消旋非洛地平的拆分

报道了一种从S-扁桃酸出发拆分得到非洛地平的绿色合成新方法。以S-扁桃酸为原料，通过酯化，酯交换，Knoevenagel反应和Michael加成环合，得到关键中间产物，1,4-二氢 2,6-二甲基-4R（2,3-二氯苯基）-3,5-吡啶二羧酸甲酯S-扁桃酸甲酯，通过乙腈重结晶得到单一的异构体，再经水解，酯化共6步得到了目标产物，用MS，¹H-NMR对产物进行了表征。

Resolution of racemic felodipine

A novel green method is reported for the resolution of racemic felodipine.S-mandelic acid was esterified to give a methyl ester,and then transesterified with methyl acetoacetate,for which process iodine was found to be a practical and useful Lewis acid catalyst.Sulfuric acid was found to be an efficient catalyst for the subsequent Knoevenagel condensation of the active methylene S-mandelic methyl acetoacetate with 2,3-dichlorobenzaldehyde under solvent free conditions.A subsequent Michael addition reaction gave diastereomers of the compound 1,4-dihydro-2,6-dimethyl-4R-(2,3-dichlorobenzene)-3,5-pyridinecarboxylic acid methyl S-mandelic methyl ester.Recrystallization from acetonitrile afforded the diastereomer which was converted into the target product felodipine.by hydrolysis and esterification.The intermediates and final product were characterized by MS and 1H-NMR spectroscopy.