- Silica sulfuric acid/NaNO2 as a novel heterogeneous system for the nitration of phenols under mild conditions
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Nitrophenols can be obtained in moderate to high yields via nitrosation-oxidation of phenols with silica sulfuric acid, NaNO2 and wet SiO2 at room temperature. In situ generation of HNO2 and a radical cation mechanism via the nitrous acid catalyzed (NAC) pathway appear to be applicable to phenol nitration using these reagents.
- Zolfigol, Mohammad Ali,Madrakian, Elahe,Ghaemi, Ezat
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- Cyclodextrin-based artificial oxidases with high rate accelerations and selectivity
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Three cyclodextrin derivatives with one to four 2-O-formylmethyl groups attached to the secondary rim were prepared and investigated as catalysts for the oxidation of aminophenols in buffered dilute hydrogen peroxide. The derivatives were found to be Michaelis-Menten catalysts and to give rate accelerations of up to 20,000 for the oxidation of 2-aminophenol to 2-amino-phenoxazin-3-one, and 12,000 for the oxidation of 2-amino-p-cresol to 2-nitro-p-cresol. While a range of differently substituted substrates was oxidized the success of the reaction was highly dependent on the substituent pattern. The ability of one of the new artificial enzymes to oxidize selectively one aminophenol from a mixture of two was investigated giving substrate selectivities of up to 16:1.
- Zhou, You,Lindb?ck, Emil,Pedersen, Christian M.,Bols, Mikael
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- Evidence from (15)N Nuclear Polarisation on the Mechanisms of Rearrangement of Nitrocyclohexadienones
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Strong (15)N nuclear polarisation is present in both the uncatalysed and acid-catalysed rearrangements of 4-methyl-4-cyclohexa-2,5-dienone but is absent from the rearrangement of 2-methyl-2-nitrocyclohexa-3,5-dienone.
- Ridd, John H.,Sandall, John P. B.,Trevellick, Susan
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- Highly efficient nitration of phenolic compounds by zirconyl nitrate
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Zirconyl nitrate was found to be an excellent reagent in the nitration of phenol and substituted phenols to give nitrated phenols. This procedure works efficiently on most of the examples at room temperature yielding nitro derivatives in fair to good yields with high regioselectivity.
- Selvam, J. Jon Paul,Suresh,Rajesh,Reddy, S. Ravinder,Venkateswarlu
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- Bromodimethylsulfonium bromide/tetrabutylammonium nitrite: An efficient catalyst mixture for the nitration of phenols
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Nitrophenols were obtained via direct nitration of phenols with tetrabutylammonium nitrite in the presence of bromodimethylsulfonium bromide at room temperature in high yields under aprotic conditions. TUeBITAK.
- Akhlaghinia, Batool,Pourali, Alireza
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- p-Toluenesulfonic acid catalyzed regiospecific nitration of phenols with metal nitrates
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Highly regiospecific mononitration of phenols and substituted phenols is accomplished employing a metal nitrate and a catalytic amount of p-toluenesulfonic acid in acetone. An exclusive ortho-selectivity was observed with excellent yields. A variety of metal nitrates were used to obtain o-nitrophenols exclusively in good to excellent yields. The use of p-toluenesulfonic acid is key for the selectivity observed.
