Catalytic hydroamination of furfuryl and tetrahydrofurfuryl alcohols with nitriles

Reaction of furfuryl and tetrahydrofurfuryl alcohols with nitriles over copper oxide catalysts under a hydrogen pressure of 15 atm at a temperature of 230C gives N-alkylfurfuryl- (yield 46–50%) and N-alkyl-tetrahydrofurfurylamines (49–53%), and N-alkylpiperidines (28–41%). A reaction mechanism is proposed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 23–26, January, 1988.     

Formation of high-spin complexes in reactions of oxides of the γ-Al2O3 type with radical pairs of sterically shielded semiquinones: A new procedure for the preparation of organometallic polyradicals and their ESR spectra

A new simple method was developed for the preparation of organometallic bi- and triradicals by the heterogeneous reaction of γ-Al₂O₃ or analogous oxides with free radicals generated in solution through the interaction of 3,6-di-tert-butyl-o-benzoquinone with 3,6-di-tert-butylpyrocatechol. An explanation was offered for the plus sign of the dipoledipole coupling constant observed previously in the ESR spectra recorded in a superstrong field at low temperatures. Deceased. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 298–302, February, 1997.     

Determination of Residual Stresses in Products in Additive Production by the Layer-by-Layer Photopolymerization Method

A computational-experimental model for identifying the residual (shrinkage) stresses arising in parts after their additive manufacturing by the layer-by-layer photopolymerizationmethod is given. The model is based on an analysis of flexible shrinkage strains of a series of specimens shaped as plate-strips with the same parameters but with different polymerization time which is prescribed in their manufacturing on the 3d-printer.     

Method of Bayesian estimates in the problem of laser gas analysis

The problem of reconstructing gas concentrations is considered for laser multicomponent gas analysis. For the differential absorption method, the procedures of signal processing are described based on the method of Bayesian estimates. It is demonstrated that the use of the method of Bayesian estimates the problem of reconstructing gas concentration both for few-and multicomponent gas mixtures allows to be solved effectively even for gases whose absorption spectrum has no noticeable maxima. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 29–35, September, 2008.     

Catalytic synthesis of N-alkyloctahydroisoindoles

Catalytic hydroamination of 1,2-bis-(hydroxymethyl)cyclohexane by aliphatic nitriles over a nickel catalyst yielded a series of N-alkyl-substituted octahydroisoindoles. Conditions for their synthesis were selected. The IR, PMR, and mass spectra and the probable mechanism of formation of these compounds are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1619–1622, December, 1990.     

New and fast statistical-thermodynamic method for computation of protein-ligand binding entropy substantially improves docking accuracy

We present a novel method to estimate the contributions of translational and rotational entropy to protein-ligand binding affinity. The method is based on estimates of the configurational integral through the sizes of clusters obtained from multiple docking positions. Cluster sizes are defined as the intervals of variation of center of ligand mass and Euler angles in the cluster. Then we suggest a method to consider the entropy of torsional motions. We validate the suggested methods on a set of 135 PDB protein-ligand complexes by comparing the averaged root-mean square deviations (RMSD) of the top-scored ligand docked positions, accounting and not accounting for entropy contributions, relative to the experimentally determined positions. We demonstrate that the method increases docking accuracy by 10-21% when used in conjunction with the AutoDock docking program, thus reducing the percent of incorrectly docked ligands by 1.4-fold to four-fold, so that in some cases the percent of ligands correctly docked to within an RMSD of 2 A is above 90%. We show that the suggested method to account for entropy of relative motions is identical to the method based on the Monte Carlo integration over intervals of variation of center of ligand mass and Euler angles in the cluster.     

Scattering of a narrow wave beam by a randomly rough locally diffuse surface subject to pulse illumination

We consider the scattering of a narrow pulse wave beam by a randomly rough surface with a complex local scattering indicatrix. Analytical expressions are found for the mean received power for a normal distribution of heights and slopes of the surface in two cases: where the direction to the receiver is close to the direction of mirror reflection and where the direction to the receiver is very different from the direction of mirror reflection. It is shown that in these two cases the echo pulse is very different in shape and is controlled by the parameters of the source and receiver, the sounding scheme, and the variance of heights of a rough surface. The received power is strongly dependent on the width of the local scattering indicatrix, and the form of this dependence is determined by the angles of illumination and reception. The analytical expressions for the mean received power are in good agreement with the results of numerical calculations. Institute for Radioelectronics and Laser Engineering of the N. é. Bauman State Technical University of Moscow, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol.42, No.4, pp. 333–339, April 1999.