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

摘要

New procedure for obtaining 3-ethyl-5-methyl 2,6-dimethyl- 4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate, in two stages. The obtaining of ethyl 2-(3- nitro)benzylideneacetoacetate from 3-nitrobenzaldehyde and ethyl acetoacetate in the presence of piperidine, glacial acetic acid and isopropanol, a second step in which the previous product is treated with methyl 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 last step is carried out in a solid phase, avoiding traces of symmetrical dihydropyridines. c) Obtaining of the dihydropyridine without a solvent, minimum production of contaminating effluent. d) Use of recyclable basic or acid catalysts. e) Low cost in the processes, minimization of reagents and residues. f) Low environmental impact. IMAGE