- Anuradha,Srinivas,Aparna,Rao, J. Madhusudana
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- Gas-phase reaction of hydroxyl radicals with m-, o- and p-cresol
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The gas-phase reaction of oxygenated aromatic compounds m-cresol,o-cresol. and p-cresol with hydroxyl radicals has been studied by GC-MS. Experiments have been performed in a large-volume photoreactor (8000 L) at 294 ± 2 K and atmospheric pressure. The relative kinetic method was used to determine the rate constants for these reactions, with 1,3,5-trimethylbenzene as a reference compound. The rate constants obtained are kOH(m-cresol) = (5.88 ± 0.92) × 10-11 cm3 molecule-1 s-1, kOH(o-cresol) = (4.32 ± 0.52) × 10 -11 cm3 molecule-1 s-1, and k OH(p-cresol) = (4.96 ± 0.75) × 10-11 cm 3 molecule-1 s-1. The degradation products observed and their respective molar yields were methyl-1,4-benzoquinone 12.4 ± 1.2%, 5-methyl-2-nitrophenol 1.5 ± 0.3%, and 3-methyl-2-nitrophenol 1.4 ± 0.3% from m-cresol, methyl-1,4-benzoquinone 5.6 ± 0.9%, and 6-methyl-2-nitrophenol 4.7 ± 0.8% from o-cresol. and 4-methyl-2-nitrophenol 17.2 ± 2.5% from p-cresol. This kinetic and product data are compared with the literature, and the reaction mechanisms are discussed. Our results are in accordance with the previous studies (Atkinson, J Phys Chem Ref Data 1989, Monograph (1), 1-246; Atkinson and Aschmann. Int J Chem Kinet 1990, 22, 59-67; Atkinson et al., Environ Sci Technol 1992, 26, 1397-1403; Atkinson et al., J Phys Chem 1978, 82, 2759-2805; Olariu et al., Atoms Environ 2002, 36, 3685-3697; Semadeni et al., Int J Chem Kinet 1995, 27, 287-304) and confirm the methyl-1,4-benzoquinone yields determined by a different experimental technique (long-path Fourier transform infrared FT-IR (Olariu et al., 2002)).
- Coeur-Tourneur, Cecile,Henry, Francoise,Janquin, Marie-Andree,Brutier, Laurent
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- Silica chloride/NaNO2 as a novel heterogeneous system for the nitration of phenols under mild conditions
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Nitrophenols can be obtained via direct nitration of phenols with silica chloride, NANO2, and wet SiO2 at room temperature in moderate to high yields.
- Zolfigol, Mohammad Ali,Shirini, Farhad,Chogamarani, Arash Ghorbani
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- Cellulose-supported Ni(NO3)2.6H2O/2,4,6- trichloro-1,3,5-triazine (TCT) as a mild, selective, and biodegradable system for nitration of phenols
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Nitration of certain phenols and naphthols in the presence of biodegradable cellulose-supported Ni(NO3)2.6H2O/2,4,6- trichloro-1,3,5-triazine was carried out in acetonitrile at room temperature. Ortho nitrated phenols were obtained regioselectively within a short reaction time with good yields. The reaction condition was mild, and the employed cellulose could be recovered several times for further use. Copyright
- Nemati, Firouzeh,Kiani, Hossein,Hayeniaz, Yaser Saeidi
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- KHSO4 as an efficient catalytic system for the regiospecific nitration of phenols with metal nitrates
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Highly regiospecific mononitration of phenol and substituted phenols was accomplished employing a metal nitrate and a catalytic amount of KHSO4 in acetonitrile. An exclusive ortho-selectivity was observed with excellent yields. A variety of metal nitrates were used to obtain o-nitrophenols exclusively in good to excellent yields. The use of KHSO4 is key for the selectivity observed.
- Baghernejad, Bita,Oskooie, Hossein A.,Heravi, Majid M.,Beheshtiha, Yahia Sh.
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- Heteropolyacids as an efficient and reusable catalytic system for the regiospecific nitration of phenols with metal nitrates
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Highly regiospecific mononitration of phenols and substituted phenols is accomplished employing a metal nitrate and a catalytic amount of heteropolyacid in acetonitrile. An xclusive ortho-selectivity was observed with excellent yields. A variety of metal nitrates were used to obtain o-nitrophenols exclusively in good to excellent yields. The use of heteropolyacid is key for the selectivity observed.
- Baghernejad, Bita,Heravi, Majid M.,Oskooie, Hossein A.,Bamoharram, Fatemeh F.
