Formation of 3Pseudorotaxanes from β-cyclodextrin and a Series of Dicarboxylic Acids with Their Corresponding α,ω-alkanedicarboxylate Anions

Inclusion complexes between β-cyclodextrin (β-CD) and a series of dicarboxylic acids (DAn, n=11-15) were prepared by co-grinding and co-precipitation methods and the 3pseudorotaxane structure of them was eluci-dated by FTIR, DTA and XRD characterizations. Inclusion complexes of β-CD and α,w-alkanedicarboxylate anions (DAn2-) were acquired by neutralizing β-CD/DAn different inclusion complexes with sodium hydrox-ide and the structure was also proved to be a pseudorotaxane structure by 1H-NMR spectra and NOESY spectrum. Both the inclusion complexes of β-CD/DAn and β-CD/DAn2- adopt the 3pseudorotaxane structure with β-CD arranged in dimers threaded onto one aliphatic chain and the binding mode of 1:1 inclusion complex was excluded based on the consideration of chain conformations     

Effect of Temperature on The Solubility of α-Amino Acids and α,ω-Amino Acids in Water

The aqueous solubilities of glycine, dl-α-alanine (2-aminopropanoic acid), dl-α-aminobutyric acid (2-aminobutanoic acid), dl-α-norvaline (2-aminopentanoic acid), dl-α-norleucine (2-aminohexanoic acid), β-alanine (3-aminopropanoic acid), γ-aminobutyric acid (4-aminobutanoic acid), 5-aminovaleric acid (5-aminopentanoic acid), and 6-aminocaproic acid (6-aminohexanoic acid) were determined from 293.15 to 323.15 K at intervals of 5.00 K using the gravimetric method. The temperature dependence of the solubility of α-amino acids and α,ω-amino acids in water is well described by the van’t Hoff equation. Linear van’t Hoff plots were used to determine the differential enthalpy of solution. The results obtained are compared with reported values in literature and are discussed in terms of the position of the ionic groups in the hydrocarbon chain.     

Reactions of Binor-S with α,ω-Diols and Organic Acids in the Presence of Inorganic Ionic Liquids

Russian Journal of Organic Chemistry - New methods have been developed for the synthesis of previously unknown ω-(hexacyclo[9.2.1.02,7.03,5.04,8.09,13]tetradecan-10-exo-yloxy)alkan-1-ols and...     

Reaction of α-Pinene with Haloacetic Acids

The reactions of -pinene with chloro-, bromo-, and trichloroacetic acids, accompanied by isomerization of -pinene, were studied.     

The Direction of Ring Fission of Unsymmetrically-substituted Succinic Anhydrides. 1. Interaction of α-Tetrahydrofurylsuccinic Anhydride with Benzylamine and 2,5-Xylidine

The reaction of -tetrahydrofurylsuccinic anhydride with amines proceeds regiospecifically at room temperature with the formation of N-substituted 2-(-tetrahydrofuryl)succinamic acids. On increasing the temperature the reaction direction is changed and the 3 isomer is mainly formed.     

Efficient Lewis Acids Catalyzed Aza-Michael Reactions of Enones with Carbamates

The β-amino carbonyl functionality is not only a segment of biologically important natural products but also a versatile intermediate for the synthesis of nitrogen-containing compounds.1 The development of novel synthetic methods leading to β-amino ketone, β-amino acids or their derivatives has attracted much attention in organic synthesis.2 Among the traditional methods for generating β-amino carbonyl compounds, Mannich-type reaction is one of the classical and powerful methods.3 However,…     

Synthesis,Transport, and Ionophoric Properties of α,ω-Biphosphorylated Azapodands: X. Membrane Transport of Organic Acids by Phosphorylated α,ω-Diazapodands

The membrane transport properties of novel phosphorylated azapodands with respect to mono- and polyfunctional carboxylic acids were studied. The structures of the transported Н-complexes are discussed, the complexing centers in the carriers are considered, and the correlations between the structure and transmembrane transport efficiency of the acid substrates are demonstrated.     

Enantioselective Hydrogenation of α-Substituted Acrylic Acids Catalyzed by Iridium Complexes with Chiral Spiro Aminophosphine Ligands

Highly active: Iridium complexes with chiral spiro aminophosphine ligands were synthesized and applied as catalysts for the asymmetric hydrogenation of α-substituted acrylic acids. The complexes were highly active catalysts, showing turnover frequencies of up to 6000?h(-1) , and catalyst loadings could be reduced to 0.01?mol?%.     

The condensation reaction of methylphosphonic acid with α,ω-diethoxydimethylsiloxanes

Russian Chemical Bulletin -     

Synthesis of α-Ketoamides by Copper-Catalyzed Reactions of Phenylacetic Acids with N,N-Dialkylformamides

A new synthetic approach for α-ketoamides was achieved by copper-catalyzed coupling reactions between N,N-dialkylformamides and phenylacetic acids. A variety of substrates were well tolerated to give yields of 46–87% (17 examples). A ¹³C-labeling experiment revealed that the carbonyl group of the products came from the phenylacetic acid.     

Alkylation of cyclododecanone with α,ω-dibromoalkanes under conditions of phase-transfer catalysis

Alkylation of cyclododecanone with ,-dibromoalkanes Br(CH) _n Br (n=3, 4, 5) under conditions of phase-transfer catalysis in the presence of KOH results in the formation of either bicyclic ketones forn=3 and 5 or a mixture of bicyclic and spirocyclic ketones forn=4.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1436–1438, August, 1994.     

Synthesis of α,ω-dichloropermethyloligosilanes by reactions of polydimethylsilane with metal chlorides

The reactions of high-molecular-weight polydimethylsilane with metal chlorides in variable oxidation states at high temperature in the absence of a solvent afford mixtures of ,-dichloropermethyloligosilanes Cl(Me₂Si) _m Cl (m= 2—9). The influence of the reaction conditions (temperature, reaction time, and the reagent ratio) on the composition and yields of the reaction products was examined.     

Analysis of {α,ω-Dichloroalkane or α,ω-Dibromoalkane] + Benzene and α,ω-Dichloroalkane + Tetrachloromethane} Mixtures in Terms of Group Contributions

Abstract

Molar excess enthalpies, H ^E _m, at 298.15K and atmospheric pressure have been determined for three binary liquid mixtures [x{1,3-dichloropropane or 1,4-dichlorobutane and 1,6-dichlorohexane} + (1 - x) tetrachloromethane]. These experimental results along with the data available in the literature on molar excess Gibbs energies, G ^E _m, activity coefficients at infinite dilution, In γ^∞ _i , and molar excess enthalpies, H ^E _m, for α,ω-dihaloalkanes + benzene or + tetrachloromethane mixtures are examined on the basis of the DISQUAC group contribution model.