Ortiz C S, de Bertorello M M
Departamento de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina.
J Pharm Sci. 1995 Jun;84(6):783-5. doi: 10.1002/jps.2600840623.
The kinetics of enolization and degradation of N-(5-methyl-4-isoxazolyl)-4-amino-1,2-naphthoquinone (1) was investigated in aqueous solutions over a pH range of 7.30 to 12.25, at 35 degrees C and at constant ionic strength (mu = 0.5) using reversed-phase HPLC. Pseudo-first-order kinetics was observed throughout the pH range studied. The rate of enolization (ke), the keto-enol equilibrium constant (Kt), and specific base catalysis rate constant (kCH) were determined. Good agreement between the theoretical pH-rate profile and the experimental data supports the proposed transformation process. The average recovery for 1 and its tautomerization product 2-hydroxy-N-(5-methyl-4-isoxazolyl)-1,4-naphthoquinone 4-imine (2) from mixtures of different composition was evaluated.
在35℃、恒定离子强度（μ = 0.5）条件下，使用反相高效液相色谱法，在pH值7.30至12.25范围内的水溶液中研究了N-(5-甲基-4-异恶唑基)-4-氨基-1,2-萘醌（1）的烯醇化和降解动力学。在所研究的整个pH范围内均观察到伪一级动力学。测定了烯醇化速率（ke）、酮-烯醇平衡常数（Kt）和特定碱催化速率常数（kCH）。理论pH-速率曲线与实验数据之间的良好一致性支持了所提出的转化过程。评估了1及其互变异构体2-羟基-N-(5-甲基-4-异恶唑基)-1,4-萘醌4-亚胺（2）在不同组成混合物中的平均回收率。
