Terpenes in organic synthesis

A seven-step synthesis ofS-(+)-hydroprene (S-1) in w037843t2/xxlarge8764.gif" alt="sim" align="MIDDLE" BORDER="0">20 % overall yield starting fromS-(+)-3,7-dimethyl-1,6-octadiene (2) of 55+-10 % optical purity is described. The introduction of an optical enhancement step in the synthetic sequence at the stage ofS-(–)-3,7-dimethyl-1-octanol (9) raises the optical purity ofS-1 from w037843t2/xxlarge8764.gif" alt="sim" align="MIDDLE" BORDER="0">50 % to w037843t2/xxlarge8764.gif" alt="sim" align="MIDDLE" BORDER="0">80 %.For part 13, see. ref.¹ Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 342–348, February, 1993.     

Temperature effect on the rate of formation of free radicals in CTAB-catalyzed decomposition of hydroperoxides

The temperature effect on the rate of the decomposition of hydroperoxides and the rate of the formation of free radicals in the oxidation of ethylbenzene with molecular oxygen in the presence of w831w203676825gu/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-phenylethyl hydroperoxide—cetyltrimethylammonium bromide (CTAB) as a catalytic system for free radical generation was studied by kinetic methods (from the oxygen consumption and hydroperoxide decomposition rates) and the inhibition method involving different acceptors of free radicals.     

Millettia ferruginea extract attenuates cisplatin-induced alterations in kidney functioning,DNA damage,oxidative stress,and renal tissue morphology

This study aimed to investigate the beneficial role of Millettia ferruginea extract (MF) in preventing cisplatin (Cisp) induced nephrotoxicity in rats. A total of 55 metabolites were identified using LC-MS analysis. The in vivo results indicated that MF pretreatment for 4 weeks (20 mg/kg b.w.) remarkably attenuated the altered renal biomarkers by decreasing the levels of plasma creatinine, urea, and uric acid when compared to the Cisp-group. The nephroprotective capacity of MF was further strengthened by histopathological observations, where Cisp + MF treated rats showed lower number of inflammatory cells and tubular degenerative changes than the Cisp-group. The harmful effects of cisplatin on renal oxidative stress indicators (MDA, SOD, CAT, and GPx), were restored by the treatment of MF. In addition, the reduction of inflammatory markers (IL-6 and TNF-α), associated with alleviating DNA fragmentation, highlighted the preventive effect of MF in kidney tissue. Additionally, MF components presented lower binding energies when docked into the active site of TNF-α and IL-6. The present findings concluded that M. ferruginea extract exhibited nephroprotective potential, which may be attributed to its antioxidant and anti-inflammatory properties. Further work is recommended to confirm the current results, explore the involved mechanism of action, and determine the therapeutic doses and time.     

A new theoretical approach to the empirical resonance energies of the aromatic hydrocarbons

In the framework of the Hückel MO approximation, the differences in total binding energy between a given molecule and the corresponding distorted Kekulé-type structure are calculated for a variety of benzenoid hydrocarbons. The total binding energy is assumed to be given by the sum of the w88j6287438g48/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-electron and w88j6287438g48/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">-electron binding energies. It is shown that there is a good linear relationship between the calculated differences in total binding energy and the w88j6287438g48/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-electron delocalization energies (DE) as obtained by using the simple Hückel MO method. This provides a physical basis for the use of the w88j6287438g48/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-electron DE as a theoretical index to the empirical resonance energy (RE). Further, by examining the changes in w88j6287438g48/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-electron binding energy between a given molecule and the corresponding distorted Kekulé-type structure, it is concluded that in benzenoid hydrocarbons the main contributor to the RE is not the w88j6287438g48/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-electron DE but the compressional energy of w88j6287438g48/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0"> bonds.     

Trans-cis Photoisomerization of 1-Methyl-4-(4′-hydroxystyryl)pyridinium in inclusion complexes ofβ-cyclodextrin and its derivatives

The effects of w380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-cyclodextrin (w380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-CyD), heptakis(2,6-di-O-methyl)-w380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-cyclodextrin (DMw380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD) and heptakis(2,3,6-tri-O-methyl)-w380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-cyclodextrin (TMw380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD) ontrans-cis photoisomerization of 1-ethyl-4-(4w380n14522661410/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">-hydroxystyryl)pyridinium (POH) have been studied in aqueous solutions. The ratio of [cis]/[trans] for POH in the photostationary state at pH 8.54 was remarkably reduced by the presence of w380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD or DMw380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD. The reduction of the [cis]/[trans] ratio in the photostationary state was explained in terms of the shift of the equilibrium of POH ₊ ^trans w380n14522661410/xxlarge8652.gif" alt="rlhar" align="MIDDLE" BORDER="0"> PO _trans + H^– toward PO _trans formation. The binding constants of w380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD and DMw380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD for PO _trans were 2.00- and 1.36-fold larger than those for POH ₊ ^trans , respectively. The binding constants of TMw380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD for both species are much smaller than those of w380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD and DMw380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD. This result indicates that PO _trans , which has a betain structure, forms stable complexes with w380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD and DMw380n14522661410/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">CyD with its hydrophobic parts inside and the charged parts outside the CyD cavities.     