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- Mild and selective nitration of phenols by zeofen
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Certain phenols and naphthols were nitrated regioselectively with zeofen in dichloromethane as solvent at room temperature and in a short reaction time to give good yields. Copyright Taylor & Francis Group, LLC.
- Bigdeli, Mohammad A.,Heravi, Majid M.,Nemati, Firouzeh
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- Efficient and selective mono and dinitration of phenols with Cr(No3)3. 2N2O4 as a new nitrating agent
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Cr(NO3)3.2N2O4 is easily prepared reagent for the efficient and selective mono or dinitration of phenolic compounds. High selectivity ratio of p-nitrophenol formation vs o-nitrophenol is also observed.
- Iranpoor, Nasser,Firouzabadi, Habib,Zolfigol, Mohammad Ali
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- Zn(NO3)2·6H2O/2,4,6-trichloro-1,3,5-triazine (TCT) a mild and selective system for nitration of phenols
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Certain phenols and naphthols were nitrated regioselectively with Zn(NO3)2·6H2O/TCT in acetonitrile as solvent at room temperature and short reaction time in good yields. The reaction condition was mild. TCT is a cheap and commercially available reagent. It performed as an acid catalyst in this transformation.
- Nemati, Firouzeh,Kiani, Hossein
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- Mononitration of phenol derivatives by guanidinium nitrate and silica sulfuric acid under mild conditions
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A mixture of guanidinium nitrate and silica sulfuric acid acts as mild and heterogeneous media for the efficient mono nitration of phenolic compounds in dichloromethane at room temperature.
- Ghorbani-Choghamarani, Arash,Goudarziafshar, Hamid,Nikoorazm, Mohsen,Naseri, Zahra
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- Vanadium pentoxide as a catalyst for regioselective nitration of organic compounds under conventional and nonconventional conditions
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Vanadium pentoxide is used as an efficient catalyst for regioselective nitration of aromatic compounds under conventional and nonconventional conditions such as ultrasonically assisted (USAR) and microwave-assisted reactions (MWAR). The reactions underwent smoothly and afforded good yields of products with high regioselectivity. Observed longer reaction times (about 8 h) in V2O5 catalyzed reactions reduced to (0.5/30 min) under sonication and (90 s) in the case of MWAR. When ortho position is blocked, para derivatives are obtained as end products while ortho nitro products are obtained when para position is blocked.
- Venkatesham,Reddy, K. Rajendar,Rajanna,Veerasomaiah
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- Microwave assisted synthesis of nitro phenols from the reaction of phenols with urea nitrate under acid-free conditions
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Urea nitrate was found to be an inexpensive, acid-free, and safe nitrating agent that provides mononitration of phenols and substituted phenols in excellent yields with exclusive ortho-selectivity under microwave irradiation. Microwave assisted reactions reduced the reaction times substantially and enhanced the product yields from good to excellent within shorter reaction times.
- Verma, Sanny,Pandita, Sangeeta,Jain, Suman L.
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- Self-powered continuous nitration method and device
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The invention belongs to the technical field of organic synthesis application, and particularly relates to a self-powered continuous nitration method and device. According to the method, a raw material (or a raw material solution) and mixed acid (or nitric acid) are added into a self-powered continuous reactor at the same time, reaction feed liquid continuously and circularly flows, is mixed and reacts in a tube pass through self-propelling force generated by stirring of an impeller, the mass and heat transfer process is completed, and the target requirement is met. According to the invention, the mass transfer and heat transfer efficiency can be improved, the heat exchange and heat transfer capabilities are improved, the reaction time is shortened, the risk degree of art is reduced, the thermal runaway risk is avoided, the reaction safety is improved, and the realization of chemical industry intrinsic safety large scale production is facilitated.
