Aziridinylketones and their cyclic anils. 12

We have measured the PMR spectra of 5, 7-diaryl-1, 4-diazabicyclo[4. ].O]hept-4-enes. We have studied the structure of the 5-(4-nitrophenyl)-7-phenyl derivative by x-ray diffraction. We show that the six-membered heterocycle has the half-chair form. The 6-H and 7-H protons of the aziridine ring are trans, while the 7-aryl is exo relative to the six-membered ring. Introduction of substituents into the aromatic ring has practically no effect on the geometry of the bicycle.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1117–1124, August, 1994.For Communication 11, see [1].     

Experimental investigation of explosive plasma antennas

Explosion-produced plasma jets formed in free spece are experimentally investigated. The feasibility of emitting pulsed electromagnetic signals by plasma jets is shown, and the emitting conditions are studied. Comparison is made between the results of experiments with short and long plasma jets. When the jet passes through the field of a helix, a short-term increase in the emitted signal is detected. A linear parametric model of interaction between the plasma jet and an exciting electromagnetic signal is proposed. The operating performance of instrumentation developed for the investigation is presented.     

Adaptive classification method and measurement of intermittent random process characteristics

Results are presented of an analytic construction and investigation of adaptive data classification algorithms for intermittent turbulence. A decision making rule is presented, relationships are derived to estimate the classification accuracy. A three-level procedure is described for processing the intermittency, including the calculation algorithms for the initial point, self-teaching, and optimal classification. It is shown that the method proposed permits realization of total automation of intermittency data processing.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 18, pp. 119–123, 1987.     

The Limiting Possibilities of Miniaturization of Open-Resonator Mirrors

Using the representation of the field of a quasioptical beam in the form of expansion over plane waves, we derive an expression determining the minimum possible size of mirrors of an open resonator (OR) in which the lowest mode with small energy losses exists. To verify the obtained expression, we study experimentally the field distribution in a semisymmetric OR using the probe method. In this case, the diameter of the scattering probe was chosen on the basis of the equation derived. The difference between the measured and calculated field distributions was smaller than 8%. It is shown that the diameter of the field spot on the OR mirrors cannot be smaller than the wavelength of a microwave oscillator. The attempts to focus a Gaussian beam to a size smaller than the wavelength lead to an increase in the diameter of the field spot.     

Nontrivial manifestation of clustering in fission of heavy nuclei at low and middle excitations

An analysis of the preferable fission path manifesting itself as a fine structure of the total kinetic energy-mass distribution of the fission fragments compelled us to put forward an absolutely new shape of the fissioning system on the descent from the fission barrier. It is a multicomponent nuclear molecule constituted by two magic clusters and a torus-like neck between.     

Quantum-Chemical Investigation of the Mechanism of Transfer of Fluorine in the Reaction of F‐TEDA‐BF4 with Dimethylenebicyclo[3.3.1]nonane

The mechanism of the reaction of the N-fluoro reagent FTEDABF₄ with dimethylenebicyclo[3.3.1]nonane was investigated by the semiempirical PM3 SCF MO method using the Cramer–Truhlar SM5.42R solvation model. It was shown that the mechanism of addition of the fluorine corresponds to classical S _N 2 nucleophilic substitution involving single-electron transfer synchronous with the cleavage–formation of C—F and N—F bonds.     

Synthesis of substituted 5-diethoxymethyl-5-ethyloxazolidines

Mixtures of stereoisomeric 2-diethoxymethyl-5-ethyloxazolidines with one of the stereoisomeric forms predominating were obtained by the reaction of 2-ethyl-2-formyloxirane diethyl acetal with alkyl-substituted Schiff bases in ethanol solution.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, 985–988, July, 1987.     

Molecular and crystal structure of tetrahydroneosophoramine

The structure of tetrahydroneosophoramine has been studied by x-ray structural analysis. Rings A, B, and C have the chair conformation, and ring D the half-chair conformation. On the basis of a semiquantitative analysis it has been shown that the strains in the molecules of tetrahydroneosophoramine and of matrine are of the same order of magnitude.Institute of Bioorganic Chemistry, Academy of Sciences of the Uzbek SSR, Tashkent. Institute of Crystallography, Academy of Sciences of the USSR, Moscow. V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 751–757, November–December, 1981.     

Cardenolide glycosides ofCheiranthus allioni. XV. Glucocheiranthoside

Another new cardenolide glycoside has been isolated from the plantCheiranthus allioni Hort., and has been named glucocheiranthoside. Its chemical structure has been established as 3β-(4′-O-β-D-glucopyranosyl-β-D-gulmoethylpyranosyloxy)-14-hydroxy-19-oxo-5β,14β-card-20(22)-enolide. State Scientific Center for Drugs, Ukraine, 310085, Kharkov, USSR. ul. Astronomicheskaya, 33. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 269–271, March–April, 1994.     

Measurement of the muon capture rate in hydrogen gas and determination of the proton's pseudoscalar coupling gP

The rate of nuclear muon capture by the proton has been measured using a new technique based on a time projection chamber operating in ultraclean, deuterium-depleted hydrogen gas, which is key to avoiding uncertainties from muonic molecule formation. The capture rate from the hyperfine singlet ground state of the microp atom was obtained from the difference between the micro(-) disappearance rate in hydrogen and the world average for the micro(+) decay rate, yielding Lambda(S)=725.0+/-17.4 s(-1), from which the induced pseudoscalar coupling of the nucleon, g(P)(q(2)=-0.88m(2)(micro))=7.3+/-1.1, is extracted.