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

摘要

New procedure for obtaining 3-isopropyl-5-(2'- methoxy)ethyl 2,6-dimethyl-4-(3'-nitrophenyl)-1,4- dihydropyridine-3,5-dicarboxylate, in three stages. The obtaining of isopropyl 2-(3'-nitro)benzylidene- acetoacetate from 3-nitrobenzaldehyde and isopropyl acetoacetate in the presence of piperidine, glacial acetic acid and isopropanol. A second step in which 2- methoxyethyl 3-aminocrotonate is obtained by treating 2- methoxyethyl acetoacetate with ammonium acetate. In the third step the products obtained previously are treated in the presence of activated alumina to give the title product. Advantages which are obtained relative to the prior art: a) Processes carried out under rapid, smooth and simple conditions, giving products of high quality. b) The time is reduced in the last step. 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 by the minimization of reagents and residues. <IMAGE>