- Selective nitration of phenols using bismuth subnitrate/charcoal in the presence of trichloroisocyanuric acid under aprotic conditions
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A mild, efficient and regioselective method for the mononitration of phenolic compounds is described using bismuth subnitrate/charcoal in the presence of trichloroisocyanuric acid in CH2Cl2 at room temperature.
- Pourali, Ali Reza,Fatemi, Fatemeh
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Read Online
- Unexpected one pot C (aryl)-N bond cleavage and Questiomycin A formation from the reduction reaction of 2-amino-6-nitrophenol derivatives
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2-Amino-6-nitrophenol derivatives 5A and 5B have been prepared from the bromonitro phenol derivative 4 using the Buchwald conditions. While attempting one pot reduction of nitro group and deprotection of phenolic benzyl group of the compounds 5A and 5B separately using Pd/C in methanol under H2 atmosphere, an unexpected C(aryl)-N bond cleavage reaction had occurred which was followed by formation of a known compound Questiomycin A (2-amino-3H-phenoxazin-3-one) 1 from both the compounds. In the present study, the danger of deamination of Buchwald products 5A and 5B under the conditions of catalytic hydrogenation and the simultaneous formation of phenoxazine 1 is disclosed.
- Mustafa, Shaik,Santhosh Reddy,Surendra Babu
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Read Online
- Light-Controlled Tyrosine Nitration of Proteins
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Tyrosine nitration of proteins is one of the most important oxidative post-translational modifications in vivo. A major obstacle for its biochemical and physiological studies is the lack of efficient and chemoselective protein tyrosine nitration reagents. Herein, we report a generalizable strategy for light-controlled protein tyrosine nitration by employing biocompatible dinitroimidazole reagents. Upon 390 nm irradiation, dinitroimidazoles efficiently convert tyrosine residues into 3-nitrotyrosine residues in peptides and proteins with fast kinetics and high chemoselectivity under neutral aqueous buffer conditions. The incorporation of 3-nitrotyrosine residues enhances the thermostability of lasso peptide natural products and endows murine tumor necrosis factor-α with strong immunogenicity to break self-tolerance. The light-controlled time resolution of this method allows the investigation of the impact of tyrosine nitration on the self-assembly behavior of α-synuclein.
- Long, Tengfang,Liu, Lei,Tao, Youqi,Zhang, Wanli,Quan, Jiale,Zheng, Jie,Hegemann, Julian D.,Uesugi, Motonari,Yao, Wenbing,Tian, Hong,Wang, Huan
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supporting information
p. 13414 - 13422
(2021/05/12)
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- Preparation method of Eltrombopag key intermediate 3'-amino-2'-hydroxybiphenyl-3-carboxylic acid
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The invention discloses a preparation method of an Eltrombopag key intermediate 3'-amino-2'-hydroxybiphenyl-3-carboxylic acid. The preparation method comprises the following steps: (1) nitrating o-bromophenol with a nitrating reagent by using water as a s
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Paragraph 0019; 0020
(2019/11/20)
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- Novel method for preparing Eltrombopag intermediate
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The invention provides a method for preparing a compound shown as the formula I (please see the formula in the description). The method specifically comprises the following steps that 1, a compound shown as the formula (II) (please see the formula in the description) reacts with a compound shown as formula (V) (please see the formula in the description) under the alkaline condition to generate a compound shown as the formula (III) (please see the formula in the description); 2, the compound shown as the formula (III) (please see the formula in the description) reacts with a compound shown as the formula (VI) (please see the formula in the description) under the alkaline condition in the presence of palladium carbon to generate a compound shown as the formula (IV) (please see the formula in the description); 3, the compound shown as the formula (IV) (please see the formula in the description) reacts in the presence of palladium carbon and a hydrogen source under the alkaline condition to generate the compound shown as the formula (I) (please see the formula in the description). According to the method, design is ingenious, protecting group removal, dechlorination and nitro reduction are together completed in the final hydrogenation process, and the purity of the obtained compound shown as the formula (I) (please see the formula in the description) is high; the most important thing is that compared with other Suzuki coupling agents, cost of palladium carbon is lower, a source of palladium carbon is wide and easy to obtain, palladium carbon can be directly recycled and reused after being simply filtered and separated, and therefore the material cost is greatly reduced; meanwhile, emission of three wastes is reduced, and the method is quite suitable for industrialized production.
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Paragraph 0059-0061
(2017/04/29)
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- BICYCLO-SUBSTITUTED PYRAZOLON AZO DERIVATIVES PHARMACEUTCIAL SALTS, PREPARATION PROCESS AND PHARMACEUTICAL USE THEREOF
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The present invention relates to bicyclo-substituted pyrazolon azo derivatives pharmaceutical acceptable salts of formula (I), methods for their preparation, pharmaceutical compositions containing the same and their use as a therapeutic agent, especially as thrombopoietin (TPO) mimetics and their use as agonists of thrombopoietin receptor. The definition of substituents in formula (I) are the same as the description.
