- Microwave-assisted reduction of aromatic nitro compounds with novel oxo-rhenium complexes
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The reduction of several aromatic nitro compounds to amines by means of the two novel catalytic systems ([IMes]2ReOBr3)/PhSiH3 and ([Py]3ReNOBr2)/PhSiH3 under microwave irradiation is here reported. These two systems were able to perform the reduction of nitro groups with higher TON and TOF when compared with previously reported systems based on oxo-rhenium core under standard heating, although they showed a lesser broad reaction scope compared with the known systems.
- Blacque, Olivier,Grieco, Gabriele
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- Method for synthesizing 2-amino-3-nitrotoluene
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The invention provides a method for synthesizing 2-amino-3-nitrotoluene. The method comprises the following steps: mixing raw materials 4-amino-3-methylbenzenesulfonic acid, zinc oxide and acetic acid, reacting at 25-100 DEG C for 4 hours, carrying out diatomite filtration, cooling the filtrate to 0-12 DEG C, dropwisely adding concentrated nitric acid, controlling the system temperature at 0-12 DEG C, reacting for 30 minutes while keeping the temperature after the drop-by-drop addition is finished, pouring the obtained reaction solution into ice water, and performing suction filtration to obtain a solid, namely a nitrification product; and mixing the nitrification product with concentrated hydrochloric acid, heating to reflux and hydrolyze for 1 h, and then carrying out aftertreatment on the reaction solution to obtain the product 2-amino-3-nitrotoluene. According to the invention, the reaction selectivity is improved, the post-treatment method is optimized, the environmental protection pressure is reduced, the environmental pollution is avoided, and the yield and purity of the target product are effectively improved.
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Paragraph 0015; 0020-0025
(2021/01/11)
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- Selectivity of the complexation reactions of four regioisomeric methylcamphorquinoxaline ligands with gold(III): X-ray, NMR and DFT investigations
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Reported are the synthesis, spectral and structural characteristics of new quinoxaline-related regioisomeric ligands L1-L4 (1,x,11,11-tetramethyl-1,2,3,4-tetrahydro-1,4-methanophenazine, x = 7, 8, 9 and 6, respectively) and their mononuclear Au(III) complexes (1-4). Fusion of the camphor moiety to the quinoxaline core made two N-atoms of quinoxaline nonequivalent while the introduction of a methyl-substituent at positions 6-9 enabled a tuning of coordination properties of L1-L4. Gold(III) complexes 1-4 and ligands L1-L4 have been studied in detailed by 1D and 2D NMR and the structures of 1-4 have been determined by X-ray crystallography. The results of these analyses revealed a regiospecific coordination of Au(III) to the sterically less hindered N-5 atom (spatially close to the non-substituted bridgehead carbon) of L1-L3, and to N-10 (spatially close to the methyl-substituted bridgehead carbon) of L4. The results of DFT calculations shed light on disparate coordination modes of L1-L4 toward the AuCl3 fragment and explain formation of single coordination products in high yield.
- Gli?i?, Biljana D.,Hoffmann, Marcin,Warzajtis, Beata,Gen?i?, Marija S.,Blagojevi?, Polina D.,Radulovi?, Niko S.,Rychlewska, Urszula,Djuran, Milo? I.
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p. 137 - 149
(2016/01/15)
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- Discovery and optimization of benzotriazine Di-N-oxides targeting replicating and nonreplicating mycobacterium tuberculosis
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Compounds bactericidal against both replicating and nonreplicating Mtb may shorten the length of TB treatment regimens by eliminating infections more rapidly. Screening of a panel of antimicrobial and anticancer drug classes that are bioreduced into cytotoxic species revealed that 1,2,4-benzotriazine di-N-oxides (BTOs) are potently bactericidal against replicating and nonreplicating Mtb. Medicinal chemistry optimization, guided by semiempirical molecular orbital calculations, identified a new lead compound (20q) from this series with an MIC of 0.31 μg/mL against H37Rv and a cytotoxicity (CC 50) against Vero cells of 25 μg/mL. 20q also had equivalent potency against a panel of single-drug resistant strains of Mtb and remarkably selective activity for Mtb over a panel of other pathogenic bacterial strains. 20q was also negative in a L5178Y MOLY assay, indicating low potential for genetic toxicity. These data along with measurements of the physiochemical properties and pharmacokinetic profile demonstrate that BTOs have the potential to be developed into a new class of antitubercular drugs.
- Chopra, Sidharth,Koolpe, Gary A.,Tambo-Ong, Arlyn A.,Matsuyama, Karen N.,Ryan, Kenneth J.,Tran, Tran B.,Doppalapudi, Rupa S.,Riccio, Edward S.,Iyer, Lalitha V.,Green, Carol E.,Wan, Baojie,Franzblau, Scott G.,Madrid, Peter B.
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p. 6047 - 6060
(2012/09/05)
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- SUBSTITUTED AROMATIC CARBOXAMIDE AND UREA DERIVATIVES AS VANILLOID RECEPTOR LIGANDS
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The invention relates to substituted aromatic carboxamide and urea derivatives, to processes for the preparation thereof, to pharmaceutical compositions containing these compounds and also to the use of these compounds for preparing pharmaceutical compositions (formula (I)).
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Page/Page column 124
(2010/11/18)
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- Palladium-catalyzed synthesis of quinoxaline derivatives
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A palladium-catalyzed reductive N-heteroannulation of enamines derived from 2-nitrobenzenamines forming mixtures of 1,2-dihydroquinoxalines and 3,4-dihydroquinoxalin-2-ones is described. The reactions are performed using bis(dibenzylideneacetone)palladium(0), 1,3-bis(diphenylphosphino)propane, and 1,10-phenanthroline in DMF under 6 atm of carbon monoxide at 70 °C.
