METHOD OF PREPARING MONOBENZOSULFONATE OF 2-[(2- AMINOETHOXY) METHYL -4- (2-CHLOROPHENYL)-1,4-DIHYDRO-6- METHYL]-3,5-PYRIDINE DICARBOXYLIC ACID 3-ETHYL-5-METHYL ESTER Russian patent published in 1999 - IPC

FIELD: chemical industry. SUBSTANCE: method comprises reacting 3-ethyl-5-methyl ester of 2-[2-(N- phthalimido)ehtoxymethyl)-4-(2-chlorophenyl) 1,4-dihydro- 6-methyl-3,5-pyridine dicarboxylic acid with N-methyl ammonium salt of benzenesulfonic acid in secondary alcohol solvent at temperature of 75-80 C and isolating desired compound by well known procedure. It is desirable to use isopropyl alcohol solvent and to purify final compound by crystallization from water. Method makes it possible to prepare desired product in one stage without isolation of amplodipin base, to use commercially available substances and to use water for crystallization. EFFECT: more efficient preparation method. 3 cl, 2 ex