Alkaloids of Nitraria komarovii. XIII. Nitramine N-oxide and the structure of dehydroschoberine

Deoxyvasicinone, d-vasicinone, -peganine, deoxypeganine, nitraramine, dihydronitraraine, nitraroxine, tryptamine, schoberine, and two new bases have been isolated for the first time from the epigeal part of the plantNitraria komarovii. The structures of the new bases have been established on the basis of spectral characteristics and chemical transformations as nitraramine N-oxide and dehydroschoberine. Nitramidine, isoschoberine, nitraroxine, nitraraine, and tetramethylenetetrahydro--carboline N-oxide were isolated from the seeds with fruit.Institute of Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 39–43, January–February, 1993.     

Alkaloids ofNitraria schoberi. Ring-chain tautomerism of the hydrolysis product of nitraramine

The chemical properties of nitraramine have been studied. The possibility has been shown of the existence of the hydrolysis product in three tautomeric forms: aminoaldehyde, carbinolamine, and semiacetal. The NMR spectra of nitraramine and its derivatives (N-acetylnitraramine, dihydronitraramine) have been analyzed and this has permitted spatial structures to be suggested for these compounds.     

Polybuffer separation of the alkaloids ofNitraria schoberi

Summary It has been established that the epigeal part of the plantNitraria schoberi L. in the budding stage contains 0.5% of alkaloids.By a combination of the fractionation of the mixture of alkaloids by polybuffer separation with other methods of separation, nine alkaloids have been isolated and studied.Fractions with a high pH value yielded the following strong bases: nitramine (pH 9 and 8), schoberidine and base A (pH 8), and nitrarine, isonitrarine, and nitramidine (pH 7). The following alkaloids were also isolated: nitraramine (pH 6.5 and 6) and schoberine and base B (pH 4 and the combined chloroform phases of the fractions with pH 7-2).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 84–87, January–February, 1977.     

The structure of the alkaloid nitraramine fromNitraria schoberi

The spatial structure of the alkaloid nitraramine has been determined by x-ray structural analysis. This has shown that it has the structure of 2,1-epoxy-1,3-propanoperhydrobenzo [3,2-d]-1,8-naphthyridine. Its reactivity has been studied.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 692–698, September–October, 1985.     

The structure of the alkaloid nitraramine fromNitraria schoberi

The spatial structure of the alkaloid nitraramine has been determined by x-ray structural analysis. This has shown that it has the structure of 2,1′-epoxy-1,3-propanoperhydrobenzo [3′,2′-d]-1,8-naphthyridine. Its reactivity has been studied.     

Nonempirical calculations of potential-energy surfaces for nucleophilic addition of H− and F− to an acetylene molecule

The minimal energy paths for the nucleophilic addition of a hydride ion (H^–) and a fluoride ion (F^–) to a molecule of acetylene (A) have been calculated with the use of 3–21++G and 3–21+G double basis sets in the framework of the Hartree-Fock-Roothaan method. The values of the total energies of the reactants, transition states, and products have been refined by means of calculations with more complete basis sets [6–31++G// 3–21++G and 6–31++G*//3–21++G for reaction (1); 6–31+G*//3–21+G and 6–31++G**//3–21+G for reaction (2)] and by taking into account the correlation energy for reaction (1) in the framework of the SCEP/6–31++*//3–21++G method. It has been established that the activation energy of reaction (2) is 15.94 kJ/mole lower than that for reaction (1), that reaction (1) is exothermic, and that the enthalpy change accompanying reaction (2) is close to zero. The character of the distribution of the electron density along the minimal energy paths of both reactions has been analyzed, and the differences appearing as a result of the replacement of the soft nucleophile H^– by the harder nucleophile F^– have been ascertained. The results of the calculations have been compared with the results available in the literature for reaction (1).Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 149–155, March–April, 1989.     

Phospholipids of the medium-fiber cotton plant variety 159-F

Summary 1. The qualitative and quantitative compositions of the PLs of an industrial medium-fiber cotton plant of variety 159-F (1972 and 1974 harvests) have been considered. It has been shown that the total PL amounted to 1.76 and 1.85% and consisted of 60–65% PC, 16–18% PI, 6–8% PE, and 10–14% of combined minor components, respectively.2. The distribution of the lipid phosphorus has been studied during the isolation of PLs by selective solvents. The lipid phosphorus amounted to 5.5% of the total phosphorus in the seed kernels.3. The qualitative and quantitative compositions of the fatty acids of the individual lipid fractions and of the individual PCs, PIs, and PEs have been determined. The position distribution of the fatty acids of the main groups of PLs has been established and a possible molecular composition has been given.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 198–202, March–April, 1977.     

