RESUMO
Aqueous film forming foams (AFFFs) have been released at fire training facilities for several decades resulting in the contamination of soil and groundwater by per- and polyfluoroalkyl substances (PFASs). AFFF compositions are proprietary and may contain a broad range of PFASs for which the chemical structures and degradation products are not known. In this study, high resolution quadrupole-time-of-flight tandem mass spectrometry (LC-QTOF-MS/MS) in combination with data processing using filtering strategies was applied to characterize and elucidate the PFASs present in concrete extracts collected at a fire training ground after the historical use of various AFFF formulations. Twelve different fluorochemical classes, representing more than 60 chemicals, were detected and identified in the concrete extracts. Novel PFASs homologues, unmonitored before in environmental samples such as chlorinated PFSAs, ketone PFSAs, dichlorinated PFSAs and perfluoroalkane sulphonamides (FASAs) were detected in soil samples collected in the vicinity of the fire training ground. Their detection in the soil cores (from 0 to 2 m) give an insight on the potential mobility of these newly identified PFASs.
Assuntos
Monitoramento Ambiental , Poluentes Ambientais/análise , Fluorocarbonos/análise , Cromatografia Líquida , Bombeiros , Retardadores de Chama/análise , Halogenação , Solo , Espectrometria de Massas em Tandem , Água/químicaRESUMO
A novel series of [4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)-2-pyrimidine-based cyclooxygenase-2 (COX-2) inhibitors, which have a different arrangement of substituents compared to the more common 1,2-diarylheterocycle based molecules, have been discovered. For example, 2-(butyloxy)-4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)pyrimidine (47), a member of the 2-pyrimidinyl ether series, has been shown to be a potent and selective inhibitor with a favourable pharmacokinetic profile, high brain penetration and good efficacy in rat models of hypersensitivity.
Assuntos
Aminas/síntese química , Inibidores de Ciclo-Oxigenase 2/síntese química , Éteres/síntese química , Pirimidinas/síntese química , Sulfonas/síntese química , Aminas/farmacologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Química Farmacêutica/métodos , Ciclo-Oxigenase 2/química , Inibidores de Ciclo-Oxigenase 2/farmacologia , Modelos Animais de Doenças , Desenho de Fármacos , Éteres/farmacologia , Humanos , Inflamação , Concentração Inibidora 50 , Camundongos , Estrutura Molecular , Doenças Neurodegenerativas/tratamento farmacológico , Pirimidinas/farmacologia , Ratos , Sulfonas/farmacologiaRESUMO
Many years of work have been invested in the identification of potent and selective COX-2 inhibitors for the treatment of chronic inflammatory pain. One issue faced by workers is the balance between the lipophilicity required for potent enzyme inhibition and the physical properties necessary for drug absorption and distribution in vivo. Frequently approaches to reduce lipophilicity through introduction of polar functionality is hampered by highly challenging chemistry to prepare key molecules. We have complemented traditional synthetic chemistry with a biotransformations approach which efficiently provided access to an array of key target molecules.
Assuntos
Inibidores de Ciclo-Oxigenase 2/síntese química , Biotransformação , Química Farmacêutica/métodos , Ciclo-Oxigenase 2/química , Inibidores de Ciclo-Oxigenase 2/farmacologia , Desenho de Fármacos , Humanos , Inflamação/tratamento farmacológico , Concentração Inibidora 50 , Modelos Químicos , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
A practical asymmetric synthesis of a highly substituted N-acylpyrrolidine on multi-kilogram scale is described. The key step in the construction of the three stereocenters is a [3+2] cycloaddition of methyl acrylate and an imino ester prepared from l-leucine t-butyl ester hydrochloride and 2-thiazolecarboxaldehyde. The cycloaddition features novel asymmetric catalysis via a complex of silver acetate and a cinchona alkaloid, particularly hydroquinine, with complete diastereomeric control and up to 87% enantiomeric control. The alkaloid serves as a ligand as well as a base for the formation of the azomethine ylide or 1,3-dipole. Experiments have shown that the hydroxyl group of hydroquinine is a critical element for the enantioselectivities observed. The cycloaddition methodology is also applicable to methylvinyl ketone, providing access to either alpha- or beta-epimers of 4-acetylpyrrolidine depending on the reaction conditions utilized. The synthesis also highlights an efficient N-acylation, selective O- versus N-methylation, and a unique ester reduction with NaBH4-MeOH catalyzed by NaB(OAc)3H that not only achieves excellent chemoselectivity but also avoids formation of the undesired but thermodynamically favored epimer. The highly functionalized target is synthesized in seven linear steps from l-leucine t-butyl ester hydrochloride with all three isolated intermediates being highly crystalline.
Assuntos
RNA Polimerases Dirigidas por DNA/antagonistas & inibidores , Hepacivirus/enzimologia , Pirrolidinas/síntese química , Pirrolidinas/farmacologia , Acrilatos/química , Acilação , Alcaloides/química , Cristalografia por Raios X , RNA Polimerases Dirigidas por DNA/metabolismo , Iminas/química , Modelos Moleculares , Estrutura Molecular , Pirrolidinas/química , Prata/química , Solventes , EstereoisomerismoRESUMO
Optimization of a pyrrolidine-based template using structure-based design and physicochemical considerations has provided a development candidate 20b (3082) with submicromolar potency in the HCV replicon and good pharmacokinetic properties.
Assuntos
Antivirais/síntese química , Hepacivirus/efeitos dos fármacos , Pirrolidinas/síntese química , RNA Polimerase Dependente de RNA/antagonistas & inibidores , Animais , Antivirais/química , Antivirais/farmacologia , Sítios de Ligação , Disponibilidade Biológica , Chlorocebus aethiops , Hepacivirus/enzimologia , Modelos Moleculares , Pirrolidinas/química , Pirrolidinas/farmacologia , RNA Polimerase Dependente de RNA/química , Ratos , Estereoisomerismo , Relação Estrutura-Atividade , Células VeroRESUMO
GW406381 (8), currently undergoing clinical evaluation for the treatment of inflammatory pain is a member of a novel series of 2,3-diaryl-pyrazolo[1,5-b]pyridazine based cyclooxygenase-2 (COX-2) inhibitors, which have been shown to be highly potent and selective. Several examples of the series, in addition to possessing favourable pharmacokinetic profiles and analgesic activity in vivo, have also demonstrated relatively high brain penetration in the rat compared with the clinically available compounds, which may ultimately prove beneficial in the treatment of pain.