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Paragraph 0065-0068
(2021/07/17)
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- 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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- Continuous flow industrial production method of O-nitro-P-methylphenol
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The invention relates to a continuous flow industrial production method of o-nitro-p-methylphenol. The method comprises the following steps: respectively conveying p-methylphenol in a molten state atthe temperature of 40-50 DEG C and dilute nitric acid with the mass concentration of 15-25% at the temperature of 25-30 DEG C into a micro-channel reactor, carrying out a reaction for 80-120 s at thetemperature of 20-30 DEG C, and washing with a sodium bicarbonate aqueous solution after the reaction is finished, and thus obtaining an o-nitro-p-methylphenol crude product; and under the conditionsthat the vacuum degree is -0.02 MPa to -0.005 MPa and the temperature is not higher than 125 DEG C, removing low-boiling-point components, heating to 140-150 DEG C, distilling, and condensing by a stainless steel condenser, and thus obtaining the product. By adopting the production method disclosed by the invention, the reaction time is greatly shortened, the safety is high, the pollutant emissionis low, the nitric acid consumption is low, the cost is low, the post-treatment is simple, the yield is 95% or above, the purity is 98% or above, and the method is particularly suitable for industrial large-scale production.
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Paragraph 0021; 0024-0029; 0032-0037; 0040-0043; 0046
(2020/06/30)
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- Copper-mediated nitrosation: 2-nitrosophenolato complexes and their use in the synthesis of heterocycles
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A simple protocol yielding ortho-substituted nitrosophenols from phenols is demonstrated, in the form of copper(II) bis(nitrosophenolato) complexes. The developed methodology was applied to a range of substrates, confirming the role of the copper in both the formation and protection of the challenging 1, 2-substitution pattern. Using polymer supported thiourea, the Cu could be stripped from the complexes and thus enabled the isolation or identification of the uncoordinated ligands and their decomposition products, in yields generally low in line with the intrinsic high reactivity of 2-nitrosophenols. The product complexes are useful intermediates as demonstrated in revisiting a formal [4 + 2] cycloaddition with dimethylacetylene dicarboxylate to synthesise bicyclic products in variable yields, revealing the product has a novel structure different from those previously reported in the literature.
- Nicholls, Alexander J.,Batsanov, Andrei S.,Baxendale, Ian R.
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- 3-(Ethoxycarbonyl)-1-(5-methyl-5-(nitrosooxy)hexyl)pyridin-1-ium cation: A green alternative to tert-butyl nitrite for synthesis of nitro-group-containing arenes and drugs at room temperature
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Due to their remarkable properties, task-specific ionic liquids have turned out to be progressively popular over the last few years in the field of green organic synthesis. Herein, for the first time, we report that a new task-specific nitrite-based ionic liquid such as 3-(ethoxycarbonyl)-1-(5-methyl-5-(nitrosooxy)hexyl)pyridin-1-ium bis(trifluoromethanesulfonyl)imides (TS-N-IL) derived from biodegradable ethyl nicotinate indeed acted as an efficient and eco-friendly reagent for the synthesis of highly valuable nitroaromatic compounds and drugs including nitroxynil, tolcapone, niclofolan, flutamide, niclosamide and nitrazepam. The bridging of an ionic liquid with nitrite group not only increases the yield and rate of direct C[sbnd]N bond formation reaction but also allows easy product separation and recyclability of a byproduct. Nonvolatile nature, easy synthesis, merely stoichiometric need and mildness are a portion of the extra focal points of TS-N-IL while contrasted with tert-butyl nitrite an outstanding and highly-flammable reagent utilized largely in organic synthesis.
