METHOD OF 3-ETHYL-5-METHYL-(+/-)-2-((2-AMINOETHOXY)METHYL)-4- -(2-CHLOROPHENYL)-1,4-DIHYDRO-6-METHYL-3,5-PYRIDINE- -DICARBOXYLATE MONOBENZENESULPHONATE PREPARATION AND INTERMEDIATE FOR PREPARING THEREOF

摘要

There is disclosed a process for the preparation of 3-ethyl- -5-methyl-(+/-)-2-((2-aminoethoxy)methyl)-4-(2-chlorophenyl)- -1,4-dihydro-6-methyl-3,5-pyridine-dicarboxylate monobenzenesulphonate (amlodipine benzenesulphonate) having the formula (I) wherein 3-ethyl-5-methyl-(+/-)-2-(2-(N-tritylamino)- -ethoxymethyl)-4-)2-chlorophenyl)-1,4-dihydro-6-methyl-3,5- -pyridinedicarboxylate is reacted with benzenesulphonic acid in a methanolic or an aqueous methanolic medium at a temperature from 20 degrees Celsius to the reflux temperature and the title compound is isolated and purified. Amlodipine benzene sulphonate is a valuable anti-ischaemic and anti-hypertensive agent.