METHOD OF PREPARING AMLODIPINE BEZYLATE Russian patent published in 2001 - IPC

FIELD: medicint. SUBSTANCE: described is improved method of preparing amplodipine bezylate, more specifically 3-ethyl-5-methyl-2-(2- aminoethoxymethyl)-4-(2-chlorophenyl)-6-methyl-1,4-dihydropyridine- 3,5 dicarboxylate. Method comprises adding 2-[2-(N-triethylamino) ethoxymethyl]-4-(2-chlorophenyl-3-ethoxycarbonyl-5-methoxycarbonyl-6- methyl-1,4-dihydropyridine to solution preprepared during addition of benzenesulfonic acid to methanol, heated to 60-65 C, maintained for 15-30 min and cooled to 45-50 C, subsequently heating the resulting mixture at reflux to 60-65 C for 4-5 h, cooling to minus 5-10 C and maintaining for 10-12 h, filtering the resulting reaction mixture distilling off solvent in vacuum at 65-70, cooling the mixture to 35-40 C, adding isopropyl alcohol, heating to 80-85 C, adding demineralized water, filtration, adding petroleum ether cooling to 0-5 C, maintaining for 1-1.5 h, centrifugation and washing with isopropyl alcohol. It is desirable to filter reaction mixture through Nutch filter, and the resulting under product is twisted, dried, ground and sifted. Method is less labor consuming and more economically advantageous and said substance retains all pharmaceutical properties. EFFECT: more efficient preparation method. 3 cl, 1 ex