- Chaudhary, Renu,Natarajan, Palani,Rani, Neetu,Sakshi,Venugopalan, Paloth
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- Nitration method for aryl phenol or aryl ether derivative
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The invention relates to a nitration method for an aryl phenol or aryl ether derivative. The method comprises the steps of stirring an aryl phenol or aryl ether compound, nitrate, trimethylchlorosilane (TMSCl) and a copper salt in an acetonitrile solution in air at room temperature, simultaneously, monitoring extent of reaction through a TLC dot plate, removing a solvent from a mixture by a rotaryevaporator after a substrate is consumed completely, and carrying out purification through a silica-gel column, thereby obtaining a nitroolefin derivative. Meanwhile, the selective mono-nitration orbis-nitration of the substrate can be achieved through controlling equivalent weight of the nitrate. Compared with the prior art, the nitration method disclosed by the invention has the advantages that the consumption of strong-acid substances is avoided, the reaction conditions are mild, the yield is high, the applicable range of the substrate is wide, reaction activity is free of obvious attenuation after an amplified reaction, and an excellent yield is still obtained, so that the method has an obvious industrial application value.
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Paragraph 0107-0112
(2020/01/03)
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- Kinetics and mechanism of trichloroisocyanuric acid/NaNO2-triggered nitration of aromatic compounds under acid-free and Vilsmeier-Haack conditions
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Kinetics and mechanism of nitration of aromatic compounds using trichloroisocyanuric acid (TCCA)/NaNO2, TCCA-N,N-dimethyl formamide (TCCA-DMF)/NaNO2, and TCCA-N,N-dimethyl acetamide (TCCA-DMA)/NaNO2 under acid-free and Vilsmeier-Haack conditions. Reactions followed second-order kinetics with a first-order dependence on [Phenol] and [Nitrating agent] ([TCCA], [(TCCA-DMF)], or [(TCCA-DMA)] >> [NaNO2]). Reaction rates accelerated with the introduction of electron-donating groups and retarded with electron-withdrawing groups, but did not fit well into the Hammett's theory of linear free energy relationship or its modified forms like Brown-Okamoto or Yukawa-Tsuno equations. Rate data were analyzed by Charton's multiple linear regression analysis. Isokinetic temperature (β) values, obtained from Exner's theory for different protocols, are 403.7?K (TCCA-NaNO2), 365.8?K (TCCA-DMF)/NaNO2, and 358?K (TCCA-DMA)/NaNO2. These values are far above the experimental temperature range (303-323?K), indicating that the enthalpy factors are probably more important in controlling the reaction.
- Bhooshan,Rajanna,Govardhan,Venkanna,Satish Kumar
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p. 445 - 462
(2019/04/10)
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- Nitration method for p-alkylphenol
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The invention discloses a nitration method for p-alkylphenol. The nitration method successively comprises the following steps: 1) adding the p-alkylphenol used as a raw material into a container, thenadding water and a catalyst, dropwise adding nitric acid under stirring, controlling a temperature of materials in the container not to exceed 25 DEG C in the dropwise adding process, and after the nitric acid is dropwise added, carrying out a reaction at 10 to 20 DEG C for 2 to 3 h; and 2) subjecting a reaction solution obtained in the step 1) to standing and layering, wherein the lower layer obtained by layering is a product (o-nitro-p-alkylphenol), and subjecting an upper-layer solution obtained by layering to cyclic reuse, i.e., cyclic nitration. By adoption of the method for synthesizingthe o-nitro-p-alkylphenol provided by the invention, the utilization rate of raw materials is high; cyclic reuse of waste acid and waste water is realized; the discharging of three wastes is reduced;the cost of production is lowered; meanwhile, a product has high purity, high yield and good industrial application value.
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Page/Page column 5-6; 8-9
(2019/04/10)
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- Preparation method of nitrification organic matter and prepared nitrification organic matter
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The invention discloses a preparation method of nitrification organic matter and the prepared nitrification organic matter, and relates to the technical field of organic synthesis. The preparation method of the nitrification organic substance comprises the following steps: introducing a nitrification acid liquid and molten-state organic matter to be nitrified into a microchannel reactor, and performing a reaction, wherein the organic matter to be nitrified is solid at normal temperature, and solidification and/or dissolution in the nitrification acid liquid does not occur in the organic matterto be nitrified after the organic matter to be nitrified is introduced into the microchannel reactor. According to the preparation method of the nitrification organic matter provided by the invention, the nitrification organic matter prepared by the method has a very good yield and purity without a solvent removal post-treatment process; in the whole process, no solvent participates in the reaction, so that the post-treatment process of solvent removal is avoided; and the method has high safety in the whole reaction process, adopts automation control, has high production efficiency and a greatly-improved production environment, and has larger industrial application value.
