- Rate of Decomposition of Murexide in Mixed Solvents: An Indicator for Proton Activity
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The rate of decomposition of murexide depends strongly on the proton concentration.The observed rate constant correlates well with the relative permittivity of the solvent.This correlation is established by measurements in binary mixtures of water-dioxane and water-ethanol between 20 and 40 deg C and may be applied to the estimation of the proton concentration in the aqueous domains of microemulsions.
- Barrabass, Susanne,Stickdorn, Katrin,Knoche, Wilhelm
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- Oxidation of Uric Acid. 4. Synthesis, Structure, and Diabetogenic Action of 5-Imino-2,4,6(1H,3H,5H)-pyrimidinetrione Salts and Their Alloxan-Like Covalent Adducts
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Three synthetic routes to salts of 5-amino-5-hydroxy-2,4,6(1H,3H,5H)-pyrimidinetrione (10) are described.The key reactions involved acid-catalyzed cleavage of 5-amino-5-ureido-2,4,6(1H,3H,5H)-pyrimidinetrione (7), conversion of uramil (8) to dehydrouramil (9) and subsequent hydration, and the condensation of alloxan (5) with ammonium salts.The carbinol ammonium salt structure 10a was unambiguously established by X-ray crystallography.New alloxan-like compounds 7, 9, and 10 were evaluated for diabetogenic activity in rats.Compound 7 was inactive, whereas compounds 9 and 10 showed the highest activity comparable to that of streptozotocin (12).
- Poje, Mirko,Rocic, Boris,Sikirica, Milan,Vickovic, Ivan,Bruvo, Milenko
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p. 861 - 864
(2007/10/02)
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- 4-Hydroxyquinolone-(2)-azomethine copper complex pigments
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A compound having the formula STR1 wherein A denotes an optionally substituted aromatic, isocyclic or heterocyclic residue; R is H, an alkyl residue having from 1 to 6 carbon atoms, an aryl residue having from 6 to 10 carbon atoms or an aralkyl residue having from 7 to 10 carbon atoms; Q is H or a methyl group; X and Y are the same or different and each is a non-water solubilizing group, or X and Y together form a fused aromatic ring system; and R1 and R2 are the same or different and each is H or an alkyl radical having from 1 to 22 carbon atoms, and R3 is hydrogen, an alkyl radical having from 1 to 22 carbon atoms or an aryl radical having from 6 to 10 carbon atoms, the alkyl radicals in R1, R2 and R3 being unsubstituted and uninterrupted or being substituted by an OH, NH2 or CN group and/or being interrupted by an ethylenic group or an oxygen, sulphur or nitrogen bridge, or two or all three of R1, R2 and R3 may form, together with the nitrogen atom to which they are attached, a heterocyclic residue, is useful for pigmenting high molecular weight organic material such as a natural or synthetic polymer or copolymer, or a coating composition for application to the surface of an article, or a printing liquid medium to yield shades from greenish yellow to red brown, exhibiting good fastness properties.
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