Stuart W. Littler

Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere

Pharmaceutical and agrochemical discovery programs are under considerable pressure to meet increasing global demand and thus require constant innovation. Classical hydrocarbon scaffolds have long assisted in bringing new molecules to the market place, but an obvious omission is that of the Platonic solid cubane. Eaton, however, suggested that this molecule has the potential to act as a benzene bioisostere. Herein, we report the validation of Eatons hypothesis with cubane derivatives of five molecules that are used clinically or as agrochemicals. Two cubane analogues showed increased bioactivity compared to their benzene counterparts whereas two further analogues displayed equal bioactivity, and the fifth one demonstrated only partial efficacy. Ramifications from this study are best realized by reflecting on the number of bioactive molecules that contain a benzene ring. Substitution with the cubane scaffold where possible could revitalize these systems, and thus expedite much needed lead candidate identification.

A Novel Route to Prepare Highly Reactive and Versatile Chromatographic Monoliths

The copolymer poly(isocyanatoethyl methacrylate-co-methyl methacrylate-co-ethylene glycol dimethacrylate) (poly(IEM-co-MMA-co-EGDMA)) was developed as a novel, facile, highly reactive and versatile monolithic matrix, which was amenable to surface functionalization with a variety of nucleophilic modifiers based on the reactive isocyanate group, producing monoliths of various chemistries suitable for chromatography. The specific surface area, pore size distribution, porosity and morphology of the monolithic matrix were characterized using a mercury intrusion porosimeter and scanning electron microscopy (SEM), respectively. Thermal analysis results revealed that the monolith was thermally stable up to 307 °C. The success of the chemical modification of the monolithic matrix was confirmed by FT-IR, solid state (13) C NMR and XPS elemental analysis, showing the high ligand density of the modified monoliths. A ligand density of up to 2.33 mmol·mL(-1) was obtained for the 1-octanol modified monolith (M1) with an isocyanate group conversion of 96.9%, indicating a high efficiency of the modification reaction. The potential application of the monoliths was demonstrated by the separation of a series of compounds. The novel monolithic columns exhibited high mechanical stability, column efficiency and good repeatability and reproducibility.

Evaluation of Aqueous Extracts from Elast-Eon Polymers for Methylene Dianiline (MDA) by High-Performance Liquid Chromatography (HPLC)

Elast-Eon polymers are a class of materials suitable for use in long-term implantable medical devices. They are the copolymers of methylene diphenyl diisocyanate (MDI) based polyurethanes and hydroxyl-terminated polydimethyl siloxane, and as a result combine the biostability and biocompatibility of silicones with the mechanical properties of polyurethanes. In order to ensure product safety and meet regulatory requirements, it is important to confirm the absence or presence of toxic 4,4′-methylene dianiline (MDA) in aqueous extracts of Elast-Eon. The present work focusses on the development of an analytical technique to detect any leachable MDA from Elast-Eon polymers. No traces of MDA could be detected in the aqueous extracts from Elast-Eon, or from sterilized and aged (accelerated oxidized) samples of Elast-Eon.

Synthesis of some 5,6-dihydro-7H-1,4,2-oxathiazepin-7-ones and 5H-4,1,3-benzoxathiazepin-5-ones

The novel heterocyclic systems 5,6-dihydro-7H-1,4,2-oxathiazepin-7-one (1) and 5H-4,1,3-benzoxathiazepin-5-one (2) were prepared by the reaction of hydroximoyl chlorides (3) with mercapto-carboxylic acids, followed by cyclization with 1,3-dicyclohexylcarbodiimide (6) or 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide HCl (7)

Corrigendum: Validating Eaton's Hypothesis: Cubane as a Benzene Bioisostere

In this Communication, a La Trobe University affiliation is missing for the author David A. Winkler. The penultimate author address entry must read: Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052 (Australia) and La Trobe Institute for Molecular Science, La Trobe University, Bundoora, 3084 (Australia).