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
作者:Ingrid F. Zattoni、Lais D. Guanaes、Letícia B. Cerqueira、Roberto Pontarolo、Diogo R.B. Ducatti、M. Eugênia R. Duarte、Miguel D. Noseda、Angela C.L.B. Trindade、Alan G. Gonçalves
DOI:10.1016/j.tetlet.2019.151129
日期:2019.10
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 is 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 is under stoichiometric BF3OEt2 could also be successfully applied with additional imine examples and under reductive amination conditions. (C) 2019 Elsevier Ltd. All rights reserved.
Bodforss, Chemische Berichte, 1931, vol. 64, p. 1108,1110
作者:Bodforss
DOI:——
日期:——
CHEKAVICHUS, B. S.;SAUSIN, A. EH.;DUBUR, G. YA., XIMIYA GETEROTSIKL. SOEDIN., 1982, N 8, 1072-1077
作者:CHEKAVICHUS, B. S.、SAUSIN, A. EH.、DUBUR, G. YA.
DOI:——
日期:——
Effect of substituents in the dihydropyridine ring on the reactivity of the ester group of 3,5-dialkoxycarbonyl-1,4-dihydropyridines
作者:B. S. Chekavichus、A. �. Sausin'、G. Ya. Dubur
DOI:10.1007/bf00506586
日期:1982.8
Synthesis of pyridinium salts from N-substituted dihydropyridines with BF3OEt2 in the absence of added oxidants
作者:Lais D. Guanaes、Diogo R.B. Ducatti、M. Eugênia R. Duarte、Sandra M.W. Barreira、Miguel D. Noseda、Alan G. Gonçalves
DOI:10.1016/j.tetlet.2015.02.119
日期:2015.4
BF3OEt2 as aromatization promoter in reactions that could be conducted without the need of the usually added oxidizing agents, such as quinones, nitrates, peroxides, and chromates. An optimization study employing an N-phenyl Hantzschester dihydropyridine (1a) to obtain the corresponding N-phenylpyridinium-containing ammonium quaternary salt (2a) was conducted to define the best conditions for the aromatization