Catalytic one-pot synthesis of [5.5.5.6]fenestrane systems via a dicobalt octacarbonyl-catalyzed tandem cycloaddition of dienediynes.

Catalytic one-pot synthesis of fenestrane derivatives from dienediynes was developed: fenestranes were synthesized in high yields by a dicobalt octacarbonyl-catalyzed tandem cycloaddition of dienediynes.

An optimised method for the accurate determination of zeranol and diethylstilbestrol in animal tissues using isotope dilution-liquid chromatography/mass spectrometry.

Isotope dilution-liquid chromatography/mass spectrometry (ID-LC/MS) has been established as a candidate reference method for the accurate determination of growth promoters (zeranol, taleranol, and diethylstilbesterol) in raw meat samples. Sample preparation processes including an enzymatic hydrolysis, extraction, and SPE clean-up were optimised. The sensitivity difference of trans- and cis-diethylstilbestrol (isomerizing in sample preparation processes) by the LC/MS was measured by running a trans/cis mixture (ratio measured by a quantitative NMR) with and without sample matrices, and applied for the determination of total diethylstilbestrol. Validity, repeatability, and reproducibility of the analytical method were tested by measuring gravimetrically fortified samples (chicken breast, bovine muscles, and porcine muscle) in a number of different time periods. Measurement results agreed with the fortified values within their uncertainties. The method provided accurate results of the target analytes in the range of 0.05-15 µg/kg with the relative expanded uncertainty of 2-15%.

Stereoselective synthesis of (+)-SCH 351448: a unique ligand system for sodium, calcium, and other cations.

(+)-SCH 351448 (Na+ salt A) was synthesized employing ring-closing olefin metathesis reaction of an open diene diester intermediate for construction of the 28-membered macrodiolide structure. The open diene diester was prepared from the monomeric hydroxy carboxylic acid and two different olefin fragments. The monomeric hydroxy acid was synthesized via Julia-Julia coupling reaction of intermediates derived from the same olefinic fragments. Oxane units in these fragments were prepared by radical cyclization reactions of beta-alkoxyacrylates. Analogous SCH 351448 salts incorporating other mono- and divalent cations may be prepared. Under acidic conditions, SCH 351448 (Na+ salt A) was the most stable complex, but SCH 351448 (Ca2+ salt) and (Na+ salt B) appear to be physiologically important species.

Diaquabis(1,3-propanediamine-kappa(2)N,N')nickel(II) bis(sulfanilate).

The title compound, [Ni(C(3)H(10)N(2))(2)(H(2)O)(2)](C(6)H(6)NO(3)S)(2), contains alternating layers of sulfanilate anions and diaquabis(1,3-propanediamine)nickel(II) cations. The Ni atom lies on an inversion centre and is hexacoordinated by the 1,3-propanediamine ligands, which function as N,N'-bidentate ligands, and the water molecules, which are in a trans arrangement. The sulfanilate anions are arranged in layers, with the sulfonate and amine groups directed towards opposite sides of the layer. The structure is stabilized by a network of hydrogen bonding between the O and N atoms of the sulfanilate anions, the water molecules, and the N atoms of the 1,3-propanediamine ligands.

A one-dimensional coordination polymer with metal-metal interactions: catena-poly[[triaquabarium(II)]-mu-aqua-kappa2O:O-di-mu-thiosalicylato-kappa4O:O].

In the title compound, [Ba(C(7)H(5)O(2)S)(2)(H(2)O)(4)](n), the Ba(II) atom lies on a mirror plane and is nine-coordinated by four bridging carboxylate O atoms of the thiosalicylate ligands, two bridging water molecules and three terminal water molecules. There is an intramolecular S-H.O hydrogen bond between the S and O atoms in the thiosalicylate ligand. A one-dimensional coordination polymer is formed via weak metal-metal interactions along polymeric zigzag chains.

Rhodium-catalyzed carbonylative [2+2+1] cycloaddition reactions: catalytic formation of bicyclic cyclohexenones [corrected].

The rhodium-catalyzed carbonylative [3+2+1] cycloaddition of trienes into bicyclohexenones has been developed. The carbonylated cycloaddition products have a high regioselectivity. This catalytic system tolerates functionalities including ether, sulfonamide, and ester.