- Preparation method of 2-methoxy-4-nitroaniline
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The invention discloses a preparation method of 2-methoxy-4-nitroaniline. The preparation method comprises the following steps of: carrying out acetylation reaction of o-methoxyaniline and acetic acid, discharging water generated in the acetylation reaction process from a reaction system, dropwisely adding fuming nitric acid into the prepared acetic acid solution of the o-methoxyacetanilide to carry out nitration reaction, adding deionized water after the nitration reaction is finished and then filtering, adding the prepared 2-methoxy-4-nitroaniline into an alkali solution to carry out hydrolysis reaction; after the hydrolysis reaction is finished, cooling the prepared reaction solution, and filtering to obtain 2-methoxy-4-nitroaniline. By adopting the method to synthesize 2-methoxy-4-nitroaniline, the acylation reaction cost is low, the nitration reaction selectivity is high, the discharge of three wastes is reduced, the production cost is reduced, the product purity is high, the yield is high, and the 2-methoxy-4-nitroaniline has a good industrial application value.
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Paragraph 0051; 0054; 0064; 0065; 0067-0073; 0078
(2019/06/12)
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- A green and recyclable ligand-free copper (I) catalysis system for amination of halonitrobenzenes in aqueous ammonia solution
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The amination of halonitrobenzenes is an important reaction to produce the corresponding nitroanilines. Direct amination of p-chloronitrobenzene (p-CNB) to p-nitroaniline (p-NAN) with aqueous NH3 solution was investigated over various transition metal salts in the absence of ligand, inorganic base and organic solvent. It was found that CuI is the most effective catalyst with respect to p-CNB conversion, p-NAN selectivity (≈ 100%) and the post-reaction separation and recycling. A high p-NAN yield of 97% could be obtained at 200 °C in 6.5 h with molar ratios of NH3/p-CNB and CuI/p-CNB of 21 and 0.1, respectively. A possible reaction mechanism was proposed, in which NH3 was not only a substrate but also a ligand to coordinate with CuI and formed a water-soluble Cu complex, and then it started the catalytic cycle. The influence of reaction variables such as NH3 concentration, CuI concentration, temperature and time on the p-CNB conversion and the p-NAN selectivity was examined. At room temperature the desired product of p-NAN is insoluble in water but the Cu complex catalyst is water-soluble and so the aqueous phase including the catalyst and NH3 can be easily separated and reused for the subsequent reaction runs. The green and sustainable system is effective for the conversion of diverse halonitrobenzenes to nitroanilines.
- Li, Yan,Shi, Ruhui,Lin, Weiwei,Cheng, Haiyang,Zhang, Chao,Arai, Masahiko,Zhao, Fengyu
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- Process for preparing red-B preparation method
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The invention relates to a preparation method for a red base B. A formylation reaction is performed on o-aminoanisole and formic acid at 80-102 DEG C on the condition that acylation reaction solvent exists, and filtration is performed to obtain o-formamide anisole after the formylation reaction is completed; the o-formamide anisole is added into a sulfuric acid solution, nitric acid is added into a reaction system to perform a nitration reaction when the temperature of the reaction system is controlled at 0-70 DEG C, and filtration is performed to obtain methoxyl-4-nitroformanilide after the nitration reaction is completed; a hydrolysis reaction is performed on the methoxyl-4-nitroformanilide on the condition that the sulfuric acid and water exist at 80-120 DEG C, after the hydrolysis reaction is completed, separation is performed, the pH value is regulated to 6-7 with sodium carbonate, and then filtration is performed to obtain the red base B. According to the preparation method, the produce yield is high, the cost is low, the quality is good, by-products are less, waste water generated in the production process of the red base B is greatly reduced, the clean production requirement is met, operation is easy and convenient, and industrialization is facilitated.
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- A PLA-TiO2 particle brush as a novel support for CuNPs: A catalyst for the fast sequential reduction and: N -arylation of nitroarenes
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The present study describes the synthesis and characterization of dispersible copper nanoparticles on a PLA-TiO2 particle brush and their catalytic efficiency in conducting sequential reactions. The prepared CuNP@PLA-TiO2 was characterized using various techniques like SEM, TEM, EDAX, FT-IR, TGA, XRD and UV-vis spectroscopy. The support controlled the size of the nanoparticles between 2-6 nm and prevented their agglomeration during catalysis. A zeta potential of -70.3 mV was measured for the dispersed catalyst, which indicated its high stability in solution. The nanoparticles were effectively used for the synthesis of biphenyl amines from nitro arenes by sequentially carrying out reduction and N-arylation in a single pot. The short reaction time of N-arylation and recyclability are the hallmark of the developed catalytic system.
