Enhancement of NO release from S-nitrosoalbumin by pollution derived metal ions.

S-Nitrosothiols act as a comparatively long-lived reservoir of releasable nitric oxide (NO) present in vivo in a variety of body fluids. Soluble constituents of air-borne particulate matter (PM) can affect S-nitrosothiol stability and deregulate NO-based biological signaling. PM aqueous extracts of standard urban dust (SRM 1648a) were prepared, and their effect on human serum S-nitrosoalbumin (HSA-NO) stability was studied. The results indicated that PM extracts induced a release of NO from HSA-NO in a dose-dependent manner. To identify the inorganic components of urban PM responsible for HSA-NO decomposition, the effects of individual metal ions and metal ion mixtures, detected in the SRM 1648a aqueous extract, were examined. The dominant role of copper ions (specifically Cu+) was confirmed, but the results did not exclude the influence of other water-soluble PM components. Measurements with the application of several common metal ion chelators confirmed that Cu2+ may participate in NO release from HSA-NO and that reduction to monovalent Cu+ (responsible for S-NO bond breaking) may occur with the participation of S-nitrosoalbumin. The addition of ascorbic acid (AscA) significantly enhanced the effectiveness of NO release by PM extracts both kinetically and quantitatively, by inducing an increase in the reduction of Cu2+ to Cu+. These results indicate that AscA present in the respiratory tract lining fluids and plasma may amplify the activity of inorganic components of PM in S-nitrosothiol decomposition.

Synthesis of N-styrenyl amidines from α,ß-unsaturated nitrones and isocyanates through CO2 elimination and styrenyl migration.

A mild, metal-free, and modular route for the preparation of N-styrenyl amidines from N-aryl-α,ß-unsaturated nitrones and isocyanates has been developed that accesses an initial oxadiazolidinone intermediate that can undergo CO(2) elimination and styrenyl migration. The use of a migration event to install N-styrenyl amidine substituents circumvents a limitation of traditional Pinner-type methods for amidine synthesis that require the use of amine nucleophiles. The modularity of the nitrone and isocyanate reagents provides access to a variety of differentially substituted N-styrenyl amidines. The scope and tolerance of the method are presented, and preliminary mechanistic data for the transformation are discussed.

Synthesis of 1,4-enamino ketones by [3,3]-rearrangements of dialkenylhydroxylamines.

The synthesis of 1,4-enamino ketones has been achieved through the [3,3]-rearrangement of dialkenylhydroxylamines generated from the addition of N-alkenylnitrones to electron-deficient allenes. The mild conditions required for this reaction, and the simultaneous installation of a fluorenyl imine N-protecting group as a consequence of the rearrangement, avoid spontaneous cyclization of the 1,4-enamino ketones to form the corresponding pyrroles and allow for the isolation and controlled divergent functionalization of these reactive intermediates. The optimization, scope, and tolerance of the new method are discussed with demonstrations of the utility of the products for the synthesis of pyrroles, 1,4-diones, and furans.

rac-cis-Dicarbonyl-chlorido{1-[2-(diphenyl-phosphanyl-κP)benz-yl]-3-(phenyl-κC(1))imidazol-2-yl-idene-κC(2)}ruthenium(II) dichloro-methane monosolvate.

In the title compound, [Ru(C(28)H(22)N(2)P)Cl(CO)(2)]·CH(2)Cl(2), the Ru(II) atom exhibits a distorted octa-hedral coordination geometry. The N-phenyl group of the ligand has undergone orthometalation; as a result, the tridentate phosphane-functionalized N-heterocyclic carbene ligand is coordinating in a meridional fashion. This complex is of inter-est with respect to transfer hydrogenation catalysis and also provides an example of C-H activation behavior in late transition metal complexes. The dichloro-methane solvent mol-ecule is disordered over two sets of sites with an occupancy ratio of 0.873 (14):0.127 (14).