作者:Reinhard Sarges、Rodney C. Schnur、John L. Belletire、Michael J. Peterson
DOI:10.1021/jm00396a037
日期:1988.1
formation from glucose, catalyzed by the enzyme aldosereductase, is believed to play a role in the development of certain chronic complications of diabetes mellitus. Spiro hydantoins derived from five- and six-membered ketones fused to an aromatic ring or ring system inhibitaldosereductase isolated from calf lens. In vivo these compounds are potent inhibitors of sorbitol formation in sciatic nerves of
Synthesis of Pyrimidines and Triazines in Ice: Implications for the Prebiotic Chemistry of Nucleobases
作者:César Menor-Salván、Dra. Marta Ruiz-Bermejo、Marcelo I. Guzmán、Susana Osuna-Esteban、Sabino Veintemillas-Verdaguer
DOI:10.1002/chem.200802656
日期:2009.4.20
nucleobases: Freeze–thaw cycles in urea (1) solutions under methane/nitrogen atmospheres lead, with application of an energy source, to the synthesis of pyrimidines (mainly cytosine (2) and uracil (3)), triazines (such as cyanuric acid (4)), and adenine. This synthesis appears to be dependent on the atmosphere and the freezing conditions. At room temperature, hydantoin (5) is obtained. However, a freezing
Ethyl 2-(methylthiomethyl)phenyl selenide 1a, telluride 1b and ethyl 2-(methylselanylmethyl)phenyl telluride 1c were prepared and treated with 1 equivalent of triflic anhydride (Tf2O) or 2 equivalents of nitrosonium salts (NOBF4 or NOPF6) at low temperature to generate the corresponding selenathia, tellurathia and telluraselena dications(2a, 2b and 2c), the structures of which were determined by NMR spectroscopy and 2b was successfully isolated.
Uracil photooxygenation occurs in acidic water (pH = 1) at 25°C, under oxygen (1 atm), irradiating with, lambda > 300 nm in the presence of selected polyoxometalates (POM). A marked diversity of photocatalytic behavior is registered for different PONIs in terms of oxidation rate and selectivity. H3PW12O40 (PW12) appears to be the most reactive photocatalyst, by far superior to isostructural complexes