- Barot, Nirav,Shaikh, Tauhid,Kaur, Harjinder
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p. 5347 - 5354
(2017/07/11)
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- Steric-Hindrance-Induced Regio- and Chemoselective Oxidation of Aromatic Amines
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Unusual regio- and chemoselective oxidation of aromatic amines hindered with ortho substituents (except -NH2, -NHCH3, and -OH) to the corresponding nitro compounds is described by use of nonanebis(peroxoic acid). The mechanistic investigation for selective oxidation of amines ortho-substituted with -NH2 or -OH showed the involvement of H-bonding between the ortho hydrogen of the adjacent -XH group (where X = NH, NR, or O) and an oxygen atom from the diperoxy acid. Various mono- and diamines are oxidized into corresponding mononitro derivatives in high yield and purity without employing any protection strategies. The protocol was also found to successful on the gram scale.
- Patil, Vilas Venunath,Shankarling, Ganapati Subray
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p. 7876 - 7883
(2015/09/01)
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- Photochemical synthesis of phenanthridines: Exploring fluoro and protected catechol substitution
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Substituted phenanthridines, such as the natural product trispheridine, have been accessed by the practical photochemical cyclization of N-benzylanilines. Functionalities, with a focus on fluoro substituents and protected catechols, are well tolerated on both the A and C rings. The phenanthridines were accessed in good to very good yields (up to 95 %) from iodinated substrates, whereas brominated substrates performed poorly in comparison (0-48 %). Substituted phenanthridines, such as the natural product trispheridine, can be accessed by the practical photochemical cyclization of N-benzylanilines, with functionalities tolerated on both the A and C rings. The phenanthridines are accessible in good to very good yields (up to 95 %) from iodinated substrates, whereas brominated substrates perform poorly in comparison (0-48 %). Copyright
- Linsenmeier, Anna M.,Williams, Craig M.,Braese, Stefan
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p. 3847 - 3856
(2013/07/25)
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- Catalytic reduction of ortho - And para -azidonitrobenzenes via tert -butoxide ion mediated electron transfer
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The reduction of a range of substituted azidonitrobenzene derivatives to the corresponding aniline is described. The chemoselective reaction proceeds cleanly and in good yield, generating minimal waste products. The process involves a thiazolium salt derived species which is proposed as a radical anion relay, with tert-butoxide as the stoichiometric reductant.
- Burnley, James,Carbone, Giorgio,Moses, John E.
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supporting information
p. 652 - 656
(2013/04/10)
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- Structural optimization of a CXCR2-directed antagonist that indirectly inhibits γ-secretase and reduces Aβ
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Amyloid β (Aβ), a key molecule in the pathogenesis of Alzheimer's disease (AD), is derived from the amyloid precursor protein (APP) by sequential proteolysis via β- and γ-secretases. Because of their role in generation of Aβ, these enzymes have emerged as important therapeutic targets for AD. In the case of γ-secretase, progress has been made towards designing potent inhibitors with suitable pharmacological profiles. Direct γ-secretase inhibitors are being evaluated in clinical trials and new strategies are being explored to block γ-secretase activity indirectly as well. In this regard, we have previously reported an indirect regulation of γ-secretase through antagonism of CXCR2, a G-protein coupled receptor (GPCR). We demonstrated that N-(2-hydroxy-4-nitrophenyl)-N′-(2-bromophenyl)urea (SB225002), a selective inhibitor of CXCR2 also plays a role in an indirect inhibition of γ-secretase. Furthermore, we reported a ~5-fold difference in the selective inhibition of APP versus Notch processing via γ-secretase following treatment with SB225002. Herein we describe the synthesis and optimization of SB225002. By determination of the structure-activity relationship (SAR), we derived small molecules that inhibit Aβ40 production with IC50 values in the sub-micromolar range in a cell-based assay and also validated the potential of CXCR2 as a new target for therapeutic intervention in AD.