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Page/Page column 25
(2016/10/09)
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- SALTS OF BICYCLO-SUBSTITUTED PYRAZOLON AZO DERIVATIVES, PREPARATION METHOD AND USE THEREOF
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The present invention relates to pharmaceutically acceptable salts of bicycle-substituted pyrazolon azo derivatives represented by general formula (I), methods for their preparation, pharmaceutical compositions comprising the same and their use as a therapeutic agent, especially as thrombopoietin (TPO) mimetics, and their use as agonists of thrombopoietin receptor. The definitions of substituents in general formula (I) are the same as the description.
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Page/Page column 12-13
(2012/05/04)
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- BICYCLO-SUBSTITUTED PYRAZOLON AZO DERIVATIVES, PREPARATION PROCESS AND PHARMACEUTICAL USE THEREOF
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The bicyclo-substituted pyrazolon-azo derivatives of formula (I) or pharmaceutical acceptable salts, hydrates or solvates thereof, methods for their preparation, pharmaceutical compositions containing the same and their use as a therapeutic agent, especially as thrombopoietin (TPO) mimetics and their use as agonists of thrombopoietin receptor are disclosed. The definition of substituents in formula (I) are the same as defined in the description.
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Page/Page column 15
(2010/10/19)
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- 3,4-Dihydro-2H-benzo[1,4]oxazine derivatives as 5-HT6 receptor antagonists
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A series of novel 3,4-dihydro-2H-benzo[1,4]oxazine derivatives has been designed and synthesized as 5-HT6 receptor antagonists. Many of the compounds displayed subnanomolar affinities for the 5-HT6 receptor and good brain penetration in rats. The relationship of structure and lipophilicity to hERG inhibition of this series of compounds is discussed.
- Zhao, Shu-Hai,Berger, Jacob,Clark, Robin D.,Sethofer, Steven G.,Krauss, Nancy E.,Brothers, Julie M.,Martin, Renee S.,Misner, Dinah L.,Schwab, Dietmar,Alexandrova, Ludmila
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p. 3504 - 3507
(2008/02/09)
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- Nitration of substituted phenols by different efficient heterogeneous systems
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Nitration of substituted phenols were carried out by the mixture of sodium nitrite and wet SiO2 (50% w/w) in the presence of four different efficient heterogeneous systems: 1) oxalic acid dihydrate (I), 2) sodium hydrogen sulphate (II), 3) aluminum hydrogen sulphate (III) and 4) silica sulphuric acid (IV) in CH2Cl2 at room temperature and high yields. Optimum conditions for theses systems and the regioselectivities of the reactions are reported.
- Habibi, Davood,Zolfigol, Mohammad Ali,Shiri, Morteza,Sedaghat, Abdolmajid
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- Thrombopoietin mimetics
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Invented are non-peptide TPO mimetics. Also invented are novel processes and intermediates used in the preparation of the presently invented compounds. Also invented is a method of treating thrombocytopenia, in a mammal, including a human, in need thereof which comprises administering to such mammal an effective amount of a selected hydroxy-1-azobenzene derivative.
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- Regulated activation of cell-membrane receptors by metal-chelating agonists
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Invented is a regulated activation of cell-membrane receptors by small molecule agents. Also invented is a method to render a cell-membrane receptor responsive to the activation by small molecule compounds by specific single point mutations in the transmembrane region.
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- Mild and regioselective oxidative bromination of aromatic compounds using ammonium bromide and oxone
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The selective mono-bromination of various activated aromatic compounds is reported using in situ generated bromine from NH4Br as a bromine source and oxone as an oxidant for the first time.
- Narender,Mohan, K.V.V. Krishna,Kulkarni,Raghavan
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p. 597 - 598
(2007/10/03)
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- Selective nitration of aromatic compounds with bismuth subnitrate and thionyl chloride
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Bismuth subnitrate/thionyl chloride have been found to be an efficient combination of reagents for nitration of a wide range of aromatic compounds in dichloromethane. Phenols, in particular, were easily mononitrated and dinitrated with the reagents by controlling the stoichiometry.
- Muathen, Hussni A.
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p. 593 - 598
(2007/10/03)
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- An efficient and regioselective oxybromination of aromatic compounds using potassium bromide and oxone
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A simple, efficient and regioselective method for oxybromination of aromatics is reported. The electrophilic substitution of bromine generated in situ from potassium bromide using oxone as an oxidant for the first time.
