Gold(III) chloride-catalyzed three-component reaction: a facile synthesis of alkynyl derivatives of 1,2-dihydroquinolines and isoquinolines

Gold(III) chloride is found to be an effective catalyst for the addition of alkynes on activated quinoline/isoquinolines to produce a series of alkynyl-substituted 1,2-dihydroquinolines and isoquinolines in a single-step operation. The easy availability of starting materials, convenient synthetic procedure, operational simplicity, and high regioselectivity makes this strategy very useful for the preparation of enyne derivatives of aza-aromatic compounds.     

Refractive index and molar refractivity of benzonitrile, chlorobenzene, benzyl chloride and benzyl alcohol with benzene at T = 298.15, 303.15, 308.15 and 313.15 K

Densities and refractive indices were measured for the binary liquid mixtures formed by benzonitrile, chlorobenzene, benzyl chloride, and benzyl alcohol with benzene at (T = 298.15, 303.15, 308.15 and 313.15 K) and atmospheric pressure over the whole concentration range. The Lorentz–Lorentz mixing rule, the Ramaswami and Anbananthan model, and the model devised by Glinski were used to study the refractive index and molar refractivity. These results have been discussed to study the type of mixing behavior between the mixing molecules. The measured data were fitted to the Redlich–Kister polynomial relation to estimate the binary coefficients and standard errors. Furthermore, the McAllister multibody interaction model is used to correlate the binary refractive index with the experimental findings. It is observed that molar refractivity, molecular interaction, and association constant can be better understood from these models.     

Fluorescent chemosensor for Cu2+ ion based on iminoanthryl appended calix[4]arene

Calix[4]arene based podands 1a of cone conformation and 1b of 1,3-alternate conformation possessing imine units and bearing anthracene moieties have been synthesized by a 1 + 2 Schiff base condensation in good yields and examined for their cation recognition abilities towards cations such as lithium, sodium, potassium, nickel, cadmium, copper, zinc, lead, silver and mercury ions by UV–vis and fluorescence spectroscopy. The calix[4]arene derivative 1b shows a selective fluorescence enhancement in presence of Cu²⁺ ions among the various metal ions tested (Li⁺, Na⁺, K⁺, Ni²⁺, Cd²⁺, Cu²⁺, Zn²⁺, Pb²⁺, Ag⁺ and Hg²⁺ ions). The colour of the solution changes from colourless to light yellow in the presence of Cu²⁺ ions. The stoichiometry of the complex formed between 1b and Cu²⁺ was found to be 1:1 as established by Job’s plot.     

Multiple topologies from glycopolypeptide-dendron conjugate self-assembly: nanorods, micelles, and organogels

Glycopolypeptides (GPs) were synthesized by ring-opening polymerization of glycosylated N-carboxyanhydride monomer and attached to hydrophobic dendrons at one chain end by "click" reaction to obtain amphiphilic anisotropic macromolecules. We show that by varying polypeptide chain length and dendron generation, an organogel was obtained in dimethylsulfoxide, while nanorods and micellar aggregates were observed in aqueous solutions. Assemblies in water were characterized by electron microscopy and dye encapsulation. Secondary structure of the GP chain was shown to affect the morphology, whereas the chain length of the poly(ethylene glycol) linker between the GP and dendron did not alter rod-like assemblies. Bioactive surface chemistry of these assemblies displaying carbohydrate groups was demonstrated by interaction of mannose-functionalized nanorods with ConA.