- Four-Selective Pyridine Alkylation via Wittig Olefination of Dearomatized Pyridylphosphonium Ylides
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Methods to synthesize alkylated pyridines are valuable because these structures are prevalent in pharmaceuticals and agrochemicals. We have developed a distinct approach to construct 4-alkylpyridines using dearomatized pyridylphosphonium ylide intermediates in a Wittig olefination-rearomatization sequence. Pyridine N-activation is key to this strategy, and N-triazinylpyridinium salts enable coupling between a wide variety of substituted pyridines and aldehydes. The alkylation protocol is viable for late-stage functionalization, including methylation of pyridine-containing drugs. This approach represents an alternative to metal-catalyzed sp2-sp3 cross-coupling reactions and Minisci-type processes.
- Dolewski, Ryan D.,Fricke, Patrick J.,McNally, Andrew
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supporting information
p. 21283 - 21288
(2021/08/25)
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- Synthesis of 4-benzylpyridines via Pd-catalyzed CH3-arylation of 4-picoline
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A highly efficient synthesis of 4-benzylpyridines was developed via Pd-catalyzed C(sp3)-H arylation between 4-picoline and aryl halides. It was found that the best yields were achieved with a simple Pd(PPh3)4 catalyst and Cs2CO3 as the base. Compared with the known methods, our reaction does not require the use of a strong organometallic reagent as the base.
- Wu, Jing,Wang, Dadian,Chen, Xiang,Gui, Qingwen,Li, Hua,Tan, Ze,Huang, Genping,Wang, Guangwei
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supporting information
p. 7509 - 7512
(2017/09/27)
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- Substituted tetrahydropyridine derivatives acting on 5-HT receptors
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PCT No. PCT/GB96/02763 Sec. 371 Date Apr. 29, 1998 Sec. 102(e) Date Apr. 29, 1998 PCT Filed Nov. 13, 1996 PCT Pub. No. WO97/18204 PCT Pub. Date May 22, 1997Compounds having formula I, or salts or prodrugs thereof: are selective agonists of the 5-HT1D alpha receptor and are useful in the treatment of migraine and associated conditions.
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- Synthesis of 1,4-dihydropyridines by regioselective additions of benzylic zinc bromides to pyridinium salts and their aromatizations to 4-benzylpyridines
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Benzylic zinc reagents add with high regioselectivity to 1-(phenoxycarbonyl) salts of methyl nicotinate to yield methyl-1-(phenoxycarbonyl)-4-benzyl-1,4-dihydronicotinates. The dihydronicotinates on heating with sulfur in decalin afford methyl 4-benzylnicotinates.
- Krapcho, A. Paul,Waterhouse, David J.,Hammach, Abdelhakim,Di Domenico, Roberto,Menta, Ernesto,Oliva, Ambrogio,Spinelli, Silvano
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p. 781 - 794
(2007/10/03)
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- A facile synthesis of 4-benzylpyridines by regiospecific addition of substituted benzylic Griganard reagents to pyridinium salts
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Substituted 4-benzylpyridines are prepared by regiospecific γ-addition of substituted benzylic Grinard reagents to pyridinium salts in fairly good yields.
- Shiao,Chia
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p. 401 - 406
(2007/10/02)
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- A facile synthesis of functionalized 4-benzylpyridines by using mixed copper, zinc benzylic organometallics
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A general approach by use of highly functionalized mixed copper zinc, benzylic organometallics to react with N-ethoxycarbonylpyridinium chloride to give regioselectively 4-benzylpyridines after oxygen oxidation in 30-75% yield is described.
- Chia,Shiao
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p. 2033 - 2034
(2007/10/02)
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- Regio- and chemoselective addition of mixed copper, zinc benzylic organometallics to functionalized pyridinium salts: A facile synthesis of functionalized 4-benzylpyridines
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2',3-Disubstituted 4-benzylpyridines 4 were synthesized in good yield by reaction of mixed copper, zinc benzylic organometallics 1 with 3-substituted 1-(ethoxycarbonyl)pyridinium chlorides 2 followed by sulfur oxidation under reflux in decalin.
- Shing,Chia,Shiao,Chau
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p. 849 - 850
(2007/10/02)
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