- Oxidation methods for aromatic diazines. Part II. Chlorinated pyrazine N-oxides
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Chlorinated pyrazines are directly oxidized to the N-oxides using dimethyldioxirane. The reactions were found to be completely regioselective and the products were easily isolated in good yields. These oxidations were comparable to the conversion of methylated pyrazines to pyrazine monoxides and dioxides described by us in part 1. Oxidation with dimethyldioxirane in acetone overcomes problems associated with the isolation of hydrophilic pyrazine N-oxides obtained by using other oxidation reagents.
- Sooter, Joseph A.,Marshall, Tadd P.,McKay, Scott E.
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- Regioselective Reaction of Heterocyclic N-Oxides, an Acyl Chloride, and Cyclic Thioethers
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Treatment of electron deficient pyridine N-oxides with 4-nitrobenzoyl chloride and a cyclic thioether in the presence of triethylamine leads to the corresponding 2-functionalized product in up to a 74% isolated yield. The transformation can also be accomplished with alternative nitrogen containing heterocycles, including quinolines, pyrimidines, and pyrazines. To expand the scope of the transformation, diisopropyl ether can be used as the reaction medium to allow for the use of solid thioether substrates.
- Frei, Przemyslaw,Heulyn Jones,Kay, Steven T.,McLellan, Jayde A.,Johnston, Blair F.,Kennedy, Alan R.,Tomkinson, Nicholas C. O.
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p. 1510 - 1517
(2018/02/10)
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- Emimycin and its nucleoside derivatives: Synthesis and antiviral activity
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The synthesis of emimycin, 5-substituted emimycin analogues and the corresponding ribo- and 2′-deoxyribonucleoside derivatives is described. Emimycin, its 5-substituted congeners and the ribonucleoside derivatives are completely devoid of antiviral activity against RNA viruses. In contrast, some of the 2′-deoxyribosyl emimycin derivatives are potent inhibitors of the replication of herpes simplex virus-1 and varicella-zoster virus, lacking cytotoxicity.
- Plebanek, Elzbieta,Lescrinier, Eveline,Andrei, Graciela,Snoeck, Robert,Herdewijn, Piet,De Jonghe, Steven
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- BENZO ‘ D!AZEPINE DERIVATIVES FOR THE TREATMENT OF NEUROLOGICAL DISORDERS
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The present invention relates to benzazepine derivatives of formula ( I ) wherein: R1 represents -C3-7 cycloalkyl optionally substituted by C1-3 alkyl; having pharmacological activity, processes for their preparation, to compositions containing them and to their use in the treatment of neurological and psychiatric disorders.
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Page/Page column 23
(2010/02/07)
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- Identification of 2-chloropyrazine oxidation products and several derivatives by multinuclear magnetic resonance
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1H, 13C, 14N and 15N NMR chemical shifts were used to prove the structures of the products of 2-chloropyrazine oxidation. It was shown that oxidation by hydrogen peroxide in acetic acid or m-chloroperbenzoic acid leads to the N4-oxide, whereas potassium persulfate in sulfuric acid gives the N1-oxide as the main product. Additionally, the results of NMR measurements of products from the nucleophilic substitution of the chlorine atom by azide anion, yielding the respective azides, and ethylation reactions of both 2-chloropyrazine N-oxides leading to the N-ethyl salts confirm the structures of both isomeric N-oxides. Protonation studies of the compounds obtained are also reported. The favoured protonation site is found to be the N atom that is not hindered by any substituents, and in some cases probably the oxygen atom of the N-oxide function. Copyright
- Cmoch, Piotr
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p. 693 - 698
(2007/10/03)
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- Pyrazinone N-oxide nucleosides and analogs thereof
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This invention relates to nucleoside and acyclo analogs containing 5- or 6-substituted 2-pyrazinone-4-N-oxide. These compounds are useful for treating various conditions including viral infections, cancer, fungal infections, bacterial infections, microbia
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- DIAZOTIZATION OF SOME AMINODIAZINE N-OXIDES
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Diazotization of a number of aminopyrazine and aminopyrimidine N-oxides affords intermediate diazonium compounds which can be converted to the corresponding bromo and chloro analogs in the presence of the appropriate halide ions.In some instances, electrophilic aromatic substitution takes place prior to the diazotization step.Nucleophilic halogenation accompanying deoxygenation occurs with 2-aminopyrimidine N-oxide in the same manner as described for some 3-amino-1,2,4-triazine 2-oxides.
- Jovanovic, Misa V.
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p. 2011 - 2018
(2007/10/02)
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