Complex polarizability as used to analyze dielectric relaxation measurements

The effect of representing dielectric properties in terms of the complex polarizability ^c = – i is examined. Loss curves ( and tan ) are shifted towards higher frequencies, revealing the existence of new relaxations and allowing the clarifications of ones already known. We have calculated the shift ratios (at maximum or tan )/ (at maximum or tan ) from the more conventional empirical equations representing the dielectric behavior. Some examples are given.     

Steroid compounds of marine sponges. VII. Preparation of derivatives of sokotrasterol and halistanol sulfates and structure-activity interrelationships among these compounds

Five new sulfated derivatives of sokotrasterol and halistanol have been obtained: 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate); 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate) 23-palmitate; 24,25-dimethyl-5-cholestane-2,3,6-triol 3-(sodium sulfate); 24,25-dimethyl-5-cholestane-2,3,6-triol 6-(sodium sulfate); and 24,25-dimethyl-5-cholestane-2,3,6-triol 2,6-di(sodium sulfate). The inhibiting and membranolytic properties of the polysulfated steroids from sponges and their derivatives have been studied. It has been shown that physiological activity in this series of compounds depends on biphilicity.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. 441–445, July–August, 1986.     

Thermal decomposition of phosphorylated hemimercaptals

Conclusions The reaction of diphenylchlorophosphine with ,,-trichloro--hydroxyethyl ethyl sulfide in the presence of triethylamine leads to the formation of -ethylthio-,,-trichloroethyl diphenylphosphonite. The reaction of diphenylchlorophosphine with dimethyl -hydroxy--propylthiophosphonate in the presence of triethylamine gives -propylthio--dimethylphosphonoethyl diphenylphosphonite. The phosphorylated hemimercaptals obtained are thermally unstable and decompose to S-alkyl diphenylthiophosphonites and the corresponding carbonyl compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2619–2621, November, 1985.     

Porphyrins. 9. New data on the polyformylation of metal complexes of etioporphyrin I

The structures of the products of the polyformylation of Cu, Ni, and Co complexes of etioporphyrin (EP) as monoformyl-, ,-diformyl-, ,-diformyl-, and ,,-triformyl-EP were established by electronic, IR, and PMR spectroscopy and mass spectrometry. -Formyl--(N-methylformaldimine)-EP and porphyrins that contain a cyclopentane ring can be formed by alkaline treatment of the Vilsmeier formylation products.See [1] for communication 8.See [2] for our preliminary communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 767–775, June, 1979.     

Extraction of Polonium from Aqueous α-Hydroxyisobutyric Acid Solutions Using Dioctyl Sulphide, Cyanex 272, Cyanex 301 or Cyanex 302 in Toluene

A study of the extraction of polonium from aqueous solutions containing -hydroxyisobutyric acid (-HIBA) was performed with four different extractants, di-n-octyl sulphide (DOS), Cyanex 272, Cyanex 301 and Cyanex 302, dissolved in toluene. The extracted complex for DOS at low -HIBA concentrations is most likely PoO(-HIB)₂·2DOS, while at higher -HIBA concentrations there seems to be a solvating effect implicating an extracted complex of the type PoO(-HIB)₂(-HIBA)₂·2DOS. For the extraction of polonium with Cyanex 272 the results are inconclusive. The extracted complex is either PoOA₂ or PoO(-HIB)₂·2HA. For extraction with Cyanex 301 or Cyanex 302 the major extracted species does not contain any -HIBA molecules. The neutral species in both cases is PoOA₂, extracted at low extractant concentrations, while at higher extractant concentrations a complex of the type PoOA₂·xHA is extracted. The extraction of polonium increases in the order Cyanex 272 < DOS < Cyanex 302 < Cyanex 301.     

Rearrangement ofα -trifluoromethyl-β-dialkylamino-β-fluoroacrylic acid N.N-dialkylamides

Conclusions When heated in the presence of a catalytic amount of BF₃ etherate,-trifluoromethyl--diethylamino--fluoroacrylic acid N, N-dimethylamide is reversibly isomerized to-trifluoromethyl--dimethylamino--fluoroacrylic acid N, N-diethylamide. The methyl esters of-trifluoromethyl--diethylammo--fluoroacrylic acid and-trifluoromethyl--phenoxy--fluoroacrylic acid N,N-dimethylamide are not isomerized under the same conditions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.1, pp.137–141, January, 1976.     

