Implementation of micelle-enabled C(sp)-C(sp) cross-electrophile coupling in pharmaceutical synthesis.

A sustainable C(sp)-C(sp) cross-electrophile coupling was developed between readily available 5-bromophthalide and 1-benzyl-4-iodopiperidine under micellar conditions, leading to a key intermediate of one of our development compounds. Copper was found to play a crucial role as a co-catalyst in this dual catalysis system. The chemistry and process were successfully demonstrated in a kilo scale to deliver sufficient drug substance to the clinical campaigns.

Transitions of tethered polymer chains: a simulation study with the bond fluctuation lattice model.

A polymer chain tethered to a surface may be compact or extended, adsorbed or desorbed, depending on interactions with the surface and the surrounding solvent. This leads to a rich phase diagram with a variety of transitions. To investigate these transitions we have performed Monte Carlo simulations of a bond fluctuation model with Wang-Landau and umbrella sampling algorithms in a two-dimensional state space.

Concentrations of the propylene metabolite propylene oxide in blood of propylene-exposed rats and humans--a basis for risk assessment.

Propylene (PE) was not carcinogenic in long-term studies in rodents. However, its biotransformation to propylene oxide (PO) raises questions about a carcinogenic risk. PO alkylates macromolecules, is a direct mutagen, and caused tumors in rodents at high concentrations.

Unexpectedly normal phase behavior of single homopolymer chains.

Employing Monte Carlo simulations, we show that the topology of the phase diagram of a single flexible homopolymer chain changes in dependence on the range of an attractive square well interaction between the monomers. For a range of attraction larger than a critical value, the equilibrium phase diagram of the single polymer chain and the corresponding polymer solution phase diagram exhibit vapor (swollen coil, dilute solution), liquid (collapsed globule, dense solution), and solid phases. Otherwise, the liquid-vapor transition vanishes from the equilibrium phase diagram for both the single chain and the polymer solution.

New monodentate chiral phosphite ligands for asymmetric hydrogenation.

We report the synthesis of new chiral monodentate phosphite ligands with a biphenyl backbone, the axial chirality of which is introduced early in the synthesis and locked by a chiral alkylenedioxy bridge. We also describe results obtained with these ligands in rhodium-catalysed asymmetric hydrogenation of various substrates.