- C-H Amination of Nitro Azaheterocyclic Compounds by Vicarious Nucleophilic Substitution
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Various nitro azaheterocyclic compounds were subjected to C H amination by vicarious nucleophilic substitution with 4H-1,2,4-triazol-4-amine (ATA). The aminated products were characterized by NMR, mass spectroscopy, and single-crystal X-ray diffraction an
- Zhou, Ru-Shuang,Cai, Chun
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supporting information
p. 88 - 92
(2021/12/03)
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- Electrochemical Nonacidic N-Nitrosation/N-Nitration of Secondary Amines through a Biradical Coupling Reaction
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An acid-free N-nitrosation/nitration of the N?H bonds in secondary amines with Fe(NO3)3 ? 9H2O as the nitroso/nitro source through an electrocatalyzed radical coupling reaction was developed. Cyclic aliphatic amines and N-heteroaromatic compounds were N-nitrosated and N-nitrated, respectively, under mild conditions. Control and competition experiments, as well as kinetic studies, demonstrate that N-nitrosation and N-nitration involve two different radical reaction pathways involving N+ and N. radicals. Moreover, the electrocatalysis method enables the preferential activation of the N?H bond over the electrode and thus provides high selectivity for specific N atoms. Finally, this strategy exhibits a broad scope and provides a green and straightforward approach to generate useful N-nitroso/nitro compounds in good yields. (Figure presented.).
- Zhao, Ji-Ping,Ding, Lu-jia,Wang, Peng-Cheng,Liu, Ying,Huang, Min-Jun,Zhou, Xin-Li,Lu, Ming
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supporting information
p. 5036 - 5043
(2020/07/13)
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- Alkynyl pyrimidine or alkynyl pyridine compound as well as composition and application thereof
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The invention relates to alkynyl pyrimidine or alkynyl pyridine compounds represented by a formula (I) or pharmaceutically acceptable salts, isomers, solvates, crystals or prodrugs thereof. The invention also discloses a pharmaceutical composition contain
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Paragraph 0097-0099
(2020/08/18)
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- PYRAZOLE DERIVATIVES AS THAT MODULATE THE ACTIVITY OF CDK, GSK AND AURORA KINASES
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The invention provides a compound of the formula (I): for use in medicine: or salts or tautomers or N-oxides or solvates thereof; wherein R1 is an optionally substituted heterocyclic group having from 3 to 12 ring members provided that the cyclic group joined to the pyrazole contains at least one heteroatom selected from N, O or S; A is a bond or -Y-(B)n-; B is C=O, NRg(C=O) or O(C=O) wherein Rg is hydrogen or C1-4 hydrocarbyl optionally substituted by hydroxy or C1-4 alkoxy; n is 0 or 1; Y is a bond or an alkylene chain of 1,2 or 3 carbon atoms in length; R2 is hydrogen; halogen; C1-4 alkoxy (e.g. methoxy); or a C1-4 hydrocarbyl group optionally substituted by halogen (e.g. fluorine), hydroxyl or C1-4 alkoxy (e.g. methoxy); R3 is selected from optionally substituted carbocyclic and heterocyclic groups having from 3 to 12 ring members or an optionally substituted C1-8 hydrocarbyl group; with the proviso that R1 is not formula (II): where X, R3’ and R4’ are defined in the claims.
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Page/Page column 134
(2008/06/13)
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- Faujasite catalysis of aromatic nitrations with dinitrogen pentoxide. The effect of aluminium content on catalytic activity and regioselectivity: The nitration of pyrazole
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The reaction of 1-chloro-2-nitrobenzene with dinitrogen pentoxide in dichloromethane catalysed by H-faujasite zeolites F-712, F-720, F-780 and F-901, giving 1-chloro-2,4-dinitro- and 1-chloro-2,6-dinitrobenzene in approximately 30:1 ratio, is a kinetically first-order process. First-order rate constants are independent of the concentration of N2O5 and proportional to the mass of catalyst used. Specific rate constants, obtained by dividing the first-order rate constant by the mass of faujasite, are constant for a given faujasite. Amongst the faujasites, they increase in approximate proportion to the aluminium content. A mechanism is proposed in which the protons in the faujasite, near aluminium in the faujasite framework, are replaced by nitronium ions derived from N2O5 in a fast pre-equilibrium process. This produces active sites for transfer of nitronium ion from faujasite to aromatic in the rate-determining step. The similar reactions of 2-nitrotoluene, too fast for kinetic study, reveal that the ratio of 2,4- to 2,6-dinitrotoluene in the product increases with the aluminium content of the faujasite. Nitration of nitrobenzene is also catalysed by faujasite. Relative reactivities of nitrobenzene, 1-chloro-2-nitro- and 1-chloro-4-nitrobenzene are compared to those found in mixed-acid nitration. Pyrazole can be nitrated readily with N2O5 over faujasites, yielding 1,4-dinitropyrazole in 80% yield under mild conditions.
- Claridge, Robert P.,Lancaster, N. Llewellyn,Millar, Ross W.,Moodie, Roy B.,Sandall, John P.B.
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p. 197 - 200
(2007/10/03)
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- Ozone-mediated Nitration of Pyrazole, Imidazole and Uracil with Nitrogen Dioxide
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In the presence of ozone, pyrazole and uracil were easily N-nitrated with nitrogen dioxide in dichloromethane at 0°C to give the corresponding 1-nitro derivatives, whilst imidazole was C-nitrated in the additional presence of methanesulfonic acid as catalyst to afford the 4-nitro derivative, each product being obtained in a satisfactory yield.
- Suzuki, Hitomi,Nonoyama, Nobuaki
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p. 244 - 245
(2007/10/03)
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- C-Nucleoside Studies. Part 20. Synthesis of Some Pyrazolopyrimidine Acyclonucleosides Related to (S)-(2,3,Dihydroxypropyl)adenine; A Direct Method for Double Functionalization of the Pyrazole Ring
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Treatment of 3(5)-alkylpyrazoles with ammonium nitrate and trifluoroacetic anhydride in trifluoroacetic acid gives 3-alkyl-1,4-dinitropyrazoles directly.This procedure, in conjunction with cine-substitution, offers a direct route for double functionalisation of the pyrazole ring. 3(5)-Cyano-5(3)--4-nitropyrazole (13), prepared in this way, was elaborated into 5-amino-3--1H-pyrazolopyrimidin-7(6H)-one (5), 7-amino-3--1H-6-methylpyrazolopyrimidin-5(6H)-one (6), its N-demethyl analogue (7), and 4-amino-5-carbamoyl-3-pyrazole (8), all of which are C-nucleoside analogues of the antiviral agent (S)-9-(2,3-dihydroxypropyl)adenine (4).
- Buchanan, J. Grant,Harrison, Mark,Wightman, Richard H.,Harnden, Michael R.
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p. 925 - 930
(2007/10/02)
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