- Synthesis of conjugated bile acids/azastilbenes as potential antioxidant and photoprotective agents
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A series of 14 bile acids/azastilbenes conjugates (1a-g and 2a-g) was prepared through the condensation of bile amides (1 and 2) and aromatic aldehydes. The newly synthesized conjugates were evaluated in vitro for their antioxidant and photoprotective activities. Six compounds (1, 1a, 1b, 2, 2a and 2b) showed promising antioxidant activity with IC50 values of 19.60-31.83 μg mL-1. The synthesized compounds presented a varied photoprotection profile, with the SPF ranging from 2 to 9. Among the 16 compounds tested for the protection against UVB sunrays, 3 compounds (2c, 2e and 2g) presented more significant protection than resveratrol and the free azastilbene 3; while the UVAPF increased from 2 in resveratrol and 5 in 3 to 5-11 in the majority of the conjugates.
- Dos Santos, Juliana Alves,Polonini, Hudson Caetano,Suzuki, érika Yoko,Raposo, Nádia R.B.,Da Silva, Adilson David
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- Synthesis, thermal and antimicrobial activity of novel organic single crystal of (E)-4-bromo-2-[(phenylimino)methyl]phenol compound
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This study focused on kinetic modelling of a specific type of multistep heterogeneous reaction comprising exothermic and endothermic reaction steps, as exemplified by the experimental kinetic curves for the thermal decomposition of (E)-4-bromo-2-[(phenyli
- Idamalarselvi,Swetha,Ramachandra Raja,Priscilla
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Read Online
- (E)-4-Bromo-2-[(phenylimino)methyl]phenol: A new polymorph and thermochromism
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A new polymorph of (E)-4-bromo-2-[(phenylimino)methyl]phenol, C13H10BrNO, is reported, together with a low-temperature structure determination of the previously published polymorph. Both polymorphs were found to have an intramolecular O - H?N hydrogen bon
- Howard, Judith A. K.,Mason, Helen E.,Sparkes, Hazel A.
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p. 1001 - 1004
(2020/11/13)
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- Design, synthesis, crystal structure and cytotoxicity studies of colorimetric fluorescent “OFF-ON” probes for rapid detection of hydrogen sulfide based on Cu(II) complex
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Four colorimetric fluorescent probes based on copper(II) complexes were synthesized and the molecular structures were characterized by X-ray diffraction, ESI-HRMS and elemental analysis. When exposed to HS?, the synthesized probes showed signif
- Shang, Xuefang,Yue, Xuejing,Chen, Yanmei,Li, Congshu,Chen, Hongli,Wang, Tianyun
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- Copper-Catalyzed Asymmetric Annulation Reactions of Carbenes with 2-Iminyl- or 2-Acyl-Substituted Phenols: Convenient Access to Enantioenriched 2,3-Dihydrobenzofurans
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We have developed a method for the highly diastereo- and enantioselective construction of 2,3-dihydrobenzofurans bearing tetrasubstituted carbon stereocenters by means of annulation reactions between carbenes and 2-iminyl- or 2-acyl-substituted phenols through catalysis by readily accessible copper(I)/bisoxazoline catalysts under mild conditions. These reactions feature a unique mechanism in which the copper catalyst serves a dual function: first it reacts with the diazo compound to generate a metal carbene, and second, upon formation of an oxonium ylide, it acts as a Lewis acid to activate the imine or ketone for diastereo- and enantioselective cyclization.
