72551-50-9Relevant academic research and scientific papers
Asymmetric Hydrogenation of 3-Substituted Pyridinium Salts
Renom-Carrasco, Marc,Gajewski, Piotr,Pignataro, Luca,de Vries, Johannes G.,Piarulli, Umberto,Gennari, Cesare,Lefort, Laurent
supporting information, p. 9528 - 9532 (2016/07/14)
The use of an equivalent amount of an organic base leads to high enantiomeric excess in the asymmetric hydrogenation of N-benzylated 3-substituted pyridinium salts into the corresponding piperidines. Indeed, in the presence of Et3N, a Rh-JosiPhos catalyst reduced a range of pyridinium salts with ee values up to 90 %. The role of the base was elucidated with a mechanistic study involving the isolation of the various reaction intermediates and isotopic labeling experiments. Additionally, this study provided some evidence for an enantiodetermining step involving a dihydropyridine intermediate.
Development of small-molecule P-gp inhibitors of the N-benzyl 1,4-dihydropyridine type: Novel aspects in SAR and bioanalytical evaluation of multidrug resistance (MDR) reversal properties
Baumert, Christiane,Günthel, Marianne,Krawczyk, S?ren,Hemmer, Marc,Wersig, Tom,Langner, Andreas,Molnár, Joséf,Lage, Hermann,Hilgeroth, Andreas
, p. 166 - 177 (2013/02/23)
Novel series of N-benzyl 1,4-dihydropyridines have been prepared by facile syntheses. All relevant substituents of the molecular scaffold have been varied. The resulting compounds were biologically evaluated as P-glycoprotein (P-gp) inhibitors. Substitutions of the N-benzyl residue favour biological activity beside respective 3-ester functions. Most active compounds were further evaluated as multidrug resistance (MDR) modulators to restore the cytotoxic properties of varying daunorubicin applications.
Reductive alkylation of pyridinium salts. Part 1. Synthesis of di-, tetra- and hexa-hydropyridine esters
MacTavish, Kohn,Proctor, George R.,Redpath, James
, p. 2545 - 2552 (2007/10/03)
Reaction of 1-methyl-, 1-benzyl- and 1-benzoyl-4-ethoxycarbonylpyridinium salts 1 with zinc and benzyl bromide produce regioselectively the 4,4-disubstituted 1,4-dihydropyridines 3 (R = CH3, PhCH2, PhCO); only the latter is stable but all are reduced catalytically to piperidines 2 (R = CH3, PhCH2, PhCO). 1-Benzoyl-4-ethoxycarbonylpyridinium chloride with zinc and benzoyl chloride or ethyl bromoacetate gives respectively 4-benzoyl- 18 or 4-ethoxycarbonylmethyl-1-benzoyl-4-ethoxycarbonyl-1,4-dihydropyridine 17, but 1-methyl-4-ethoxycarbonylpyridinium iodide 1 (R = CH3, X = I) with benzoyl chloride gives 3-benzoyl-4-ethoxycarbonyl-1-methyl-1,2-dihydropyridine 21.The action of zinc and benzyl bromide on 1-methyl- and 1-benzyl-3-ethoxycarbonylpyridinium salts 5 gives, after catalytic hydrogenation, mixtures of 2- and 4-benzyl-5-ethoxycarbonyl-1,2,3,4-tetrahydropyridines 6 and 7 (R = CH3 or PhCH2) but similar treatment of 1-benzoyl-3-ethoxycarbonylpyridinium chloride 5 (R = PhCO, X = Cl) yields selectively the stable 4-benzyl-3-ethoxycarbonyl-1,4-dihydropyridine 9.Treatment of 1-methyl- or 1-benzoyl-3-ethoxycarbonylpyridinium salts 5 with zinc and benzoyl chloride gives a mixture of products. 1-Methyl-2-ethoxycarbonylpyridinium iodide 11 (R = CH3, X = I) reacts with zinc and benzyl bromide giving, after catalytic hydrogenation, 2-, 4- and 6-benzyl-2-ethoxycarbonyl-1-methylpiperidines 12, 13 and 14 (R = CH3) in the ratio 2:7:1, but 1-benzyl-2-ethoxycarbonylpyridinium bromide 11 (R = PhCH2, X = Br) gives only 1,4-dibenzyl-2-ethoxycarbonylpiperidine 13 (R = PhCH2).
MUTUAL EFFECTS OF THE STRUCTURE IN THE REACTIONS OF BENZYL BROMIDES WITH PYRIDINES
Shpan'ko, I. V.,Korostylev, A. P.,Shved, E. N.,Litvinenko, L. M.
, p. 1562 - 1565 (2007/10/02)
The rate of the reactions of benzyl bromides with pyridines in nitrobenzene at 40 deg C was measured.The nonadditivity of the joint action of the electronic effects of substituents in the molecules of the reagents on the reactivity of the benzyl bromide-p
