Full stereochemical assignment and synthesis of the potent anthelmintic pyrrolobenzoxazine natural product CJ-12662

The structure of the unusual anthelmintic pyrrolobenzoxazine terpenoid natural product CJ-12662 was established by X-ray crystallography and partial synthesis from 2-chloronitrobenzene. An unusual Meisenheimer-type rearrangement was used to provide the core pyrrolobenzoxazine heterocycle, and coupling of a tetracyclic pyrrolobenzoxazine lactone with the terpene alcohol was used to complete the synthesis of CJ-12662.     

Finite-size scaling and particle-size cutoff effects in phase-separating polydisperse fluids

We study the liquid-vapor phase behavior of a polydisperse fluid using grand canonical simulations and moment free energy calculations. The strongly nonlinear variation of the fractional volume of liquid across the coexistence region prevents naive extrapolation from detecting the cloud point. We describe a finite-size scaling method which, nevertheless, permits accurate determination of cloud points from simulations of a single system size. By varying a particle-size cutoff, we find that the cloud point density is highly sensitive to the presence of rare large particles; this could affect the reproducibility of experimentally measured phase behavior in colloids and polymers.     

Quantum dot-labelled polymer beads by suspension polymerisation

CdSe quantum dots with polymerisable ligands have been incorporated into polystyrene beads, via a suspension polymerisation reaction, as a first step towards the optical encoding of solid supports for application in solid phase organic chemistry.     

Spaces with Vanishing ℓ2-Homology and their Fundamental Groups (after Farber and Weinberger)

We characterize those groups which can occur as the fundamental groups of finite CW-complexes with vanishing ²-homology (the first examples of such groups were obtained by Farber and Weinberger).     

A unique approach to the synthesis of a dengue vaccine and the novel tetrasaccharide that results

An approach to the development of a dengue vaccine by synthesizing the hexasaccharide epitope on the viral surface is examined. The stereochemical and structural challenges include the synthesis of a β-mannoside bond. Synthesis of this bond is approached via a trisaccharide analogue portion of the epitope. A novel tetrasaccharide with a mannose–mannose anomeric linkage results in the course of the synthetic attempts.