- One-pot synthesis of azo compounds in the absence of acidic or alkaline additives
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A one-pot method for the synthesis of azo compounds by the reaction of β-naphthol with aryl amines using t-BuONO as the nitrosonium source in DCM at room temperature was developed. This method features mild reaction conditions, a simple experimental procedure, and is free of acidic or alkaline additives.
- Cheng, Xin-Wang,Duan, Pan,Liu, Ting-Ting,Yan, Jiao-Zhao,Zeng, Yao-Fu
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p. 486 - 490
(2020/10/22)
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- An environmentally friendly approach to the green synthesis of azo dyes with aryltriazenes via ionic liquid promoted C-N bonds formation
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An efficient and green approach for the synthesis of azo dyes has been developed via the Br?nsted acidic ionic liquid (IL) promoted diazo coupling reaction of naphthols with aryltriazenes. The reaction was carried out with the aryltriazenes as diazotizing
- Zhang, Yonghong,Liu, Yonghong,Ma, Xiaoqian,Ma, Xia,Wang, Bin,Li, Hongguang,Huang, Yan,Liu, Chenjiang
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p. 438 - 444
(2018/06/14)
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- Mild preparation method for structural analogs of Sudan I
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The invention discloses a mild preparation method for structural analogs of Sudan I, and belongs to the technical field of organic chemistry. According to the method, dehydrogenation of N'-p-toluenesulfonyl aromatic hydrazine is promoted by utilizing alkali and oxygen in air to form an aryl diazo compound in situ; then a series of 1-aryl azo-2-naphthol Sudan I analogs are prepared by coupling with2-naphthol. By adopting the method disclosed by the invention, the strategy of producing an explosive intermediate in situ is used, so that 1-aryl azo-2-naphthol is conveniently and safely synthesized. The mild preparation method disclosed by the invention is mild in reaction conditions, wide in substrate applicability, simple and convenient to operate, lower in cost, less in by-products, high inproduct purity, and easy to separate and purify and can be suitable for relatively-large-scale preparation.
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Paragraph 0043-0045
(2018/07/30)
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- Convenient and rapid diazotization and diazo coupling reaction via aryl diazonium nanomagnetic sulfate under solvent-free conditions at room temperature
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For the first time, nanomagnetic-supported sulfonic acid is used for conversion of several types of aromatic amine, containing electron-withdrawing groups as well as electron-donating groups to the corresponding azo dyes in excellent yield. The synthesis of these compounds is described by the sequential diazotization-diazo coupling of various aromatic amines with sodium nitrite, nanomagnetic supported sulfonic acid and coupling agents under solvent-free conditions at room temperature. This new method offers several advantages including short reaction time, mild reaction conditions, avoidance of harmful acids, and simple work-up procedure. More importantly, aryldiazonium salts supported on magnetic nanoparticles (aryl diazonium nanomagnetic sulfate) were sufficiently stable to be kept at room temperature in the dry state.
- Koukabi, Nadiya,Otokesh, Somayeh,Kolvari, Eskandar,Amoozadeh, Ali
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- An environmentally friendly approach to the green synthesis of azo dyes in the presence of magnetic solid acid catalysts
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A solvent-free, efficient and green approach for the synthesis of azo dyes has been developed by the diazo coupling reactions of aromatic amines with β-naphthol in the presence of sulfonic acid functionalized magnetic Fe3O4 nanoparticles (Fe3O4@SiO2-SO3H) by a grinding method at room temperature. This green methodology aims to overcome the limitations and drawbacks of the previously reported methods such as low temperature, use of acids, alkalis and toxic solvents, instability of diazonium salts at room temperature, modest yields, and long reaction times. Moreover, the attractive advantages of the process include mild conditions with excellent conversions, simple product isolation process, inexpensive procedure and recyclability of the magnetic catalyst. This journal is
- Safari, Javad,Zarnegar, Zohre
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p. 17738 - 17745
(2015/06/15)
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- Substituent effect on the tautomerization of 1-arylazonaphthalen-2-ols by mass spectrometric analysis
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An electron-ionization (EI) mass spectra of a series of 1-arylazonaphthalen-2-ols was obtained for studying the substituent effect on the fragmentation. The correlation between the ratio, molecular ion and fragment ion, and Hammett's constants is applied to examine the effect of the substituent on the fragmentation. The negative correction between the ratio, Imolecular ion/(I171amu + I143amu + I115amu), and Hammett's constants indicates an electron-withdrawing group destabilized the molecular ion. An unusual long-range hydrogen transfer demonstrates an important role in the fragmentation process Mass spectra of a series of 1-arylazonaphthalen-2-ols were obtained for studying the substituent effect on the fragmentation. The correlation between the ratio of molecular ion and fragment ion, and Hammett's constants is applied to examine the effect of substituent on the fragmentation. The negative correction indicates an electron-with-drawing group destabilized the molecular ion. An unusual long-range hydrogen transfer demonstrates an important role in the fragmentation process.
