- Small organic molecules with tailored structures: Initiators in the transition-metal-free C-H arylation of unactivated arenes
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Simple, small organic molecules containing nitrogen and oxygen atoms in their structures have been disclosed to catalyze transition-metal-free C-H arylation of unactivated arenes with aryl iodides in the presence of tBuOK. In this article, an optimized catalytically active molecule, (2-(methylamino)phenyl)methanol, was designed. A broad range of aryl iodides could be converted into the corresponding arylated products at 100 °C over 24 h with good to excellent yields. Mechanistic experiments verified that radicals participated in this catalytic transformation and that the cleavage of the aromatic C-H bond was not the rate determining step. A K+ capture experiment by 18-crown-6 emphasized the significance of the cation species of the strong base. Fourier transform infrared spectroscopy proved that the catalytic system was activated by the hydrogen bonds between small organic molecules and tBuOK. Also, a clear mechanism was proposed. This transition-metal-free method affords a promising system for efficient and inexpensive synthesis of biaryls via a user-friendly approach, as confirmed by scale-up experiments.
- Chen, Suqing,Chen, Wenjun,Chen, Yu,Liu, Zhenghui,Mu, Tiancheng,Wang, Peng,Yan, Zhenzhong
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p. 14500 - 14509
(2020/04/27)
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- ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES
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A compound having the formula Ir(LA)(LB), where LA has a structure of Formula I and LB is a bidentate ligand is disclosed. In the structure of Formula I, rings A, B, C, and D are each independently 5- or 6-membe
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Paragraph 0155-0157
(2019/11/19)
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- A Micellar Catalysis Strategy for Suzuki-Miyaura Cross-Couplings of 2-Pyridyl MIDA Boronates: No Copper, in Water, Very Mild Conditions
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Suzuki-Miyaura (SM) cross-couplings of 2-pyridyl MIDA boronates can be successfully carried out in the complete absence of copper by attenuation of the Lewis basicity associated with the pyridyl nitrogen using selected substituents (e.g., fluorine or chlorine) on the ring. This strategy imparts additional synthetic options compared with existing approaches based on the use of Lewis acids or N-oxides. Thus, access to highly valued 2-substituted pyridyl rings via an initial Suzuki-Miyaura coupling can be followed by dehalogenation, SNAr reactions, or a second SM coupling to arrive at 2,6-disubstituted pyridyl arrays, all run in a single pot, enabled by micellar catalysis in water. Accessing targets within drug-like space is demonstrated in a four-step, one-pot sequence. Computational data suggest that the major role being played by electron-withdrawing substituents in promoting these cross-couplings without the need for copper is to slow the rates of protodeboronation of intermediate 2-pyridylboronic acids.
- Isley, Nicholas A.,Wang, Ye,Gallou, Fabrice,Handa, Sachin,Aue, Donald H.,Lipshutz, Bruce H.
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p. 8331 - 8337
(2017/12/08)
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- Oxygen-promoted Pd/C-catalyzed Suzuki-Miyaura reaction of potassium aryltrifluoroborates
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A simple and highly efficient protocol has been developed for the Pd/C-catalyzed ligand-free Suzuki-Miyaura reaction of potassium aryltrifluoroborates. In this catalytic system, the results demonstrate that oxygen plays a positive role in the cross-coupling reaction. In addition, this catalytic system could be successfully applied to synthesize biaryl compounds containing a carbazole moiety and the catalyst was recycled seven times without significant loss of catalytic activity.
