Thiosemicarbazone modification of 3-acetyl coumarin inhibits Aβ peptide aggregation and protect against Aβ-induced cytotoxicity.

Aggregation of amyloid β peptide (Aβ) is an important event in the progression of Alzheimer's disease. Therefore, among the available therapeutic approaches to fight with disease, inhibition of Aβ aggregation is widely studied and one of the promising approach for the development of treatments for Alzheimer's disease. Thiosemicarbazone compounds are known for their variety of biological activities.

Antitumor activity of a rhenium (I)-diselenoether complex in experimental models of human breast cancer.

Rhenium (I)-diselenother (Re-diselenoether) is a water soluble metal-based compound, combining one atom of rhenium and two atoms of selenium. This compound has been reported to exhibit marked activities against several solid tumor cell lines. We now disclose an improved synthesis of this complex.

Determination of the absolute configuration of phosphinic analogues of glutamate.

A series of phosphinic glutamate derivatives (e.g.LSP1-2111) have been proven to be potent agonists of metabotropic glutamate (mGlu) receptors and shown promising in vivo activity.

Uptake and efflux of rhenium in cells exposed to rhenium diseleno-ether and tissue distribution of rhenium and selenium after rhenium diseleno-ether treatment in mice.

Unlabelled: We proposed a new water-soluble rhenium diseleno-ether compound (with one atom of Re and two atoms of Se) and investigated the uptake of Re into the nucleus of malignant cells in culture exposed to the compound for 48 h and its efflux from the nucleus after a post-exposure period of 48 h, as DNA is the main target of Re. We also studied the distribution of both Re and Se in the main organs after an oral administration of 10 or 40 mg/kg Re diseleno-ether to mice for four weeks, five days-a-week.

Materials And Methods: Re and Se concentrations were assayed by inductively coupled plasma mass spectrometry (ICP-MS).

Influence of the diamine on the reactivity of thiosulfonato ruthenium complexes with hydrosulfide (HS-).

We have recently reported that cationic thiosulfonato ruthenium complexes [(p-cymene)Ru(bipy)(SSO(2)Ar)](+) (bipy: 2-2'-bipyridine, Ar: phenyl or p-tolyl) react with thiolates (RS(-), R = alkyl or aryl) by cleavage of the S-SO(2) bond and formation of a new S-S bond. In this work, we report that the outcome of the reaction is different if the hydrosulfide anion (R = H) is used, the product obtained being the hydrogen(sulfido) derivative [(p-cymene)Ru(bipy)(SH)](+). The bipy ligand is crucial in this result, and its replacement by ethylenediamine leads to a different product, the trisulfido-bridged dinuclear complex [[(p-cymene)Ru(en)(S)](2)S](2+).

Synthesis of a Fe(II)SH complex stabilized by an intramolecular N-H···S hydrogen bond, which acts as a H2S donor.

Through use of the reversible protonation of an iron(II) complex containing a deprotonated carboxamido moiety, we prepared and fully characterized the first hydrogen(sulfido)iron(II) complex stabilized by an intramolecular hydrogen bond, which acts as a H(2)S donor in solution.

Characterization of cobalt(III) hydroxamic acid complexes based on a tris(2-pyridylmethyl)amine scaffold: reactivity toward cysteine methyl ester.

Six Co(III) complexes based on unsubstituted or substituted TPA ligands (where TPA is tris(2-pyridylmethyl)amine) and acetohydroxamic acid (A), N-methyl-acetohydroxamic acid (B), or N-hydroxy-pyridinone (C) were prepared and characterized by mass spectrometry, elemental analysis, and electrochemistry: [Co(III)(TPA)(A-2H)](Cl) (1a), [Co(III)((4-Cl(2))TPA)(A-2H)](Cl) (2a), [Co(III)((6-Piva)TPA)(A-2H)](Cl) (3a), [Co(III)((4-Piva)TPA)(A-2H)](Cl) (4a) and [Co(III)(TPA)(B-H)](Cl)(2) (1b), and [Co(III)(TPA)(C-H)](Cl)(2) (1c). Complexes 1a-c and 3a were analyzed by (1)H NMR, using 2D ((1)H, (1)H) COSY and 2D ((1)H, (13)C) HMBC and HSQC, and shown to exist as a mixture of two geometric isomers based on whether the hydroxamic oxygen was trans to a pyridine nitrogen or to the tertiary amine nitrogen. Complex 3a exists as a single isomer that was crystallized.

