与基于肽的咪唑啉丁-4-酮相比,由抗疟疾药物的N-(α-氨基酰基)衍生物,伯氨喹和酮合成的那些在37°C的pH 7.4中出乎意料地稳定。在60°C的pH范围0.3–13.5下,研究了基于伯氨喹的咪唑啉丁-4-酮的水解动力学。水解成母体α-氨基酰基伯氨喹的特征是S形的pH速率分布,反映了咪唑烷二-4-酮的结合形式和质子化形式(在N-1下)的自发分解。动力学确定的p K a值为ca。3.6–4.0,即4 p K a单元比氨基酸酰胺的单元低,因此暗示在pH 7.4的咪唑烷基-4-酮的水解涉及联合形式。该形式的反应性随氨基酸α-取代基的空间拥挤而降低。与此相反,速率常数的非离子化形式急剧增加用于从环酮衍生的咪唑烷-4-酮,可由解释的观察自发分解余应变(内应变)的影响。这些结果与水解的涉及一个S的机制一致Ñ酰胺基离去后,咪唑啉丁-4-一C2-N3键的1型单分子裂解。在计算研究的支持下,质子化咪唑啉丁
Imidazolidin-4-one Derivatives of Primaquine as Novel Transmission-Blocking Antimalarials
作者:Maria João Araújo、Joana Bom、Rita Capela、Catarina Casimiro、Paula Chambel、Paula Gomes、Jim Iley、Francisca Lopes、José Morais、Rui Moreira、Eliandre de Oliveira、Virgílio do Rosário、Nuno Vale
DOI:10.1021/jm0494624
日期:2005.2.1
Imidazolidin-4-one derivatives of primaquine were synthesized as potential double prodrugs of the parent drug. The title compounds inhibit the development of the sporogonic cycle of Plasmodium berghei, affecting the appearance of oocysts in the midguts of the mosquitoes. The imidazolidin-4-ones are very stable, both in human plasma and in pH 7.4 buffer, indicating that they are active per se. Thus