| 摘要 |
<p>The invention relates to an improved process for the preparation of asymmetrical 1,4-dihydro-pyridine-dicarboxylic acid esters of general Formula (I) (wherein R?1 and R2¿ each stands for lower alkyl or an ethyl group substituted by methosy or cyano, with the proviso that R?1 and R2¿ are different; R¿3? stands for lower alkyl optionally substituted by hydroxy or halogen, or a benzyloxymethyl group or a group of the general Formula -CH2-O-CH2-CH2-X; X stands for halogen, azido or -NR?4R5; R4 and R5¿ are identical or different and each stands for hydrogen or lower alkyl, or R?4 and R5¿ together with the nitrogen atom, they are attached to, form a phthaloyl group; A is nitro or halogen and n is 1 or 2).</p> |