Combination of three metals for the treatment of cancer: gallium, rhenium and platinum. 1. Determination of the optimal schedule of treatment.

Platinum is well known for its anticancer activity, firstly used as cis-diaminedichloroplatinum (II) (CDDP), with a wide range of activity. Its main mechanism of action involves its binding to DNA. Gallium, another metal, has also demonstrated apoptotic effects on malignant cells, but through interaction with targets other than DNA, such as the membrane, cytoskeleton and proteasome, and on enzyme activities.

Hydroxamic acids as potent inhibitors of Fe(II) and Mn(II) E. coli methionine aminopeptidase: biological activities and X-ray structures of oxazole hydroxamate-EcMetAP-Mn complexes.

New series of acids and hydroxamic acids linked to five-membered heterocycles including furan, oxazole, 1,2,4- or 1,3,4-oxadiazole, and imidazole were synthesized and tested as inhibitors against the Fe(II) , Co(II) , and Mn(II) forms of E. coli methionine aminopeptidase (MetAP) and as antibacterial agents against wild-type and acrAB E. coli strains.

Synthesis and biological activity of mouse hepcidin peptide analogs containing three disulfide bridges: manual and microwave-assisted solid-phase peptide synthesis.

Hepcidin, a 25 amino acid peptide hormone containing a complex network of four disulfide bonds is the hormone regulator of iron homeostasis. Three bridges synthetic peptide analogs have been prepared following two synthetic strategies and two oxidation procedures: i) a microwave-assisted solid phase synthesis followed by air oxidation of the six free cysteines ii) a manual solid phase synthesis followed by stepwise deprotection and oxidation of cysteine pairs. All the peptides with different connectivities have been characterized by MALDI ToF spectrometry, and tested for their ability to degrade the cellular iron exporter, ferroportin.

An alternate route to disulfanido complexes by nucleophilic attack of thiolates on ruthenium-bound thiosulfonato ligands.

The reaction of the thiosulfonato complexes [(p-cym)Ru(bipy)(S-SO(2)R)](+) (R = Ph, p-Tol) with the thiolates R'S(-) (R' = alkyl or aryl) leads to S-S bond cleavage and to the quantitative formation of the corresponding disulfanido derivatives [(p-cym)Ru(bipy)(S-SR')](+). The aryldisulfanido complexes also react with benzyl thiolate by S-S bond cleavage to give [(p-cym)Ru(bipy)(SSCH(2)Ph)](+).

Reductive metalation of cyclic and acyclic pseudopeptidic bis-disulfides and back conversion of the resulting diamidato/dithiolato complexes to bis-disulfides.

Cyclic and acyclic pseudopeptidic bis-disulfides built on an o-phenylene diamine scaffold were prepared: (N(2)H(2)S(2))(2), 1a, N(2)H(2)(S-SCH(3))(2), 1b, and N(2)H(2)(S-StBu)(2), 1c. Reductive metalation of these disulfides with (PF(6))[Cu(CH(3)CN)(4)] in the presence of Et(4)NOH as a base, or with (Et(4)N)[Fe(SEt)(4)] and Et(4)NCl, yields the corresponding diamidato/dithiolato copper(III) or iron(III) complex, (Et(4)N)[Cu(N(2)S(2))], 2, or (Et(4)N)(2)[Fe(N(2)S(2))Cl], 5. These complexes display characteristics similar to those previously described in the literature.

New fluorescent zinc complexes: towards specific sensors for hydrogen sulfide in solution.

Two new fluorescent zinc complexes 1 and 2 have been synthesized by reaction of the complex Tp(Ph,Me)Zn(OH) with 7-hydroxy-4-methylcoumarin (MUH) or 7-mercapto-4-methylcoumarin (MUSH). While the alcoholato derivative Tp(Ph,Me)Zn(MU) 1 is not efficient for sensing hydrogen sulfide, the thiolato complex Tp(Ph,Me)Zn(MUS) 2 is a colorimetric "turn-on" and fluorescence "turn-off" sensor which shows high selectivity for hydrogen sulfide in the presence of additional thiols like cysteine or glutathione.

