RESUMO
This study investigated the roles of diverse free available chlorine (FAC) species including HOCl/OCl-, H2OCl+, Cl2O, and Cl2 in the degradation of micropollutants. The degradation of 5 micropollutants was significantly affected by pH, FAC dosage, and chloride (Cl-) concentration. The reaction orders in FAC (n) of 5 micropollutants (acetaminophen, carbamazepine, naproxen, gemfibrozil, and mecoprop) ranged from 1.4 ± 0.2 to 2.1 ± 0.3 at pH 3 - 5, evidencing the importance of Cl2O and Cl2 for micropollutant abatement. A simplified method for the determination of second-order rate constants (k) of specific FAC species with micropollutants was developed. Herein, the k for neutral/dissociated forms of 5 micropollutants with Cl2 and Cl2O were determined in the ranges of 9.3 (± 0.2) × 102 â¼ 2.9 (± 0.2) × 109 M-1 s-1 and 1.8 (± 0.1) × 104 â¼ 3.7 (± 0.6) × 109 M-1 s-1, respectively. They were 4 - 7 orders of magnitude higher than those of HOCl, whereas those of OCl- and H2OCl+ were negligible. By using kinetic modeling, Cl2 was more important under acidic conditions and higher Cl- levels with contributions of 37.9 - 99.2% at pH 5 in pure water. Cl2O played a dominant role in micropollutant degradation in pure water (56.4 - 87.3%) under neutral conditions. Furthermore, both Cl2 and Cl2O played vital roles in the formation of disinfection byproducts (DBPs) during chlorination of carbamazepine and natural organic matter. This study highlights the overlooked roles of Cl2O and Cl2 in micropollutant abatement and DBP formation during chlorination.
Assuntos
Poluentes Químicos da Água , Purificação da Água , Halogenação , Purificação da Água/métodos , Concentração de Íons de Hidrogênio , Cinética , Cloro , Desinfecção , CarbamazepinaRESUMO
A series of novel pyrazino[2,1-a]isoquinolin compounds were designed, synthesized, and their antifungal activities in vitro were evaluated. The results showed that all of the title compounds exhibited antifungal activities. Most of them exhibited stronger antifungal activities than the lead compounds; compound 7c is more potent than fluconazole against two of the three tested fungal strains. The studies presented here provide a new structural type for the development of novel antifungal agents.
Assuntos
Antifúngicos/síntese química , Desenho de Fármacos , Isoquinolinas/síntese química , Pirazinas/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Candida/enzimologia , Cryptococcus neoformans/efeitos dos fármacos , Cryptococcus neoformans/enzimologia , Inibidores das Enzimas do Citocromo P-450 , Fungos/efeitos dos fármacos , Fungos/enzimologia , Isoquinolinas/química , Isoquinolinas/farmacologia , Testes de Sensibilidade Microbiana , Modelos Moleculares , Estrutura Molecular , Pirazinas/química , Pirazinas/farmacologia , Esterol 14-Desmetilase , Trichophyton/efeitos dos fármacos , Trichophyton/enzimologiaRESUMO
A series of novel pyrazino[2,1-a]isoquinolin compounds were designed and synthesized, and their antifungal activities in vitro were evaluated. The results showed that all of the compounds exhibited antifungal activities. Some of them exhibited stronger antifungal activities than that of lead compounds and among them compound 11b was the most potent one, which showed more potent than that of the active control fluconazole to the four of the five tested fungi. The studies presented here provide a new structural type for the development of novel antifungal agents.