Choice of the best region for channel-by-channel summation of estimating the intensity of single photopeaks

The influence of partial peak width integration on the statistical error has been investigated. It has been shown that integration of the central photopeak part —±(0.55–0.64) FWHM for narrow peaks and ±(0.50–0.53) FWHM for wide peaks-allows to decrease the statistical error 1.5–2.0 times in comparision with the TPA method. The results obtained are valid both for real photopeaks and for smoothed spectra. The theoretical results have been confirmed by experimental data.     

Adsorption of low level51Cr(VI) from aqueous solution by bismuth trioxide: Kinetic and IR study

Radiotracer technique has been used for the investigation of adsorption of chromium (VI) traces on bismuth trioxide from aqueous solution. The effect of pH (2–10), concentration of chromate solution (10^–6–10^–2M) and temperature (303–323 K) has been thoroughly investigated. The influence of certain foreign ions has also been studied. The calculated kinetic and thermodynamic parameters indicate the first order rate law, spontaneity and exothermic nature of the adsorption process. Further, IR studies have established the chemical interaction between the sorbate and sorbent and a possible mechanism of the sorption process based on ligand exchange has been proposed.     

Labdanoids ofMarrubium anisodon

The first chemical investigation has been made of Marrubium anisodon (fam. Lamiaceae). Two diterpenoids of the labdane type — vulgarol and manubiin — have been isolated. An x-ray analysis has been performed for the latter and its crystal amd molecular structures have been determined.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 54–58, January–February, 1996. Original article submitted December 11, 1995.     

Investigation of the dioxane lignin of the cotton plant

Summary 1. The dioxane lignins of the stems of cotton plants in the early vegetation period, DLA-I, and in the flowering period, DLA-II, have been investigated. Their developed semiempirical formulas have been established by elementary and functional-group analyses.2. The amounts of catechol structural units in cotton-plant dioxane lignins have been determined for the first time.3. The molecular-weight distribution of the dioxane lignins has been studied and it has been shown that they have high molecular weights (22,000–23,500).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 80–83, January–February, 1976.     

Kinetics and mechanism of oxidation of arsenic(III) by ferriccyanide in methanol-water mixtures

Summary The kinetics of the outer-sphere oxidation of the arsenic(III) by ferricyanide have been studied spectrophotometrically in MeOH–H₂O solvent mixtures covering the range 0–65 wt% at the range of 20–45°C. The effect of solvent on rate of the reaction has been investigated. On the basis of this study, a mechanism of this reaction has been suggested and the activation thermodynamic parameters are calculated.     

Amino acid sequences of sturin A and of nudiventrin A

Nudiventrin and sturin have been fractionated and it has been shown that each of them consists of two components, A and B, their ratio in sturin being 10:1. The amino acid sequences of these proteins have been determined and it has been shown that they have the same primary structure.M. V. Lomonosov Moscow State University. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 76–82, January–February, 1980.     

Bisindoles. 18. Some electrophilic substitution reactions in the 1,2-di(indol-5-yl)ethane series

A quantum-chemical calculation has been made and the laws of the electron-density distribution in the molecule of 1,2-di(indol-5-yl)ethane have been determined. The electrophilic substitution reactions most characteristic for it have been studied.For communications 15–17, see [1–3].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 73–77, January, 1984.     

Analogs of oxytocin with L- and D-pentafluorophenylalanines in the second position

Summary 1. The separation of pentafluorophenylalanine into optical antipodes has been effected.2. Two new analogs of oxytocin — [2-L-pentafluorophenylalanine]oxytocin and [2-D-pentafluorophenylalanine]oxytocin — have been synthesized and their uterotonic activities have been studied.3. It has been shown that donor — acceptor interaction plays a fundamental role in the stimulation of the biological effect.A. A. Zhdanov Leningrad State University. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 392–398, May–June, 1977.     