1-Aryl-6-azauracile, 6. Mitt.: Synthese der isomeren 1-Naphthyl-6-azauracile

Zusammenfassung Auf übliche Art wurden folgende Verbindungen hergestellt: -Naphtylhydrazono-cyanacetylcarbamidsäureäthylester (1 a), 1-(-Naphthyl)-5-cyano-6-azauracil (2 a), 1-(-Naphthyl)-6-azauracil-5-carbonsäure (3 a), 1-(-Naphthyl)-6-azauracil (4 a), Amidoxim der 1-(-Naphthyl)-6-azauracil-5-carbonsäure (5 a), 1-(-Naphthyl)-5-[5-methyl-1,2,4-oxdiazolyl(3)]-6-azauracil (6 a) und die entsprechenden -Isomere aller dieser Verbindungen (1 b–6 b).5. Mitt.:J. Slouka, Mh. Chem.97, 448 (1966).     

Über halogen- und stickstoffhaltige Derivate aliphatischer Carbonsäuren, 6. Mitt.: Über die Gewinnung von α-Oximino- und α-Nitrodicarbonsäureestern

Zusammenfassung Aus den entsprechenden -Bromestern werden durch Umsetzung mit Natriumnitrit die -Oximinodicarbonsäuredimethylester C₇ und C₉ und der , -Dioximinoazelainsäuredimethylester erhalten. -Methyladipinsäure wird zum Gemisch aus -Bromund -Bromester umgesetzt. Mit Natriumnitrit wird -Nitro-und -Oximino--methyladipinsäuredimethylester erhalten.

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The -oximino dicarboxylic dimethyl esters of C₇ and C₉ and the , -dioximino azelaic acid dimethyl ester are received from the corresponding -bromo esters by reaction with sodium nitrite. -Methyladipic acid is reacted with bromine to a mixture of the -bromo and -bromo ester. Reaction with sodium nitrite gives the -nitro ester and the -oximino ester of -methyl adipic acid.

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5. Mitt.:H. Reinheckel, Mh. Chem.98, 1217 (1967).     

Synthesis of α-alkyl- and α,α-dialkyl-β-phenyltryptamines

A new method was developed for the synthesis of -alkyl- and ,-dialkyl--phenyltryptamines based on alkylation of nitroalkanes with -phenyl-nor-gramine.     

Telomerization of ethylene and carbon tetrachloride or chloroform in the presence of the hexacarbonyls of chromium,molybdenum, and tungsten

summary The reaction of telomerization of ethylene with carbon tetrachloride or chloroform is initiated by hexacarbonyls of chromium, molybdenum, and tungsten at 115–120, forming ,,,-tetrachloroalkanes and ,,-trichloroalkanes. respectively.     

Titrimetric determination of α-substituted cystines and α-substituted cysteines with N-Bromosuccinimide

Summary N-Bromosuccinimide has been employed as a titrant for the determination of -substituted DL-cystines and -substituted DL-cysteines. Using NBS and Bordeaux Red indicator, quantitative recoveries in the 1–5 mg range were obtained for L-cystine, L-cysteine, L-methionine, and the -substituted DL-cystines. With NBS and the iodine displa'cement procedure, quantitative recoveries in the 10--20 mg range were obtained for L-cysteine and the s-substituted DL-cysteines.

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Zusammenfassung N-Bromsuccinimid (NBS) wurde zur Titration von -substituierten DL-Cystinen sowie DL-Cysteinen herangezogen. Mit Bordeaux-Rot als Indikator erhält man quantitative Ergebnisse im Bereich von 1–5 mgL-Cystin,L-Cystein,L-Methionin bzw. -substituierten DL-Cystinen. Mit Hilfe des Jodverdrängungsverfahrens führt NBS zu quantitativen Ergebnissen im Bereich von 10–20 mgL-Cysteine bzw. -substituierten DL-Cysteinen.

