1753-62-4Relevant academic research and scientific papers
Alkylation of the 2-hydroxypyridine anion in ionic liquid media
Vavilina,Zicmanis,Mekss,Klavins
, (2008)
The alkylation reaction of the ambident 2-hydroxypyridine anion was examined in ionic liquid media. Ionic liquids increase the alkylation reaction rate in comparison with molecular liquids, as well as the level of impact on the reaction rates of the count
A porphyrin molecule that generates, traps, stores, and releases singlet oxygen
Changtong, Chuchawin,Carney, Daniel W.,Luo, Lan,Zoto, Christopher A.,Lombardi, John L.,Connors, Robert E.
, p. 9 - 13 (2013)
Tetraphenylporphyrin (H2TPP), covalently linked to four 2-pyridone moieties was synthesized (II) and studied. This composite molecule, in combination with light and ground state oxygen, has the ability to generate, trap, store, and release singlet oxygen. The process can be operated reversibly without detectable decomposition or side reactions using light with wavelength greater than 500 nm. Oxidation of the target molecule, 2-chloroethyl ethyl sulfide (CEES), by singlet oxygen released from the endoperoxide of the porphyrin-2-pyridone molecule (I) is demonstrated. Spectroscopic and kinetic data do not reveal evidence of perturbation between the porphyrin and pyridone ring systems of II. The decomposition kinetics for the endoperoxide adduct I are first order with activation parameters ΔH? = 26.7 (kcal/mol) and ΔG? = 24.0 (kcal/mol). Experimental and computational studies of unattached N-benzyl-2-pyridone peroxide are reported and compared to the experimental data for I.
Selectivity under microwave irradiation. Benzylation of 2-pyridone: an experimental and theoretical study
de la Hoz, Antonio,Prieto, María Pilar,Rajzmann, Michel,de Cózar, Abel,Díaz-Ortiz, Angel,Moreno, Andrés,Cossío, Fernando P.
, p. 8169 - 8176 (2008)
The reaction of 2-pyridone with benzyl bromide in the absence of base and under solvent-free conditions has been studied experimentally and by computational methods. This reaction was one of the first reported examples in which modification of selectivity under microwave irradiation was observed. C- and/or N-alkylations were obtained depending on the benzyl halide and the heating system. N-Alkylation through mechanism A (SN2 mechanism) is kinetically favoured while C-alkylation through an SN1-type mechanism is thermodynamically favoured and is observed under microwave irradiation. Two SN1-type mechanisms (mechanisms B and C) have been calculated, mechanism C being a kind of SNi. The influence of the pyridone/benzyl bromide ratio was studied. A second molecule of pyridone stabilizes the transition state and assists the leaving of the bromide ion. The occurrence of C-alkylation under microwave irradiation is explained by the predominance of the thermodynamic control in these conditions. Under microwave irradiation N-alkylation through an SN1-type mechanism (mechanism C) can also occur. The dependence of the outcome of N-alkylation on the benzyl bromide ratio has been explained by a shift in the mechanism from SN2 to SN1 under microwave irradiation. Computational calculations have shown to be a useful tool for determination of the origin of the selectivity under microwave irradiation.
Ibogaine analogues. Synthesis and preliminary pharmacological evaluation of 7-heteroaryl-2-azabicyclo[2.2.2]oct-7-enes
Passarella, Daniele,Favia, Raffaele,Giardini, Alessandra,Lesma, Giordano,Martinelli, Marisa,Silvani, Alessandra,Danieli, Bruno,Efange, Simon M. N.,Mash, Deborah C.
, p. 1007 - 1014 (2003)
Synthesis of 7-heteroaryl-2-azabicyclo[2.2.2]oct-7-enes by cycloaddition and subsequent cross-coupling reaction is described. Binding affinity of these novel compounds towards the characteristic receptorial targets of ibogaine is illustrated.
Solvent-free benzylations of 2-pyridone. Regiospecific N-or C-alkylation
Almena, Ines,Diaz-Ortiz, Angel,Diez-Barra, Enrique,De La Hoz, Antonio,Loupy, Andre
, p. 333 - 334 (1996)
Regiospecific N-or C-benzylations of 2-pyridone are observed in solvent-free conditions in the absence of base. The regioselectivity is controlled by the heating technique (microwave irradiation or conventional heating) or, using microwaves, by the emitte
Intramolecular reactivity of trans [4+4] photodimers of 2-pyridones
Chen, Peiling,Carroll, Patrick J.,Sieburth, Scott McN.
