RESUMO
Noncatalyzed, regio- and stereoselective hypochlorite oxidation of 3-aminothieno[2,3-b]pyridine-2-carboxamides is presented. Unexpectedly, the oxidation proceeded by different mechanistic pathways, and different products were formed, depending on the nature of solvents used. A possible mechanism, the structure of products, kinetics and dynamics of intramolecular processes, and biological activity of products are discussed.
RESUMO
The goal of present work is the study of NO releasing mechanisms in nitrofuroxanoquinoline (NFQ) derivatives. Mechanisms of their structural non-rigidity and pathways of NO donation - spontaneous or under the action of sulfanyl radicals or photoirradiation - were considered in details, both experimentally and quantum chemically. Furoxan-containing systems of the discussed type are not capable of spontaneous or photoinduced decomposition under mild conditions, and sulfanyl (radical) induced processes are the most preferable. It was shown that appropriate modification of NFQ through [3 + 2] cycloaddition and subsequent aromatization is a powerful tool to design new prospective donors of NO molecule. Two newly obtained NFQ derivatives were proven to have unusually high NO activity in full accordance with the theoretical model. We hope that these examples will encourage community to seek for new NO active molecules among cycloadducts and modified furoxanes.
