查看更多>>摘要：Organometallic rhodium(I) complexes of the general type [(COD)(NHC)RhCl] (where COD = 1,5-cyclooctadiene, NHC = N-heterocyclic carbene) were prepared according to a two-step transmetalation method via a silver carbene intermediate. The procedure was supported by microwave irradiation allowing reduced reaction periods. The complexes were evaluated for cytotoxic effects in selected cancer cell lines, namely HT-29 colon adenocarcinoma, MDA-MB-231 breast carcinoma and MCF-7 breast adenocarcinoma, and generally triggered strong cytotoxic effects with IC50 values in the low micromolar range. Evaluation of structure-activity relationships clearly indicated a preference for branched isopropyl side chains at the nitrogen atoms of the NHC ligands versus non-branched ethyl side chains. Further studies on selected examples in HT-29 cells indicated that this could be the result of a higher cellular uptake. (C) 2022 Elsevier B.V. All rights reserved.
Elias, Anil J. J.Verma, AshutoshDolui, PritamHazra, Susanta...
7页
查看更多>>摘要：Herein, we report an 'on-water' methodology for the selective synthesis of bis C -H bond functionalized ferrocene derivatives under relatively mild reaction conditions. In this work, 8-aminoquinoline and picolinamide were used as selective, inexpensive, and easily removable bidentate directing groups on ferrocene and the reactions were performed exclusively in water. Reaction of ferrocene 8-aminoquinoline carboxamide with various aryl/alkyl iodides using 5 mol% of Pd(OAc)(2) and water as the solvent resulted in 61- 93% isolated yield of the cyclopentadienyl bis-arylated products. Similarly, using ferrocene-picolinamide as the substrate with aryl iodides, 55-98% yield of the cyclopentadienyl substituted ferrocene derivatives were obtained. The heterogeneity and stability of substrates, catalyst, and products under 'on-water' reaction conditions enabled us to explore the solvent, i.e., water and the catalyst's reusability. Control experiments confirm the in situ formation of palladacycles during the reaction. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this contribution, we report about the synthesis, the aggregation properties and their application in cross-coupling catalysis of two new designer surfactants comprising a rigid hydrophobic portion based on beta-sitosterol directly linked by an etheric bond to methyl polyoxoethylene chains. The proposed amphiphilic compounds represent a minimalistic approach with respect to the Lipshutz's third generation designer surfactant Nok. The amphiphiles displayed improved chemical stability, shorter synthesis, and good properties in Pd-catalyzed cross-coupling reactions in water under mild conditions, as compared with other neutral commercially available surfactants. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Ferrocene derivatives often exhibit anticancer activity. For example, our group has developed aminoferrocene-based (AF) prodrugs, which are activated in the presence of reactive oxygen species (ROS), present in large quantities in cancer cells. The activation reaction leads to formation of AF's, whose redox potential is shifted by 300-400 mV to negative values as compared to the parent AF prodrugs. Correspondingly, these drugs are very electron rich and can, therefore, act as catalysts of generation of highly toxic hydroxyl radicals (HO ?) from H2O2. That contributes to the cytotoxicity of AF prodrugs. Unfortunately, AF's are chemically very unstable. Therefore, their lifetime in cells is < 1 h that limits the anticancer activity of the AF prodrugs. In this paper we report on new 4-ferrocenylaniline-based (4-FcAn) prodrugs. These are activated in the presence of ROS thereby releasing 4-FcAn. We confirmed that 4-FcAn is more electron rich than the corresponding prodrug (delta E-1/2 = 86 mV) and can generate HO ? from H2O2 analogously to AF. Furthermore, we observed that (a) 4-ferrocenylanilines are substantially more stable ( > 6 h) than AF's and (b) the corresponding prodrugs are substantially more active than the structurally related AF prodrugs. We found that, analogously to AF prodrugs, the new prodrugs exhibit their anticancer activity via generation of ROS in cancer cells.(c) 2022 Published by Elsevier B.V.
