Barry R. Steele

Nanomaterials play an increasingly important role in current medicinal practice. As one of the most significant causes of human mortality, and one that is increasing year by year, Alzheimer’s disease (AD) has been the subject of a very great body of research and is an area in which nanomedicinal approaches show great promise. Dendrimers are a class of multivalent nanomaterials which can accommodate a wide range of modifications that enable them to be used as drug delivery systems. By means of suitable design, they can incorporate multiple functionalities to enable transport across the blood–brain barrier and subsequently target the diseased areas of the brain. In addition, a number of dendrimers by themselves often display therapeutic potential for AD. In this review, the various hypotheses relating to the development of AD and the proposed therapeutic interventions involving dendrimer–base systems are outlined. Special attention is focused on more recent results and on the importance of aspects such as oxidative stress, neuroinflammation and mitochondrial dysfunction in approaches to the design of new treatments.

Catalysis of cross-coupling reactions under phosphane-free conditions represents an important ongoing challenge. Although transition metal complexes based on the thiosemicarbazone unit have been known for a very long time, their use in homogeneous catalysis has been studied only relatively recently. In particular, reports of cross-coupling catalytic reactions with such complexes have appeared only in the last 15 years. This review provides a survey of the research in this area and a discussion of the prospects for future developments.

Ring‐alkylated primary, secondary and tertiary anilines have been ethylated with ethylene at benzylic positions in a simple and inexpensive one‐pot procedure which is mediated bythe use of the superbase system nBuLi/LiK(OCH₂CH₂NMe₂)₂in the presence of Mg(OCH₂CH₂OEt)₂. Primary and secondary anilines are ethylated readily at ortho‐benzylic positions but with difficulty or not at all at other positions. Tertiaryanilines are ethylated at all positions. Mono‐ or diethylation occurs depending on the steric constraints present.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Activated metals for organic synthesis are often prepared by reduction of metal salts using alkali metal aromatic radical anions. The reduction of magnesium chloride has been examined by NMR. Whereas the expected reduction to the metal occurred with lithium or potassium naphthalene radical anion, under certain conditions, with sodium naphthalene radical anion, no metallic magnesium was precipitated and dark red solutions were obtained. It was also found that solutions of sodium naphthalene radical anion in tetrahydrofuran, in the presence of a catalytic amount of magnesium chloride, quickly became diamagnetic. A mechanism involving bimetallic species is postulated to explain the results.

Four palladium chelate complexes with S‐ or Se‐containing substituted salicylaldehyde Schiff‐base derivatives have been synthesized. Spectroscopic and crystallographic data indicate that, in the complexes, the deprotonated salicylaldehyde ligand is bound to the metal in an O,N,S (or Se)‐terdentate coordination mode, forming one six‐ and one five‐membered chelate ring. The complexes are thermally and air stable and efficiently catalyze the Suzuki–Miyaura cross‐coupling of aryl bromides with phenylboronic acid in air.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)