Selective Modification of Chitin and Chitosan: En Route to Tailored Oligosaccharides.

Chitin and chitosan are attractive biopolymers with enormous structural possibilities for chemical modification, creating platforms for new chemical entities with a broad scope of applications, ranging from material science to medicine. During the last few years, incredible efforts have been dedicated to the regioselective modification of these biopolymers paving the way for improved properties and tailored activities. Herein, the most recent advances in chitin/chitosan regioselective modification, reaction conditions, selectivity, and the impact on its applications are highlighted.

Indole based cyclooxygenase inhibitors: synthesis, biological evaluation, docking and NMR screening.

The close structural similarity between the two cyclooxygenase (COXs) isoforms and the absence of selective inhibitors without side effects continues to stimulate the development of novel approaches towards selective anti-inflammatory drugs. In the present study a small library of new indolic compounds involving two different substitutions patterns at the indole scaffold was synthesized. In order to establish a relation between the spatial distribution of known functional groups related with inhibitory activity, two substitution patterns were explored: one with substituents at N-1, C-3, C-5 positions and another at C-2, C-3 and C5 positions.

Stereoselective glycosylation of glucosamine: the role of the N-protecting group.

Oligosaccharides and glycoconjugates play an important role in biological processes. The use of these complex polymers as biocompatible materials for medicinal applications as well as therapeutic agents for the treatment of several diseases has attracted considerable interest. However, these investigations require large and pure amounts of glycostructures.

Developments towards regioselective synthesis of 1,2-disubstituted benzimidazoles.

1,2-Disubstituted benzimidazoles play an important role in several areas and particularly as drug discovery targets. Herein, several methods to assemble these structures are reviewed, from the classical approaches to the more recently developed metal-catalyzed intramolecular amination process, the cascade arylamination/condensation reaction and polymer-supported benzimidazole assembly under microwave conditions.