- Visible-Light-Induced ortho-Selective Migration on Pyridyl Ring: Trifluoromethylative Pyridylation of Unactivated Alkenes
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The photocatalyzed ortho-selective migration on a pyridyl ring has been achieved for the site-selective trifluoromethylative pyridylation of unactivated alkenes. The overall process is initiated by the selective addition of a CF3 radical to the alkene to provide a nucleophilic alkyl radical intermediate, which enables an intramolecular endo addition exclusively to the ortho-position of the pyridinium salt. Both secondary and tertiary alkyl radicals are well-suited for addition to the C2-position of pyridinium salts to ultimately provide synthetically valuable C2-fluoroalkyl functionalized pyridines. Moreover, the method was successfully applied to the reaction with P-centered radicals. The utility of this transformation was further demonstrated by the late-stage functionalization of complex bioactive molecules.
- Jeon, Jinwon,He, Yu-Tao,Shin, Sanghoon,Hong, Sungwoo
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supporting information
p. 281 - 285
(2019/11/26)
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- Visible Light-Mediated Decarboxylative Alkylation of Pharmaceutically Relevant Heterocycles
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A net redox-neutral method for the decarboxylative alkylation of heteroarenes using photoredox catalysis is reported. Additionally, this method features the use of simple, commercially available carboxylic acid derivatives as alkylating agents, enabling the facile alkylation of a variety of biologically relevant heterocyclic scaffolds under mild conditions.
- Sun, Alexandra C.,McClain, Edward J.,Beatty, Joel W.,Stephenson, Corey R. J.
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supporting information
p. 3487 - 3490
(2018/06/26)
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- Hydroheteroarylation of Unactivated Alkenes Using N-Methoxyheteroarenium Salts
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We report the first reductive coupling of unactivated alkenes with N-methoxy pyridazinium, imidazolium, quinolinium, and isoquinolinium salts under hydrogen atom transfer (HAT) conditions, and an expanded scope for the coupling of alkenes with N-methoxy pyridinium salts. N-Methoxy pyridazinium, imidazolium, quinolinium, and isoquinolinium salts are accessible in 1-2 steps from the commercial arenes or arene N-oxides (25-99%). N-Methoxy imidazolium salts are accessible in three steps from commercial amines (50-85%). In total 36 discrete methoxyheteroarenium salts bearing electron-donating, electron-withdrawing, alkyl, aryl, halogen, and haloalkyl substituents were prepared (several in multigram quantities) and coupled with 38 different alkenes. The transformations proceed under neutral conditions at ambient temperature, provide monoalkylation products exclusively, and form a single alkene addition regioisomer. Preparatively useful and complementary site selectivities in the addition of secondary and tertiary radicals to pyidinium salts are documented: harder secondary radicals favor C-2 addition (2->10:1), while softer tertiary radicals favor bond formation to C-4 (4.7->29:1). A diene possessing a 1,2-disubstituted and 2,2-disubstituted alkene undergoes hydropyridylation at the latter exclusively (61%) suggesting useful site selectivities can be obtained in polyene substrates. The methoxypyridinium salts can also be employed in dehydrogenative arylation, borono-Minisci, and tandem arylation processes. Mechanistic studies support the involvement of a radical process.
- Ma, Xiaoshen,Dang, Hester,Rose, John A.,Rablen, Paul,Herzon, Seth B.
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supporting information
p. 5998 - 6007
(2017/05/04)
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- METABOTROPIC GLUTAMATE RECEPTOR NEGATIVE ALLOSTERIC MODULATORS (NAMS) AND USES THEREOF
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Provided herein are small molecule active metabotropic glutamate subtype-2 and -3 receptor negative allosteric modulators (NAMs), compositions comprising the compounds, and methods of using the compounds and compositions.
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Paragraph 00460
(2016/01/01)
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- BRIDGED, BICYCLIC HETEROCYCLIC OR SPIRO BICYCLIC HETEROCYCLIC DERIVATIVES OF PYRAZOLO[1,5-A]PYRIMIDINES, METHODS FOR PREPARATION AND USES THEREOF
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Compounds of formula A: Formula (1) pharmaceutically acceptable salts thereof are described, which selectively inhibit Raf kinase activity and are useful for treating disorders mediated by Raf kinases.
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Page/Page column 38
(2009/10/21)
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- Pharmacologically active pyridine derivatives and processes for the preparation thereof
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N-phenyl-2-pyrimidineamine derivatives of formula I STR1 wherein the substituents are as defined in claim 1 and the derivatives of formula I can be used, for example, in the treatment of tumour diseases.
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- Formation of the N-oxides of heteroaromatic nitrogen compounds by perfluorinated oxaziridines
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On treatment with perfluoro-cis-2,3-dialkyloxaziridines, mono-, bi-, and tricyclic nitrogen heteroaromatics afford the corresponding N-oxides under mild reaction conditions and in medium to high yields. The course of the reaction is not altered by the presence of various residues on the ring or in side chains and the N-oxides of polyfunctional, naturally occurring compounds have been prepared.
- Balsarini, Christian,Novo, Barbara,Resnati, Giuseppe
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- An Excellent Method for the Mild and Safe Oxidation of N-Heteroaromatic Compounds and Tertiary Amines
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Selective, mild and safe N-oxidation of N-heteroaromatic compounds and tertiary amines affording high product yields was achieved by using the H2O2-urea/phthalic anhydride system. Key Words: N-Oxidation / Hydrogen peroxide / Urea / Phthalic anhydride
- Kaczmarek, Lukasz,Balicki, Roman,Nantka-Namirski, Pawel
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p. 1965 - 1966
(2007/10/02)
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- New description of substituent effect on electronic spectra by means of substituent constants-VI. Ultraviolet spectra of 4-substituted pyridine N-oxides and blue shifted iodine bands of their EDA complexes with iodine
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Electronic spectra of 4-substituted pyridine N-oxides and their EDA complexes with iodine were studied.The substituent effect on the near u.v. 1A1 intramolecular CT bands of the N-oxides and on the blue shifted iodine bands caused by CT complex formation are discussed in terms of a general equation, theoretically derived in order to describe the substituent effect on electronic spectra by means of substituent constants.The results are quite successful and supported by semi-empirical SCFMO-Cl calculations.Based on the results mentioned above, the character of n-? type N-oxide-iodine CT complexes is also examined.The complex formation constants(log K) and pKa values of the N-oxides correlate especially well, indicating that the CT interaction mechanism cannot be neglected in proton addition reactions such as hydrogen bonding and pKa values.
- Uno, Bunji,Kano, Kenji,Kaida, Naoki,Kubota, Tanekazu
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p. 937 - 944
(2007/10/02)
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