- Wallace, Jeffery M.,S?derberg, Bj?rn C.G.,Tamariz, Joaquín,Akhmedov, Novruz G.,Hurley, Mathew T.
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p. 9675 - 9684
(2008/12/22)
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- Highly chemoselective nitration of aromatic amines using the Ph3P/Br2/AgNO3 system
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The use of PPh3/Br2/AgNO3 provides a new reagent system for the novel and highly chemoselective nitration of aromatic amines under mild reaction conditions.
- Iranpoor, Nasser,Firouzabadi, Habib,Nowrouzi, Najmeh,Firouzabadi, Dena
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p. 6879 - 6881
(2007/10/03)
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- Syntheses and resolutions of new chiral biphenyl backbones: 2-Amino-2′-hydroxy-6,6′-dimethyl-1,1′-biphenyl and 2-amino-2′-hydroxy-4,4′,6,6′-tetramethyl-1,1′- biphenyl
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The new chiral backbones (R)-(+)- and S-(-)-2-amino-2′-hydroxy-6,6′-dimethyl-1,1′-biphenyl and (R)-(+)- and (S)-(-)-2-amino-2′-hydroxy-4,4′,6,6′- tetramethyl-1,1′-biphenyl were synthesized from o-methylaniline and 2,4-dimethyl-aniline respectively in seven steps. A new resolution method was developed to provide homochiral enantiomers (from diastereomeric salts) in reasonably high yields. The absolute configuration of the new biphenyls was confirmed by X-ray structural analysis.
- Liang, Yuxue,Gao, Shuang,Wan, Huihui,Wang, Junwei,Chen, Huilin,Zheng, Zhuo,Hu, Xinquan
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p. 1267 - 1273
(2007/10/03)
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- Synthesis and characterization of a superoxo complex of the dicobalt cofacial diporphyrin [(μ-O2)Co2(DPB)(1,5-diphenylimidazole) 2][PF6], the structure of the parent dicobalt diporphyrin Co2(DPB), and a new synthesis of the free-base cofacial diporphyrin H4(DPB)
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Chemical oxidation of the dicobalt cofacial diporphyrin Co2II/II(DPB), followed by exposure to dioxygen affords the bridged superoxo complex [(μ-O2)Co2(DPB)] [PF6]. This μ-superoxo complex has been implicated in possible mechanisms of four-electron dioxygen reduction by dicobalt cofacial diporphyrins but had not been isolated and fully-characterized previously. Although the superoxo complex is unstable with respect to loss of dioxygen, addition of 2 equiv of 1,5-diphenylimidazole yields [(μ-O2)Co2 III/III(DPB)(1,5-diphenylimidazole)2][PF6], a μ-superoxo complex that is stable toward loss of dioxygen. Analytically pure samples of the latter complex have been prepared, and their spectral and electrochemical properties are described. The crystal structure of the parent dicobalt cofacial diporphyrin Co2II/II(DPB) is reported. The Co-Co distance (3.726 (1) A?) and other structural features are compared to those of Co2(FTF4) and of other known metallo-DPB structures. A new, improved total synthesis of the free-base porphyrin H4(DPB) is presented. The combination of new reaction sequences, increased reaction scales, and improved product yields allows for large scale synthesis (gram quantities) of the free-base porphyrin needed to develop fully the coordination chemistry of the cofacial metallodiporphyrins.
- Collman, James P.,Hutchison, James E.,Lopez, Michel Angel,Tabard, Alain,Guilard, Roger,Seok, Won K.,Ibers, James A.,L'Her, Maurice
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p. 9869 - 9877
(2007/10/02)
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- Ruthenium-optically active phosphine complex
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A ruthenium-optically active phosphine complex having, as a ligand, BICHEP which means 2,2'-bis(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl represented by formula (I): STR1 is disclosed, which can catalyze asymmetric syntheses, such as asymmetric hydrogenation, asymmetric isomerization, and asymmetric silylation, exhibiting excellent catalytic activity and providing high optical purity.
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- Synthesis of Atropisomeric 2,2'-Bis(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl (BICHEP) and Its Use in Rh(I)-catalyzed Asymmetric Hydrogenation of Prochiral Olefins
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The atropisomeric bis(dialkylarylphosphine) ligands, (R)-(-)- and (S)-(+)-2,2'-bis(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl (BICHEP) (1) have been newly synthesized, whose Rh(I) complexes are highly efficient catalysts for asymmetric hydrogenations of ethyl α-(benzamido)cinnamate and dimethyl itaconate in up to 98percent yields and 98-99percent enantiomeric excess.
- Miyashita, Akira,Karino, Haruhiko,Shimamura, Jun-ichi,Chiba, Takeshi,Nagano, Katsuhiko,et al.
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p. 1849 - 1852
(2007/10/02)
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- Direct Nitration of Anilines Using Nitrocyclohexadienones
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Nitrocyclohexadienones (in particular, 2,3,5,6-tetrabromo-4-methyl-4-nitro-2,5-cyclohexadienone) are used as reagents for the direct nitration of anilines.Depending on the conditions, good yields of C-nitroanilines are obtained.Under the same conditions, N,N-dimethylaniline is converted into N-methyl-N-nitroaniline.
- Lemaire, M.,Guy, A.,Boutin, P.,Guette, J. P.
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p. 761 - 763
(2007/10/02)
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