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Paragraph 0023; 0045-0096
(2019/07/29)
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- Silica-supported perchloric acid and potassium bisulfate as reusable green catalysts for nitration of aromatics under solvent-free microwave conditions
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Silica-supported perchloric acid and bisulfate (SiO2/HClO4 and SiO2/KHSO4) have been developed as reusable green catalysts for nitration of aromatic compounds using NaNO2 in acetonitrile medium under conventional and solvent-free microwave conditions. The reaction times under microwave irradiation are significantly shorter than conventional method even though the yields obtained in microwave-assisted reactions are comparable with those obtained under reflux conditions.
- Kumar, M. Satish,Sriram, Y. Hemanth,Venkateswarlu,Rajanna,Sudhakar, M. Sai,Venkanna, Purugula,Saiprakash
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supporting information
p. 59 - 67
(2017/12/26)
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- Sodium perborate/NaNO2/KHSO4-triggered synthesis and kinetics of nitration of aromatic compounds
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Sodium perborate (SPB) was used as efficient green catalyst for NaNO2/KHSO4-mediated nitration of aromatic compounds in aqueous acetonitrile medium. Synthesis of nitroaromatic compounds was achieved under both conventional and solvent-free microwave conditions. Reaction times were comparatively shorter in the microwave-assisted than conventional reaction. The reaction kinetics for nitration of phenols in aqueous bisulfate and acetonitrile medium indicated first-order dependence on [Phenol], [NaNO2], and [SPB]. Reaction rates accelerated with introduction of electron-donating groups but retarded with electron-withdrawing groups. Kinetic results did not fit well quantitatively with Hammett’s equation. Observed deviations from linearity were addressed in terms of exalted Hammett’s constants (σˉ or σeff), para resonance interaction energy (ΔΔGp) parameter, and Yukawa–Tsuno parameter (r). This term provides a measure of the extent of resonance stabilization for a reactive structure that builds up charge (positive) in its transition state. The observed negative entropy of activation (?ΔS#) suggests greater solvation and/or cyclic transition state before yielding products.
- Rajanna,Muppidi, Suresh,Pasnoori, Srinivas,Saiprakash
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p. 6023 - 6038
(2018/09/21)
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- Room-Temperature, Water-Promoted, Radical-Coupling Reactions of Phenols with tert -Butyl Nitrite
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A radical-radical cross-coupling reaction of phenols with tert -butyl nitrite has been developed with the use of water as an additive. This method allows the construction of C-N bonds under an air atmosphere at room temperature, providing the ortho -nitrated phenol derivative in moderate to good yields.
- Wei, Wen-Ting,Zhu, Wen-Ming,Liang, Weida,Wu, Yi,Huang, Hui-Yan,Huang, Yi-Ling,Luo, Junfei,Liang, Hongze
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supporting information
p. 2153 - 2156
(2017/09/26)
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- Highly efficient protocol for the aromatic compounds nitration catalyzed by magnetically recyclable core/shell nanocomposite
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An efficient protocol for the nitration of aromatic compounds in the presence of a catalytic amount of sulfuric acid-functionalized silica-based magnetic core/shell nanocomposite was reported. The designed products were obtained in high yields in relatively short reaction times at room temperature under solvent-free conditions. The nanocatalyst was simply recovered from the reaction mixture by using an external magnet and efficiently reused for several times. The characterization of particle size, morphology and elemental analysis of the nanocatalyst were provided by scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses, respectively.