Influence of cyclodextrins on nitrosation of drugs

The World Health Organization issued a nitrosation procedure (NAP Test) which allows to carry out nitrosation under standard conditions. It has proved that the in vitro reaction rates of the fast nitrosatable drugs piperazine, cimetidine and ethambutol are not influenced by w503/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-, w503/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">- and w503/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-cyclodextrin. On the contrary, w503/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-, w503/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-cyclodextrin and heptakis-2,6-di-O-methyl-w503/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-cyclodextrin enhance the nitrosation of the slower nitrosatable 1-ephedrine and fencamfamine significantly. This possible reaction must be considered if nitrosatable drugs are formulated with cyclodextrins to be administered to human beings.     

Synthesis and ozonization of (+)-4α-(1-trimethylsilyloxyethen-1-yl)-2-carene

(+)-4w3/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-(1-Trimethylsilyloxyethen-1-yl)-2-carene was synthesized, and the products of its ozonization were identified.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1984–1987, October, 1995.     

Root determination by use of Padé approximants

In this paper we describe a new technique for generating iteration formulas — of arbitrary order — for determining a zero (assumed simple) of a functionf, assumed analytic in a region containing the zero. The 1/p Padé Approximant (pw832w32067v3/xxlarge8807.gif" alt="gE" align="MIDDLE" BORDER="0">0) to the functiong(t)w832w32067v3/xxlarge8801.gif" alt="equiv" align="MIDDLE" BORDER="0">f(z) is formed wherez=w+t, using the Taylor series forf at the pointw, an approxination to the zero off. The value oft for which the 1/p Padé Approximant vanishes provides the basis of iteration formulas of orderp+2.Some known iteration formulas, e.g., Newton-Raphson's, Halley's and Kiss's of order of convergence two, three and four, are directly obtained by settingp=0,1 and 2, respectively.     

Figures of merit of magnetostrictive single crystal iron-gallium alloys for actuator and sensor applications

Energy density, magnetomechanical coupling factor and a dimensionless sensing gage factor of 〈1 0 0〉 oriented single crystal iron-gallium alloys with 16, 17.5, 19, 24.7 and 29 at% gallium were studied as functions of stress and magnetic field. To estimate these quantities, the samples were characterized under different quasi-static stress and magnetic field conditions. The experimental behavior was modeled using an energy-based non-linear approach. Both the experimental data and the model simulations were used to calculate material parameters such as magnetic permeability, piezo-magnetic strain coefficient (d₃₃), inverse piezo-magnetic coefficient (stress sensitivity, d*₃₃) and Young's modulus in the material. These quantities were used to obtain energy density, magnetomechanical coupling factor and sensing gage factor as functions of magnetomechanical conditions. Maximum energy density of around 3 kJ/m³, magnetomechanical coupling factor higher than 0.75 and sensing gage factor on the order of 10³ were calculated.     

Demulsification Efficiency of Some New Demulsifiers Based on 1,3,5-Triethanolhexahydro-1,3,5-triazine

This study mainly concentrates on the synthesis of three novel demulsifiers and the investigation of their demulsification efficiency. The demulsifiers were derived from 1,3,5-triethanolhexahydro-1,3,5-triazine, which was prepared by the reaction of monoethanol amine with formaldehyde. The 1,3,5-triethanolhexahydro-1,3,5-triazine was ethoxylated by introducing 20 units of ethylene oxide and then esterified at different molar ratios with oleic acid (1, 2, and 3) to give three demulsifiers, namely, E₂₀TO, E₂₀TO₂, and E₂₀TO₃. The chemical structures of the prepared demulsifiers were confirmed by ¹H NMR and FTIR spectrum. The demulsification efficiency of these demulsifiers was tested on the natural water-in-oil (w/o) emulsions (50% water content). From the obtained results, it has been found that the investigated demulsifiers have a great potential to break the w/o emulsions. The trioleat ester (E₂₀TO₃) exhibited the maximum demulsification efficiency (96%) after 120 minutes at 55°C.