Journal of the Brazilian Chemical Society | |
Determination of the pKa values of some biologically active and inactive hydroxyquinones | |
SantAna, Antônio Euzébio G.1  Ossowski, Tadeusz1  Goulart, Marília O. F.1  University of Gdansk, Poland1  Falkowski, Piotr1  Abreu, Fabiane C. de1  Liwo, Adam1  Universidade Federal de Alagoas, Maceió, Brazil1  Zarzeczanska, Dorota1  Costa, Cicero de Oliveira1  Miranda, Paulo Rogério B.1  | |
关键词: acid dissociation constants; hydroxyquinones; pH-metric titration; hybrid pH-metric/UV titration; molluscicidal activity; | |
DOI : 10.1590/S0103-50532008000100025 | |
学科分类:化学(综合) | |
来源: SciELO | |
【 摘 要 】
The apparent dissociation constants (pKa) of four 2-hydroxynaphthoquinones, differently substituted at C-3, were determined in water:ethanol (1:1, v/v) solutions by pH-metric and hybrid pH-metric/UV titration methods. Isolapachol (pKa < 6) was more acidic than lapachol (pKa > 6). Two pKa values were determined for each of the methylamino-derivatives investigated, the first relating to the enol function and the second to the ammonium salt. It was determined that under physiological pH, these derivatives would be to a large extension, zwitterionic. The possible effects of the measured parameters on the biological activities of the studied compounds are discussed.
【 授权许可】
Unknown
【 预 览 】
Files | Size | Format | View |
---|---|---|---|
RO201912050580341ZK.pdf | 750KB | download |