- Liu, Chun,Liu, Chao,Li, Xin-Min,Gao, Zhan-Ming,Jin, Zi-Lin
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p. 631 - 634
(2016/05/19)
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- Facile Route to 2-Fluoropyridines via 2-Pyridyltrialkylammonium Salts Prepared from Pyridine N-Oxides and Application to 18F-Labeling
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Among known precursors for 2-[18F]fluoropyridines, pyridyltrialkylammonium salts have shown excellent reactivity; however, their broader utility has been limited because synthetic methods for their preparation suffer from poor functional group
- Xiong, Hui,Hoye, Adam T.,Fan, Kuo-Hsien,Li, Ximin,Clemens, Jennifer,Horchler, Carey L.,Lim, Nathaniel C.,Attardo, Giorgio
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supporting information
p. 3726 - 3729
(2015/08/18)
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- C-H FLUORINATION OF HETEROCYCLES WITH SILVER (II) FLUORIDE
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The present invention provides compositions and methods for the selective C-H fluorination of nitrogen-containing heteroarenes with AgF2, which has previously been considered too reactive for practical, selective C-H fluorination. Fluorinated heteroarenes are prevalent in numerous pharmaceuticals, agrochemicals and materials. However, the reactions used to introduce fluorine into these molecules require pre-functionalized substrates or the use of F2 gas. The present invention provides a mild and general method for the C-H fluorination of nitrogen-containing heteroarene compounds to 2-fluoro-heteroarenes with commercially available AgF2. In various embodiments, these reactions occur at ambient temperature within one hour and occur with exclusive selectivity for fluorination at the 2-position. Exemplary reaction conditions are effective for fluorinating diazine heteroarenes to form a single fluorinated isomer.
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Paragraph 0073; 0074; 0075; 0076
(2015/02/19)
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- Synthesis and late-stage functionalization of complex molecules through C-H fluorination and nucleophilic aromatic substitution
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We report the late-stage functionalization of multisubstituted pyridines and diazines at the position α to nitrogen. By this process, a series of functional groups and substituents bound to the ring through nitrogen, oxygen, sulfur, or carbon are installed. This functionalization is accomplished by a combination of fluorination and nucleophilic aromatic substitution of the installed fluoride. A diverse array of functionalities can be installed because of the mild reaction conditions revealed for nucleophilic aromatic substitutions (SNAr) of the 2-fluoroheteroarenes. An evaluation of the rates for substitution versus the rates for competitive processes provides a framework for planning this functionalization sequence. This process is illustrated by the modification of a series of medicinally important compounds, as well as the increase in efficiency of synthesis of several existing pharmaceuticals.
- Fier, Patrick S.,Hartwig, John F.
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supporting information
p. 10139 - 10147
(2014/08/05)
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- Selective C-H fluorination of pyridines and diazines inspired by a classic amination reaction
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Fluorinated heterocycles are prevalent in pharmaceuticals, agrochemicals, and materials. However, reactions that incorporate fluorine into heteroarenes are limited in scope and can be hazardous. We present a broadly applicable and safe method for the site-selective fluorination of a single carbon-hydrogen bond in pyridines and diazines using commercially available silver(II) fluoride. The reactions occur at ambient temperature within 1 hour with exclusive selectivity for fluorination adjacent to nitrogen. The mild conditions allow access to fluorinated derivatives of medicinally important compounds, as well as a range of 2-substituted pyridines prepared by subsequent nucleophilic displacement of fluoride. Mechanistic studies demonstrate that the pathway of a classic pyridine amination can be adapted for selective fluorination of a broad range of nitrogen heterocycles.
- Fier, Patrick S.,Hartwig, John F.
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p. 956 - 960
(2013/12/04)
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- Palladium-catalyzed Suzuki-Miyaura cross-coupling reaction of potassium 2-pyridyl trifluoroborate with aryl (heteroaryl) halides
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Palladium-catalyzed Suzuki-Miyaura cross-coupling reaction of potassium pyridine-2-trifluoroborates and various aryl (heteroaryl) halides can generate the corresponding desired coupling products with moderate to good yields. It can be carried out under the conditions with ethanol as solvent, Pd(OAc) 2 and SPhos as catalyst system and Na2CO3 as a base.
- Ren, Wei,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
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p. 1351 - 1358
(2012/03/10)
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- INDANE DERIVATES AS MUSCARINIC RECEPTOR AGONISTS
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The present invention relates to compounds of Formula I: I which are agonists of the M-1 muscarinic receptor.
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- MUSCARINIC AGONISTS
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The present invention relates to compounds of Formula (I): which are agonists of the M-1 muscarinic receptor.
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- MUSCARINIC AGONISTS
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The present invention relates to compounds of Formula (I): which are agonists of the M-1 muscarinic receptor.
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- Site-selective C-H fluorination of pyridines and diazines with AgF2
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A procedure that yields 2-fluoro-6-phenylpyridine as a colorless oil is presented. Color change through the course of reaction is observed. Flash chromatography on silica gel is performed to purify the crude material to afford the product. Following the p
- Fier, Patrick S.,Hartwig, John F.
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