- A Novel One-Pot Synthesis of N,N-Dimethylaminopyridines by Diazotization of Aminopyridines in Dimethylformamide in the Presence of Trifluoromethanesulfonic Acid
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Abstract: Diazotization of aminopyridines in the presence of trifluoromethanesulfonic acid gives the corresponding pyridinyl trifluoromethanesulfonates instead of expected diazonium salts. Pyridinyl trifluoromethanesulfonates can be converted to N,N-dimethylaminopyridines on heating in dimethylformamide via replacement of the trifluoromethanesulfonyloxy group. The reaction is accelerated under microwave irradiation. A novel one-pot procedure has been proposed for the synthesis of 2- and 4-(dimethylamino)pyridines from commercially available aminopyridines. The procedure provides high yields of the target products, and it can be regarded as an alternative to the known methods of synthesis of N,N-dimethylpyridin-4-amine (DMAP) widely used as base catalyst in organic synthesis.
- Filimonov, V. D.,Krasnokutskaya, E. A.,Potapova, M. I.,Sanzhiev, A. N.
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p. 1023 - 1028
(2020/07/25)
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- Amination of Aromatic Halides and Exploration of the Reactivity Sequence of Aromatic Halides
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A base-promoted amination of aromatic halides has been developed using a limited amount of dimethylformamide (DMF) or amine as an amino source. Various aryl halides, including F, Cl, Br, and I, have been successfully aminated in good to excellent yields. Although the amination of aromatic halides with amines or DMF is usually considered as an aromatic nucleophilic substitution (SNAr) process, and the reactivity of an aromatic halide is F > Cl > Br > I, the reactivity of aromatic halides in this system was found to be I > Br a‰ F > Cl. This protocol also showed a good regioselectivity for multihalogenated aromatics. This protocol is valuable for industrial application due to the simplicity of operation, the unrestricted availability of amino sources and aromatic halides, transition metal-free conditions, no requirement for solvent, and scalability.
- Yang, Chu,Zhang, Feng,Deng, Guo-Jun,Gong, Hang
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p. 181 - 190
(2019/01/10)
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- Iridium- and rhodium-catalyzed dehydrogenative silylations of C(sp 3) - H bonds adjacent to a nitrogen atom using hydrosilanes
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Now that is just silylated: In the presence of iridium or rhodium catalysts, C(sp3) - H bonds adjacent to a nitrogen atom were silylated by the aid of a pyridine-directing group. In iridium catalysis, a hydrogen-trapping reagent such as norbornene or tert-butylethylene, which is usually required in late transition-metal-catalyzed dehydrogenative coupling reactions, was not required. In rhodium catalysis, however, 1 equivalent of COD (1,5-cyclooctadiene) was necessary to induce higher conversion. Copyright
- Mita, Tsuyoshi,Michigami, Kenichi,Sato, Yoshihiro
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supporting information
p. 2970 - 2973
(2014/01/06)
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- PYRAZOLO [1,5-ALPHA] PYRIMIDINYL DERIVATIVES USEFUL AS CORTICOTROPIN-RELEASING FACTOR (CRF) RECEPTOR ANTAGONISTS
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CRF receptor antagonists are disclosed which may have utility in the treatment of a variety of disorders, including the treatment of disorders manifesting hypersecretion of CRF in mammals. The CRF receptor antagonists of this invention have the following structure: (I); and pharmaceutically acceptable salts, esters, solvates, stereoisomers and prodrugs thereof, wherein R1, R2a, R2b, Y, Het, n, o, R6, Ar and R7 are as defined herein. Compositions containing a CRF receptor antagonist in combination with a pharmaceutically acceptable carrier are also disclosed, as well as methods for use of the same.
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Page/Page column 38-39
(2008/06/13)
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- Design of 2,5-dimethyl-3-(6-dimethyl-4-methylpyridin-3-yl)-7-dipropylamino- pyrazolo[1,5-a]pyrimidine (NBI 30775/R121919) and structure-activity relationships of a series of potent and orally active corticotropin-releasing factor receptor antagonists
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We previously shown that 3-phenylpyrazolo[1,5-a]pyrimidines exemplified by 8 were potent antagonists of the human corticotropin-releasing factor-1 receptor. A series of 3-pyridylpyrazolo-[1,5-a]pyrimidines 15, 25-30, 34, and 35 containing a weakly basic pyridine ring at the 3-position of the bicyclic nucleus was designed to reduce lipophilicity from the initial leads such as 7. Here, we showed that these 3-pyridyl compounds exhibited potent antagonists at the human CRF1 receptor. Moreover, the hydrophilic and weakly basic pyridine moiety increased the water solubility of some analogues. Compound 26h exhibited good binding affinity at the human CRF1 receptor with a Ki value of 3.5 nM. As a functional antagonist, it dose-dependently inhibited CRF-stimulated cAMP production in cells expressing the CRF1 receptor (IC50 = 50 nM), and CRF-stimulated ACTH release from cultured rat pituitary cells (IC50 = 20 nM). 26h had a log P value of 4.9 and water solubility of greater than 10 mg/mL. Pharmacokinetic studies in rats showed that 26h was orally bioavailable and able to penetrate into the brain. 26h has been demonstrated in vivo efficacy in animal behavioral models that measure anxiolytic activity. These results suggest that analogues from this series were potent CRF1 receptor antagonists with proper physicochemical properties and good pharmacokinetic profiles. 26h was developed into a clinical compound and exhibited efficacy in patients with major depression.
- Chen, Chen,Wilcoxen, Keith M.,Huang, Charles Q.,Xie, Yun-Feng,McCarthy, James R.,Webb, Thomas R.,Zhu, Yun-Fei,Saunders, John,Liu, Xin-Jun,Chen, Ta-Kung,Bozigian, Haig,Grigoriadis, Dimitri E.
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p. 4787 - 4798
(2007/10/03)
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