- Narender,Srinivasu,Ramakrishna Prasad,Kulkarni,Raghavan
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p. 2313 - 2318
(2007/10/03)
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- N-cyclopropyl-2-difluoromethoxy-3-halogenoanilines and intermediates for the preparation thereof
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N-Cyclopropyl-2-difluoromethoxy-3-halogenoanilines which serve as important intermediates in the preparation of quinolonecarboxylic acids useful as synthetic antimicrobial agents from industrially inexpensive and easily available raw materials; and intermediates for the preparation thereof. Specifically, compounds represented by the general formula (1), (2) and (3), wherein X is halogeno; and Y is nitro or amino, (2) wherein X is halogeno; and R1is lower alkyl, (3) wherein X is halogeno; and R is hydrogen or —CH═C(CO2R2)2, R2being lower alkyl.
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- REACTION OF AROMATIC COMPOUNDS WITH NUCLEOPHILIC REAGENTS IN LIQUID AMMONIA. XIII. DIRECTION OF HYDROXYLATION OF 2-HALONITROBENZENES BY POTASSIUM HYDROXIDE
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The reaction of 2-fluoronitrobenzene with potassium hydroxide and molecular oxygen in liquid ammonia at -33 deg C gave 2-nitrophenol.In contrast to 2-fluoronitrobenzene, both the halogen and hydrogen in the ortho and para positions to the nitro group are replaced in the reactions of 2-chloro- and 2-bromonitrobenzenes, KOH, and O2.In the case of 2-bromonitrobenzene, there is significant formation of a compound, formally corresponding to reductive dehalogenation (nitrobenzene and its hydroxylation product, 4-nitrophenol) and bromination of the nitrophenols formed in the position to the hydroxy group.
- Malykhin, E. V.,Kolesnichenko, G. A.,Shteingarts, V. D.
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p. 1149 - 1152
(2007/10/02)
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- REACTION OF AROMATIC COMPOUNDS WITH NUCLEOPHILIC REAGENTS IN LIQUID AMMONIA. VII. DIRECTION OF HYDROXYLATION OF 3-SUBSTITUTED (Cl, Br, I, NO2) NITROBENZENES WITH POTASSIUM HYDROXIDE
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The reaction of 3-chloro-, 3-bromo-, and 3-iodonitrobenzenes with potassium hydroxide and oxygen in liquid ammonia (-33 deg C) leads to the formation of nitrohalogenophenols, corresponding to substitution of the hydrogen atom at the orto and para positions of the ring in relation to the nitro group by a hydroxy group.In the case of the last two substrates it also leads to the corresponding 2-halogeno-3',4'-dinitrodiphenylamines.In view of the fact that substitued diphenylamines are formed under the same conditions as a result of the reaction of 3-nitroaniline with 3-halogenonitrobenzenes it is suggested that 3-bromo- and 3-iodonitrobenzenes are partly converted into 3-nitroaniline through the intermediate formation of 3-nitrodehydrobenzene.During dehydroxylation in the absence of oxygen the proportion of the phenols corresponding to substitution of the hydrogen atom at the para position to the nitro group by the hydroxy group increases, and the degree of transformation of the inital compounds decreases. 2,4-Dinitrophenol is formed with a low yield during the reaction of 1,3-nitrobenzene and potassium hydroxide in the presence of oxygen or in an atmosphere of argon.
- Malykhin, E. V.,Kolesnichenko, G. A.,Shteingarts, V. D.
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p. 720 - 726
(2007/10/02)
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- Ortho-Specific Bromination of Phenols
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Phenol as well as 3-substituted phenols are brominated exclusively in the ortho positions by N.N-dibromomethylamine, yielding 2.6-dibrominated phenols in excellent yields.Phenols bearing an ortho-substituent need N-bromomethylamine as the brominating agent to take up one bromine atom into the free ortho-position. para-Bromination is not observed in either case. 1-Naphthol gives 2-bromo-1-naphthol, 8-hydroxyquinoline gives 7-bromo-8-hydroxyquinoline with 80percent and 98percent yield respectively. ortho-Specific chlorination of phenols was carried out in some cases using N-chloro-alkylamines.
- Schmitz, Ernst,Pagenkopf, Ingeborg
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p. 998 - 1006
(2007/10/02)
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- Theoretical Calculations of Chemical Interactions. Part 4. Aromatic Nucleophilic Substitutions and SN2 Reactions of 4- and 6-Substituted 2-Nitroanisoles
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The reactions of 4-R- and 6-R-2-nitroanisoles (R=Me, Br) in neat cyclohexylamine and piperidine have been studied.The reactions with cyclohexylamine lead to the respective aromatic nucleophilic substitution products while the reactions with piperidine mainly yield the substituted nitrophenols.It was found that 6-R-2-nitroanisoles react faster than the respective 4-R-2-nitroanisoles.The absence of the expected primary steric effect is thought to be due to the spatial arrangement of the methoxide group, which adopts a conformation perpendicular to the ring plane when it is surrounded by two ortho-substituents.CNDO and INDO calculations for different conformations of the substrates give support to this assumption.
- Nudelman, N. Sbarbati,Palleros, Daniel R.
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p. 805 - 810
(2007/10/02)
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