High nuclearity manganese(III) compounds containing phenol-pyrazole ligands: the influence of the ligand on the core geometry

Three high-nuclearity manganese(III) clusters have been synthesized and characterized: [Mn?(μ?-O)?(phpzH)?(thf)?] (1), [Mn?(μ?-O)?(phpzH)?(EtOH)?]·2EtOH (2), and [Mn?(μ?-O)?(μ?-Br)?(HphpzEt)?(phpzEt)] (3). Compounds 1 and 2 contain a [Mn?(μ?-O?)(phpzH)?] core in which antiferromagnetic interactions between the manganese(III) ions are found. Compound 3 is a hexanuclear manganese(III) cluster in which weak ferromagnetic interactions appear to be operative. The formation and the stability of the cluster cores in relation to the type of phenol-pyrazole ligand and the reaction conditions are discussed.     

Novel 3‐benzoyl‐2‐piperazinylquinoxaline derivatives as potential antitumor agents

A series of new benzoylquinoxaline derivatives ( 7‐26 ) was synthesized and evaluated for antitumor activity against a panel of 60 human cell lines at the NCI of Bethesda. Among the compounds which have passed the preliminary screening, compound 23 exhibited the best profile and growth inhibition activity at 100 ‐ 10 μM. The compounds were then tested towards a folate‐dependent enzymes bio‐library including Thymidylate synthases enzymes and human Dihydrofolate reductase at 10 μM. The most of compounds exhibited a moderate inhibitory activity towards all or some of the enzymes tested with detectable inhibition constants (K_i) values in the range of 0.6‐70 μM. Compounds 21, 23, 24 showed K_i in the range of 10‐38 μM against both hDHFR and hTS.     

Amination of CF3-enones with nosyloxycarbamates

CF3-enones showed a different reactivity in amination reactions with nosyloxycarbamates. 4-Oxazolines or vinyl carbamates were obtained as unique products depending on the nature of double-bond substituents and on the choice of carbamates and bases. Starting from trans-trifluoroacetyl olefins carrying a heterocyclic residue or the p-methoxyphenyl group on the double bond, a rare loss of CF3CO was observed when the aminations were performed under heterogeneous conditions using CaO as the base.     

Stability of the equilibrium state of the equation system of a viscous barotropic gas in the model of atmosphere

Abstract We consider the system of equations of viscous gas motion whose pressure is related to the density by the law with 1<γ <2, in a domain defined by two levels of geopotential. Under the force due to geopotential and the Coriolis force, we prove the stability of the equilibrium state in a suitable Sobolev space. Keywords: Viscous barotropic gas, Equilibrium state, Coriolis force Mathematics Subject Classification (2000): 35Q35, 76N15     

Essential oils of Daucus carota subsp. carota of Tunisia obtained by supercritical carbon dioxide extraction

The essential oils and supercritical CO2 extracts of wild Daucus carota L. subsp. carota from two different sites in Tunisia were investigated. The main components of the essential oil of the flowering and mature umbels with seeds from Sejnane were eudesm-7(11)-en-4-ol (8.2 - 8.5%), carotol (3.5 - 5.2%), sabinene (12.0 -14.5%), a-selinene (7.4 - 8.6) and 11-alpha-(H)-himachal-4-en-1-beta-ol (12.7 - 17.4%), whereas the oils from Tunis were predominantly composed of elemicin (31.5 - 35.3%) and carotol (48.0 - 55.7%). The antimicrobial activity of the essential oils were assayed by using the broth dilution method on Escherichia coli ATCC 35218 and Staphylococcus aureus ATCC 43300, and clinical strains of Candida albicans and C. tropicalis 1011 RM. The MIC values obtained were all > 2.5% (v/v).     

