Current Organic Chemistry - Volume 9, Issue 5, 2005

Ambruticin is a unique example of antibiotics isolated from the fermentation media of gliding bacteria. Since the last decade, it has emerged as one of the most intensively studied derivative due to its oral antibiotic properties and due to its unique architecture. This structurally exceptional molecule bearing ten stereogenic centers contains a tetrahydropyranyl ring, a divinylcyclopropyl ring, and a dihydropyranyl ring linked to each other via three (E) double bonds. This review is aimed at highlighting the recent progresses in the area, including the biological activity, a comparison of the 4 total syntheses and the original strategies developed for the partial syntheses.

Prostaglandins (PG's) are a very important class of naturally occurring physiologically active substances, which have been the subject of continuous attention by biologists, pharmacists and chemists since their discovery in the 1930s. Pharmacological studies have shown that prostaglandins exhibit an extremely broad spectrum of activity such as on the smooth muscles of various organs, their mediating role in the central and peripheral nervous systems, in inflammatory processes, and their hormone-like and antihormonal activities. Due to the diversified biological activity and rapid metabolism of the natural prostaglandins, a lot of effort has been done to synthesize prostaglandin analogs. Particularly interesting are the prostaglandin analogs containing heteroatoms in the cyclopentane ring which have received a great deal of attention in relation to their potential biological properties and diversified biological activity. This article is dedicated to Prof. Sune K. Bergstrom (in memoriam) for his milestone contributions to prostaglandin research.

This review will update the use of organodilithium intermediates in synthetic organic chemistry, paying special attention to their use in carbon-carbon bond forming reactions, in which two equal or different electrophiles are introduced (at once or in a two-step process) in the structure of the starting material. This methodology allows the generation of polyfunctionalized organic molecules in a very direct manner through only one synthetic operation: tandem lithiation-reaction with electrophiles.

N-acetyl-galactosamine appended amino acid esters, the new biomaterials are hydrogels formed through the supramolecular assembly in water. They consist of small molecule with hybrid structure. At one end, these molecules contain a polar moiety that is hydrophobic due to its favourable interaction with water and at the other end, two non-polar moieties forming a hydrophobic group are linked through an aminoacetate unit. These materials possess extremely high affinity towards water molecules, and thus the ability to form hydrogel at very low concentrations creating a dense network of nanofibres. This review summarises the combinatorial approach used for the synthesis of these novel materials, screening and optimization, and their applications.