- Maleki, Ali,Aghaei, Morteza,Paydar, Reza
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p. 485 - 490
(2017/01/10)
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- Potassium Periodate/NaNO2/KHSO4-Mediated Nitration of Aromatic Compounds and Kinetic Study of Nitration of Phenols in Aqueous Acetonitrile
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Synthesis and kinetics of potassium periodate(KIO4)/NaNO2/KHSO4)-initiated nitration of aromatic compounds have been studied in aqueous acetonitrile medium. Synthesis of nitroaromatic compounds is achieved under conventional and solvent-free microwave conditions. Reaction times in microwave-assisted reaction are comparatively less than in conventional reaction. The reaction kinetics for the nitration of phenols in aqueous bisulfate and acetonitrile medium indicated first-order dependence on [phenol], [NaNO2], and [KIO4]. An increase in [KHSO4] accelerated the rate of nitration under otherwise similar conditions. The rate of nitration increased in the solvent of high dielectric media (solvents with high dielectric constant (D)). Observed results were in accordance with Amis and Kirkwood plots [log k′ vs. (1/D) and [(D ? 1)/(2D + 1)]. These observations probably indicate the participation of anionic species and molecular or (dipolar) species in the rate-determining step. In addition, the plots of (log k′) versus volume% of organic solvent were also linear, which probably indicate the importance of both electrostatic and nonelectrostatic forces, solvent–solute interactions during nitration of phenols. Reaction rates accelerated with the introduction of electron-donating groups and retarded with electron-withdrawing groups, but results could not be quantitatively correlated with Hammett's equation and depicted deviations from linearity. These deviations could probably be attributed to cumulative effects arising inductive, resonance, and steric effects. Leffler's plot (ΔH# vs. ΔS#) was found linear indicating the compensation (cumulative) effect of both enthalpy and entropy parameters in controlling the mechanism of nitration.
- Sriram, Y. Hemanth,Fatima, Touheeth,Rajanna,Kumar, M. Satish,Raju, R. Madhusudan
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supporting information
p. 622 - 632
(2017/06/30)
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- A phenol compound green nitration method and application
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The invention discloses a green nitrification method and application for a phenolic compound, belonging to the technical field of organic synthesis. The method provided by the invention comprises the following steps: with the phenolic compound as a raw material, dissolving the phenolic compound into a solvent at room temperature, adding sodium nitrite, then dropwise adding hydrogen peroxide into the obtained reaction solution, adding water-soluble metalloporphyrin at room temperature and starting reaction, carrying out nitrification reaction under stirring, then carrying out extraction by using an organic solvent, and carrying out vacuum concentration and column chromatographic separation so as to obtain a target product. The nitrification method provided by the invention has the advantages of mild reaction conditions, no need of heating, convenient operation and easy treatment of products. The green nitrification reaction is suitable for the phenolic compound.
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Paragraph 0048; 0049; 0050; 0051
(2017/08/24)
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- Prussian Blue/NaNO2 as an Efficient Reagent for the Nitration of Phenols in Aqueous Bisulfate and Acetonitrile Medium: Synthetic and Kinetic Study
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The reaction kinetics of Prussian blue (PB)/NaNO2 initiated for the nitration of phenols by in aqueous bisulfate and acetonitrile medium indicated first-order dependence on [phenol], [NaNO2], and [PB]. An increase in [KHSO4] accelerated the rate of nitration under otherwise similar conditions. The rate of nitration was faster in the solvent of higher dielectric constant (D). Observed results were in accordance with Amis and Kirkwood plots [log k′ vs. (1/D) and [(D ? 1)/(2D + 1)]. These findings together with the linearity of plots, log k′ versus (vol% of acetonitrile (ACN)) and mole fraction of (nx) ACN, probably indicate the importance of both eloctrostatic and nonelctrostatic forces, solvent–solute interactions during nitration of phenols. Reaction rates accelerated with the introduction of electron-donating groups and retarded with electron-withdrawing groups, which are interpreted by Hammett's theory of linear free energy relationship. Hammett's reaction constant (ρ) is a fairly large negative (ρ 0) value, indicating attack of an electrophile on the aromatic ring. Furthermore, an increase in temperature decreased the reaction constant (ρ) values. This trend was useful in obtaining isokinetic temperature (β) from Exner's plot of ρ versus 1/T. Observed β value (337.8 K) is above the experimental temperature range (303–323 K), indicating that the enthalpy factors are probably more important in controlling the reaction.
