T:Toxic;
105-39-5Relevant articles and documents
Enhanced Electrophilicity of Heterobimetallic Bi-Rh Paddlewheel Carbene Complexes: A Combined Experimental, Spectroscopic, and Computational Study
Collins, Lee R.,Van Gastel, Maurice,Neese, Frank,Fürstner, Alois
, p. 13042 - 13055 (2018)
Dirhodium paddlewheel complexes are indispensable tools in modern organometallic catalysis for the controlled decomposition of diazo-compounds. Tuning the reactivity of the thus-formed transient carbenes remains an active and dynamic field of research. Herein, we present our findings that the distal metal center plays an as yet underappreciated role in modulating this reactivity. Replacement of one rhodium atom in the bimetallic core for bismuth results in the formation of a significantly more electrophilic carbene complex. Bismuth-rhodium catalysts thereby facilitate previously unknown modes of reactivity for α-diazoester compounds, including the cyclopropanation of alkenes as electron deficient as trichloroethylene. While dirhodium paddlewheel complexes remain the catalysts of choice for many carbene-mediated transformations, their bismuth-rhodium analogues exhibit complementary reactivity and show great potential for small molecule and solvent activation chemistry. DFT calculations highlight the importance of metal-metal bonding interactions in controlling carbene electrophilicity. The paucity of these interactions between the 4d orbitals of rhodium and the 6p orbitals of bismuth results in weaker π-back-bonding interactions for bismuth-rhodium carbene complexes compared to dirhodium carbene complexes. This leads to weakening of the rhodium-carbene bond and to a more carbene-centered LUMO, accounting for the observed enhancement in bismuth-rhodium carbene electrophilicity. These findings are supported by a detailed spectroscopic study of the "donor-donor" carbene complexes Rh2(esp)2C(p-MeOPh)2 (19) and BiRh(esp)2C(p-MeOPh)2 (20), employing a combination of UV-vis and resonance Raman spectroscopy. The results reveal that carbene chemoselectivity in MRh(L)4 catalysis can be modulated to a previously unrecognized extent by the distal metalloligand.
Discovery of novel triazolophthalazine derivatives as DNA intercalators and topoisomerase II inhibitors
Sakr, Helmy,Ayyad, Rezk R.,El-Helby, Ali A.,Khalifa, Mohamed M.,Mahdy, Hazem A.
, (2021)
A new series of triazolophthalazine derivatives was designed and synthesized as topoisomerase II (Topo II) inhibitors and DNA intercalators. The synthesized derivatives were evaluated in vitro for their cytotoxic activities against three human cancer cell lines: HepG2, MCF-7, and HCT-116 cells. Compound IXb was the most potent counterpart with IC50 values of 5.39 ± 0.4, 3.81 ± 0.2, and 4.38 ± 0.3 μM, as it was about 1.47, 1.77, and 1.19 times more active than doxorubicin (IC50 = 7.94 ± 0.6, 6.75 ± 0.4, and 5.23 ± 0.3 μM) against HepG2, MCF-7, and HCT-116 cells, respectively. Additionally, the binding affinity of the synthesized compounds toward the DNA molecule was assessed using the DNA/methyl green assay. Compound?IXb showed an excellent DNA binding affinity with an IC50 value of 27.16 ± 1.2 μM, which was better than that of the reference drug doxorubicin (IC50 = 31.02 ± 1.80 μM). Moreover, compound IXb was the most potent member among the tested compounds when investigated for their Topo II inhibitory activity. Furthermore, compound IXb induced apoptosis in HepG2 cells and arrested the cell cycle at the G2/M phase. Additionally, compound IXb showed Topo II poisoning effects at 2.5 μM and Topo II catalytic inhibitory effects at 5 and 10 μM. Finally, molecular docking studies were carried out against the DNA–Topo II complex and DNA, to investigate the binding patterns of the designed compounds.
An efficient chemoenzymatic synthesis of the bactericide lapyrium chloride
Rustoy, Eduardo M.,Baldessari, Alicia
, p. 4628 - 4632 (2005)
An efficient route for large-scale preparation of lapyrium chloride, a broad-spectrum antimicrobial surfactant, was developed from chloroacetic acid in four steps, three of them enzymatic. Due to the chemoselective behavior of the biocatalysts, lapyrium chloride was obtained in a high degree of purity and yield, from mild reaction conditions and following a low environmental impact methodology. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
Using remote substituents to control solution structure and anion binding in lanthanide complexes
Tropiano, Manuel,Blackburn, Octavia A.,Tilney, James A.,Hill, Leila R.,Placidi, Matteo P.,Aarons, Rebecca J.,Sykes, Daniel,Jones, Michael W.,Kenwright, Alan M.,Snaith, John S.,Sorensen, Thomas Just,Faulkner, Stephen
, p. 16566 - 16571 (2013)
A study of the anion-binding properties of three structurally related lanthanide complexes, which all contain chemically identical anion-binding motifs, has revealed dramatic differences in their anion affinity. These arise as a consequence of changes in the substitution pattern on the periphery of the molecule, at a substantial distance from the binding pocket. Herein, we explore these remote substituent effects and explain the observed behaviour through discussion of the way in which remote substituents can influence and control the global structure of a molecule through their demands upon conformational space. Peripheral modifications to a binuclear lanthanide motif derived from α,α′-bis(DO3 Ayl)-m-xylene are shown to result in dramatic changes to the binding constant for isophthalate. In this system, the parent compound displays considerable conformational flexibility, yet can be assumed to bind to isophthalate through a well-defined conformer. Addition of steric bulk remote from the binding site restricts conformational mobility, giving rise to an increase in binding constant on entropic grounds as long as the ideal binding conformation is not excluded from the available range of conformers.
