Optimal Control of a Gliding Parachute System

The necessary conditions for an extremum are used to write an optimal control program for a gliding parachute system, whose motion in a horizontal plane is described by standard nonlinear differential equations. The boundary-value problem is solved by the method of Krylov and Chernous'ko.     

Antiradical activity of 5-amino-1,3,6-trimethyluracil in the radical chain oxidation of ethylbenzene as the model system

The antiradical activity of 5-amino-1,3,6-trimethyluracil was quantitatively measured in the initiated radical chain oxidation of ethylbenzene as the model system. The rate constant of the reaction of 5-amino-1,3,6-trimethyluracil with the ethylbenzene peroxyl radical at 333 K was found: k ₇ = (2.1 ± 0.3) × 10⁵ L mol^?1 s^?1. The kinetics of 5-amino-1,3,6-trimethyluracil consumption in the course of the radical chain oxidation of ethylbenzene was studied. The stoichiometric inhibition factor was determined to be f = 2.     

Inhibiting effect of 6-methyluracil derivatives on the free -radical oxidation of 1,4-dioxane

The antioxidation activity of 5-substituted 6-methyluracils was quantitatively estimated in the model system of initiated radical-chain oxidation of 1,4-dioxane. The rate constants of the reactions of 1,4-dioxane peroxide radicals with 6-methyluracil (1), 6-methyl-5-piperidinouracil (2), 6-methyl-5-morpholinomethyluracil (3), 6-methyl-5-morpholinouracil (4), 6-methyl-5-methylaminouracil (5), 5-ethylamino-6-methyluracil (6), and 5-hydroxy-6-methyluracil (7) were measured. Among compounds 1–7, derivative 7 is most efficient with an inhibition rate constant of (5.2±0.1) · 10⁴ L mol^-1 s^-1 (60 °C).     

Acid-Base Properties of 5-Hydroxy-1,3,6-trimethyluracil in Aqueous Solutions

Russian Journal of General Chemistry - 5-Hydroxy-1,3,6-trimethyluracil has been studied using 1H, 13C, and 15N NMR as well as UV spectroscopy. The constants and thermodynamic characteristics of its...     

A Procedure for Preparing Effective Immunomodulators and Antioxidants: 5-Hydroxy-6-methyluracil and 5-Hydroxy-1,3,6-trimethyluracil

Russian Journal of Applied Chemistry - 5-Hydroxy-6-methyluracil is an acting agent of Oxymethyluracilum drug, an immunostimulator with a broad spectrum of pharmacological activity. Its synthesis is...     

Kinetics of the radical-chain oxidation of methyl oleate inhibited by 5-amino-6-methyluracil and 5-amino-1,3,6-trimethyluracil

Kinetics and Catalysis - The effects of 5-amino-6-methyluracil (AMU) and 5-amino-1,3,6-trimethyluracil (ATMU) on the rate of oxygen uptake in methyl oleate (MO) radical-chain oxidation initiated by...     

Claisen aromatic amino rearrangement in the series of fluorinated anilines

The effect ofmeta-substituents in the aromatic ring on the route of Claisen rearrangement ofN-(pent-3-en-2-yl)-3-fluoro(or 3-trifluoromethyl, 3,4-difluoro)anilines induced by ZnCl₂ was investigated. The formation of two possibleortho-alkenylated reaction products was observed. The ratio of these isomers depends on the nature of the acid catalyst. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 188–190, January, 1998.     

Effect of Succinic Acid on the Antiradical Properties of 5-Hydroxy-6-Methyluracil

Kinetics and Catalysis - The antiradical activity of the associates of 5-hydroxy-6-methyluracil with succinic acid, whose compositions differed in the succinic acid content, in a model system for...     

Free-radical chain oxidation of 1,4-dioxane inhibited by 2-thio-6-aminouracil

The effect of 2-thio-6-aminouracil on the oxygen uptake kinetics has been studied in 1,4-dioxane free-radical chain oxidation as a model system. The presence of a thiocarbonyl group in the 2-position of the uracil ring makes 6-aminouracil highly reactive towards 1,4-dioxane peroxy radicals. The rate constant of the 1,4-dioxane peroxy radical interaction with 2-thio-6-aminouracil has been measured to be k₇ = (3.0 ± 0.5) × 10⁵ L mol^–1 s^–1 (333 K). The stoichiometric inhibition factor f = 1.1 ± 0.1 has been determined.