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Abstract: Na7(CoO3)2 was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursors (Co3O4, NaN3 and NaNO3) were heated in a special regime up to 450 °C and annealed at this temperature for 100 h in specially designed silver containers. Single crystals have been grown by the subsequent annealing of the reaction product at 500 °C for 1000 h, in silver crucibles which were sealed in glass ampules under dried Ar. According to the X-ray analysis of the crystal structure at 273 K (, , , , , , 1841 independent reflections, (all data)) there is only one independent position of Co atoms, which are trigonally planar coordinated by oxygen. The CoO3 triangles with cobalt in an average oxidation state of +2.5 are isolated from each other. No charge ordering was also detectable by X-ray single crystal diffraction at 100 K. Na7(CoO3)2 shows Curie–Weiss behaviour down to . The best fit of the susceptibility data yields an average value of the magnetic moment (per cobalt) and , supporting strongly the presence of Co+2 and Co+3 , in equal amounts. At 11 K one observes an onset of antiferromagnetic order. The substance is semiconducting with a band gap of 47.7 kJ (0.495 eV). [Copyright &y& Elsevier]

Abstract: K3Na(RuO4)2 and Rb3Na(RuO4)2 were prepared by solid state reactions of RuO2, Na2O2, and RbO2 or KO2, respectively, at 873 K under oxygen pressure. K3Na(RuO4)2 performs a structural transition at 467 K and transforms from a monoclinic form at room temperature (, , , , , , single crystal data, 1231 independent reflections, , ) into a trigonal high temperature modification (Rietveld refinement from X-ray powder data, , , , , 4053 data points, , ) which is isotypic to glaserite, K3Na(SO4)2. The rubidium analogue, Rb3Na(RuO4)2, does not show a phase transition down to 100 K. According to the structure determination from single crystal X-ray data, Rb3Na(RuO4)2 (, , , , 281 independent reflections, , ) is isotypic to glaserite and the HT phase of K3Na(RuO4)2. The magnetic measurements confirm the presence of hexavalent ruthenium displaying paramagnetic behaviour along with antiferromagnetic interactions at lower temperatures. The Raman measurements also confirm the tetrahedral coordination of ruthenium with oxygen. [Copyright &y& Elsevier]

Separation and stereochemical attribution of the two enantiomers of the neurotoxin 1-trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo) has been achieved by applying chromatography on a chiral phase HPLC column in hyphenation with circular dichroism (CD) spectroscopy (LC-CD coupling). Assignment of the absolute configuration of TaClo and its N-methyl analog has been achieved by quantum chemical CD calculations and has finally been confirmed by single-crystal X-ray diffraction analyses of the two enantiomers of N-formyl-TaClo as obtained in enantiomerically pure form by crystallization. [Copyright &y& Elsevier]

A broad variety of enantiopure axially chiral 2-aminomethyl-1-(2-oxyphenyl)naphthalenes were prepared via short and efficient synthetic pathways by using the ‘lactone method’ for the regio- and stereoselective construction of the biaryl axis. Their in vitro activity against Trypanosoma cruzi, the causative agent of Chagas'' disease, was evaluated. In particular, the M-configured atropisomers, with the 2-oxy function equipped with an O-triflate group, were found to exhibit good antitrypanosomal activities (down to IC50=1.6 μg/mL), combined with low levels of cytotoxicity. [Copyright &y& Elsevier]

1-Trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo, 2) is a mammalian alkaloid that readily originates in the human organism, by Pictet–Spengler condensation of endogenously present tryptamine (Ta) and the non-natural hypnotic agent trichloroacetaldehyde (chloral, Clo). Due to its structural analogy to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 1), TaClo is discussed to possibly contribute to the pathogenesis of Parkinson''s disease acting as an environmental toxin. Previous investigations on rats and neuronal cell cultures revealed 2 to be capable of inducing severe disturbances on the dopamine metabolism. In this paper, we report on the effects of 2 on the activity of tyrosine hydroxylase [l-tyrosine, tetrayhydropteridine/oxygen oxidoreductase (3-hydroxylating), EC 1.14,16.2; TH] in vitro using rat brain homogenates prepared from the TH-rich nucleus accumbens. TaClo (2) dose-dependently inhibited basal TH activity (IC50=3 μM), and after enzyme activation by pituitary adenylate cyclase-activating polypeptide (PACAP-27), it also reduced l-DOPA formation (IC50=15 μM). Moreover, two presumable TaClo metabolites, 2-methyl-TaClo (N-Me-TaClo, 3) and 1-dichloromethylene-1,2,3,4-tetrahydro-β-carboline (1-CCl2-THβC, 4), which were synthesized in good yields, also proved to be potent inhibitors of TH, with the strongest effect on basal activity (similar to TaClo) being observed for 3 (IC50=3 μM). In contrast to TaClo, however, 3 and 4 showed biphasic effects after TH activation with PACAP-27, inducing a marked increase of enzyme activity in the nanomolar range (<0.1 μM), while TH activity was nearly completely blocked at high concentrations (IC100=0.1 mm). An X-ray diffraction investigation on the 3-dimensional structure of the 1-CCl2-THβC-derived trifluoroacetamide 7 revealed the voluminous and quite rigid dichloromethylene substituent to be only moderately twisted out of the β-carboline ring ‘plane’, thus resulting in an inreased ring strain of the partially hydrogenated pyrido moiety accompanied by a strong steric hindrance of Cl(1), Cl(2), C(13), and N(2), which pushes the N-trifluoroacetyl group upwards to an even higher extent than for the TaClo-related trifluoroacetamide 8. [Copyright &y& Elsevier]