3044-71-1Relevant articles and documents
Syntheses and anti-HIV and human cluster of differentiation 4 (CD4) down-modulating potencies of pyridine-fused cyclotriazadisulfonamide (CADA) compounds
Lumangtad, Liezel A.,Claeys, Elisa,Hamal, Sunil,Intasiri, Amarawan,Basrai, Courtney,Yen-Pon, Expedite,Beenfeldt, Davison,Vermeire, Kurt,Bell, Thomas W.
, (2020/11/20)
CADA compounds selectively down-modulate human cell-surface CD4 protein and are of interest as HIV entry inhibitors and as drugs for asthma, rheumatoid arthritis, diabetes and some cancers. Postulating that fusing a pyridine ring bearing hydrophobic subst
Ni: Vs. Pd in Suzuki-Miyaura sp2-sp2 cross-coupling: A head-to-head study in a comparable precatalyst/ligand system
West, Matthew J.,Watson, Allan J. B.
supporting information, p. 5055 - 5059 (2019/06/03)
The Suzuki-Miyaura reaction is a cornerstone method for sp2-sp2 cross-coupling in industry. There has been a concerted effort to enable the use of Ni catalysis as an alternative to Pd in order to mitigate cost and improve sustainability. Despite significant advances, ligand development for Ni-catalyzed Suzuki-Miyaura cross-coupling remains underdeveloped when compared to Pd and, as a consequence, ligands for Ni-catalyzed processes are typically taken from the Pd arena. In this study we evaluate the effect of using a similar Ni and Pd precatalyst based on a common bidentate ligand (dppf) in a head-to-head format for the most common type of biaryl couplings, establishing the practical implications of direct replacement of Pd with Ni, and identifying the potential origins of these observations in a mechanistic context.
Anti-Markovnikov Hydroarylation of Unactivated Olefins via Pyridyl Radical Intermediates
Boyington, Allyson J.,Riu, Martin-Louis Y.,Jui, Nathan T.
supporting information, p. 6582 - 6585 (2017/05/29)
The intermolecular alkylation of pyridine units with simple alkenes has been achieved via a photoredox radical mechanism. This process occurs with complete regiocontrol, where single-electron reduction of halogenated pyridines regiospecifically yields the corresponding radicals in a programmed fashion, and radical addition to alkene substrates occurs with exclusive anti-Markovnikov selectivity. This system is mild, tolerant of many functional groups, and effective for the preparation of a wide range of complex alkylpyridines.
Simple and Clean Photo-induced Methylation of Heteroarenes with MeOH
Liu, Wenbo,Yang, Xiaobo,Zhou, Zhong-Zhen,Li, Chao-Jun
supporting information, p. 688 - 702 (2017/05/15)
Heteroarene methylation utilizing a cheap and safe methylation source without involving transition metals represents an important yet challenging objective. Here, a simple and clean catalyst-free protocol for the methylation of various heteroarenes (including six- and five-membered types) is described under light irradiation. This protocol employs cheap, readily available, and abundant MeOH as both the solvent and the methylation source. It was found that adding dichloromethane (DCM) as a co-solvent could significantly increase the yield of the methylation products. Heteroarenes bearing various functional groups could be methylated and tri-deuteromethylated successfully. Deuterium labeling studies suggested that the newly generated methyl group in the products consisted of two hydrogens from the methyl group and one hydrogen from the OH group in MeOH.
Alcohols as alkylating agents in heteroarene C-H functionalization
Jin, Jian,MacMillan, David W. C.
