Properties of two polymerizable surfactants aqueous solutions: dodecylethylmethacrylatedimethylammonium bromide and hexadecylethylmethacrylatedimethylammonium bromide. I. Critical micelle concentration

The aggregation of two polymerisable surfactants dodecylethylmethacrylatedimethylammonium bromide (C₁₂PS) and hexadecylethylmethacrylatedimethylammonium bromide (C₁₆PS) was studied with a battery of methods. Both surfactants form premicelles at low concentration, and show a critical micelle concentration and a transition between spherical and rod-like micelles. The micelle ionization degree and the adsorption at the air/solution interface were also studied. Results are interpreted on the basis of the conformation of the polar head group.     

A general and efficient CuI/BtH catalyzed coupling of aryl halides with thiols

We report an exceptionally mild, general and efficient copper catalyzed cross coupling reaction of aryl bromides and thiols using 0.5 mol % CuI and 1 mol % benzotriazole. Experimental simplicity, generality, functional group tolerance and low cost of the catalyst are advantages of the protocol.     

A Microcalorimetric Study of Host–Guest Complexes of α-Cyclodextrin with Alkyl Trimethyl Ammonium Bromides in Aqueous Solutions

Interactions between α-CD and three alkyl trimethyl ammonium bromides, a homologues series of surfactants, in aqueous solutions have been investigated with titration microcalorimetry at 298.15 K. The results are discussed in the light of the amphiphilic interaction and the iceberg structure of water molecules existing around the hydrophobic tail of the surfactant. The stoichiometry of the host–guest complex changes from 1:1 to 2:1, as the number of carbon atoms (n) in the hydrophobic chain, C_nH_2n+1, increases from 8 to 14. All the complexes are quite stable, with the apparent experiential stability constants being β₁ = 2.65 × 10³ dm³-mol⁻¹, β₂ = 4.85 × 10⁶ dm⁶-mol⁻², β₂ = 6.50 × 10⁶ dm⁶-mol⁻², respectively for n = 8, 12, 14. All the complexation processes are shown to be enthalpy driven, and the standard enthalpy effect (−ΔH⁰) increases while standard entropy change (ΔS⁰) decreases with elongation of the hydrophobic chain.     

A novel P,S-heterodonor ligand and palladium(0) complex catalyzed Suzuki cross-coupling reaction

Axially dissymmetric P,S-heterodonor ligand L3 synthesized from BINOL is an effective promoter in the palladium(0)-catalyzed Suzuki cross-coupling reaction of phenylboronic acid with aryl bromides and iodide at 60-80 °C. On the basis of ¹³C and ³¹P NMR spectroscopic investigation and X-ray diffraction, it was revealed that N,N-dimethylthiocarbamate-phosphine ligand L3 might be a P,S-heterodonor bidentate ligand to palladium(0) center.     

Ammonium Chloride Promoted Palladium-Catalyzed UIImann Coupling of Aryl Bromide

In water, ammonium chloride was found to promote palladium-catalyzed Ullmann coupling reactions of aryl bromides. In the presence of Pd/C, zinc, NH4Cl, and water, coupling of various aryl bromides was carried out smoothly to afford the corresponding homocoupling products in moderate yields.     

Synthesis of 2-(3-furyl)-1H-benzimidazoles from 2-phenacyl-1H-benzimidazoles

C-Alkylation at the active methylene group of 2-phenacyl-1H-benzimidazoles with phenacyl bromides proceeds highly selectively with the formation of the corresponding 1,4-diketones, which on heating with hydrochloric acid are cyclized with the formation of the previously unknown 2-(2,5-diaryl-3-furyl)-1H-benzimidazoles. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1637–1645, November, 2007.     

Reactions of 1-acyl-2-bromoacetylenes with dithiocarbamic acids

2-Acyl-2-bromoacetylenes react with dithiocarbamic acids in aprotic solvents (acetonitrile, chloroform, or ether) to give 5-acyl-2-diethylamino(heteryl)-1,3-dithiolium bromides, which on reaction with secondary amines (diethylamine or morpholine) undergo cleavage of the 1,3-dithiole ring to give 1-acyl-2-diethyl(morpholyl)dithiocarbamoyl-2-diethylamino(morpholyl)ethylenes. X-ray crystallographic studies on the product from one of these reactions has shown it to be 5-thenoyl-2-diethylamino-1,3-dithiolium bromide.Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, 664033 Irkutsk. A. V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, 117331 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1850–1856, August, 1992.     

Synthesis of (Z)-trisubstituted olefins with all substituents different from methylvia α,β-disubstituted (E)-acroleins

(E)-2,3-Disubstituted allyl bromides readily accessible in two steps from the corresponding enals react with dialkyl cuprates in a high regio- and stereoseiective fashion to give (Z)-trisubstituted olefins with all substituents different from methyl. This reaction was used in the synthesis of benzyl 7-methyl-3-propyldeca-(2Z,6Z)-dienyl ether, a derivative of a component of the sex pheromone of the lesser apple wormLaspeyresia pomonella L. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1381–1386, July, 1998.     

A practical synthetic method for vinyl chlorides and vinyl bromides from ketones via the corresponding vinyl phosphate intermediates

A new synthetic method for the preparation of vinyl chlorides and vinyl bromides from acyclic and cyclic ketones is described. Vinyl halides are practically obtained from the corresponding vinyl phosphate intermediates with triphenylphosphine dihalide.     

Rapid palladium-catalyzed aminations of aryl chlorides with aliphatic amines under temperature-controlled microwave heating

Rapid Buchwald-Hartwig amination of electron neutral and rich aryl chlorides and bromides have been achieved using temperature-controlled microwave heating. Primary and secondary aliphatic amines can be coupled with these substrates in good yields within a reaction time of only 10 min.