Isoxazoles. VII: Hydrolysis of 4-Methyl- 5-isoxazolylnaphthoquinone Derivatives in Aqueous Solutions
作者:Marcela R. Longhi、Maria M. de Bertorello、Margarita C. Brinón
DOI:10.1002/jps.2600800616
日期:1991.6
4-naphthoquinone-4-imine (3) and 5-amino-4-methylisoxazole (4), were isolated. The pathway for degradation of 1 in acidic and neutral pH followed consecutive first-order kinetics since 2 undergoes hydrolysis giving 2-hydroxy-1,4-napthoquinone (6) and 2-methylcyanoacetamide (5). No appreciable buffer effect on the degradation of 1 and 2 was observed for any of the buffer species in this study. The pH-rate
在70°C下研究了溶液中2-(4-甲基-5-异恶唑基胺)-N-(4-甲基-5-异恶唑基)-1,4-萘醌-4-亚胺(1)的降解动力学在1.75至12.85的pH范围内,离子强度恒定为0.5。通过吸收和二阶导数紫外光谱法确定降解速率。在酸性和中性pH中鉴定出两种降解产物。它们分别是4-N-(4-甲基-5-异恶唑基)-1,2-萘醌(2)和2-甲基-氰基乙酰胺(5)。在碱性pH下,分离出两种降解产物2-羟基-N-(4-甲基-5-异恶唑基)-1,4-萘醌-4-亚胺(3)和5-氨基-4-甲基异恶唑(4)。 。1在酸性和中性pH中的降解途径遵循连续的一级动力学,因为2经历水解后生成2-羟基-1,4-萘醌(6)和2-甲基氰基乙酰胺(5)。在本研究中,没有观察到任何缓冲液对1和2降解的影响。pH速率曲线显示1的特定酸和特定的碱性催化作用,2的特定酸催化。在中性pH范围内发生1和2的最大稳定性。