, p. 87 - 90 (2015/09/15)
Redox processes and radical intermediates are found in many biochemical processes, including deoxyribonucleotide synthesis and oxidative DNA damage. One of the core principles underlying DNA biosynthesis is the radical-mediated elimination of H2O to deoxygenate ribonucleotides, an example of 'spin-centre shift', during which an alcohol C-O bond is cleaved, resulting in a carbon-centred radical intermediate. Although spin-centre shift is a well-understood biochemical process, it is underused by the synthetic organic chemistry community. We wondered whether it would be possible to take advantage of this naturally occurring process to accomplish mild, non-traditional alkylation reactions using alcohols as radical precursors. Because conventional radical-based alkylation methods require the use of stoichiometric oxidants, increased temperatures or peroxides, a mild protocol using simple and abundant alkylating agents would have considerable use in the synthesis of diversely functionalized pharmacophores. Here we describe the development of a dual catalytic alkylation of heteroarenes, using alcohols as mild alkylating reagents. This method represents the first, to our knowledge, broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the successful merger of photoredox and hydrogen atom transfer catalysis. The value of this multi-catalytic protocol has been demonstrated through the late-stage functionalization of the medicinal agents, fasudil and milrinone.
Copper-catalyzed formal C-N bond cleavage of aromatic methylamines: Assembly of pyridine derivatives
Huang, Huawen,Ji, Xiaochen,Wu, Wanqing,Huang, Liangbin,Jiang, Huanfeng
, p. 3774 - 3782 (2013/06/05)
An efficient copper-catalyzed C-N bond cleavage of aromatic methylamines was developed to construct pyridine derivatives. With neat conditions and facile operation, the fragment-assembling strategy affords a broad range of 2,4,6-trisubstituted pyridines in up to 95% yield from simple and readily available starting materials. Interestingly, when pyridin-2-yl methylamine was employed as the substrate, α-alkylation reaction of ketones readily occurred to give β-(pyridin-2-yl) ketones instead of the 2,4,6-trisubstituted pyridines.
Rhenium-catalyzed regioselective synthesis of multisubstituted pyridines from β-enamino ketones and alkynes via C-C bond cleavage
Yamamoto, Shun-Ichi,Okamoto, Kana,Murakoso, Makiko,Kuninobu, Yoichiro,Takai, Kazuhiko
supporting information; experimental part, p. 3182 - 3185 (2012/07/28)
A new method is described for the regioselective synthesis of multisubstituted pyridine derivatives. Treatment of N-acetyl β-enamino ketones with alkynes in the presence of the rhenium catalyst, Re 2(CO)10, gives multisubstituted pyridines regioselectively. In this reaction, the N-acetyl moieties are important for the selective formation of the multisubstituted pyridines. This reaction proceeds via insertion of alkynes into a carbon-carbon single bond of β-enamino ketones, intramolecular nucleophilic cyclization, and elimination of acetic acid.
Preparation of ?-Deficient Heteroarylzinc Halides by Oxidative Addition of Active Zinc and Its Palladium-Catalyzed Reaction
Sakamoto, Takao,Kondo, Yoshinori,Murata, Naoko,Yamanaka, Hiroshi
, p. 9713 - 9720 (2007/10/02)
The oxidative addition of active zinc to iodo- and bromo-substituted ?-deficient heteroarenes such as pyridine, pyrimidine, and quinoline gave the corresponding heteroarylzinc halides which were transformed to the arylated and benzoylated derivatives by palladium-catalyzed reaction.
STUDIES ON THE REACTION OF N-VINYLIMIDOYL COMPOUNDS WITH ACETYLENIC DIENOPHILES
Zielinski, W.,Mazik, M.
, p. 1113 - 1119 (2007/10/02)
The reaction of N-vinylimidoyl compounds with acetylene derivatives as a potential method of pyridine moiety synthesis has been examined.The mechanism of the reaction has been discussed basing on the net atomic charges determined by MNDO method for the substrates and intermediate products and the experimental data.
Hydrogenolysis of 3-methyl-4-phenylmethyl-5(2H)-isoxazolone derivatives: A reinvestigation
Batra, Sanjay,Seth, M,Bhaduri, A P
, p. 60 - 62 (2007/10/02)
Hydrogenolysis of 3-methyl-4-phenylmethyl-5(2H)-isoxazolone (2a) and its derivatives 2b-e, 5a-e, 6a-e and 9a,b have been carried out over Pd/C and Raney-nickel.The products have been isolated and characterized.The intermediate products of hydrogenolysis of 2b-e have been trapped and simultaneous cleavage of N - O and C - C bonds in 9a,b has been suggested to explain the formation of the hydrogenolysis products 10a,b and 3a,b.