Synthesis of Privileged Scaffolds by Using Diversity‐Oriented Synthesis

An elegant reagent‐controlled strategy has been developed for the generation of a diverse range of biologically active scaffolds from a chiral bicyclic lactam. Reduction of the chiral lactam with LAH or alkylation with LHMDS to trigger different cyclization reactions have been shown to generate privileged scaffolds, such as pyrrolidines, indolines, and cyclotryptamines. Their amenability to substitution allows us to create various compound libraries by using these scaffolds. In silico studies were used to estimate the drug‐like properties of these compounds. Selected compounds were subjected to anticancer screening by using three different cell lines. In addition, all these compounds were subjected to antibacterial screening to gauge the spectrum of biological activity that was conferred by our DOS methodology. Gratifyingly, with no additional iterative cycles, our method directly generated anticancer compounds with potency at low nanomolar concentrations, as represented by spiroindoline 14 .     

Sizing nanoparticle-covered droplets by extrusion through track-etch membranes

Interfacial segregation of nanoparticles on droplets, such as water droplets in oil, is achieved by mixing or shaking organic solutions of the nanoparticles with water. This typically results in the formation of droplets with a large distribution of sizes, ranging from 10 microm to greater than 200 microm in diameter. Here we describe the application of track-etch membranes to control the size of these nanoparticle-coated droplets. Passing nanoparticle-coated droplets through the membranes substantially reduces their size by breaking up the droplets during the extrusion process and reforming droplets of comparable size to the membrane pore diameter. When the nanoparticles used in these sizing procedures are covered with functional ligands, stabilization of the post-extrusion diameter is achieved by polymerization/cross-linking of the ligand periphery.     

Chiral α-alkylation/arylation in 1-phenyl-2-(1-pyrrolidinyl)-1-propanol through Grignard reactions

Complete asymmetric induction has been achieved during Grignard alkylations/arylations resulting in (1S,2R)- and (1R,2R)-1-phenyl-1-alkyl/aryl-2-(1-pyrrolidinyl)-1-propanols which are isolated as hydrochlorides.     

High-pressure ethylene oxidation behind reflected shock waves

Oxidation of ethylene/air mixtures has been investigated behind reflected shock waves in a shock tube of 76 mm in diameter. Experiments were performed within the temperature range of 1060–1520 K, pressures of 5.9–16.5 atm, and stoichiometries of  = 0.5, 1.0, and 2.0. Emissions of OH (308.9 nm), CH (431.5 nm) and C₂ (516.5 nm) molecules, pressures and ion current records were implemented to measure ignition times of the mixture along the centreline of the tube and in the boundary layer. Empirical correlations for ethylene ignition times have been deduced from the experimental data. Auto-ignition modes (strong, transient and weak) and ignition limits of the mixtures were identified comparing velocities of reflected shock wave and reaction front at different locations from the reflecting wall. Extensive database for validations of high-temperature ethylene reaction mechanism and numerical methods for reaction flow simulations has been obtained from experimental observations.     

On the kinetics of nanoparticle self-assembly at liquid/liquid interfaces

We investigate the concentration and size dependent self-assembly of cadmium selenide nanoparticles at an oil/water interface. Using a pendant drop tensiometer, we monitor the assembly kinetics and evaluate the effective diffusion coefficients following changes in the interfacial tension for the early and late stages of nanoparticle adsorption. Comparison with the coefficients for free diffusion reveals the energy barrier for particle segregation to the interface. The formation of a nanoparticle monolayer at the oil/water interface is characterised by transmission electron microscopy.