- On the Virtue of Indium in Reduction Reactions. A Comparison of Reductions Mediated by Indium and Zinc: Is Indium Metal an Effective Catalyst for Zinc Induced Reductions?
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Indium(0)-mediated reductions have been reported for the transformation of several functional groups (imines, oximes, nitro groups, isoxazolidines, and conjugated alkenes, among others), prompted by the opportunity of performing the reactions in aqueous media and green conditions. We describe here the comparison of several reactions using indium or the less expensive zinc, carried out in order to evaluate the effective advantages brought about indium metal. We found some reactions for which use of In is mandatory and others where Zn worked equally well or even better. The reduction of hydroxylamines to the corresponding amines was the only reduction for which use of In provided much better results than Zn and was also possible to apply an efficient catalytic version with use of 2–5 mol-% In in the presence of stoichiometric Zn. Applicability of this catalytic reduction to “one-pot” model processes is also demonstrated.
- Matassini, Camilla,Bonanni, Marco,Marradi, Marco,Cicchi, Stefano,Goti, Andrea
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supporting information
p. 1106 - 1113
(2019/12/24)
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- Cobalt complex, preparation method thereof, and application thereof in selective catalysis of transfer hydrogenation reaction of cyano group
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The invention discloses a cobalt complex, a preparation method thereof, and an application thereof in the selective catalysis of a transfer hydrogenation reaction of a cyano group. The structural formula of the cobalt complex is represented by formula I. The cobalt complex is prepared through a reaction of a cobalt salt and an NNP ligand or a PNP ligand under the protection of an inert atmosphere;and the chemical formula of the cobalt salt is CoX12, wherein X1 represents halogen, a sulfate radical, a perchlorate radical, a hexafluorophosphate radical, a hexafluoroantimonate radical, a tetrafluoroborate radical, a trifluoromethanesulfonate radical or a tetra(pentafluorophenyl)borate radical. The cobalt complex can be used in the selective catalysis of the transfer hydrogenation reaction ofthe cyano group to obtain a primary amine compound, a secondary amine compound and a tertiary amine compound, the primary amine compound, the secondary amine compound and the tertiary amine compoundare important intermediates in a series of subsequent functionalizing reactions, and the cobalt complex has a very high catalysis activity, and has great research values and a great application prospect.
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Paragraph 0165-0167; 0170
(2018/05/07)
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- Synthesis method of bacterial infection resistant medicine intermediate
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The invention belongs to the technical field of chemical medicine intermediate synthesis, and particularly relates to a synthesis method of a bacterial infection resistant medicine intermediate. Liquid ammonia and acrylic ester are used as raw materials for preparing a diester type secondary amine compound 1; then, through cyclization, piperidone is prepared; then, scientific reaction catalysts, temperature and time are used; substitution reaction of secondary amine and iso-propyl iodide is used; the target product is synthesized through six-step reaction; the yield of the whole route reachesup to 35 percent.
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Paragraph 0026; 0034; 0035
(2018/07/30)
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- RECYCLABLE CATALYSTS FOR CHLORINATION OF ORGANIC ACIDS AND ALCOHOLS
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The present invention discloses recyclable polymeric catalyst of Formula I, for chlorination of organic acids and alcohols using chlorinating agents such as carbonyl chloride, oxalyl chloride or thionyl chloride, wherein, ‘m’ on the pendent groups on polystyrene backbone can have values from 1 to 5 and R is the alkyl group ranging from C1 to C5.
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Paragraph 0066-0068
(2017/10/10)
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- Mild and Selective Cobalt-Catalyzed Chemodivergent Transfer Hydrogenation of Nitriles
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Herein, we describe a selective cobalt-catalyzed chemodivergent transfer hydrogenation of nitriles to synthesize primary, secondary, and tertiary amines. The solvent effect plays a key role for the selectivity control. The general applicability of this procedure was highlighted by the synthesis of more than 70 amine products bearing various functional groups in high chemoselectivity. Moreover, this mild system achieved >2000 TONs (turnover numbers) for the transfer hydrogenation of nitriles.
- Shao, Zhihui,Fu, Shaomin,Wei, Mufeng,Zhou, Shaolin,Liu, Qiang
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supporting information
p. 14653 - 14657
(2016/11/23)
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- N-alkylated cyclen cobalt(III) complexes of 1-(chloromethyl)-3-(5,6,7- trimethoxyindol-2-ylcarbonyl)-2,3-dihydro-1H-pyrrolo[3,2-f]quinolin-5-ol DNA alkylating agent as hypoxia-activated prodrugs
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A series of cobalt complexes of the potent DNA minor groove alkylator 1-(chloromethyl)-3-(5,6,7-trimethoxyindol-2-ylcarbonyl)-2,3-dihydro-1H- pyrrolo[3,2-f]quinolin-5-ol (seco-6-azaCBI-TMI) were prepared from a series of N-substituted cyclen ligands. The final N-substituted complexes carried formal overall charges ranging from +2 to -2 and showed limited improvements in solubility. They showed similar stabilities to that of the complex with the unsubstituted cyclen ligand, and large but variable attenuation of the cytotoxicity of the free alkylator (2-30-fold), compared to 150-fold for the unsubstituted ligand. However, they had oxic/hypoxic ratios (2-22-fold) comparable to that of the unsubstituted cyclen complex (5).