     

Catalytic activity of transition metal silicides in hydrogen oxidation

The catalytic activity of transition metal silicides in H₂ oxidation is much higher compared to metal-like carbides, which can be due to the lower electronegativity of silicon compared to carbon.

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, , .

     

Transformed steroids. 121. Synthesis of the δ-lactone of 3β-acetoxy-16α-hydroxy-6-oxo-24-nor-5α-chol-17(20)-en-23-oic acid

The synthesis of the ¹⁷⁽²⁰⁾-16 analog of natural chiogralactone is described. Attempts to introduce a 6-oxo group directly into the -lactone proved unsuccessful, since the first stage — saponification — took place with the formation of three products: the 3-hydroxy--lactone, the 3-hydroxy-²⁰⁽²²⁾-lactone, and the 15,17(20)-dienoic acid. The synthesis of the desired compound was effected from the ethyl ester of the 5,16-dienoic acid by the scheme 3-acetate3-tosylate6-hydroxy-3,5-cyclosteroid6-oxo-3,5-cyclosteroid6-oxo-5H--lactone. It has been shown that the cyclopropane ring in the 3,5-cyclosteroid -lactone is extremely stable under the conditions of acid treatments.N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 184–187, March–April, 1981.     

Circular Dichroism Spectra of 5- and 7-Bromo-6-ketosteroids

Circulardichroismspectra of 5- and 7-bromo-6-ketosteroidsof the cholestane and stigmastane serieswere studied. A negative Cotton effect corresponding to the n-* -transition of the ketone was observed in the CD spectra of 5-bromo-6-ketosteroids at 300 nm. The analogous Cotton effect was positive in CD spectra of 7-bromo-6-ketosteroids.     

Asymmetric catalytic synthesis of lysine by hydrogenation of α-nitrocaprolactam

Conclusions The enantioselective hydrogenation of-nitrocaprolactam (I) is effected on a chiral Pd complex, obtainedin situ in the presence of S--phenylethylamine, to give S--aminocaprolactam (II), hydrolysis of which gives S-lysine. The optical yield varies from 1 to 13% according to the solvent and concentration of chiral ligand. On a Pd complex with S-N-isopropyl--phenylethylamine, enantioselective hydrogenation of (I) gives an excess of the S-enantiomer of (II) (2%). On a Pd complex with S-phenylalaninol, hydrogenation of (I) leads to the R configuration of (II) with EE 7.2%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1597–1600, July, 1987.     

Synthesis of triterpene glycosides

Summary The acyl -D-glucopyranoside, the acyl -D-xylopyranoside, the acyl D- and L--arabinopyranosides, and the acyl -D-lactoside of 18-glycyrrhetic acid, and also the acyl -D-lactoside of 18-glycyrrhetic acid have been synthesized. The acid and alkaline hydrolysis of the compounds obtained has been studied.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 1, pp. 13–19, 1968     

Geometry of α-cyclodextrin inclusion complex with m-nitrophenol deduced from quantum chemical analysis of carbon-13 chemical shifts

The host-guest orientation and the position of the guest m-nitrophenol (MNP) in the -cyclodextrin (-CD)-MNP inclusion-complexation induced carbon-13 NMR chemical shifts of MNP with those predicted by quantum chemical calculation. In the calculation, the non-polar environmental effect produced by the -CD cavity on the carbon-13 shifts of included guest molecule has been formulated by the so-called NMR solvent effect theory. Here, carbon-13 shift displacements are assumed to be induced by transference of the guest from polar aqueous phase with higher dielectric constant to the non-polar -CD cavity with lower dielectric constant. Among a variety of host-guest orientation investigated, only the geometry in which the nitrophenyl group is located in the -CD cavity and the hydroxyl groups is exposed to the aqueous phase can reproduce qualitatively the observed carbon-13 shift displacements of MNP. This geometry is consistent with that in the solid state determined by the X-ray method.     

A new synthetic strategy of cyclooligosaccharides

An effective synthetic strategy for preparing a new type of cyclooligosaccharide is proposed and along this plan, -, -, and -cycloaltrins, made up from six to eight (14)-linked D-altropyranoses, have been prepared in 36, 52, and 37% overall yields from the corresponding cyclodextrins.