Synthesis of 1,4,5,6-tetrahydropyridine derivatives starting from trans-3-chloro-1,3-alkadien-5-ones

A method has been developed for the synthesis of 3-carbethoxy-2-methyl-6-(oxoalkylidene)-1,4,5,6-tetrahydropyridines by reaction of trans-3-chloro-1,3-alkadien-5-ones with ethyl aminocrotonate. It is shown that the corresponding vinylacetylanic ketones are intermediate products of the reactions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 497–500, April, 1987.     

Effect of the Concentration of Sulfate Lignin on the Aggregation Stability of Its Aqueous Dispersions

The dependence of the aggregation stability of an aqueous dispersion of sulfate lignin on its concentration in the system is investigated by spectrophotometry within the wide range of pH values. It is shown that an increase in the concentration of sulfate lignin shifts the onset of its coagulation separation into the region of higher pH values.     

New method for calculation of intensities of X-rays and thermal neutrons scattered dynamically in defected single crystals

We propose a new method for calculating intensities of X-rays and thermal neutrons, dynamically scattered in defected single crystals by comparing the dynamical theory of Bragg diffraction of X-rays and thermal neutrons in perfect single crystals with the theory of their small-angle scattering.     

New method for calculating the intensities of X rays and thermal neutrons diffracted in single crystals with defects

A new method is proposed to calculate the intensities of X rays and thermal neutrons diffracted in single crystals with defects. This method is based on comparing the dynamic theory of the Bragg diffraction of X rays and thermal neutrons in perfect single crystals with the small-angle scattering theory.     

Influence of the Kraft Lignin Concentration on the Efficiency of Its Coagulation Recovery from Aqueous Electrolyte Solutions

The dependence of the aggregation stability of aqueous suspension of kraft lignin on its concentration in the system was studied spectrophotometrically in wide ranges of pH and sodium chloride concentrations.     

Low-molecular-mass bioregulators. II. Synthesis of methyl (±)-tetradeca-2E,4,5-trienoate — The sex pheromone ofAcanthoscelides obtectus

A preparative method has been developed for obtaining methyl (±)-tetradeca-2E,4,5-trienoate — the racemate of the sex pheromone of the dried-bean beetle. Using methyl 4-chlorotetradec-5-ynoate as an example, a detailed study has been made of the dependence of the regiochemistry of reduction on the activity of a zinc-copper couple, the methods of its activation, and the acidity of the proton donor.Institute of Organic Chemistry, Academy of Sciences of the Armenian SSR, Erevan. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 96–102, January–February, 1990.     

Growth of profiled single crystals of lithium iodate using a shaper from polymer nanoparticles

A possibility of growth of profiled single crystals of α-LiIO₃ with a hollow channel using a shaper from polymer nanoparticles is showed. A method of creating the nanoparticles of polystyrene is described.     

Problem of Stabilizing a Switching System Using a Piecewise-Linear Control System

The problem of stabilizing a mathematical hybrid system with switchings between the operating modes is solved. Each of these modes is associated with nonlinear differential equations that have control parameters. The switching instances (conditions) are control components. A stabilizer must be designed in positional form that allows the trajectory of the entire nonlinear system to reach the target set in the phase space for a (prescribed) finite time. To solve the problem, k]an apparatus of continuous piecewise-linear Lyapunov functions is used along with the corresponding piecewise-linear control functions. A theorem concerning the sufficient conditions for the stabilizability of a hybrid system in the considered class of controls is proved. An algorithm for constructing the Lyapunov functions and the stabilizer is given.

     

Nonlinear optical activity and spectroscopy of L-nitrohistidine monohydrate

Comparative investigation of vibrational (IR and Raman) and NMR spectra of L-nitrohistidine monohydrate (L-NH·H₂O) and L-histidine (L-His) has been performed with allowance for structural data. Nonlinear-optical activity and the range of transparency of L-NH·H₂O are determined. Influence of nitrogroup on structural, spectral, and nonlinear-optical properties is emphasized.     

Low-molecular-mass bioregulators. III. Synthesis of tridec-4E-enyl acetate — The sex pheromone ofKeiferia lycopersicella

A new method has been developed for the synthesis of tridec-4E-enyl acetate — the sex pheromone of the tomato pinworm Keiferia lycopersicella.Institute of Organic Chemistry, Academy of Sciences of the Armenian SSR, Erevan. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 102–106, January–February, 1990.