| 摘要 |
<p>A method of preparing the R- or S- form of the calcium antagonist amlodipine, or of an acid addition salt thereof, which comprises (i) forming a salt of R,S-2-(2-azidoethoxymethyl)-4-(2-chlorophenyl)-5-methoxycarbonyl-6-met hyl-1,4-HY # dihydropyridine-3-carboxylic acid with cinchonidine and separating said salt into its diastereomeric forms by fractional crystallisation; (ii) converting said separated salts into the free acids by acidification; (iii)esterifying the free carboxy groups to ethoxycarbonyl; and (iv) reducing the azido groups to amino, thus producing separated R-(-)- and S-(+)- amlodipine, and isolating the separated forms of amlodipine as such or in acid addition salt form. The invention also includes the novel intermediates obtained by the above process.</p> |