- Liang, Xin-Shen,Li, Rui-Dong,Wang, Xiao-Chen
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supporting information
p. 13885 - 13889
(2019/08/26)
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- New platinum(II) one-armed Schiff base complexes for blue and orange PHOLEDs applications
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The condensation of different groups substituted salicylaldehydes with aniline and 2,4,5-trifluoroaniline, afforded five one-armed Schiff base ligands HL1, HL2, HL3, HL4 and HL5. And their platinum(II) complexes Pt(L1)2, Pt(L2)2, Pt(L3)2, Pt(L4)2, Pt(L5)2 and PtL5·DMSO were prepared through the metallation of ligands with K2PtCl4. All ligands and complexes were characterized by 1H NMR, infrared spectroscopy, mass spectrometry and single crystal X-ray diffraction. And their thermal stability, photophysical properties, and electrochemical behaviors were investigated in detail. Using these complexes as phosphorescent emitting materials, blue to orange light-emitting devices were fabricated with moderate efficiencies. The maximum current efficiency, power efficiency, and brightness for the 3.0 wt % Pt(L3)2 doped OLED are 1.12 cd A?1, 0.62 l m W?1 and 1521 cd m?2, respectively. Given the synthetic simplicity and ease of structural variation, the results here indicate that these platinum(II) Schiff base complexes are good candidates for phosphorescent OLEDs.
- Zhang, Jie,Zhu, Xunjin,Zhong, Aiguo,Jia, Wenping,Wu, Fengshou,Li, Dan,Tong, Hongbo,Wu, Chenglin,Tang, Wenyuan,Zhang, Ping,Wang, Lei,Han, Deman
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p. 153 - 162
(2016/12/28)
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- Vanadyl binary schiff base complexes containing N2O2 coordination sphere: Synthesis, ab initio calculations and thermodynamic properties
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Some vanadyl complexes were synthesized by treating a methanolic solution of the appropriate Schiff base ligand and one equivalent of VO(SO 4)2 to yield [(VOL2 1-14)](L= Salicylaldehyde's derivatives, Schemes 1,
- Asadi, Mozaffar,Ghatee, Mohammad Hadi,Torabi, Susan,Mohammadi, Khosro,Moosavi, Fatemeh
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- Synthesis and evaluation of oxovanadium(iv) complexes of Schiff-base condensates from 5-substituted-2-hydroxybenzaldehyde and 2-substituted- benzenamine as selective inhibitors of protein tyrosine phosphatase 1B
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Five oxovanadium(iv) complexes, which were divided into two groups, [V IVO(bhbb, nhbb)(H2O)2] (tridentate ligands: H2bhbb = 2-(5-bromo-2-hydroxylbenzylideneamino)benzoic acid, 1; H2nhbb = 2-(5-nitro-2
- Han, Hong,Lu, Liping,Wang, Qingming,Zhu, Miaoli,Yuan, Caixia,Xing, Shu,Fu, Xueqi
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p. 11116 - 11124
(2012/10/30)
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- Halide substituted Schiff-bases: Different activities in methyltrioxorhenium(VII) catalyzed epoxidation via different substitution patterns
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This report shows the influence of halide substituted Schiff-bases as ligands of methyltrioxorhenium (MTO) in epoxidation catalysis. Therefore, selected Schiff-bases were prepared by the reaction of hydroxy-benzaldehydes and aniline derivates. These differently substituted Schiff-bases were tested as MTO-ligands in cyclooctene-and 1-octene-epoxidation. Although no great disparities among the substitution patterns have been found, some conclusions can be drawn. Flourines are inferior to chlorines or bromines as substituents. Halides in ortho-position lead to higher activities than in para-or meta-position. The balance between electron donating and withdrawing influences at the Schiff-base plays a prominent role in their utility as ligand to MTO in epoxidation catalysis.
- Altmann, Philipp,Cokoja, Mirza,Kühn, Fritz E.
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experimental part
p. 51 - 55
(2012/03/11)
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- Methyltrioxorhenium-catalyzed oxidation of pseudocumene for vitamin e synthesis: A study of solvent and ligand effects
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Vitamin E is an essential food component of major economical relevance with important antioxidant properties and biological activity. The oxidation of pseudocumene to trimethyl-1,4-benzoquinone would be a key transformation in an alternative industrial production of α-tocopherol that is important for the antioxidant activity of vitamin E. The methyltrioxorhenium (MTO)-catalyzed oxidation of pseudocumene has been revisited to offer a more environmentally friendly, economically beneficial and milder approach to this important industrial product. It has been observed that by choosing the solvent and Lewis base additives (as ligands of MTO), both yield and chemoselectivity are considerably improved, allowing milder reaction conditions compared to previously reported protocols.