, p. 2351 - 2359 (2007)
Photodimers of 2-pyridones are cycloocta-1,5-dienes with two lactam bridges. These, and related structures, undergo halogenation to give rearranged products in which an amide nitrogen has intercepted an initial halonium ion. For the trans isomer, a transi
PhICl2/NH4SCN-Mediated Oxidative Regioselective Thiocyanation of Pyridin-2(1H)-ones
Tao, Shanqing,Xiao, Jiaxi,Li, Yadong,Sun, Fengxia,Du, Yunfei
, p. 2536 - 2546 (2021/07/31)
The reaction of pyridin-2(1H)-ones with PhICl2 and NH4SCN enables an efficient regioselective thiocyanation, leading to the synthesis of the biologically interesting C5 thiocyanated 2-pyridones in good to high yields. The mechanistic pathway of this metal-free approach is postulated to involve the formation of the reactive thiocyanogen chloride from the reaction of PhICl2 and NH4SCN followed with the regioselective electrophilic thiocyanation of the pyridin-2(1H)-one ring.
Manganese-Promoted Regioselective Direct C3-Phosphinoylation of 2-Pyridones
Chantarojsiri, Teera,Kittikool, Tanakorn,Phakdeeyothin, Kunita,Yotphan, Sirilata
supporting information, p. 3071 - 3078 (2021/07/22)
A highly efficient and regioselective manganese-induced radical oxidative direct C?P bond formation between 2-pyridones and secondary phosphine oxides was developed. The C3-selective phosphinoylation was conveniently achieved through a combination of substoichiometric manganese and persulfate oxidant under mild conditions. Various 3-phosphinoylated pyridone products can be obtained in moderate to high yields. Preliminary mechanistic studies suggest that the reaction is likely to involve a radical pathway induced by catalytically active Mn3+ species.
Rhodium-Catalyzed C4-Selective C-H Alkenylation of 2-Pyridones by Traceless Directing Group Strategy
Hazra, Sunit,Hirano, Koji,Miura, Masahiro
, p. 1388 - 1393 (2021/03/03)
A rhodium-catalyzed C4-selective C-H alkenylation of 3-carboxy-2-pyridones with styrenes has been developed. The carboxylic group at the C3 position works as the traceless directing group, and the corresponding C4-alkenylated 2-pyridones are obtained exclusively with concomitant decarboxylation. Unlike the reported procedures, the exclusive C4 selectivity is uniformly observed even in the presence of potentially more reactive C-H bonds at the C5 and C6 positions. By using this strategy, the multiply substituted 2-pyridone can be prepared via sequential C-H functionalization reactions.
Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis
Zhou, Min-Jie,Zhang, Lei,Liu, Guixia,Xu, Chen,Huang, Zheng
supporting information, p. 16470 - 16485 (2021/10/20)
The value of catalytic dehydrogenation of aliphatics (CDA) in organic synthesis has remained largely underexplored. Known homogeneous CDA systems often require the use of sacrificial hydrogen acceptors (or oxidants), precious metal catalysts, and harsh reaction conditions, thus limiting most existing methods to dehydrogenation of non- or low-functionalized alkanes. Here we describe a visible-light-driven, dual-catalyst system consisting of inexpensive organophotoredox and base-metal catalysts for room-temperature, acceptorless-CDA (Al-CDA). Initiated by photoexited 2-chloroanthraquinone, the process involves H atom transfer (HAT) of aliphatics to form alkyl radicals, which then react with cobaloxime to produce olefins and H2. This operationally simple method enables direct dehydrogenation of readily available chemical feedstocks to diversely functionalized olefins. For example, we demonstrate, for the first time, the oxidant-free desaturation of thioethers and amides to alkenyl sulfides and enamides, respectively. Moreover, the system's exceptional site selectivity and functional group tolerance are illustrated by late-stage dehydrogenation and synthesis of 14 biologically relevant molecules and pharmaceutical ingredients. Mechanistic studies have revealed a dual HAT process and provided insights into the origin of reactivity and site selectivity.
