83300-85-0Relevant academic research and scientific papers
1,4-Dihydropyridine/BF3OEt2 for the reduction of imines: Influences of the amount of added BF3OEt2 and the substitution at N-1 and C-4 of the dihydropyridine ring
Zattoni, Ingrid F.,Guanaes, Lais D.,Cerqueira, Letícia B.,Pontarolo, Roberto,Ducatti, Diogo R.B.,Duarte, M. Eugênia R.,Noseda, Miguel D.,Trindade, Angela C.L.B.,Gon?alves, Alan G.
supporting information, (2019/09/12)
We have evaluated four 1,4-dihydropyridines (DHPs 1a, 1b, 1c and 1d) as reducing agents, which presented free (hydrogenated) or phenyl-substituted N-1 and C-4 positions of the DHP ring. Reactions combining each of the DHP and different amounts of BF3OEt2 were evaluated for the reduction of imine 2a (N-benzylideneaniline). DHP simultaneously substituted at N-1 and C-4 (1a), and DHP substituted at C-4 (1b) gave lower yields for reduction of 2a in comparison with DHPs 1c and 1d (both unsubstituted at the C-4 position). By evaluating the amount of added BF3OEt2 to the reaction mixture, we have found that DHP 1c (substituted at N-1) provided its best yield for amine 3a (82%) when associated with stoichiometric amounts BF3OEt2, while DHP 1d (N-1- and C-4-unsubstituted derivative) was more effective (90% yield) with catalytic quantities of the Lewis acid. The reaction system using DHP 1c under stoichiometric BF3OEt2 could also be successfully applied with additional imine examples and under reductive amination conditions.
EFFECT OF SUBSTITUENTS IN THE DIHYDROPYRIDINE RING ON THE REACTIVITY OF THE ESTER GROUP OF 3,5-DIALKOXYCARBONYL-1,4-DIHYDROPYRIDINES
Chekavichus, B. S.,Sausins, A. S.,Dubur, G. Ya.
, p. 818 - 823 (2007/10/02)
The reactivity of the ester group of 3,5-dialkoxycarbonyl-1,4-dihydropyridines upon reaction with nucleophilic reagents increases when substituents are absent in the ortho positions relative to the ester group and also in the case of steric disruption of the coplanarity of the β-aminovinylcarbonyl system when substituents are introduced at the nitrogen atom in 2,6-dimethyl derivatives.Mono- and dicarboxylic acids were obtained by hydrolysis of such esters.Thus use of esters of propiolic acid esters and arylamines in the Hantzsch synthesis made it possible to obtain 1-aryl-2,6-unsubstituted derivatives of 1,4-dihydropyridine.
