Phenoxathin chemistry. Remarks concerning the benzoylation reaction of phenoxathin

Benzoylation of phenoxathiin leads to a mixture of 2- and 3-benzoylphenoxathiins. Starting from 3-phenoxathiincarbonyl chloride and benzene in the presence of anhydrous aluminum chloride, 2-benzoylphenoxathiin was obtained instead of the 3-substituted isomer. Treating 3-benzoylphenoxathiin with aluminum chloride and hydrogen chloride a rearrangement reaction took place, leading to 2-benzoylphenoxathiin.Faculty of Chemistry, Organic Chemistry Department, University of Bucharest, 90–92 Panduri Road, Romania 76233. Romanian Academy, C. D. Nenitzescu Institute of Organic Chemistry, Splaiul Independentei, 202, Bucharest, Romania. Faculty of Pharmacy, Organic Chemistry Department, University of Medicine and Pharmacy Carol Davila, 6 Traian Vuia Street, Bucharest, Romania. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 999–1003, July, 1998.     

Mechanisms of broadening of emission lines of a laser-induced plasma generated on the surface of rigid targets

This article reports the results of an experimental investigation of the basic mechanisms that cause the broadening of emission lines of a laser-induced plasma generated on the surface of rigid targets in a gaseous atmosphere. The contribution of Stark and resonance mechanisms of emission-line broadening for the resonance doublet Al I 3s²3p²P_3/2,1/2-3s²4s²S_1/2 and triplet Mg I 3s3p³P _0,1,2 ⁰ -3s4s³S₁ is discussed. The concentrations of neutral Al atoms in the laser-induced plasma are evaluated by the magnitude of resonance line broadening. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 2, pp. 234–237, March–April, 2000.     

Estimation of the Fulfillment of the Local Thermodynamic Equilibrium Criterion for the Plasma Generated by Laser Pulses of Various Shapes at the Surface of a Solid Target

The results of experimental estimation of the fulfillment of the local thermodynamic equilibrium (LTE) criterion for the plasma generated by laser pulses of various duration at the surface of a solid target placed in a gaseous atmosphere at standard pressure are given in the present paper. The fulfillment of all the LTE criteria is demonstrated for an ensemble of neutral atoms contained in the plasma generated by a giant laser pulse or by a laser pulse whose complex shape represents several giant pulses against the background of free-running laser oscillations. The plasma excited by the radiation of a Nd : YAG laser with energy 0.4 J per pulse is examined. We have recorded a resonance broadening of atomic Al and Mg lines. This has allowed us to estimate the density of neutral atoms contained in a plasma plume.     

Spektrophotometrische untersuchungen der reaktion des palladiums mit thioxanthren-3-aldoxim

Zusammenfassung Die Reaktion zwischen Palladium und Thioxanthren-3-aldoxim (I) wurde spektrophotometrisch untersucht. Mit überschüssigem I bildet sich ein mit Benzol oder Chloroform extrahierbarer Komplex. Die Extraktion mit Benzol erfolgt am besten aus einer 0,5-n salpetersauren, Quecksilbernitrat enthaltenden Lösung, da so der Einfluß von Chloridionen vermieden wird. Die Extinktion wird bei 380 nm gemessen, wo die Absorption des Reagens vernachlässigbar ist. Im Bereich 0,25-8g Pd/ml ist die Extinktion der Konzentration proportional. Zahlreiche Fremdionen stören nicht. Sulfat muß vorher mit Barium gefällt werden, Osmium und Ruthenium lassen sich durch Destillation entfernen und Gold kann durch Extraktion mit Äthylacetat oder Äther beseitigt werden. In Abwesenheit von Quecksilbernitrat bildet sich ein Komplex im Verhältnis PdR= 14, in Anwesenheit von Quecksilbernitrat im Verhältnis 16.

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Spectrophotometric investigations of the reaction of palladium with thioxanthrene-3-aldoxime

Summary The reaction between palladium and thioxanthrene-3-aldoxime (I) was studied spectrophotometrically. A complex that can be extracted with benzene or chloroform is produced with excess of I. The extraction with benzene succeeds best from 0.5M solution containing nitric acid and mercuric nitrate so that the influence of chloride ions is averted. The extinction is measured at 380 nm, where the absorption of the reagent is negligible. The extinction is proportional to the concentration in the region 0.25–8g Pd/ml. Numerous foreign ions do not interfere. Sulfate must be removed previously by precipitation with barium; osmium and ruthenium can be removed by distillation, and gold can be removed by extraction with ethylacetate or ether. In the absence of mercuric nitrate there is formed a complex in the ratio of PdR=14, while in the presence of mercury nitrate the ratio is 16.

     

Femtosecond Laser Filamentation in Liquid Spray

Russian Physics Journal - The paper presents the femtosecond laser filamentation, which splits the liquid spray into two jets. The dependence is suggested for the acoustic signal and the...     

Combination of organic acid and heat–moisture treatment: impact on the thermal,structural, pasting properties and digestibility of maize starch

Journal of Thermal Analysis and Calorimetry - Maize is the most important source of starch used for industrial applications. Its starch properties can be improved by either single or double...     

Ethanol production by a flocculant yeast strain in a CSTR type fermentor with cell recycling

Tests were performed in a continuous stirred tank reactor (CSTR), with and without cell recycling, to produce ethanol. The reactor without cell recycling produced the kinetic model of ethanol production, whereas the reactor with cell recycling allowed for a study of process stability. The Levenspiel kinetic model was adopted; however, in the case of fermentation with cell recycling, the coefficient of cell death was added. It was observed that cellular viability varied greatly throughout the fermenting process and that microaeration is of fundamental importance in maintaining the stability of the process.     

Synthesis of n-(phenoxathiin-2-carbonyl)-or N-(thianthrene-2-carbonyl)-N′-arylthioureas

The reactions of phenoxathiin-2-carbonyl-or thianthrene-2-carbonyl-isothiocyanates with certain primary amines lead to the formation of corresponding N-substituted-N-hetaroylthiocarbamides. The aforementioned isothiocyanates were obtained in situ by reactions of phenoxathiin-2-or thianthrene-2-carbonyl chlorides with KSCN. The new compounds were characterized by elemental analysis and spectral data (IR,¹H and¹³C NMR).Analytical Laboratory-Biofarm, 99 Logofat Tautu Street, Bucharest, Roumania. Faculty of Pharmacy, Organic Chemistry Departament, University of Medicine and Pharmacy Carol Davila, 6 Traian Vuia Street, Bucharest, Roumania, Faculty of Chemistry, Organic Chemistry Department, University of Bucharest, 90–92 Panduri Road, 76233, RoumaniaPublished in Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1681–1686, December, 1999.     

Syntheses of New Carbonyl Derivatives from α-Halohetaryl Ketones

The Kröhnke reaction of 2-bromoacetylphenoxathiin and 2--bromophenoxathiin 10,10-dioxide, through N-ylide and S-ylide intermediates, leading to the corresponding glyoxals, was described. The condensation reaction of 2--bromoacetylphenoxathiin with aromatic o-hydroxy aldehydes and further cyclization to new furan derivatives was also performed. The new compounds were characterized through elemental analysis and spectral data (IR, ¹H NMR and ¹³C NMR).     

Essential oils and their constituents: anticonvulsant activity

A literature-based survey of plants species and their essential oils with anticonvulsant activity was carried out. As results, 30 species belonging to 13 families and 23 genera were identified for their activities in the experimental models used for anticonvulsant drug screening. Thirty chemical constituents of essential oils with anticonvulsant properties were described. Information on these 30 species is presented together with isolated bioactive compound studies.