Parallel solution-phase synthesis of acrylonitrile scaffolds carrying L-alpha-amino acidic or D-glycosyl residues

A practical and straightforward protocol for the preparation of a solution-phase library of acrylonitrile scaffolds is reported. Target compounds were obtained in high yield, stereoselectivity, and purity by two simple and practical steps from cyanoacetic acid. Moreover, our study proposes a synthetic approach starting from the constructed library to obtain three-membered heterocycles.     

A Palladium‐Catalyzed Carbonylation Approach to Eight‐Membered Lactam Derivatives with Antitumor Activity

The reactivity of 2‐(2‐alkynylphenoxy)anilines under PdI₂/KI‐catalyzed oxidative carbonylation conditions has been studied. Although a different reaction pathway could have been operating, N‐palladation followed by CO insertion was the favored pathway with all substrates tested, including those containing an internal or terminal triple bond. This led to the formation of a carbamoylpalladium species, the fate of which, as predicted by theoretical calculations, strongly depended on the nature of the substituent on the triple bond. In particular, 8‐endo‐dig cyclization preferentially occurred when the triple bond was terminal, leading to the formation of carbonylated ζ‐lactam derivatives, the structures of which have been confirmed by XRD analysis. These novel medium‐sized heterocyclic compounds showed antitumor activity against both estrogen receptor‐positive (MCF‐7) and triple negative (MDA‐MB‐231) breast cancer cell lines. In particular, ζ‐lactam 3 j′ may represent a novel and promising antitumor agent because biological tests clearly demonstrate that this compound significantly reduces cell viability and motility in both MCF‐7 and MDA‐MB‐231 breast cancer cell lines, without affecting normal breast epithelial cell viability.     

X-Ray Structural Analysis of Ethyl [2,2-dimethyl-6-(Δ2-thiazolin-2-yl)-4H-1,4-benzoxazin-3-one-4-yl]butyrate

With the aim of discovering new molecules with K⁺ channel modulating properties, we have synthesized analogues of cromakalim, an important molecule which shows specific affinity toward the K⁺ channels, by replacing the benzopyrane ring with a benzoxazine moiety. As a part of this study, we have synthesized and characterized, in solution and in the solid state as well, the compound ethyl [2,2-dimethyl-6-(²-thiazolin-2-yl)-4H-l,4-benzoxazin-3-one-4-yl]butyrate (V). This compound exhibits in the solid state the following parameters: molecular formula C₁₉H₂₄N₂O₄S, triclinic, space group , M_w = 376.5, a = 12.581(3) Å, b = 5.485(4) Å, c = 14.612(2) Å, = 91.85(2), = 108.9(3), = 82.04(4), V = 944.7 ų, Z = 2, d = 1.323 g·cm^–3. We describe here the synthesis and discuss the solid-state conformation of this new molecule; when tested on rat aorta ring precontracted with phenylephrine, the compound showed a concentration-dependent relaxation comparable to that measured for cromakalin taken as reference drug.     

Synthesis and Liquid-Crystalline Properties of Diazabutadiene Complexes of Rhenium(I)

New N,N '-bis(4-((4-alkoxybenzoyl)oxy)phenyl)-1,4-diaza-1,3-butadiene (L) ligands, obtained by condensation of 4-((alkoxybenzoyl)oxy)anilines and glyoxal, were complexed to different [ReX(CO)(3)] fragments to give the complexes [ReX(L)(CO)(3)] (X = Cl, Br, I) and [Re(CF(3)SO(3))(L)(CO)(3)].THF. The chloro and bromo complexes were obtained by direct reaction of the ligands with [ReX(CO)(5)] (X = Cl, Br), while the iodo and triflato derivatives were obtained via metathesis of the chloro or bromo precursors with potassium iodide or silver triflate respectively. The liquid-crystalline behavior of the ligands and the related rhenium complexes has been studied by means of optical microscopy, differential scanning calorimetry, and small angle X-ray diffraction. Nematic and smectic C phases were observed when the coordinated counteranions were Cl, Br, and I, respectively; the triflato derivatives were not mesomorphic.