- N-alkylation of N-trimethylsilylimidazole
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The reaction of N-trimethylsilylimidazole with alkyl chloroacetates is studied. This process yields a mixture of N-alkylation and quarternization products in the ratio dependent on the reaction conditions. The reaction mechanism is discussed. 1H NMR data show that high melting point and low solubility of 1-imidazolylacetic acid in organic solvents are evidently caused by the formation of strong intermolecular hydrogen bonds, whereas in water zwitterionic structures with the protonation of both nitrogen atoms are formed.
- Lebedev,Sheludyakov,Lebedeva,Frolov,Shatunov,Ustinova,Kovaleva
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- Synthesis and in vitro antitumor activity of water soluble sulfonate- and ester-functionalized silver(I) N-heterocyclic carbene complexes
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The novel N-heterocyclic carbene ligand precursor NaHImPrSO3 (sodium 3,3′-(1H-imidazole-3-ium-1,3-diyl)dipropane-1-sulfonate) and the related silver carbene complex [Na4(ImPrSO3) 2]AgCl have been synthesized and characterized. Recrystallization of the analogous [ImAcEt]AgCl complex allowed the development of X-ray analysis which led to achieve relevant structural information concerning this silver(I) derivative. Both sulfonate- and ester-functionalized silver(I) N-heterocyclic carbenes (NHCs) were evaluated for their antiproliferative activities in a wide panel of human cancer cells. Complex [Na 4(ImPrSO3)2]AgCl showed a significant in vitro antiproliferative activity that was correlated with its strong ability to inhibit thioredoxin reductase. The inhibition of this selenoenzyme determined an alteration of the cellular redox environment thus leading to the induction of the apoptotic cell death through the activation of the ASK-1 pathway.
- Gandin, Valentina,Pellei, Maura,Marinelli, Marika,Marzano, Cristina,Dolmella, Alessandro,Giorgetti, Marco,Santini, Carlo
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- Synthesis and biological activity of ester- and amide-functionalized imidazolium salts and related water-soluble coinage metal N-heterocyclic carbene complexes
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N-Heterocyclic carbene (NHC) ligand precursors, namely, HImACl [1,3-bis(2-ethoxy-2-oxoethyl)-1H-imidazol-3-ium chloride] and HImBCl {1,3-bis[2-(diethylamino)-2-oxoethyl]-1H-imidazol-3-ium chloride}, functionalized with hydrophilic groups on the imidazole rings have been synthesized and were used in the synthesis of corresponding carbene complexes of silver(I) and copper(I), {[ImA]AgCl}, {[ImA]CuCl}, and {[ImB]2Ag}Cl. Related AuINHC complexes {[ImA]AuCl} and {[ImB]AuCl} have been obtained by transmetalation using the silver carbene precursor. These compounds were characterized by several spectroscopic techniques including NMR and mass spectroscopy. HImBCl and the gold(I) complexes {[ImA]AuCl} and {[ImB]AuCl} were also characterized by X-ray crystallography. The cytotoxic properties of the NHC complexes have been assessed in various human cancer cell lines, including cisplatin-sensitive and -resistant cells. The silver(I) complex {[ImB]2Ag}Cl was found to be the most active, with IC50 values about 2-fold lower than those achieved with cisplatin in C13*-resistant cells. Growth-inhibitory effects evaluated in human nontransformed cells revealed a preferential cytotoxicity of {[Im B]2Ag}Cl versus neoplastic cells. Gold(I) and silver(I) carbene complexes were also evaluated for their ability to in vitro inhibit the enzyme thioredoxin reductase (TrxR). The results of this investigation showing that TrxR appeared markedly inhibited by both gold(I) and silver(I) derivatives at nanomolar concentrations clearly point out this selenoenzyme as a protein target for silver(I) in addition to gold(I) complexes.
- Pellei, Maura,Gandin, Valentina,Marinelli, Marika,Marzano, Cristina,Yousufuddin, Muhammed,Dias, H.V. Rasika,Santini, Carlo
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- Method for synthesizing amino acid imidazolium salt in aqueous solution by microwave irradiation
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The invention discloses a method for synthesizing amino acid imidazolium salt in an aqueous solution by microwave irradiation. The method comprises the following steps: taking a microwave reactor, adding amino acid, methanal, glyoxal and water to the microwave reactor, adding an acidic material to allow amino acid to be dissolved in the water, performing a stirring reaction for 1-3 h at 50-75 DEG C under the microwave irradiation, performing aftertreatment after reaction completion to obtain a target product 1, taking the target product 1 as a raw material, and then performing functionalization to obtain corresponding carboxylic ether and amide. The method synthesizes chiral functionalized N-heterocyclic carbene precursor imidazolium salt under the microwave irradiation; introduction of carboxylic acid, other functional groups and chirality is realized by taking amino acid as an amine component in a synthesis phase of imidazolium salt; the method has the advantages that raw materials are cheap and easy to obtain, a reaction condition is mild, intermediate compounds are stable and the possibility of deterioration is low.
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Paragraph 0075; 0076; 0077
(2017/08/29)
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- Amino acid-derived N-heterocyclic carbene palladium complexes for aqueous phase Suzuki-Miyaura couplings
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In this work, three ligands produced from amino acids were synthesized and used to produce five bis- and PEPPSI-type palladium-NHC complexes using a novel synthesis route from sustainable starting materials. Three of these complexes were used as precatalysts in the aqueous-phase Suzuki-Miyaura coupling of various substrates displaying high activity. TEM and mercury poisoning experiments provide evidence for Pd-nanoparticle formation stabilized in water.
- Steeples, Elliot,Kelling, Alexandra,Schilde, Uwe,Esposito, Davide
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p. 4922 - 4930
(2016/07/06)
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