- Carril, Monica,Altmann, Philipp,Drees, Markus,Bonrath, Werner,Netscher, Thomas,Schuetz, Jan,Kuehn, Fritz E.
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experimental part
p. 55 - 67
(2011/11/30)
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- Sulfonic acid supported on hydroxyapatite-encapsulated-γ-Fe 2O3 nanocrystallites as a magnetically separable catalyst for one-pot reductive amination of carbonyl compounds
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A novel, environmentally friendly procedure has been developed for the preparation of secondary or tertiary amines by one-pot reductive amination of carbonyl compounds using sodium borohydride in the presence of a magnetically recoverable sulfonic acid supported on hydroxyapatite-encapsulated-γ- Fe2O3 [γ-Fe2O3@HAP-SO 3H] at room temperature. The catalyst was easily separated from the reaction mixture by applying an external magnet and reused for six cycles without significant loss of catalytic activity.
- Deng, Jia,Mo, Li-Ping,Zhao, Fei-Yang,Hou, Lan-Lan,Yang, Li,Zhang, Zhan-Hui
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experimental part
p. 2576 - 2584
(2011/10/18)
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- Antihyperglycemic, α-glucosidase inhibitory and DPPH free radical scavenging activity of 5-bromosalicylaldehyde and schiff bases
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α-Glucosidase inhibition and DPPH free radical scavenging by 5-bromosalicylaldehyde and some Schiff bases have been measured. 5-Bromosalicylaldehyde shows lowest IC50 value (8.80 μM) for α-glucosidase inhibition and also shows good results in in vivo experiments for antihyperglycemic potential. Springer Science+Business Media, LLC 2010.
- Misra, Sristicheta,Pandeya, Krishna Bihari,Tiwari, Ashok Kumar,Ali, Amtul Zehra,Saradamani, Thimmapatruni,Agawane, Sachin Bharat,Madhusudana, Kuncha
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experimental part
p. 1431 - 1437
(2012/05/20)
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- Catalytic asymmetric mannich-ketalization reaction: Highly enantioselective synthesis of aminobenzopyrans
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"Chemical Equation Present" Domino catalysis: We have developed the first enantioselective domino Mannich-ketalization reaction of o-hydroxy benzaldimines with electron-rich alkenes (see scheme). The new reaction sequence provides an easy and direct acces
- Rueping, Magnus,Lin, Ming-Yuan
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supporting information; experimental part
p. 4169 - 4172
(2010/07/05)
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- Catalytic asymmetric inverse-electron-demand (IED) [4+2] cycloaddition of salicylaldimines: Preparation of optically active 4-aminobenzopyran derivatives
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The catalytic asymmetric inverse-electron-demand (IED) [4+2] cycloaddition of various salicylaldehyde-derived N-arylimines with electron-rich alkenes in the presence of chiral BINOL-derived phosphoric acid catalysts has been studied with the aim of obtaining optically active 4-aminobenzopyran derivatives. Dienophiles such as 2,3-dihydro-2H-furan, benzyl N-vinylcarbamate and 2-vinylindole have been employed. Copyright
- Bernardi, Luca,Comes-Franchini, Mauro,Fochi, Mariafrancesca,Leo, Virginia,Mazzanti, Andrea,Ricci, Alfredo
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supporting information; experimental part
p. 3399 - 3406
(2011/02/23)
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- Stability Constants of Some Bivalent Metal Ion Chelates of Schiff Bases Derived from 2-Hydroxy-5-bromobenzaldehyde
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Potentiometric studies have been carried out on metal chelates of Mg(2+), Cd(2+), Zn(2+), Co(2+), Ni(2+) and Cu(2+) with N-(2-hydroxy-5-bromobenzylidene)-aniline, N-(2-hydroxy-5-bromobenzylidene)-4-methylaniline, and N-(2-hydroxy-5-bromobenzylidene)-4-chl
- Mayadeo, M. S.,Nalgirkar, Jyoti V.
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p. 456 - 457
(2007/10/02)
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