合成路线1

An enantioselective synthesis of efonidipine has been described: The enantioselective hydrolysis of 5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinan-2-yl)-2,6-dimethyl-4-(3-n itrophenyl)-1,4-dihydropyridine-3-carboxylic acid propionyloxymethyl ester (I) with lipase AH in 2,5-dimethyltetrahydrofuran saturated with water gives the corresponding free acid of the (S)-isomer (III), while the propionyloxymethyl ester of the (R)-isomer (II) remains undisturbed. After chromatographic separation, the (R)-ester (II) is hydrolyzed with NaOH in methanol to the (R)-acid (IV). Finally, both enantiomerically pure acids (III) and (IV) are separately esterified with 2-(N-benzyl-N-phenylamino)ethanol in the usual way.