4-Oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine (2-thiouracil) is reacted with a series of diazotized aromatic amines to give compounds On the other hand compound is -methylated by methyl iodide giving 4-oxo-2-methylthioxo 1,2,3,4tetrahydropyrimidine which inturn is reacted with a series of diazotized aromatic amines giving arylazo derivatives of the type . In another reaction compound is hydrolyse...

Low concentrations of the dye tetraiodofluorescein activate native aspartate transcarbamylase (aspartate carbomoyltransferase, carbomoylphosphate:L-aspartate carbomoyltransferase, EC 2.1.3.2), while high concentrations inhibit the enzyme's activity [Jacobsberg, L. B., Kantrowitz, E. R. & Lipscomb, W. N. (1975) J. Biol. Chem. 250, 9238-9249]. This dye is now shown to produce similar effects upon...

A series of phosphinegold(I) thionucleobase analogues, [R(3)PAu(SR(x))] (R = Et, Ph or chexyl; HSR(1) = 2-mercaptobenzoic acid, HSR(2) = 2-thiouracil, HSR(3) = 6-mercaptopurine and HSR(4) = 6-thioguanine) have been examined for their in vitro cytotoxicity in L1210 murine leukemia cells in culture. The range of ID(50) values (continuous 48 h exposure) for the complexes is 0.041 - 0.131 muM. The ...

Dogs fed a diet containing butter, cholesterol, and thiouracil develop severe hypercholesterolemia. Both a p and 8-lipoprotein cholesterol and phospholipid increase whereas these lipids in the a, fraction appear to decrease. Comparison of the dextran sulfate-precipitable lipoproteins with lipoprotein fractions obtained by ultracentrifugation a t densities 1.019, 1.063, and 1.21 and with paper e...

THE main pathway of cholesterol catabolism involves the conversion of cholesterol to bile acids which are eliminated via the bile and feces. As liver cholesterol is considered to exist in equilibrium with serum cholesterol, nutritional factors accelerating cholesterol catabolism may lower the serum cholesterol level. Furthermore, it is well known that hypercholesterolemia and subsequent experim...

The deactivation mechanism after ultraviolet irradiation of 2-thiouracil has been investigated using nonadiabatic dynamics simulations at the MS-CASPT2 level of theory. It is found that after excitation the S2 quickly relaxes to S1, and from there intersystem crossing takes place to both T2 and T1 with a time constant of 400 fs and a triplet yield above 80%, in very good agreement with recent f...

The accidental observation that the thyroid gland of the tumor-bearing rat was not enlarged after the oral administration of thiouracil was made while investigating the possible role of the thyrotrophic hormone (TSH) as a fat-mobilizing hormone (14). Further experiments were carried out to ensure that the effect was not limited to a particular strain of rat or type of tumor, or due to the actio...

The solvatochromic responses of uric acid (Ua), 6-amino-2-thiouracil (ATU) and a series of their complexes dissolved in ten solvents of different polarity have been measured. The solvent-dependent UV/Vis spectroscopic absorption maxima, λ(max), are assigned to the corresponding electronic transitions and analyzed using SPSS program, regression analysis and Kamlet and Taft methods. The observed ...

Partially purified samples of thymidine phosphorylase were obtained from four preparations of human uterine leiomyomas and uteri using the method of Yoshimura et al. (1990), Biochim. Biophys. Acta 1034, 107-113. Among the studied twelve pyrimidine derivatives, 5-bromouracil, 5-nitrouracil, 5-fluorouracil, 6-aminouracil, 4, 6-dihydroxy-5-nitropyrimidine are competitive inhibitors, while allyloxy...