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.     

Synthesis of modified amino acids containing nucleic acid purine bases

The reaction of hydrazides of adenylyl- or hypoxanthinyl-9-alkylcarboxylic acids with sodium nitrite in acid media gives reactive azides of purinyl-9-alkylcarboxylic acids which condense with ()-aminocarboxylic and ,-diaminocarboxylic acids to give N(N)-(adenylyl-9-alkanoyl) aminocarboxylic, N-(adenylyl-9-)- and N-(hypoxanthinyl-9-alkanoyl)-,-diaminocarboxylic acids. The deamination of N-(adenyl-yl-9-alkanoyl)aminocarboxylic acids gives N-(hypoxanthinyl-9-alkanoyl)aminocarboxylic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 126–130, January, 1985.     

Synthesis of optically active 9-purinyl-α-amino acids

A general method for the synthesis of optically active 9-purinyl--amino acids by condensation of 5-amino-4,6-dichloropyrimidine with ,-diamino carboxylic acids and subsequent cyclization of the N-(5-amino-4-chloro-6-pyrimidinyl)-amino acids with triethyl orthoformate was developed. A number of 6-substituted -amino--(9-purinyl) carboxylic acids were obtained by nucleophilic substitution of the chlorine atom in the -amino--(6-chloro-9-purinyl) carboxylic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1690–1695, December, 1982.     

Simple Estimations of Dynamic Polarizabilities and Dispersion Coefficients Using the Spectral Moment Method

A modification of the spectral moment technique is suggested to calculate the frequency-dependent polarizabilities (i ) and ( ) and the corresponding dispersion constants. Unlike the previous schemes, this method uses the spectral moments S _q with positive values of q. Both variational and nonvariational methods are tested. An effective nonvariational procedure is worked out which isolates a regular (odd) component from the Brown–Rebane functional for (i ). Fast convergence to exact values is achieved by using a suitable renormalization of the electron transition pseudospectrum. The method is illustrated by the semiempirical and ab initio calculations of molecular systems of various classes.     

Synthesis of α, α, ω-trihydropolyfluoroalkyl chlorophosphates by the reaction between α,α,ω-trihydropolyfluoroalkyl phosphites and sulfuryl chloride

Conclusions An efficient method for the synthesis of ,,-trihydropolyfluoroalkyl chlorophosphates is by reacting ,,-trihydropolyfluoroalkyl dichlorophosphites and bis-(,,-trihydropolyfluoroalkyl) phosphites with sulfuryl chloride. It has been found that in three-coordinated polyfluoroalkyl phosphites, the high electronegativity of the polyfluoroalkyl groups hinders cleavage of the latter on reaction with sulfuryl chloride, thereby facilitating the formation of oxidation products.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 146–149, January, 1988.     

Electrochemical oxidation of tetramethyl esters of α,α,ω,ω-alcaneteracarboxylic acids

Cyclization of esters of butane-1,1,4,4- and pentane-1,1,5,5-tetracarboxylic acids during electrolysis in methanol in the presence of Nal produces, with a yield of 95%, the esters of cyclobutane-1,1,2,2- and cyclopentane-1,1,2,2-tetracarboxylic acids. Under similar conditions, esters of the highest ,,,-alkanetetracarboxylic acids undergo iodation and hydroxymethylation due to electrical oxidation of methanol to formaldehyde. During electrolysis in methanol in the presence of NaOAc, the esters of ,,,-alkanetetracarboxylic acids undergo effective hydroxymethylation, followed by cyclization into substituted five- and six-member lactones, or tetrahydrofurans when structurally possible.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2332–2339, October, 1992.     

Reaction ofα,α-dichloro-ω-bromoalkanes andα,α-dichloro-ω-bromoalkenes with benzylmagnesium and allylmagnesium halides

Conclusions The,-dichloro--bromoalkanes and,-dichloro--bromoalkenes react with the benzyl- and allylmagnesium halides in tetrahydrofuran solution to give,-dichloroalkyl(alkenyl)benzenes,,-dichloroalkadienes in high yields. For all practical purposes the reactions do not go in ether.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 886–890, April, 1972.     

