Procedure for obtaining 3-ethyl-5-methyl 2,6-dimethyl-4- (2',3'-dichlorophenyl)-1,4-dihydropyridine-3,5- dicarboxylate

摘要

New procedure for obtaining 3-ethyl-5-methyl 2,6-dimethyl- 4-(2',3'-dichlorophenyl)-1,4-dihydropyridine-3,5- dicarboxylate, in two stages. The obtaining of methyl 2- (2',3'-dichloro)benzylideneacetoacetate from methyl acetoacetate and 2,3-dichlorobenzaldehyde in the presence of piperidine, glacial acetic acid and isopropanol. A second step in which it is treated with ethyl 3- aminocrotonate in the presence of activated alumina to give the title product. Advantages which are obtained by this procedure relative to the prior art: a) Processes carried out under rapid, smooth and simple conditions, giving products of high quality. b) The reaction time is less. c) The last step is carried out in a solid phase, avoiding traces of symmetrical dihydropyridines. d) Obtaining of the dihydropyridine without a solvent, minimum production of contaminating effluent. e) Use of recyclable basic or acid catalysts. f) Low cost of the processes, minimization of reagents and residues. g) Low environmental impact.