Bis(2,2'-bipyridyl-κN,N')bis-(2-hydroxy-benzoato)-κO;κO,O-cadmium(II) methanol solvate.

The title compound, [Cd(C(7)H(5)O(3))(2)(C(10)H(8)N(2))(2)]·CH(3)OH, contains one monomeric seven-coordinate cadmium complex and one methanol solvate mol-ecule. The Cd(II) atom is coordinated to two 2,2'-bipyridyl ligands via the N atoms and to two salicylate anions (Hsal(-)) via the carboxyl-ate O atoms, which act as monodentate ligand for the one and bidentate ligand for the second. The Cd(II) atom exhibits a {6 + 1} environment, approximately described as a distorted capped octa-hedron with the apical positions occupied by one of the two N atoms belonging to one bipyridyl ligand and one of the two carboxyl-ate O atoms from the monodentate Hsal(-) ligand.

Synthesis, structural analysis and anticonvulsant activity of a ternary Cu(II) mononuclear complex containing 1,10-phenanthroline and the leading antiepileptic drug valproic acid.

The synthesis and characterization of the binary complex of copper(II) with the antiepileptic drug valproic acid sodium salt (Valp) and the related ternary complex with 1,10-phenanthroline (phen) are reported, as well as the anticonvulsant properties of the latter. The characterization was carried out by means of elemental analyses, infrared (IR), UV-visible (UV-vis) spectrophotometry and Electron Paramagnetic Resonance (EPR). The X-ray crystal structure of the mononuclear complex bis(2-propylpentanoate)(1,10-phenanthroline)copper(II) [Cu(Valp)(2)phen] is showed for the first time.

Synthesis, characterization, and reactivity of alkyldisulfanido zinc complexes.

The alkyldisulfanido zinc complexes Tp(iPr,iPr)Zn(SSR) and Tp(Ph,Me)Zn(SSR) where Tp(iPr,iPr) is hydridotris-((3,5-isopropyl)pyrazolyl)borate, Tp(Ph,Me) is hydridotris-((3-phenyl,5-methyl)pyrazolyl)borate, and (SSR) is tert-butyldisulfanido or triphenylmethanedisulfanido were synthesized by reaction between the corresponding hydroxo complexes TpZn(OH) and the synthetic persulfide RSSH. All the complexes were characterized by elemental analysis and (1)H NMR spectroscopy, and representative members of the class were also structurally characterized. The reactivity of the alkyldisulfanido TpZn(SSR) complexes with thiols was studied.

Synthesis and characterization of mononuclear hydroxamato and hydroximato complexes of iron(III) based on the tris-(2-pyridylmethyl)amine ligand.

The reaction of acetohydroxamic (CH3C(O)-NHOH), benzhydroxamic acid (PhC(O)-NHOH) or 1-hydroxypyridin-2(1H)-one (pyrC(O)-NOH) in the presence of tris-(2-pyridylmethyl)amine (TPA), sodium methoxide and an iron(III) salt yields the mononuclear complexes [Fe(TPA)(CH3C(O)-NHO)]2+ (), [Fe(TPA)(PhC(O)-NHO)]2+ () and [Fe(TPA)(pyrC(O)-NO)]2+ (). The hydroxamato complexes and are easily converted to their hydroximato form [Fe(TPA)(CH3C(O)=NO)]+ () and [Fe(TPA)(PhC(O)=NO)]+ () by addition of base. The complexes described were characterized by UV-vis spectroscopy, EPR and cyclic voltammetry, as well as single-crystal X-ray crystallography for and .

Metalation of cyclic pseudopeptidic thiosulfinates with Ni(II) and Zn(II) after ring opening: a mechanistic investigation.

Thiosulfinates are an emerging class of oxidized sulfur species that are frequently supposed to be involved in biochemical processes. Reaction of 12- and 10-membered ring pseudopeptidic thiosulfinates 1a (4,4,7,7-tetramethyl-1,3,4,7,8,10-hexahydro-5,6,1,10-benzodithiadiazacyclododecine-2,9-dione 5-oxide) and 1b (3,3,6,6-tetramethyl-1,8-dihydro-4,5,1,8-benzodithiadiazecine-2,7(3H,6H)-dione 4-oxide) with a Ni(II) salt leads after ring cleavage under alkaline conditions to the isolation of diamidato/thiolato/sulfinato complexes. These two thiolato/sulfinato complexes of nickel, which can also be prepared by dioxygen oxidation of the parent diamidato/dithiolato complexes, were characterized by X-ray crystallography.