Intercalation of α,ω-Alkanediamines in Layered Aluminium Dihydrogen Triphosphate Dihydrate

Intercalation of ,-alkanediamines, NH₂(CH₂) _n NH₂ (n = 3–10), into layered aluminium dihydrogen triphosphate dihydrate, AlH₂(P₃(O₁₀... 2H₂O, was investigated by XRD, DTA-TG, elemental analysis, and solid-state ³¹P, ¹³C and ²⁷Al NMR. ,-Alkanediamines are intercalated to form a monomolecular layer in the interlayer region, in which the alkanediamines incline at 57 ± 5° to the phosphate layers, whereas n-alkylamines form a bilayer structure with the same inclination angle. Two amino groups in an ,-alkanediamine molecule bridge the layered sheets of phosphates.     

Force constant calculations of the LAM-1 modes ofn-alkanes and their substituted α-Monohalo- and α,ω-dihalo- species in their extended zig-zag planar configurations as found in urea inclusion compounds

Force constants were determined for the C₈, C₁₀, C₁₂ and C₁₄ series ofn-alkanes C _n H_{2n + 2} using an approximate SVFF calculation and observed LAM = 1 wave numbers. In this calculation the hydrogen atoms were neglected and only the carbon backbone chain and terminal atoms were considered; this was valid since only low-frequency vibrations were under consideration. Using force constant transfer, the wavenumbers of the LAM = 1 accordion modes for the analogous -C_n H_2n + 1 X and ,-C_n H_2nX₂ species, where X = C1, Br or I were calculated. For -chloroalkanes and ,-dichloroalkanes, them = 1 accordion modes are calculated to be in the 220–130 cm^–1 and 200–120 cm^–1 regions, respectively. For the bromo- and iodo-analogues them = 1 accordion modes are calculated to be in the 200–100 cm^–1, 150–90 cm^–1 and in the 170–100, 135–80 cm^–1 regions, respectively.     

Some transformations of α,ω-bis(1,3-thiazan-2-thion-4-on-3-yl)alkanes

The reaction of ,-bis(1,3-thiazan-2-thion-4-on-3-yl)alkanes with hydrazine gives the corresponding ,-di(4-thiosemicarbazido)alkanes, which are readily acylated. Subsequent dehydration of the acylation products gives the corresponding 5,5-dialkyl-,-bis(2,3-dihydro-1,2,4-triazole-3-thion-4-yl)alkanes, which are converted to 5,5-dialkyl- , -bis (1,2,4-triazol4-yl)alkanes by known methods. The UV and ER spectral data are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1060–1062, August, 1977.     

New α,ω-diamido and α,ω-diamino mono-and bi-bridged acridine dimers

A novel set of dimers derived from 9-amino acridine was prepared and characterized by¹H and¹³CNMR. These derivatives are bridged at several different positions of the heterocyclic moieties, by the way of ,-diamido or ,-diamino side-chains. Additionally the preparation of some bi-bridged compounds was achieved.

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Neue ,-Dimaido- und ,-Diamino-Mono- und Bi-überbrückte Acridin-Dimere

Zusammenfassung Es wurde eine neue Reihe von Dimeren des 9-Aminoacridins hergestellt und mittels¹H und¹³C-NMR charakterisiert. Diese Derivate sind an verschiedenen Positionen des Heterocyclus mit ,-Diamido- oder ,-Diamino-Seitenketten überbrückt. Zusätzlich wurden auch einige zweifachüberbrückte Verbindungen hergestellt.

     

An improved method for preparing α,ω-dinitroalkanes

Summary We have suggested an improved method for preparing , -dinitroalkanes which consists in the action of silver nitrite on , -dibromoalkanes in petrofeum ether medium with heating.     

Enazide, 2. Mitt.: Synthese von 1,3-Diaryl-3-azido-propenonen (α-Azidochalkonen)

Zusammenfassung Durch Kondensation von verschiedenen -Azidoacetophenonen mit aromatischen Aldehyden wurde eine Reihe von -Azidochalkonen erhalten.

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Synthesis of 1.3-diaryl-2-azido-propenones (-azido-chalcones)

Some -azido-chalcones are prepared by condensation of -azido-acetophenones with aromatic aldehydes.

     

Reaction of 2-mercaptopyrimidines with some α,ω-dihaloalkanes

Conclusions In the reaction of some 2-mercapto-4,6-disubstituted pyrimidines with different,-dihaloalkanes, thiazolepyrimidine and pyrimidothiazine salts, 2-(-haloalkylthio)-4,6-disubstituted pyrimidines, and,-bis (4,6-disubstituted pyrimidinyl-2-thio) alkanes are formed. The structure of the products of the reactions is a function of the nature of the substituents in the pyrimidine ring, the number of methylene groups in the,-dihaloalkanes, and the ratio of the reagents.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1396–1402, June, 1984.     