查看更多>>摘要：In this paper, TMU-3 with the general formula [HDMA](2)[Zn-2(BDC)(3)(DMA)(2)] 6DMF as a type of metal-organic framework materials (MOFs) was employed as a support for palladium nanoparticles to preparation a reusable heterogeneous catalyst with high performance (Pd@TMU-3). The Pd@TMU-3 catalyst was synthesized through a simple impregnation procedure and ion exchange of cations HDMA(+) and Pd2+ in the TMU-3 and then was characterized by FT-IR, XRD, BET, FE-SEM, ESD-MAP, TGA, TEM, and ICP-OES. Based on the results, Pd@TMU-3 with 1.3 moll% loading of Pd exhibited excellent efficiency in the Sonogashira coupling reaction between phenylacetylene and aryl halides with both electron-donor and electron-acceptor groups, and the products were produced good to excellent yields. The heterogeneous nanocatalyst can be a promising candidate in green chemistry due to its high catalytic performance in a short reaction time, high purity of products, recoverability, facile preparation, and easy transfer, which can notably decrease the costs as well as possible pollutions. (C) 2022 Published by Elsevier B.V.
查看更多>>摘要：Four organometallic N-acylhydrazones of the general formulae [M{(eta(5)-C5H4)-CH= N -NH -C(O)-(C5H4-N)}(CO)(3)] [(with M = Re ( 5a ) or Mn ( 6a )] and [M{(eta(5)-C5H4)-C(Me)=N -NH -C(O)-(C5H4-N)}(CO)(3)] [(with M = Re ( 5b ) or Mn ( 6b )] were prepared by reaction of aldehyde/methyl ketone organometallic precursors with isoniazid (INH). All compounds were fully characterized using conventional spectroscopic techniques (FT-IR, H-1 and C-13{ H-1} NMR, mass spectrometry, and high-resolution mass spectrometry). The X-ray crystal structures of cyrhetrenyl compounds ( 5a and 5b ) are also reported. This structural analysis indicated that both compounds exhibited an E-configuration of the substituents on the-C(R-1) = N (R-1 = H or Me). The biological activity of the four analogous organometallic compounds ( 5 and 6 ) to INH and their organics counterpart {[(C6H5)-C(R)= N -NH -C(O)-(C5H4-N)] where R = H (NAH -H ) or R = Me (NAH-Me)} were evaluated on Mycobacterium tuberculosis ( M. tuberculosis ) in the standard strain H(37)Rv ATCC 27,294. The replacement of a hydrogen atom by a methyl group on the acylhydrazone moiety led to a significant increase in antitubercular properties. The compounds 5b and 6b (R-1 = Me) were at least 36-and 18-fold more effective than 5a and 6a (R-1 = H ) , respectively. The cyrhetrenyl derivative ( 5b ) was the most active complex against M. tuberculosis . This compound was shown to be about 2-times more effective than its organic analog (NAH-Me) and showed activity comparable to antitubercular drug INH. In vitro toxicity assays against murine macrophage cells J774A.1 (ATCC TIB-67) were also conducted, and selectivity indexes were determined for the most promising compounds. All N-acylhydrazones showed a moderated cytotoxic profile, similar to the isoniazid and rifampicin (RIF) control drugs, while 5b exhibited better selectivity index (SI) concerning the organic counterpart NAH-Me. Based on the anti-TB activity, cytotoxicity, and selectivity index, compound 5b has more potential for evolution as a new antitubercular agent. (c) 2022 Published by Elsevier B.V.
查看更多>>摘要：We developed a new method to isolate a natural pigment of mesobiliverdin IX alpha (MBV) directly from phycocyanin of Thermoleptolyngbya sp. O-77 and synthesized a water-soluble Cp *Ir complex with the isolated MBV ligand. To obtain a high yield of MBV, we modified the conventional method by adding additional two steps: the protease digestion of phycocyanin by trypsin and the isolation of MBV by hydrophobic and silica gel column chromatographies. The Cp *Ir complex with MBV ligand was characterized by electrospray ionization-mass spectrometry, ultraviolet-visible-near-infrared absorption spectroscopy, Xray photoelectron spectroscopy, 1 H NMR spectroscopy, and H-H correlation spectroscopy. This is the first example of a platinum-group metal complex with MBV as a ligand. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：A B S T R A C T One of the main challenges of modern chemical industry is the inevitable transition to greener, more sustainable manufacturing processes that utilize raw materials more effectively, minimize waste streams, and avoid the use of toxic and hazardous materials. The development of new iron-based catalytic systems can eliminate the need for the currently widely used, costly and potentially toxic heavy metal catalysts in industrially relevant chemical reactions. Prominent examples of such processes include transition metal catalyzed cross-coupling reactions for formation of carbon-carbon (C -C) bonds. This minireview outlines recent developments in the area of iron-catalyzed cross-coupling chemistry during the last couple of decades, with special emphasis on the use of propargylic substrates and Grignard reagents as coupling partners. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )
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