Hydrolysis and Acyl Migration of a Catechol Monoester of l-Dopa: l-3-(3-Hydroxy-4-pivaloyloxyphenyl)alanine
作者:Masaki Ihara、Shigeru Nakajima、Akihiro Hisaka、Yoshimi Tsuchiya、Yumiko Sakuma、Hiroko Suzuki、Koichi Kitani、Mitsuo Yano
DOI:10.1002/jps.2600790811
日期:1990.8
Hydrolysis and acyl migration studies on L-3-(3-hydroxy-4-pivaloyloxyphenyl)alanine (1, NB-355), which produced long-lasting plasma L-dopa levels after oral dosing, have been conducted. Compound 1 exists as pure 4-O-pivaloyl-L-dopa in the solid state, but it converts rapidly to a mixture of the 3- and 4-O-isomers in solution. The rate of acyl migration increased with increases in pH and temperature
已经进行了对L-3-(3-羟基-4-新戊酰氧基苯基)丙氨酸(1,NB-355)的水解和酰基迁移的研究,该口服后口服L-多巴水平持续升高。化合物1以纯4-O-新戊酰基-L-多巴的形式存在,但在溶液中迅速转化为3-和4-O-异构体的混合物。酰基迁移率随pH和温度的升高而增加,并且在平衡状态下4-O-异构体的含量为53-59%。1到L-多巴(6)的水解速率也随pH和温度的升高而增加,并在中性和碱性pH值下急剧加速。用O-新戊酰基-L-酪氨酸(3),二-O-新戊酰基-L-多巴(4)或L-多巴甲酯(5)未观察到在中性pH下的快速水解。由于这种化学稳定性,1在大鼠血浆中的水解速度远快于其他测试的儿茶酚酯。但是,在pH 6.0的大鼠肠匀浆中,被测试的酯中1的水解速度最慢,主要是由对二异氟磷酸酯(DFP)敏感的酯酶水解。因此,由于存在一个相邻的羟基,因此1在水解和酰基迁移方面显示出独特的体外特征。口服1后