Reactions of 2-mercaptopyrimidines with α, ω-bromochloro- and α, ω-bromofluoroalkanes

The reactions of 2-mercaptopyridines with , -bromohaloalkanes have given the corresponding haloalkylthiopyrimidines and , -bis(2-pyrimidylthio)alkanes. The IR spectra of the compounds obtained have been recorded and some of their constants have been determined.     

Synthesis of 1,1-dihydroperfluorooxaalkan-1-ols and their interaction with terephthaloyl chloride

A series of 1,1-dihydroperfluorooxaalkan-1-ols and ,,,-tetrahydroperfluorooxaalkanediols has been synthesized. Some tercphthalates were synthesized by the reaction of these alcohols and diols with terephthaloyl chloride.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1573–1576, June, 1996.     

Derivatives of 2-mercapto-6-methyluracil

The reaction of the sodium salt of 2-mercapto-6-methyluracil with , -dibromoalkanes Br(CH₂)Br (n=1,4,5,6) has given the corresponding , -bis(4-hydroxy-6-methyl-2-pyrimidinylthio) alkanes. The reaction of the same salt with 1,2-dibromoethane gave 7-methyl-5-oxo-2,3,4,5-tetrahydrothiazolo[3,2-a]pyrimidine and 5-methyl-7-oxo-2,3,4,7-tetrahydrothiazolo[3,2-a]pyrimidine, and its reaction with 1,3-dibromopropane led to 8-methyl-6-oxo-3,4,5,6-tetrahydro-2H-pyrimidino[2,1-b]-1,3-thiazine.     

Thermodynamics of Binding of α:-Cyclodextrin to Straight-Chain Alkyl Derivatives in Aqueous Solution

Apparent standard Gibbs energy, enthalpy, entropy, and heatcapacity data of the interactions of -cyclodextrin (CD) to some n-carboxylatesH(CH₂)_nCOO^- (n = 4–6), are determined by isothermal titration microcalorimetryat different temperatures in phosphate buffer, pH 9.0, assuming a 1 : 1 model indilute solution. Modelling of contributions of the thermodynamic properties of the solutionindicates that CD undergoes conformational change upon binding to homologousseries of n-carboxylates, n-alcohols, ,-alkane dicarboxylates and ,-alkane diols.     

Zur Behandlung induktiv wirksamer Gruppen in der LCAO-MO-Methode (Hückelmethode), 1. Mitt.: Allgemeine Theorie

Zusammenfassung Der induktive Effekt einer an ein aromatisches oder konjugiertes System gebundenen GruppeG wird durch die Änderung desCoulombintegrals desjenigen C-Atoms, an das die GruppeG direkt gebunden ist, berücksichtigt, indem für dieses _s = + angesetzt wird. Der den induktiven Effekt quantitativ beschreibende Parameter kann aus UV-Spektren abgeleitet werden. Die Prozedur dieser halbempirischen Bestimmung von wird allgemein beschrieben und begründet.Mit 1 AbbildungDie wesentlichen Teile dieser Arbeit wurden während meiner Zugehörigkeit zur Quantum Chemistry Group des Mathematical Institute, University of Oxford, im Studienjahr 1957/58 ausgeführt. Vgl. Progress Report, Session 1957–1958, S. 26.     

Simultaneous flow measurement of specific heats and thermal expansion coefficients of liquids: Aqueoust-BuOH mixtures and neat alkanols and alkanediols at 25°C

A flow method is described for the simultaneous measurement of volumetric specific heat capacities c _p ^v and thermal expansion coefficients of liquids, using a Picker heat capacity microcalorimeter. the method involves a simple sequence of operations in which the calorimeter unit is used alternately to measure a difference in volumetric specific heats at constant flow rate and temperature, or a flow rate variation resulting from a temperature scan on a flow cell. The precision of the method in measurements is close to 1% which is comparable to that of current dilatometric methods; the overall time for the combined c _p ^v - measurement is less than 30 minutes. Typical uses and reliability of the method are illustrated through results for aqueous NaCl solutions, t-BuOH-water mixtures, and ,-diols (C₂–C₅) at 25°C. The and c _p ^v values in homologous series of normal alkanes, alcohols and diols appear well represented by equations comprising two contributions, one related to the hydrocarbon chain length, the other dependent on the number density of –OH groups. The general trends in these data and comparison with similar results for H₂O₂ and H₂O illustrate the magnitude of the c _p ^v and anomalies in liquid water.