Reactions of 2,3-Dichloro- and 2,3,5-Trichloro-4,4-ethylenedioxy-2-cyclopentenones with Some O-, S-, and N-Nucleophiles

2,3-Dichloro- and 2,3,5-trichloro-4,4-ethylenedioxy-2-cyclopentenones react with allyl and benzyl alcoholates and thiolates and benzylamine to give products resulting from Ad_NE substitution of the 3-chlorine atom, [1,3]-sigmatropic rearrangement, and cleavage of the C¹-C² bond.     

Porphyrins

Treatment of porphyrins or their copper complexes containing meso-dimethylaminomethyl or meso-dimethylformaldimino groups with lithium borohydride or diborane leads to the corresponding aminoborane derivatives. The reaction of the aminoboranes with trifluoroacetic acid was investigated, and trifluoroacetoxyborane complexes were isolated.     

Glycosides of marine invertebrates. XXVI. Holothurin A from the Pacific Ocean holothurianHolothvria squamifera. Isolation of the native aglycone

The known triterpene tetraoside holothurin A has been isolated from the Pacific Ocean holothurianHolothuria squamifera. By using two independent methods — enzymatic cleavage and two-stage Smith degradation — 22,25-epoxyholost-9(11)-ene-3,12,17-triol, C₃₀H₄₆O₆, which is the native aglycone of holothurin A, was obtained. The structure of the native aglycone has been established on the basis of the results of IR, mass, and PMR spectroscopy.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 448–451, July–August, 1984.     

The Effectiveness of Rhodiola rosea L. Preparations in Alleviating Various Aspects of Life-Stress Symptoms and Stress-Induced Conditions—Encouraging Clinical Evidence

Rhodiola rosea L. has a long history of use in traditional medicine to stimulate the nervous system, treat stress-induced fatigue and depression, enhance physical performance and work productivity and treat gastrointestinal ailments and impotence. Apart from its well-established traditional use, a significant number of publications on the clinical efficacy of various R. rosea preparations can be found in the literature. The majority of these studies are related to the efficacy of R. rosea in terms of cognitive functions and mental performance, including various symptoms of life-stress, fatigue and burnout. The beneficial effects of this medicinal plant on enhancing physical performance have also been evaluated in professional athletes and non-trained individuals. Moreover, even though most evidence originates from pre-clinical trials, several clinical studies have additionally demonstrated the remediating effects of R. rosea on cardiovascular and reproductive health by addressing non-specific stress damage and reversing or healing the disrupted physiologies and disfunctions. Overall, in accordance with its aim, the results presented in this review provide an encouraging basis for the clinical efficacy of R. rosea preparations in managing various aspects of stress-induced conditions.     

New experimental data on the 10B(n, αt)4He reaction

A new technique is described that makes it possible to detect reaction products with the escape of charged particles occurring on components of working gas under the action of fast neutrons. This technique is unique since it offers the possibility of studying reactions for which more than two charged particles are generated in an output channel. This work studies interactions between neutrons and ¹⁰B nuclei, where two α-particles and tritium nucleus are produced as reaction products.     

Ion-selective and complexation properties, vibrational spectra, and crystal and molecular structure of 1,5-bis[2-(hydroxyethoxyphosphoryl)phenoxy]-3-oxapentane

The ion-selective properties of 1,5-bis[2-(hydroxyethoxyphosphoryl)phenoxy]-3-oxapentane H₂R² have been described. The molecular and crystal structure of H₂R² has been determined by powder X-ray crystallography and IR spectroscopy. The molecule has the twofold symmetry axis, orthorhombic crystal system, space group Pbcn, a = 16.830(2) ?, b = 8.866(15) ?, c = 15.7190(2) ?, V = 2346.1(6) ?³, Z = 4. A new CuR² · 2H₂O complex has been synthesized and characterized.     

Formation of active species in spark discharge and their possible use

The chemical effects of self-sustained spark discharge with an energy per pulse of 5.9 × 10⁻² J, a pulse repetition frequency of 10 Hz, and a spark-gap breakdown voltage of 6 kV have been studied. The discharge generated a UV photon flux of (2.5 ± 0.3) × 10¹⁵ cm⁻² s⁻¹ with an energy density of (2 ± 0.3) × 10⁻³ J cm⁻¹ s⁻¹ and the emission spectrum maximum at 220 nm. The action of the discharge on water samples leads to a decrease in pH and to buildup of oxidizing and reducing species. The formation of HO₂^· radicals with an initial yield of (1.2 ± 0.3) × 10⁻⁶ mol L⁻¹ s⁻¹ has been detected in the liquid. The initial yields of acid residues (increment in [H⁺]), oxidants, and reducing agents are (5.8 ± 1.6) × 10⁻⁷, (3.3 ± 1) × 10⁻⁶, and (4.2 ± 1) × 10⁻⁷ mol equiv L⁻¹s⁻¹, respectively. The formation of NO₃⁻ and NO₄⁺ ions, nitrosamines, and organic compounds has been established.     

Interacting boson approximation for two-quasiparticle and collective states

The boson-fermion mapping problem is investigated for the case when pure collective quadrupole and two-quasiparticle modes are considered. Approximate expressions of the boson images of the fermion operators are derived.Dedicated to the memory of M. Gmitro.     

Approximate method of calculating stresses in a rectangular plate locally loaded by a harmonic force

From double trigonometric series for bending moments the slowly converging components are picked out. When the loading facets are small compared with the width of the plate, they are approximately summed by the analytical method. This simplifies substantially the calculation of bending moments and stresses in the zone of small loading facets compared with the usual expansion with respect to the natural vibration forms.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 20, pp. 84–88, 1989.