Enzyme-catalyzed preparation of methyl (R)-N-(2,6-dimethylphenyl)alaninate: a key intermediate for (R)-metalaxyl
作者:Oh-Jin Park、Sang-Hyun Lee、Tae-Yoon Park、Sang-Who Lee、Koon-Ho Cho
DOI:10.1016/j.tetasy.2005.01.033
日期:2005.3
A biocatalytic approach for the production of (R)-metalaxyl, mefenoxam, has been developed. A practical synthesis of methyl (R)-N-(2,6-dimethylphenyl)alaninate, a key intermediate for (R)-metalaxyl, has been developed by the use of lipase-catalyzed hydrolytic kinetic resolution and chemical racemization of the remaining ester. At high concentrations in aqueous media (300 g/L) lipases were stable and
已经开发了用于生产(R)-甲霜灵,甲芬沙星的生物催化方法。(R)-N-(2,6-二甲基苯基)丙氨酸甲酯((R)-甲霜灵的关键中间体)的实用合成方法是利用脂肪酶催化的水解动力学拆分和剩余酯的化学外消旋作用开发的。在高浓度的水性介质(300 g / L)中,脂肪酶是稳定的,并具有中等至良好的转化率和出色的对映选择性(> 98%ee)。使用简单的萃取程序从剩余的酯中分离出酸产物,并将该酸用甲醇酯化,得到甲基(R)-N-(2,6-二甲基苯基)丙氨酸盐,对映体过量(> 98%ee)没有任何减少。随后与甲氧基乙酰氯的化学偶合提供对映体纯的(R)-甲霜灵(> 98%ee)而没有外消旋化。