Ethly (+)-(2S, 3S) -3- [(S) -3-methyl-1- (3-methylbutylcarbamoyl) butylcarbamoyl] -2- oxirane-carboxylate (EST ; la) is expected to be useful as an oral therapeutic agent for muscular dystrophy on the basis of its potent inhibitory activities against the cysteine proteinases involved in the myofibrillar protein degradation that occurs in the disease. Through extensive investigations aimed at developing a new synthetic method for la that would be suitable for industrial application, it has been found that L-arginine can be used as a new, efficient resolving agent to obtain optically pure L-trans-epoxysuccinic acid (3a), and the active ester method using p-nitrophenol is very effective in the coupling reaction of ethyl L-trans-epoxysuccinate (7a) and L-leucine isoamylamide (8a) because of the extremely low formation of by-products. To examine the contribution of the stereochemistry of the trans-epoxysuccinic acid and leucine moieties to the inhibitory activity against cysteine proteinases, the diastereomers (lb-d) of la were synthesized by a similar method and the rate constants of inactivation of papain by la-d were measured. Compound la, having L-trans-epoxysuccinic acid and L-leucine moieties, showed the most potent activity among them.
Ethly (+)-(2S, 3S)-3-[(S)-3-甲基-1-(3-甲基丁基
氨基甲酰基)丁基
氨基甲酰基]-2-环氧
羧酸酯(EST;la)预计将作为治疗肌肉萎缩症的口服药物,因为它对与疾病相关的肌
纤维蛋白降解中涉及的半胱
氨酸
蛋白酶具有强大的抑制活性。通过广泛的研究,旨在开发一种适用于工业应用的新合成方法,发现
L-精氨酸可以作为新的高效分离剂,用于获得光学纯的L-反-环氧
富马酸(3a),而使用
对硝基苯酚的活性酯方法在乙基L-反-环氧
富马酸(7a)和
L-亮氨酸异戊酰胺(8a)之间的偶联反应中非常有效,因为副产物的生成极少。为了检查反-环氧
富马酸和亮
氨酸部分的立体
化学对半胱
氨酸
蛋白酶抑制活性的贡献,采用类似的方法合成了la的二叠体(lb-d),并测量了la-d对
木瓜蛋白酶的灭活速率常数。化合物la,具有L-反-环氧
富马酸和
L-亮氨酸部分,显示出其中最强的活性。