Biomimetic zinc funnel complexes based on calix[6]N3ArO ligands: an acid-base switch for guest binding.

The coordination chemistry of Zn in an N(3)ArOH environment has been explored. The ligands are based on calix[6]arenes that present two imidazole arms and an amino phenol moiety at the narrow rim. Three different types of complexes have been characterized.

Calix[6]tren and copper(II): a third generation of funnel complexes on the way to redox calix-zymes.

Mono-copper enzymes play an important role in biology and their functionality is based on Cu(II)/Cu(I) redox processes. Modeling a mono-nuclear site remains a challenge for a better understanding of its intrinsic reactivity. The first member of a third generation of calixarene-based mono-copper "funnel" complexes is described.

Synthesis, crystal structures, and anti-convulsant activities of ternary [Zn(II)(3,5-diisopropylsalicylate)(2)], [Zn(II)(salicylate)(2)] and [Zn(II)(aspirinate)(2)] complexes.

Following observations that bis(3,5-diisopropylsalicylato)diaquazinc(II), [Zn(II)(3,5-DIPS)(2)(H(2)O)(2)], had anti-convulsant activity, bis(acetylsalicylate)diaquazinc(II), [Zn(II)(aspirinate)(2)(H(2)O)(2)], and the Zn(II) ternary 1,10-phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (neocuproine, NC) or dimethyl sulfoxide (DMSO) complexes of Zn(II)3,5-diisopropylsalicylate, salicylate, and acetylsalicylate were synthesized and spectroscopically characterized. Anti-convulsant and Rotorod toxicity activities of these complexes were determined to examine their anti-convulsant and undesirable central nervous stimulant or depressant activities of these Zn(II) non-steroidal anti-inflammatory agent complexes. Bis(3,5-diisopropylsalicylato)-1,10-phenanthorlinezinc(II), [Zn(II)(3,5-DIPS)(2)(phen)], (1) has one bidentate phen ligand and two mono-deprotonated 3,5-DIPS ligands.

Interactions of a new alpha-aminophosphinic derivative inside the active site of TLN (thermolysin): a model for zinc-metalloendopeptidase inhibition.

A new alpha-aminophosphinic compound able to inhibit both zinc-containing exopeptidases and endopeptidases has been crystallized with TLN as a model in order to investigate the mode of zinc recognition by the phosphinic moiety and to evaluate the potential role of the free alpha-amino group in the formation of enzyme-inhibitor complexes. In addition to the main interactions between the backbone of the inhibitor and the enzyme active site, it is observed that the phosphinic group acts as a distorted bidentate ligand for the zinc ion, while the free alpha-amino function does not directly participate in interactions within the active site. Association of the present data and the K(i) values of various analogues of the inhibitor towards TLN and neprilysin suggests differences in the hydrophobicity of the S(1)-S(2) domains of the enzymes.

The 2.2 A resolution structure of thermolysin (TLN) crystallized in the presence of potassium thiocyanate.

A new crystallization protocol for thermolysin (EC 3.4.24.

N-[2-(Indan-1-yl)-3-mercapto-propionyl] amino acids as highly potent inhibitors of the three vasopeptidases (NEP, ACE, ECE): In vitro and In vivo activities.

We have previously reported the design of a lead compound 1a for the joint inhibition of neprilysin (NEP, EC 3.4.24.

Synthesis, crystal structure, EPR properties, and anti-convulsant activities of binuclear and mononuclear 1,10-phenanthroline and salicylate ternary copper(II) complexes.

Two ternary Cu(II) complexes of 1,10-phenanthroline (phen) and singly (Hsal(-)) or dideprotonated (sal(2-)) salicylate ligands were synthesized, their X-ray crystal structure and electron paramagnetic resonance spectral characteristics determined, and evaluated for anti-convulsant activities in the maximal electroshock (MES) and Metrazol models of seizure and Rotorod toxicity. The X-ray crystal structure of [bis(1,10-phenanthroline)-mu-bis(salicylato-O,O')dicopper(II)] dihydrate, 1, ([Cu(II)(2)(phen)(2)(sal)(2)].2[H(2)O]), shows it to be binuclear.