Calculations of silicooxygen ring vibration frequencies

In the work model calculations of the vibrations of ideally isolated silicooxygen rings (using PM3 method) have been carried out. three-, four-, and six-membered rings have been considered. It has been found that that the three-membered silicooxygen rings are flat and practically undeformed showing D_3h symmetry. The rings of higher number of ring members (i.e. n>3) are deformed to some extent. The deformation reveals itself most significantly in the Si–O–Si bond angles distribution. In the case of all the rings the bridging Si–O–Si bonds are ca. 0.02–0.04 Å shorter than the non-bridging Si–O⁻ bonds. Hypothetical IR spectra for all the rings considered have been also calculated. Analysis of these hypothetical spectra leads to the conclusion that the whole spectrum can be divided into four wavenumbers regions, 1200–1100 cm⁻¹ stretching Si–O(Si) vibrations; 1000–800 cm⁻¹ stretching Si–O⁻ vibrations; 800–600 cm⁻¹; the region in which a band characteristic of silicooxygen rings appears, and below 600 cm⁻¹ bending ⁻O–Si–O⁻ and (Si)O–Si–O(Si). It has been also found that as the number of ring members increases the ‘ring band’ shifts to lower wavenumbers: 725 cm⁻¹ for three-membered rings, 650 cm⁻¹ for four-membered rings and 610 cm⁻¹ for six-membered rings. Calculated spectra have been compared with the experimental spectra of cyclosilicates. They showed good agreement in the 1200–600 cm⁻¹ region. In the experimental spectra as well as in the calculated ones, with increasing the number of ring members the ‘ring band’ shifts towards lower wavenumbers.     

In vitro biosynthesis,isolation, and activities of nuclear glycoproteins

It has been shown by HPLC, electrophoresis, etc., that, in vitro, the nuclei of neurons of rabbit and cow brains synthesize two glycoproteins (M 25–30 kDa and 10–15 kDa). The influence of some neurotropic compounds on the kinetics of the nuclear protein synthesis has been investigated. New inhibitors of this biosynthesis have been found.A. S. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax 627071. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 112–118, January–February, 1994.     

Synthesis of the C-terminal tetrapeptide of the oxytocin sequence using various protective groups for the cysteine thiol function

The synthesis of amides of tetrapeptides with the 6–9 sequence of oxytocin containing various protective groups for the thiol function has been performed by 2+2 and 1+3 schemes. Relationships between the yield of tetrapeptide and the structures of the protective groups have been obtained. An advantage of trityl and benzyl protective groups for masking the tiol function of cysteine has been shown. The signals of the¹³C NMR spectra of the compounds obtained have been interpreted.All-Union Scientific-Research Institute of Blood Substitutes and Hormone Preparations, Moscow. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 400–406, May–August, 1992.     

Adsorption studies of cesium on potassium copper nickel hexacyanoferrate(II) from aqueous solutions

Adsorption of cesium from aqueous solutions on potassium copper nickel hexacyanoferrate(II) (KCNF) has been investigated in batch experiments and optimized as a function of concentration of acids, salts and adsorbate using a radiotracer technique. The results are presented in terms of distribution coefficient, K_d (ml·g^–1). The uptake of cesium obeys a Freundlich adsorption isotherm over the concentration range of 3.7 to 37 mmol·l^–1 with b values of 0.77, 0.68 and 0.56 at temperatures of 293, 313, 333 K, respectively. The Langmuir adsorption isotherm is followed in the concentration range of 15 to 75 mmol·l^–1 in the same temperature range. The values of limiting adsorption concentration (C_m) have been found to be 2.58, 2.44 and 2.32 mmol·g^–1. The heat of adsorption was calculated as 26.43 kJ·mol^–1. The influence of a number of anions and cations on cesium retention has also been studied. Column experiments have been performed and breakthrough have been obtained under different operating conditions. The low cesium capacity of 1.1 mmol·g^–1 has been obtained under dynamic conditions as compared to batch experiments. Desorption of cesium from the column has been achieved (45.4%) by nitric acid solution of 8M concentration at a flow rate of 0.5 ml·min^–1.     

Ab initio Calculation of the charge distribution and the ligand field splitting in the tetrahedral halo complexes CuCl 4 2− 4 and NiCl 4 2−

The charge distribution and the ligand field splitting in the tetrachloro complexes CuCl ₄ ^2– and NiCl ₄ ^2– have been investigated by means of the restricted Hartree-Fock method. A rather large basis set of contracted Gaussian type orbitals has been employed. The charge distributions have been analysed by means of Mulliken population analyses. The ligand field splitting 10Dq has been compared with literature results known for the octahedral cluster NiF ₆ ^4– occurring in KNiF₃. A detailed analysis has been carried out for CuCl ₄ ^2– . From calculations on a selected number of states of NiCl ₄ ^2– the Racah parameters B and C have been obtained.