Mini-Reviews in Organic Chemistry - Volume 4, Issue 1, 2007

This review concentrates on both the protein receptor and guest binding abilities of carbohydrate clusters based on a cyclodextrin core. The combination of both complexation abilities is the basis of one of the pursued approaches for developing site-specific drug delivery systems. Influence on the molecular recognition properties of the number of appended saccharides, the type of carbohydrate clustering and the type of the spacer arms, among other factors, are discussed.

The preparation, structure, and reactivity of benzo-annelated cyclic polysulfides, which principally contain five- and seven-membered rings, are described together with the chemistry of their related compounds. The stereochemistry of benzopentathiepins and the electrochemistry of benzotrithioles are also discussed.

A synthetic maneuver from 1,6-diacetyl- and 1,6-diformyl-1,3,5-cycloheptatrienes toward various 1,6-methano[10]annulenes, such as diaryl-substituted, cyclobutene-annulated, and thiophene-annulated derivatives and its quinodimethane-type compound, and 4,9-methanothia[11]annulenes is spotlighted based on our recent research efforts. The crystal structure analysis of the annulenes, discussion of mechanistic details of a key cyclization step and application of some annulene derivatives to a material in organic electroluminescent devices are also described.

We developed a novel technology for core-corona polymeric nanoparticles having hydrophilic polymer chains with functional groups. Polystyrene nanoparticles immobilized with the mannose-specific lectin concanavalin A could efficiently capture human immunodeficiency virus type 1 (HIV-1) particles and gp120 antigens on their surface. Since the antigen-capturing nanoparticles were capable of inducing humoral and cellular immune responses to HIV-1, they could be developed as a mucosal vaccine against HIV-1 infection.

In this paper, we shed light on the recent methodologies used for preparing uronic acids; the typical components of glycosaminoglycans (GAGs). The L-ido synthon is a key challenge in oligosaccharide synthesis and there is a constant need for its efficient preparation. Difficulties in obtaining these rare sugars from natural sources have required chemists to develop general and simple routes for their syntheses. The conformational flexibility of L-iduronic acid is analyzed to better understand its remarkable protein adaptability and resulting diverse biological activities and its impact on oligosaccharides synthesis. The synthesis of the new type of 1-N-iminosugars that represented glycosidase and glycosyltransferase inhibitors and served as chemotherapeutic agents is discussed in the final section.

In electrospray ionization mass spectrometry (ESI-MS), charge formation is proposed to occur as a result of acid-base reactions or a coordination with metal cations. However, the increasing number of papers have reported the formation of radical ions (molecular ions) as a result of loss of one or two electrons. In this paper, we present an overview of the current literature on the balance between the formation of molecular ions and of protonated forms of organic compounds in ESI-MS. Correlations between the radical formation process and the ionization energy, calculated by molecular orbital methods or obtained by eletrochemical techniques, were applied to explain this apparently unexpected behavior. The use of high level theoretical methods especially designed to produce accurate thermochemical data is also reported.

Green chemistry is a field that encompasses a wide range of environmentally benign technologies. This review discusses the principles of green chemistry, as well as recent applications of these principles to the Diels-Alder reaction, with a focus on benign solvent systems. Specifically, Diels-Alder reactions in water, ionic liquids, supercritical carbon dioxide, and solvent-free systems will be reviewed up to February 2006.

This review is segmented into three main parts; the preparations, structures and reactions of the 1- benzoselenopyrylium and 1-benzotelluropyryrlium salts. Synthetic work has been achieved by transformation from the selenochromones and tellurochromones in two steps. A study shows that these salts, although being stable compounds, are highly reactive with various nucleophiles to afford the successful 2- or 4-substituted selenochromene and tellurochromene derivatives.