Palladium‐Catalyzed Chemoselective and Biocompatible Functionalization of Cysteine‐Containing Molecules at Room Temperature

The third generation of aminobiphenyl palladacycle pre‐catalyst “G3‐Xantphos” enables functionalization of peptides containing cysteine in high yields. The conjugation (bioconjugation) occurs chemoselectively at room temperature under biocompatible conditions. Extension of the method to protein functionalization allows selective bioconjugation of the trastuzumab antibody.     

Adsorption properties of novel gemini surfactants with nonidentical head groups

Novel environmentally friendly gemini surfactants, each with two hydrophilic and two hydrophobic groups, have been synthesized and their physicochemical properties investigated. One of the hydrophilic groups is a methyl-capped polyoxyethylene chain with mol wt 350, 550, and 750 g/mol, respectively, and the other is a sulfate group; the hydrophobic part of the surfactant is made from oleylnitrile. This nitrile derivative of the fatty acid is used to achieve good hydrolytic stability. Du Nouy ring and maximum bubble pressure tensiometry were used for equilibrium and dynamic surface tensions, gamma(e) and gamma(t), respectively. The aqueous-phase critical micelle concentrations of the heterogeminis (HGs) have been investigated. The results have been compared with those for mixtures of standard surfactants sodium decylsulfate and octaoxyethyleneglycol mono n-decyl ether under equivalent conditions. The HGs are shown to exhibit improved performance over the mixed system both in terms of micellization and surface tension lowering. Dynamic surface tension (DST) studies were performed to investigate air-water adsorption mechanisms. A diffusion-limited mechanism was confirmed in the initial stages of adsorption. However, closer to the equilibrium the DST data are inconsistent with a diffusion-only mechanism. In particular, the HGs show a larger deviation from diffusion control as compared to the model mixture, which is a signature of slower adsorption kinetics. In addition to air-water interfaces, properties of these HGs have also been investigated at solid silica-solution surfaces by optical reflectometry. These surfaces were either naturally hydrophilic or rendered hydrophobic by chemical modification. On either surface the maximum amount of adsorbed surfactant was found to increase when the polyoxyethylene chain length decreases.     

Adsorption of Pb(II) and Ni(II) From Aqueous Solution by a High-Capacity Industrial Sewage Sludge-Based Adsorbent

In the present study, adsorption of Ni(II) and Pb(II) from aqueous solution was investigated using activated carbon synthesized with industrial wastewater sludge. The synthesized adsorbent was analyzed using nitrogen adsorption–desorption and Fourier transfer infrared (FTIR) techniques. Batch adsorption mode was used to evaluate the effect of solution pH, contact time, adsorbent dose, initial metal ion concentration, and temperature on the adsorption capacity of the synthesized adsorbent. The kinetic data were analyzed using different kinetic models. The pseudo-second-order equation gave the best fit to the experimental data for both metal ions. The equilibrium isotherm data were analyzed using the Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) isotherm models. The results showed that the data obtained for the Ni(II) and Pb(II) adsorption are in good agreement with the Langmuir model. The Langmuir mono-layer maximum adsorption capacities for Ni(II) and Pb(II) ions were estimated to be 74.06 and 88.76 mg g^?1 at 25°C, respectively. In addition, the thermodynamic studies proved that the adsorption process of both metals could be considered endothermic.     

An Efficient Synthesis of Enediyne and Arenediyne Lactams

Enediyne and arenediyne lactams are easily synthesized from (Z)-dichloroethylene and o-dibromobenzene.     

Bioreduction of Acetophenone Derivatives by Red Marine Algae Bostrychia radicans and B. tenella,and Marine Bacteria Associated

The biocatalytic reduction of acetophenone derivatives was exploited by using algal biomass from Bostrychia radicans and B. tenella producing exclusively (S)‐2‐phenylethanols with high enantiomeric excess (>99% ee). Bacterial populations associated with algal biomass were identified as the Bacillus genus. This report deals with the first investigations involving the use of marine bacteria associated with B. radicans and B. tenella marine algae for the biocatalytic reduction of acetophenone derivatives.     

Cs2CO3 in pyrrolidinone promoted hydration of functionalized (hetero)aryl nitriles under metal-free conditions

An efficient hydration reaction of various (hetero)aryl nitriles using Cs₂CO₃ in pyrrolidinone is described. This new metal-free protocol proved to be highly effective and general to synthesize a variety of (hetero)aryl amides.     

An efficient synthesis of 3‐triazolyl‐2(1H)‐quinolones by CuTC‐catalyzed azide–alkyne cycloaddition reaction

A facile and efficient Cu(I)‐catalyzed azide–alkyne cycloaddition reaction for the synthesis of a series of 3‐triazolyl‐2(1H)‐quinolones 3 have been developed using 3‐azido‐quinolin‐2(1H)‐one as the coupling partner. The optimized reaction conditions involve the use of eco‐ friendly ethanol as the solvent in the presence of copper(I) thiophene‐2‐carboxylate as the catalyst, to afford good to excellent yields of 3‐triazolyl‐2(1H)‐quinolone derivatives of biological interest. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis of Potential Cytotoxic α-Methylene γ-Lactams

α-Methylene γ-lactones are known to have physiological activity, especially as cytotoxic agents, and are widely found in nature (1). However they are often toxic which makes them inappropriate for cancer treatment.     

Copper-catalyzed reductive coupling of tosylhydrazones with amines: a convenient route to α-branched amines

A general procedure for the reductive coupling of N-tosylhydrazones with amines in the presence of Cu(acac)(2) and Cs(2)CO(3) has been developed. The protocol is very effective and chemoselective with various primary and secondary aliphatic amines, aminoalcohols as well as azole derivatives to give α-branched amines in good yields.