- Lu, Guo-Liang,Stevenson, Ralph J.,Chang, John Yu-Chih,Brothers, Penelope J.,Ware, David C.,Wilson, William R.,Denny, William A.,Tercel, Moana
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experimental part
p. 4861 - 4867
(2011/09/21)
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- Synthesis of dendritic tryptophan derivatives and investigation on dendritic effects of their fluorescence and reactivity
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Two series of dendritic tryptophan derivatives have been synthesized and characterized, their emission spectra in different solvents and the reactivity of tryptophan were investigated and compared. There was a progressive shielding effect of the tryptophan in the emissive wavelengths of dendrimers increased with the size or generation of the dendritic shell.
- He, Dongsheng,He, Gu,Guo, Li
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scheme or table
p. 454 - 460
(2012/04/10)
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- Bone targeting prodrugs based on peptide dendrimers, synthesis and hydroxyapatite binding in vitro
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Novel bone targeting naproxen prodrugs with poly(aspartic acid) moieties and with two and three poly(aspartic acid) sequences peptide dendrimers were synthesized using a conventional method. The modified naproxen conjugates were incubated with hydroxyapatite in PBS at physiological conditions over 16h. The study revealed the hydroxyapatite binding properties of poly(aspartic acid) and it was found that the peptide dendrimer prodrugs exhibited a faster initial binding and a greater total binding. The obtained binding data in vitro indicated that the peptide dendrimers with poly(aspartic acid) sequences were useful for the development of new bone targeting molecules for drug delivery to bone.
- Ouyanga, Liang,Huang, Wencai,Hea, Gu,Guo, Li
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experimental part
p. 272 - 277
(2010/04/23)
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- Indium-mediated reduction of hydroxylamines to amines
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(Matrix presented) A novel and simple procedure for reduction of hydroxylamines to the corresponding amines by means of indium powder in aqueous media is reported. Applicability to one-pot reactions and isoxazolidine N-O bond reduction is also demonstrated. A catalytic version of the process using 2-5% In in the presence of other metals (Zn, Al) has been successfully developed.
- Cicchi, Stefano,Bonanni, Marco,Cardona, Francesca,Revuelta, Julia,Goti, Andrea
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p. 1773 - 1776
(2007/10/03)
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- Substituted β-alanines
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The invention is directed to physiologically active compounds of general formula (I): wherein R1 is hydrogen, halogen, lower alkyl or lower alkoxy; X1, X2 and X6 independently represent N or CR2; and one of X3, X4 and X5 represents CR3 and the others independently represents N or CR2 where R2 is hydrogen, halogen, lower alkyl or lower alkoxy; and R3 represents a group —L1—(CH2)n—C(=O)—N(R4)—CH2—CH2—Y; and their prodrugs, and pharmaceutically acceptable salts and solvates of such compounds and their prodrugs. Such compounds have valuable pharmaceutical properties, in particular the ability to regulate the interaction of VCAM-1 and fibronectin with the integrin VLA-4 (à4β1).
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Page column 98
(2010/01/30)
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- Bis(pyrimidine)-based palladium catalysts: Synthesis, X-ray structure and applications in Heck-, Suzuki-, Sonogashira-Hagihara couplings and amination reactions
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The synthesis of N,N-bis(pyrimid-2-yl)amine (1), N-acetyl-N,N-bis(pyrimid-2-yl)amide (2), N-norborn-2-ene-5-ylbis(pyrimid-2-yl)carbamide (4) is described. The Pd-complex N-acetyl-N,N-bis(pyrimid-2-yl)amine palladium dichloride (3) has been prepared from compound 2 and its X-ray structure has been determined. A polymer supported catalytic system (6) was prepared via ring-opening metathesis copolymerization of 4 with 1,4,4a,5,8,8a-hexahydro-1,4,5,8-exo-endo-dimethanonaphthalene (HDMN-6) and subsequent loading with PdCl2. Both the homogeneous and heterogeneous catalysts 3 and 6 were active in Heck-, Suzuki-, Sonogashira-Hagihara-type couplings and amination reactions using aryl iodides, bromides and chlorides.
- Buchmeiser, Michael R.,Schareina, Thomas,Kempe, Rhett,Wurst, Klaus
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- MICHAEL-TYPE ADDITION OF DIETHYL PHOSPHORAMIDATE TO α,β-UNSATURATED ESTERS
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Michael-type addition of diethyl phosphoramidate to α,β-unsaturated esters occurs when the reactants are refluxed in toluene or xylene with an excess of potassium carbonate in the presence of tetrabutylammonium bromide (TBABr).Dephosphorylation of methyl and ethyl acrylate adducts leads to the respective β-alanine esters. Key words: Diethyl phosphoramidate; α,β-unsaturated esters; Michael-type addition; β-alanine esters; phase-transfer catalysis.
- Osowska-Pacewicka, K.,Zawadzki, S.,Zwierzak, A.
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- 99mTc Complexes with Hexadentate Tricatechol Ligands
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The tricatechol ligand trisamine hydrochloride, TRIPACE (9), is prepared from tris(3-chloropropyl)amine (5) and the potassium salt of 2,2-dimethyl-1,3-benzodioxol-4-ol (7).This ligand is capable of reducing the 99m- ion to lower valent 99mTc and subsequent complexation of the reduced 99mTc ion.The structures of 5 and of trisamine (8) are determined by X-ray diffration.
- Hahn, Ekkehardt F.,Rupprecht, Stefan
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p. 481 - 486
(2007/10/02)
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