1753-62-4Relevant articles and documents
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
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.
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
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.
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.
Environmentally benign nucleophilic substitution reaction of arylalkyl halides in water using CTAB as the inverse phase transfer catalyst
Godha, Atul K.,Thiruvengadam, Jayaraman,Abhilash, Viswanadhan,Balgi, Prajwal,Narayanareddy,Vignesh, Kumaresan,Gadakh, Amol V.,Sathiyanarayanan,Ganesh, Sambasivam
supporting information, p. 16041 - 16045 (2019/10/28)
An environmentally benign, practically scalable and highly selective C-arylalkylation of active methylene compounds is developed using CTAB as the inverse phase transfer catalyst in water. The methodology developed is elaborated into the one-pot synthesis of quinoline derivatives and also applicable to the regioselective N-aralkyl of 2-pyridones.
