Mini-Reviews in Organic Chemistry - Volume 6, Issue 2, 2009

This review presents the synthesis of macrobicyclic compounds built from triphenylmethane, triphenylphosphine oxide units and other three-dimensional molecules with an aromatic core, as well as some fullerene precursors and buta-1,3-diynediyl spacers. The dependence of the coupling yield on the solvent, catalysts (Cu+ and/or Cu2+) and presence of oxygen is also addressed. The formation of inclusion complexes of these cage molecules with appropriately sized neutral guests such as solvent molecules (acetonitrile, benzene, dichloromethane, chloroform), cubane, benzyl cyanide and structural information of the host derivatives are also reviewed.

Recently, erbium triflate has found to have a wide application in organic synthesis. Owing to its high oxophilicity, it has been used for reactions involving epoxide ring with applications both in laboratory and industrial organic chemistry. Moreover, it easily catalyzes the Ferrier rearrangement of glycals, the cleavage of protecting groups, the synthesis of imines and Diels Alder reactions.

Recent works devoted to the oxygenations of saturated, aromatic as well as olefinic hydrocarbons are surveyed, and the emphasis is made on the author's own publications. Both soluble metal complexes and solid metal compounds catalyze oxidative transformations of hydrocarbons. Hydrogen peroxide, alkyl peroxides, and peroxy acids were used in these reactions as oxidants. The catalytic systems often include obligatory co-catalysts, for example, nitrogen-containing bases or acids (inorganic, carboxylic or amino acids).

The present review is aimed to summarize recent research on the O-coupling reactions of arenediazonium, ArN2 +, ions with different alcohols under acidic conditions. Encapsulating in a nutshell their mechanisms, it appears that two possible products may be formed depending on experimental conditions, namely a highly unstable aryl cation, Ar+, that yields substitution products and a reactive diazo ether, namely Ar-N=N-O-R, which initiates a radical mechanism through the formation of aryl radicals Ar• to yield reduction products.

Shape memory polymer is an important area of interest in the polymer science research because of its many applications in industry such as biomedical, smart textiles, actuations and so on. Among the shape memory polymers, temperature responsive shape memory polymers are gaining much attention to the scientist as their transition temperature for shape memory behavior could be easily tailored by engineering the polymer structure prior to polymer synthesis. An attempt has been taken in this review paper to review the research and development in temperature responsive shape memory polymers. This review is not intended to be comprehensive, but provides an overview of the temperature responsive shape memory polymers. The mechanisms of temperature responsive shape memory behaviors has been discussed. The review was also covers various temperature responsive shape memory polymers viz. shape memory polyurethane, shape memory copolymer, network polymer structure with shape memory property and shape memory hydro gel. Finally, the paper was concluded with some of the prospective applications of temperature responsive shape memory polymers in various segments.

Bacteria have adapted in environments where free iron is severely limited, secreting small iron chelating molecules. One group of these siderophores contains a thiazoline ring in its structure. These compounds isolated from bacteria will be presented and different aspects of their chemistry including synthesis will be presented.

Terpenoids are natural products of great interest due to their broad application scope. They are employed as agrochemicals, drugs, fragrances, flavours and pigments. In the search of new derivatives with improved properties, the use of biocatalysts is being constantly increased, especially in redox processes. They can give rise to stereo- and regioselective products and/or compounds functionalized in remote positions difficult to reach by means of traditional organic chemistry. In this review, the application of whole cell catalyzed biotransformations of terpenoids to obtain new drug targets or to increase the pharmacological activity is presented.

This review discusses the most active natural and synthetic compounds demonstrating the antimycobacterial activity at minimum inhibiting concentrations (MIC) of 5 μg/ml or less. For better insight into the “structure-activity” relationships, we occasionally considered compounds with high values of MIC. The review covers the period from 2001 to 2007. The data are grouped according to chemical structures, namely, nitrogen-, oxygen-, and sulfur-containing heterocyclic compounds, peptide, alkaloids, terpenoids, and others.

Only 5-15% of the ∼25000 existing species of plants have been examined for the presence of biologically active compounds. The ancient medical systems use a much larger palette of herbs for therapy. Systematic drug discovery involving using cues provided from traditional medical systems is bound to produce a new generation of green drugs. Curcumin the primary active ingredient in Curcuma longa is used as a model to enunciate the concept of green drug development. Synthetic and formulation based approaches to optimize the bioactivity of curcumin is presented.