REDUCTIVE DEHALOGENATION OF α-HALOGENATED CARBONYL AND CYANO COMPOUNDS WITH THE HEXAMETHYLDISILANE/TETRAKIS(TRIPHENYLPHOSPHINE)PALLADIUM SYSTEM
Urata, Hisao,Suzuki, Hiroharu,Moro-Oka, Yoshihiko,Ikawa, Tsuneo
, p. 367 - 374 (1982)
Treatment of α-halogenated carbonyl or cyano compounds with hexamethyldisilane in the presence of catalytic amounts of tetrakis(triphenylphosphine)-palladium gives the corresponding parent carbonyl or cyano compounds in excellent yields via oxy-?-allyl(trimethylsilyl)palladium intermediates.
Inhibition of acetylcholinesterase by coumarin-linked amino acids synthetized via triazole associated with molecule partition coefficient
De Sousa, Bianca L.,Leite, Jo?o P.V.,Mendes, Tiago A.O.,Varej?o, Eduardo V.V.,Chaves, Anna C.S.,da Silva, Júnio G.,Agrizzi, Ana P.,Ferreira, Priscila G.,Pilau, Eduardo J.,Silva, Evandro,dos Santos, Marcelo H.
, p. 652 - 664 (2021/02/16)
A previous study for the identification of acetylcholinesterase (AChE) inhibitors demonstrated that the hybrid between tyrosol, the 1,2,3-triazole nucleus, and the coumarin group, namely 7-({1-[2-(4-hydroxyphenyl)ethyl]-1H-1,2,3-triazol-4-yl}methoxy)-4-methyl-2H-chromen-2-one (10), has a high enzyme inhibitory activity. Here, we synthesized analogues of 10 via triazole with pharmacophoric groups represented by tyrosine, phenylalanine, tryptophan, and glycine in addition to evaluating the impact of coumarin-linked amino acids on AChE inhibition. We obtained eight triazoles, six of which are undescribed. In general, the presence of carboxylic acid decreased the inhibitory activity, while aromatic amino acids increased enzymatic inhibition compared to glycine. The derivative containing tyrosine, structurally most similar to 10, presented the lowest inhibition percentage, indicating that phenolic hydroxyl is not the preponderant factor for inhibition. Molecular docking was not enough to explain in vitro experiments. On the other hand, MlogP (logP calculated by the Moriguchi method) was related positively to enzymatic inhibition. To increase the hydrophobicity of the molecules, we tested the esterified triazole derivatives comparatively with the enzyme. The compound ethyl 2-(4-(((4-methyl-2-oxo-2H-chromen-7-yl)oxy)methyl)- 1H-1,2,3-triazol-1-yl)acetate (6) presented an increment of inhibitory activity of 46.97 ± 1.75% at 100 μmol L-1. We also associated the best activity with the lowest van der Waals volume and molar mass values.
Synthesis, in silico Study and Antimicrobial Evaluation of New Diesters Derived from Phthaloylglycine
Alves, Francinara S.,Barbosa-Filho, José M.,Cordeiro, Laísa V.,Huang, Min-Fu N.,Lima, Edeltrudes O.,Neto, Hermes Diniz,Souza, Helivaldo D. S.,Trindade, Emmely O.,de Athayde-Filho, Petr?nio F.,de Lima, Priscila S. V.,de Oliveira, Rafael F.,de Sousa, Abra?o P.
, p. 953 - 962 (2020/10/14)
New diesters derived from phthaloylglycine (7a-7i) were synthesized and their structures characterized by infrared, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The compounds were evaluated in an in silico study, which demonstrated positive features indicating a possible drug candidate. The diesters showed antifungal activity ranging from moderate to strong against strains of Candida. Compounds 7a, 7b, 7c, 7e and 7i had a moderate minimum inhibitory concentration (MIC) of 1024 μg mL?1 against all fungal strains, while 7h showed a very good MIC of 256 μg mL?1 against Candida albicans, Candida parapsilosis and Candida krusei and 64 μg mL?1 against Candida tropicalis. However, only 7h and 7i were able to inhibit bacterial growth of strains of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli with an MIC of 1024 μg mL?1
