tool in related benzylic C(sp3)-H functionalization chemistry.
- Jiang, Jian-An,Du, Jia-Lei,Liao, Dao-Hua,Wang, Zhan-Guo,Ji, Ya-Fei
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supporting information
p. 1406 - 1411
(2014/03/21)
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- Studies on benzofuran-7-carboxamides as poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors
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Benzofuran-7-carboxamide was identified as a novel scaffold of poly(ADP-ribose) polymerase-1 (PARP-1) inhibitor. A series of compounds with various 2-substituents including (tertiary amino)methyl moieties substituted with aryl ring and aryl groups containing tertiary amines, were synthesized and biologically evaluated to elucidate the structure-activity relationships and optimize the potency. 2-[4-(Pyrrolidin-1-ylmethyl)phenyl]-benzofuran-7- carboxamide (42) was the most potent as an IC50 value of 40 nM among those.
- Lee, Sunkyung,Yi, Kyu Yang,Lee, Byung Ho,Oh, Kwang Seok
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experimental part
p. 1147 - 1153
(2012/07/14)
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- Process for nucleophilic fluoroalkylation of aldehydes
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Aryl difluoromethyl sulfone adds to alkehydes under phase transfer conditions to give novel substituted alcohols of the general formula wherein R is an aryl, cycloaliphatic, sec- or tert-aliphatic, or heterocyclic group and Ar is an aryl group. The substituted alcohols of formula I are of particular utility as intermediates in the synthesis of a variety of useful end products. For example, the products of formula I may be utilized in desulfonylation reactions, oxidation reactions and fluorination reactions.
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