Síntese de compostos re-sensibilizadores de bactérias resistentes a antibióticos

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em QuímicaO presente trabalho apresenta a síntese de uma série de depsipeptídeos derivados de alanina e lactato como modelos para porção modificada do pepidoglicano, Ala-Lac, de bactérias resistentes a vancomicina, utilizando condições reacionais brandas e reagentes simples e de baixo custo.Os depsipeptídeos foram sintetizados através de uma metodologia envolvendo acoplamento de L- -hidroxiácidos e L-aminoácidos N-protegidos, seguido de desproteção. Foram preparados uma série de compostos aromáticos e alifáticos simples contendo -nucleófilos como grupos oxima, hidroxilamina e ácido hidroxâmico. É apresentada ainda a síntese de moléculas possuindo em sua estrutura nucleófilos potentes e um grupamento básico. E finalmente, são reportadas as preparações de derivados dinucleofílicos da prolina como alternativa aos derivados da prolina sintetizados por Chiosis e Boneca para clivagem seletiva e catalítica da ligação Ala-Lac. Os compostos preparados nesta tese tiveram sua atividade anti-herpética avaliada utilizando como modelos virais vírus com genoma DNA: herpes simplex vírus tipo 1 (HSV-1), cepas 29R (resistente ao aciclovir) e KOS. Porém, apesar da baixa citotoxidade apresentada, os derivados estudados não se mostraram promissores frente às cepas 29R e KOS

Rhodium(II)-Catalysed Intramolecular O-H Insertion of alpha-Diazo-gamma-Azido-delta-Hydroxy-beta-Ketoesters: Evidence for a Novel Sigmatropic Rearrangement of an Allylic Azide Intermediate

The Rh2(OAc)4 catalyzed intramolecular O-H insertion reaction of delta-hydroxy-alpha-diazoesters affords 3(2H)-furanone-2-carboxylates in good yield but with moderate selectivity (d.e. ca 60%). The initially formed 2,5-substituted cis-furanones were found to epimerize to the corresponding 2,5-trans isomers when subjected to silica gel chromatography. The Rh2(OAc)4 catalyzed decomposition of gamma-azido-delta-hydroxy-alpha-diazoesters also furnished 3(2H)-furanone-2-carboxylates. These compounds are derived by a sequential O-H insertion reaction followed by a concerted [3,3]-sigmatropic shift of the allylic azide intermediate

Simple method for fast deprotection of nucleosides by triethylamine-catalyzed methanolysis of acetates in aqueous medium

A straightforward methodology for deacetylation of protected ribonucleosides was developed based on triethylamine-catalyzed solvolysis in aqueous methanol. Reactions are completed in a few minutes under microwave irradiation and the free nucleosides are obtained in high yield after simple evaporation of volatiles. Other important features include the involvement of readily available reagents and the compatibility with diverse functional groups, which make this process very attractive for broad application

Reações multicomponentes de biginelli e de mannich nas aulas de química orgânica experimental: uma abordagem didática de conceitos da química verde

The introduction of Mannich and Biginelli multicomponent reactions in a practical Organic Chemistry course is presented in this article. Procedures described in the literature were adapted for use under the simple conditions available in undergraduate laboratories and were selected on the basis of Green Chemistry principles and practicality of synthesis. The reactions are easy to carry out and all products are readily isolated as crystalline solids with yields ranging from moderate to high

new pre clinical evidence of anti inflammatory effect and safety of a substituted fluorophenyl imidazole

Abstract Acute Respiratory Distress Syndrome (ARDS) is an inflammatory condition with high mortality rates, and there is still no pharmacological approach with proven effectiveness. In the past few years, several imidazole small molecules have been developed to treat conditions in which inflammation plays a central role. In the present work, we hypothesize that a novel substituted fluorophenyl imidazole synthetized by our research group would present in vivo anti-inflammatory effect in an ARDS murine model induced by LPS. Results shows that the fluorophenyl imidazole has the ability to inhibit leukocyte migration to the bronchoalveolar lavage fluid and lung tissue of animals challenged intranasally with LPS. Furthermore, this inhibition is followed with reduction in myeloperoxidase activity, nitric oxide metabolites generation and cytokines (TNF-α, IL-6, IL-17, IFN-γ and IL-10) secretion. This effect is at least partly related to the capacity of the fluorophenyl imidazole in inhibit p38 MAPK and NF-κB phosphorylation. Finally, fluorophenyl imidazole showed no signs of acute oral toxicity in the toxicological protocol suggested by OECD 423. Taken together, the results shows that fluorophenyl imidazole is a promising prototype for the development of a novel anti-inflammatory drug in which p38 MAPK and NF-κB plays a pivotal role

Selenocianato alílico, processo de obtenção e usos do mesmo e composição de enxaguatório bucal

Universidade Federal de Santa CatarinaUniversidade Federal do Rio Grande do SulQuímicaFarmáciaDepositad

Rhodium(II)-Catalysed Intramolecular O-H Insertion of a-Diazo-g-Azido-d-Hydroxy-b-Ketoesters: Evidence for a Novel Sigmatropic Rearrangement of an Allylic Azide Intermediate

The Rh2(OAc)4 catalyzed intramolecular O-H insertion reaction of delta-hydroxy-alpha-diazoesters affords 3(2H)-furanone-2-carboxylates in good yield but with moderate selectivity (d.e. ca 60%). The initially formed 2,5-substituted cis-furanones were found to epimerize to the corresponding 2,5-trans isomers when subjected to silica gel chromatography. The Rh2(OAc)4 catalyzed decomposition of gamma-azido-delta-hydroxy-alpha-diazoesters also furnished 3(2H)-furanone-2-carboxylates. These compounds are derived by a sequential O-H insertion reaction followed by a concerted [3,3]-sigmatropic shift of the allylic azide intermediate