Liquid-phase catalytic hydrogenation of 3,4-dichloronitrobenzene over Pt/C catalyst under gradient-free flow conditions in the presence of pyridine

Experimental data on nitro compound uptake, the intermediate product accumulation, and the corresponding amine compound generation were obtained on hydrogenating 3,4-dichloronitrobenzene over Pt/C catalyst in the gradient-free flow regime in the presence and absence of pyridine. In addition, a side reaction of dehalogenation was investigated. The role of pyridine admixture on every step of the process was analyzed and the rate of hydrogenation of the nitro compound was determined both in the presence and in the absence of inhibitor.

     

Synthesis of 6-acylpyrido[2,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidine derivatives from 5-acetyl-4-aminopyrimidine hydrochlorides

Reaction of 2,6-disubstituted 5-acetyl-4-aminopyrimidine hydrochlorides with acetylacetone or benzoylacetone afforded new substituted 6-acylpyrido[2,3-d]pyrimidines. The reaction of these hydrochlorides with ethyl acetoacetate also proceeds according to the classical version of the Friedländer condensation to form the corresponding pyrido[2,3-d]pyrimidine-6-carboxylic acid esters.     

The first synthesis of furazano[3,4‐b][1,6]naphthyridines

Reaction of 6‐acetyl‐7‐aminofurazano[3,4‐b]pyridines with DMFDMA afforded N,N‐dimethylformamidines that were cyclized to the novel furazan‐fused [1,6]naphthyridine system by treatment with sodium methylate in good yield. The tricyclic system is characterized by X‐ray crystallography.     

Instrument for analyzing the composition of multicomponent ion beams

A compact multichannel mass analyzer is described, which enables one to analyze the composition of multicomponent ion beams.     

Off-diagonal quark distributions in pions in the effective single-instanton approximation

Nonperturbative functions that parametrize off-diagonal hadronic matrix elements of the light-cone leading-twist quark operators are considered. These functions are calculated within the proposed relativistic quark model allowing for the nontrivial structure of the QCD vacuum, special attention being given to gauge invariance. Hadrons are treated as bound states of quarks; strong-interaction quark-pion vertices are described by effective interaction Lagrangians generated by instantons. The parameters of the instanton vacuum, such as the effective radius of the instanton and the quark mass, are related to the vacuum expectation values of the quark-gluon operators of the lowest dimension and to low-energy pion observables.     

Synthesis of trichloromethylpyrimidines and trichloromethylpyrimido [4,5-<Emphasis Type="Italic">d</Emphasis>]pyrimidines from alkyl 2-(diaminomethylidene)-3-oxobutyrates and trichloroacetonitrile

Heterocyclization of alkyl 2-(diaminomethylidene)-3-oxobutyrates with trichloroacetonitrile yields alkyl 4-mino-6-methyl-2-trichloromethylpyrimidine-5-carboxylates. The latter compounds react with aryl isocyanates to produce the corresponding pyrimidinylureas, which undergo cyclization to 3-aryl-5-methyl-7-trichloromethylpyrimido[4,5- d]pyrimidine-2,4(1H,3H)-diones under the action of MeONa in MeOH.     

Status of the lepton g − 2 and effects of hadronic corrections

The electron and muon anomalous magnetic moments (AMM) are measured in experiments and studied in the Standard Model (SM) with the highest precision accessible in particle physics. The comparison of the measured quantity with the SM prediction for the electron AMM provides the best determination of the fine structure constant. The muon AMM is more sensitive to the appearance of New Physics effects and, at present, there appears to be a three- to four-standard deviation between the SM and experiment. The lepton AMMs are pure relativistic quantum correction effects and therefore test the foundations of relativistic quantum field theory in general, and of quantum electrodynamics (QED) and SM in particular, with highest sensitivity. Special attention is paid to the studies of the hadronic contributions to the muon AMM which constitute the main source of theoretical uncertainties of the SM.     

Interaction of high-power x rays with sapphire crystals and quartz based materials

The interaction of high-power (10¹¹ W/cm²) soft (1–3 keV) x-rays with inorganic oxides (Al₂O₃ and SiO₂) is studied. It is found that when the wavelength of the x rays is comparable to the lattice constant of the crystal, besides generation of a high concentration of hot electrons and holes, there is broadening of the 2 p O²⁻-subband in the upper valence band owing to the local action of the strong x-ray field on regular oxygen sites. As a consequence, depending on the intensity of the x-ray pulses, a broadening of the fast (<1 ns) core-valence x-ray luminescence spectra is observed. Fiz. Tverd. Tela (St. Petersburg) 39, 286–289 (February 1997)     

Synthesis of S,N-ketenacetals from β-dicarbonyl compounds and methyl thiocyanate

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 941–942, April, 1988.