2654-66-2Relevant academic research and scientific papers
Synthesis of Enantioenriched 2-Alkyl Piperidine Derivatives through Asymmetric Reduction of Pyridinium Salts
Qu, Bo,Mangunuru, Hari P. R.,Wei, Xudong,Fandrick, Keith R.,Desrosiers, Jean-Nicolas,Sieber, Joshua D.,Kurouski, Dmitry,Haddad, Nizar,Samankumara, Lalith P.,Lee, Heewon,Savoie, Jolaine,Ma, Shengli,Grinberg, Nelu,Sarvestani, Max,Yee, Nathan K.,Song, Jinhua J.,Senanayake, Chris H.
supporting information, p. 4920 - 4923 (2016/10/18)
An Ir-catalyzed enantioselective hydrogenation of 2-alkyl-pyridines has been developed using ligand MeO-BoQPhos. High levels of enantioselectivities up to 93:7 er were obtained. The resulting enantioenriched piperidines can be readily converted into biologically interesting molecules such as the fused tricyclic structures 5, 6, and 7 in 99:1 er, providing a novel, concise synthetic route to this family of chiral piperidine-containing compounds.
Asymmetric Hydrogenation of Pyridinium Salts with an Iridium Phosphole Catalyst
Chang, Mingxin,Huang, Yuhua,Liu, Shaodong,Chen, Yonggang,Krska, Shane W.,Davies, Ian W.,Zhang, Xumu
supporting information, p. 12761 - 12764 (2016/02/18)
Iridium-catalyzed asymmetric hydrogenation of N-alkyl-2-alkylpyridinium salts provided 2-aryl-substituted piperidines with high levels of enantioselectivity. Simple benzyl and other alkyl groups successfully activated the challenging pyridine substrates toward hydrogenation. The use of the unusual chiral-phosphole-based MP2-SEGPHOS was the key to the success of this approach which provides a versatile and practical procedure for the synthesis of chiral piperidines. Ring to ring: Simple N-benzyl and N-alkyl groups successfully activated pyridine substrates toward hydrogenation. The use of the unusual chiral phosphole-based ligand L was the key to the success of this approach, which provides a versatile and practical procedure for the synthesis of chiral piperidines. cod=1,5-cyclooctadiene.
Efficient and chemoselective reduction of pyridines to tetrahydropyridines and piperidines via rhodium-catalyzed transfer hydrogenation
Wu, Jianjun,Tang, Weijun,Pettman, Alan,Xiao, Jianliang
supporting information, p. 35 - 40 (2013/03/13)
Promoted by iodide anion the rhodium complex dimer, [Cp RhCl 2]2, catalyzes efficiently the transfer hydrogenation of various quaternary pyridinium salts under mild conditions, affording not only piperidines but also 1,2,3,6-tetrahydropyridines in a highly chemoselective fashion, depending on the substitution pattern at the pyridinium ring. The reduction is conducted in azeotropic formic acid/triethylamine (HCOOH-Et 3N) mixture at 40 °C, with catalyst loadings as low as 0.005mol% being feasible. Copyright
The role of ion/neutral complexes in the fragmentation of N-benzyl-(alkylpyridinium) ions
Kuck, Dietmar,Grützmacher, Hans-Friedrich,Barth, Dieter,Heitkamp, Sandra,Letzel, Matthias C.
body text, p. 159 - 166 (2012/07/13)
N-Benzylpyridinium ions bearing an alkyl group at the pyridine nucleus were studied as potential precursors of gaseous ion/neutral complexes. The occurrence of I/N complexes [C6H5CH2 + ? alkylpyridine] was probed by the reactivity of the potential benzylic hydride donor sites present in the ortho-, meta- and para-alkyl groups (R = methyl, ethyl, isopropyl and benzyl). Collision-induced dissociation of the ions, carried out in an electrical ion cage mass spectrometer, revealed that hydride transfer strongly depends both on the energy requirements of the hydride transfer but also on the position of the hydride donor. Hydride transfer, giving rise to the loss of toluene, was found to occur exclusively with those N-benzylpyridinium ions which bear an isopropyl or a benzyl substituent in the ortho position of the pyridine ring, thus reflecting the intermediacy of I/N complexes. All of the putative hydride donor alkyl groups were found to be non-reactive in the meta and para positions, as were methyl and ethyl groups even in the ortho positions. Density functional calculations (B3LYP/6-311+G/3d,2p)//(B3LYP/6-31+G(d)) on the hydride-transfer and simple-cleavage channels were carried out to help rationalizing these observations. The results suggest that the intra-complex hydride abstraction from the 3- and 4-isopropyl- and from the 3- and 4-benzylpyridine neutrals, although being thermodynamically favorable, is suppressed by substantial intra-complex rotational (or reorientation) barriers.
COMPOUNDS FOR TREATING DISORDERS MEDIATED BY METABOTROPIC GLUTAMATE RECEPTOR 5, AND METHODS OF USE THEREOF
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Page/Page column 144, (2010/11/03)
Provided herein are compounds and methods of synthesis thereof. The compounds provided herein are useful for the treatment, prevention, and/or management of various disorders, such as neurological disorders, psychiatric disorders, neuromuscular disorders, gastrointestinal disorders, lower urinary tract disorder, and cancer. Compounds provided herein modulate the activity of metabotropic glutamate receptor 5 (mGluR5) in the central nervous system or the periphery. Pharmaceutical formulations containing the compounds and their methods of use are also provided herein.
Protective effect of 1-benzyl-2-R-pyridinium halides in steel acid corrosion
Yurchenko,Pilipenko,Yurchenko,Krivovyaz
, p. 2039 - 2040 (2008/02/08)
The inhibiting effect of 1-benzoyl-2-R-pyridinium halides on the acid corrosion of steel was studied and compared with that of 1-phenacylmethyl-2-R- pyridinium halides.
2-Cyano-Δ3-piperideines. 12. Stereochemistry of Formation of N-Benzyl-2-cyano-Δ3-piperideines and Facile Isomerization on Alumina to 2-Cyano-Δ4-piperideines. A Potentially General Route to the Synthesis of 2,6-Disubstitute
Bonin, Martine,Romero, Jose Ricardo,Grierson, David S.,Husson, Henri-Philippe
, p. 2392 - 2400 (2007/10/02)
The reaction of the piperideine N-oxides 1a-f with trifluoroacetic anhydride in CH2Cl2 at 0 deg C (Polonovski-Potier reaction) led to the formation of the N-benzyl-2-cyano-Δ3-piperideines 3a-f.Epimeric mixtures were obtained for the amino nitri