- Lin, Shaw-Tao,Lin, Lee-Hui,Lin, Yi-Cang,Ding, Mei-Fan
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p. 257 - 262
(2015/03/31)
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- Fluorescent azo disperse dyes from 3-(1,3-benzothiazol-2-yl)naphthalen-2-ol and comparison with 2-naphthol analogs
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Five novel fluorescent azo disperse dyes were synthesized using different diazotized aromatic amines followed by coupling with 3-(1,3-benzothiazol-2-yl) naphthalen-2-ol. These dyes were characterized by FT-IR, 1H NMR and mass spectroscopy. These azo disperse dyes were applied on polyester and their fastness properties were evaluated. A parallel series of dyes using 2-naphthol in place of benzothiazolyl were made to investigate the effect of benzothiazolyl moiety on the fastness properties. This investigation showed that the dyes containing benzothiazolyl residue have better fastness properties than that of the azo disperse dyes based on 2-naphthol. Effect of pH on photo physical properties was also studied.
- Satam, Manjaree A.,Sekar, N.,Raut, Rajesh K.
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p. 92 - 103,12
(2020/08/20)
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- No carrier-added nucleophilic aromatic radiofluorination using solid phase supported arenediazonium sulfonates and 1-(aryldiazenyl)piperazines
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This Letter concerns the investigation of a solid phase based method for no carrier-added nucleophilic [18F]fluorination of aromatic compounds via de-diazofluorination. Initial screening of reaction conditions was conducted using soluble analog
- Riss, Patrick J.,Kuschel, Sonja,Aigbirhio, Franklin I.
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supporting information; experimental part
p. 1717 - 1719
(2012/05/04)
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- Fe(HSO4)3 as an Efficient Catalyst for Diazotization and Diazo Coupling Reactions
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Diazo coupling reactions of aromatic amines with 2-naphthol in a green, efficient and easy procedure is described. Ferric hydrogensulfate catalyses this reaction in water at room temperature and short reaction time with high yields. The antibacterial activities of the synthesized compounds against four pathogenic bacteria are also investigated.
- Rahimizadeh, Mohammad,Eshghi, Hossein,Shiri, Ali,Ghadamyari, Zohreh,Matin, Maryam M.,Oroojalian, Fatemeh,Pordeli, Parvaneh
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p. 716 - 719
(2013/05/08)
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- Arenediazonium o-benzenedisulfonimides: Some kinetics of azo coupling reactions with naphthols
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Kinetic investigation of azo coupling reactions between naphthols and 4-methoxy- and 4-nitrobenzenediazonium o- benzenedisulfonimides has been carried out for comparison with the related benzenediazonium tetrafluoroborates. The data clearly indicate that the two kinds of diazonium salts show very similar reactivities. This fact emphasizes that arenediazonium o-benzenedisulfonimides, which are very stable, may be used as alternatives to the more usual diazonium salts. The azo coupling reactions between 4-nitro-and 4-methoxybenzenediazonium salts and 1-bromo-2- naphthol, performed with equimolecular amounts of both reagents, showed the unexpected formation of large amounts of 1-bromo-4-nitrobenzene and 1-bromo-4-methoxybenzene. Some mechanistic implications of this behaviour are discussed. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Boga, Carla,Degani, Jacopo,Del Vecchio, Erminia,Fochi, Rita,Forlani, Luciano,Todesco, Paolo E.
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p. 3837 - 3843
(2007/10/03)
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- One-pot diazo coupling reaction under microwave irradiation in the absence of solvent
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Diazotization and coupling reactions were carried out in one pot by inducing with microwave irradiation in the absence of solvent.
