Search results for "Medicinal"

Strong Influence of the Ancillary Ligand over the Photodynamic Anticancer Properties of Neutral Biscyclometalated IrIII Complexes Bearing 2-Benzoazol…

2018

In this paper, the synthesis, comprehensive characterization and biological and photocatalytic properties of two series of neutral IrIII biscyclometalated complexes of general formula [Ir(C^N)2(N^O)], where the N^O ligands are 2‐(benzimidazolyl)phenolate‐N,O (L1, series a) and 2‐(benzothiazolyl)phenolate‐N,O (L2, series b), and the C^N ligands are 2‐(phenyl)pyridinate or its derivatives, are described,. Complexes of types a and b exhibit dissimilar photophysical and biological properties. In vitro cytotoxicity tests conclusively prove that derivatives of series a are harmless in the dark against SW480 cancer cells (colon adenocarcinoma), but express enhanced cytotoxicity versus the same cel…

Synthesis, reactivity and structural studies of selenide bridged carboranyl compounds.

2006

Reaction of the lithium salt Li[1-R-1,2-closo-C(2)B(10)H(10)] with selenium under mild conditions, followed by hydrolysis gave the diselenide compound (1-Se-2-R-1,2-closo-C(2)B(10)H(10))(2) in contrast to the well-reported mercapto compounds 1-SH-2-R-1,2-closo-C(2)B(10)H(10) obtained using a similar synthetic procedure. Details for the preparation and X-ray structural characterisation of the new compounds (2-Me-1,2-closo-C(2)B(10)H(10))(2)Se, (1-Se-2-R-1,2-closo-C(2)B(10)H(10))(2) (R = Me, Ph, ) are specified. To further explore the mechanism of the dimerization reaction, the complex [Au(1-Se-2-Me-1,2-closo-C(2)B(10)H(10))(PPh(3))] was synthesized, confirming the existence of the intermedia…

A P-chirogenic β-aminophosphine synthesis by diastereoselective reaction of the α-metallated PAMP–borane complex with benzaldimine

2004

International audience; The diastereoselective synthesis of a P-chirogenic β-aminophosphine ligand with carbon–carbon bond formation of the ethano bridge in a 3:1 ratio via reaction of an α-metallated P-chirogenic phosphine borane with a benzaldimine is described. The diastereoselectivity is attributed to a transition state where the lithium cation chelates the phosphine borane carbanion and the nitrogen of the imine and the attack of the C@N occurs on the face opposite to the P–B bond, due to its interaction with the antibonding P–B bond. The major diastereoisomeric β-aminophosphine borane was then separated and decomplexed into the corresponding β-aminophosphine under neutral conditions a…

Palladium Catalyzed [3+2] Cycloaddition of Vinyl Aziridine and Indane-1,3-diones: Diastereo- and Enantioselective Access to Spiro-Pyrrolidines

2020

A mild and efficient palladium-catalyzed [3+2] cycloaddition of vinylaziridine and indane-1,3-diones has been realized. The resulting spiro-pyrrolidines were provided in excellent yields and, with the introduction of the leucine-derived phosphine ligand, moderate to good enantio­- and diastereoselectivities.

PdII-mediated integration of isocyanides and azide ions might proceed via formal 1,3-dipolar cycloaddition between RNC ligands and uncomplexed azide

2016

Reaction between equimolar amounts of trans-[PdCl(PPh3)2(CNR)][BF4] (R = t-Bu 1, Xyl 2) and diisopropylammonium azide 3 gives the tetrazolate trans-[PdCl(PPh3)2(N4t-Bu)] (67%, 4) or trans-[PdCl(PPh3)2(N4Xyl)] (72%, 5) complexes. 4 and 5 were characterized by elemental analyses (C, H, N), HRESI+-MS, 1H and 13C{1H} NMR spectroscopies. In addition, the structure of 4 was elucidated by a single-crystal X-ray diffraction. DFT calculations showed that the mechanism for the formal cycloaddition (CA) of N3− to trans-[PdCl(PH3)2(CNMe)]+ is stepwise. The process is both kinetically and thermodynamically favorable and occurs via the formation of an acyclic NNNCN-intermediate. The second step of the fo…

Triazole vs. triazolium carbene ligands in the site-selective cyclometallation of o-carboranes by M(iii) (M = Ir, Rh) complexes

2018

Ir(iii) and Rh(iii)-mediated site-selective cage B-H and C-H bond activation in o-carboranylmethyl derivatives has been achieved. The selectivity of the reaction is related to the electron donating properties of the ligand. 1,2,3-Triazole-derivatives use the N2 position of the triazole ring to direct the selective o-carborane B-H bond activation, whereas the corresponding triazolylidene derivatives lead to the cage C-H bond activation with complete site-selectivity.

Deprotonation of Benzoxazole and Oxazole Using Lithium Magnesates

2005

International audience; The first deprotonations of oxazole and benzoxazole using lithium magnesates are described. The reactions occurred in tetrahydrofuran at room temperature using 1/3 equiv of lithium tributylmagnesate. As 2-lithiooxazole and 2-lithiobenzoxazole, lithium tri(2-oxazolyl)magnesate and lithium tri(2-benzoxazolyl)magnesate very rapidly and completely isomerized to the more stable 2-(isocyano)enolate and 2-(isocyano)phenolate type structures, respectively, a result shown by NMR analysis. The isolation of 2-substituted oxazoles and benzoxazoles in medium to good yields after electrophilic trapping was interpreted in two ways:  (1) the equilibration between the open and closed…

A Selenium-Nitrogen Chain with Selenium in Different Oxidation States

2017

Alkali Blues: Blue‐Emissive Alkali Metal Pyrrolates

2019

2-Iminopyrroles [HtBu L, 4-tert-butyl phenyl(pyrrol-2-ylmethylene)amine] are non-fluorescent π systems. However, they display blue fluorescence after deprotonation with alkali metal bases in the solid state and in solution at room temperature. In the solid state, the alkali metal 2-imino pyrrolates, M(tBu L), aggregate to dimers, [M(tBu L)(NCR)]2 (M=Li, R=CH3 , CH(CH3 )CNH2 ), or polymers, [M(tBu L)]n (M=Na, K). In solution (solv=CH3 CN, DMSO, THF, and toluene), solvated, uncharged monomeric species M(tBu L)(solv)m with N,N'-chelated alkali metal ions are present. Due to the electron-rich pyrrolate and the electron-poor arylimino moiety, the M(tBu L) chromophore possesses a low-energy intra…

Synthesis, crystal structure, DFT and biological activity of E-pyrene-1-carbaldehyde oxime and E-2-naphthaldehyde oxime

2020

Abstract The aldoximes E-pyrene-1-carbaldehyde oxime 1 and E-2-naphthaldehyde oxime 2 were synthesized, in ca. 90% yield, by treatment of pyrene-1-carbaldehyde or 2-naphthaldehyde, respectively, with hydroxylamine hydrochloride and sodium carbonate in MeOH. Compounds 1 and 2 were characterized by IR, 1H and 13C{1H} NMR spectroscopies, elemental analyses and single crystal X-ray diffraction (in the case of 1). The studied system (compound 1) showed significant amounts of H⋯H (44.4%), C⋯H (25.4%) and C⋯C (13.3%) intermolecular interactions in addition to the short N⋯H (5.9%) and O⋯H (6.2%) intermolecular interactions. These interactions affect the molecular packing of the studied system in th…