- Bakshi, Pancham,Jin, Chao,Broutin, Pierre,Berhane, Beniam,Reed, Jon,Mullan, Michael
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experimental part
p. 8102 - 8112
(2010/03/24)
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- 2-Methoxy-4-nitrobenzenediazonium salt as a practical diazonium-transfer agent for primary arylamines via tautomerism of 1,3-diaryltriazenes: Deaminative iodination and arylation of arylamines without direct diazotization
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1,3-Diaryltriazenes, prepared from a 2-methoxy-4-nitrobenzenediazonium salt and primary arylamines, exist as "azo-transfer" tautomers in which the 2-methoxy-4-nitrophenyl group is present on the saturated nitrogen atom and forms a hydrogen bond between the 2-methoxy group and the N-H moiety. The synthetic utility of the diazonium salt as a practical diazonium-transfer agent for primary arylamines via tautomerism of the 1,3-diaryltriazenes has been demonstrated by the deaminative iodination and arylation of the arylamines without direct diazotization. The starting 2-methoxy-4-nitrophenylamine can be easily recovered after the reactions.
- Saeki, Tomoyuki,Son, Eun-Cheol,Tamao, Kohei
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p. 1654 - 1658
(2007/10/03)
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- A convenient copper-catalyzed direct animation of nitroarenes with 9-alkylhydroxylamines
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O-Alkylhydroxylamines, particularly O-methylhydroxylamine, aminate nitroarenes in the presence of a strong base and a copper catalyst to give aminonitroarenes in good yields, ortho- or para-Animation with respect to the nitro group takes place, and in some cases the ortho-aminated product is preferentially obtained. With 3-substituted nitrobenzenes where the substituent has a lone pair of electrons, preferential amination occurs at the 2-position to give the sterically most congested 3c-f, 14 and 22g.
- Seko, Shinzo,Miyake, Kunihito,Kavvamura, Norio
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p. 1437 - 1444
(2007/10/03)
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- Nitroarylamines via the Vicarious Nucleophilic Substitution of Hydrogen: Amination, Alkylamination, and Arylamination of Nitroarenes with Sulfenamides
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A new reaction of sulfenamides with electrophilic arenes under basic conditions is described. The σ adducts formed from nitroarenes and the anions of sulfenamides undergo elimination of thiol to produce the corresponding o- and/or p-nitroanilines. This reaction is analogous to the known alkylation and hydroxylation of nitroarenes via the vicarious nucleophilic substitution of hydrogen (VNS). The reaction gives access to a wide range of substituted nitroanilines, nitronaphthylamines, and aminoheterocycles. By means of the reaction with N-alkyl- and N-arylsulfenamides, it is possible to obtain N-alkylnitroanilines and nitrodiarylamines. By varying the structure of sulfenamide and the reaction conditions, particularly the nature and concentration of the base, it is possible to control the orientation of animation.
- Makosza, Mieczyslaw,Bialecki, Maciej
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p. 4878 - 4888
(2007/10/03)
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- Direct Amination of Nitrobenzenes by Vicarious Nucleophilic Substitution
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4-Amino-1,2,4-triazole reacts at 25 deg C with nitrobenzene and some substituted nitrobenzenes in the presence of potassium tert-butoxide in Me2SO to give 4-nitroanilines in good yields.The reaction represents an extension of Makosza's vicarious substitution to a convenient nitrogen nucleophile.
- Katritzky, Alan R.,Laurenzo, Kathleen S.
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p. 5039 - 5040
(2007/10/02)
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- Process for the printing with developing dyes
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Cellulosic material is printed with a paste containing the alkaline solution of a coupler, the dispersion of a diazotable aromatic amine, a nitrite and a thickener and the dyestuff is developed on the fiber by acidic steaming or by adding solutions of organic acids and steaming or drying.
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- Azo pigments derived from 2-hydroxy-3-carboxynaphthalene containing a substituted or unsubstituted phthalimide
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Azo pigments derived from 2-hydroxy-3-carboxy-naphthalene and containing a substituted or unsubstituted phthalimide radical. The majority give red colorations and due to their excellent fastness properties are particularly valuable for use in surface coatings and resins.
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