- Jin, Jin,Wen, Zhong,Long, Jiang,Wang, Yongmei,Matsuura, Teruo,Meng, Jiben
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p. 829 - 834
(2007/10/03)
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- New dry arenediazonium salts, stabilized to an exceptionally high degree by the anion of o-benzenedisulfonimide
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Arenediazonium o-benzenedisulfonimides 3 (20 examples, yield >90%) were prepared in the dry state by diazotization of aromatic amines with (-pentyl nitrite and o-benzenedisulfonimide in glacial acetic acid or formic acid at 0-5°C. Unlike most diazonium salts in the dry state, salts 3 are very highly stable.
- Barbero, Margherita,Crisma, Marco,Degani, Lacopo,Fochi, Rita,Perracino, Paolo
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p. 1171 - 1175
(2007/10/03)
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- Reaction of Triazene 1-Oxides: Novel Synthesis of Solid Arenediazonium Chlorides
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Treatment of 1,3-diaryltriazene 1-oxides with oxalyl chloride in dry toluene at room temperature gives only solid arenediazonium chlorides; however, treatment with acetyl and benzoyl chlorides does not afford the corresponding diazonium chlorides.
- Mohamed, Shaaban K.,Gomaa, Mohsen A.-M.,Nour El-Din, Ahmed M.
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p. 166 - 167
(2007/10/03)
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- A Simple Route for the Synthesis of Chlorosubstituted Arylazobenzenes, Arylazonaphtalenes, and Arylazopyrazoles
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The reaction of arylazophenoles and arylazohydroxypyrazoles (or their tautomer hydrazones) 10, 11, and 15 with POCl3 in dimethylformamide yields chlorosubstituted arylazobenzenes or arylazopyrazoles 12, 13 and 16, resp., in moderate to high yields.The substitution of the OH-group by the Cl-moiety is favoured by acceptor substituents in the aryl fragments ortho- and/or para-linked to the azo group.In case that arylazocompounds derived from resorcinol are used the substitution reaction runs in a stepwise manner giving raise to the formation of o-hydroxy-p-chlorosubstit uted azo compounds 18 primarily and then of dichlorosubstituted azo compounds 19.
- Guenther, R.,Jaehne, E.,Hartmann, H.,Schulze, M.
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p. 945 - 954
(2007/10/02)
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- The Photochemistry of Some Methoxy and Dimethylamino Derivatives of Azoxybenzene
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The photochemistry of the six azoxybenzene derivatives carrying a methoxy and/or a dimethylamino group in positions 4/4' has been examined in alcogols and in benzene and found to lead to different processes.The photo-Wallach rearrangement takes place for all except the disubstituted derivatives.This process involves an intermediate, which either gives back the starting azoxy or is converted to the final o-hydroxy derivative through acid catalysis as well as by the previously reported basic catalysis or via cleavage to diazonium ions, which can be trapped before recombination.Oxygen shift to yield the isomeric azoxy derivative (only one precedent known) is a general, one-way process, leading in every case to the azoxy benzene with the N->O group far from the ring carrying the stronger electron-donating substituent.Differently from the photo-Wallach rearrangement, this process shows little solvent dependence.The dimethylamino derivatives undergo also or exclusively different fragmentations, such as intramolecular hydrogen abstraction and cleavage of either the N=N or the C-N bond.The solvent and substituent effect upon electronic spectra, reaction quantum yield, and product distribution are discussed.The photochemistry is attributed to a ?,?* state with strong internal charge transfer.
- Albini, Angelo,Fasani, Elisa,Moroni, Micaela,Pietra, Silvio
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- TAUTOMERIC TRANSFORMATIONS AND COLOR OF MONOAZO DYES. I. DYES BASED ON 3-SUBSTITUTED 2-NAPHTHOLS
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1-(4-X-phenylazo)-3-Y-2-naphthols, in which X = OMe, NEt2, NHC6H4OMe-4; Y = H, COOH, CONHC6H4OMe-4, CONH(CH2)2OH, OH, COOEt, CON(CH2)5, and also 1-(4-diethylaminophenylazo)-3-Y-2-hydroxybenzocarbazoles, in which Y = COOH, CONHC6H4OMe-4, COOMe, were synthe
- Traven', V. F.,Kostyuchenko, E. E.,Mkhitarov, R. A.,Men'shikova, N. F.,Oreshin, M. M.,Stepanov, B. I.
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p. 922 - 930
(2007/10/02)
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