- Srinivas, Pasnoori,Suresh, Muppidi,Rajanna,Krishnaiah
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supporting information
p. 209 - 218
(2017/02/05)
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- Tertiary Butyl Nitrite Triggered Nitration of Phenols: Solvent- and Structure-Dependent Kinetic Study
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Nitration of phenols with tertiary butyl nitrite (TBN) obeyed second-order kinetics with a first-order dependence on [TBN] and [phenol] under acid-free conditions. Reaction rates were significantly altered by a change in the dielectric constant and other physical properties of solvent. The rate of nitration increased with an increase in temperature (303-323 K) in different solvent media (acetonitrile, dichloroethane, CCl4, dimethyl formamide (DMF), and toluene). The rates of nitration (log k) could not fit into either Amis or Kirkwood plots [log k' vs. (1/D) or [(D - 1)/(2D + 1)], but the trends were better explained by the basic form of multivariate linear solvent energy relationships (MLSER) suggested by the Koppel and Palm approach on the one hand and the Kamlet and Taft approach on the other hand. These observations probably substantiate that cumulative contributions of basic solvent parameters (equilibrium as well as frictional solvent effects) and solvent-solute interactions for solvation of transition state during nitration of phenols. Reaction rates accelerated with the introduction of electron-donating groups and retarded with electron-withdrawing groups. Accordingly, the reactivity of structurally different phenols was found to follow the following sequence: p-OH > p-MeO > p-Me > H > m-Me > p-Cl > p-Br > m-Cl > p-NO2 > m-OH. The results are interpreted by Hammett's theory of linear free energy relationship. The reaction constant (Hammett's ρ) is a measure of the sensitivity of the reaction toward the electronic effects of the substituent. The rho (ρ) values obtained from the present experiments are fairly large negative values (ρ CH3) versus σ? or, Es or combined Taft's relationship. However, Charton's MLRA of the log k with polar, resonance, steric, hydrophobicity, and molar refractivity showing a very good linear relationship was obtained. It is of interest to note that when log kexp values are correlated with log kcal a perfect linearity is obtained with a correlation coefficient of unity, indicating the consonance between experimental and calculated rate constants in the present work.
- Kumar, M. Satish,Rajanna,Venkateswarlu,Rao, K. Lakshman
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supporting information
p. 171 - 196
(2016/04/09)
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- Environment-friendly bionic catalytic nitration method for phenolic compound
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The invention discloses an environment-friendly bionic catalytic nitration method for a phenolic compound and belongs to the technical field of organic synthesis. The method provided by the invention comprises the steps of dissolving the phenolic compound, which serves as a raw material, in a solvent at normal temperature, adding sodium nitrite into the solution, then, dropwise adding hydrogen peroxide into the reaction solution, adding metal-doped Al-MCM-41 molecular sieves into the reaction solution at normal temperature so as to start a reaction, carrying out stirring so as to carry out a nitration reaction, and then, carrying out suction filtration, organic solvent extraction, depressurized concentration and column chromatography separation, thereby obtaining a target product. According to the nitration method disclosed by the invention, the reaction conditions are mild, heating is not required, the operation is convenient, and the product is easy to treat. The nitration method is applicable to an environment-friendly bionic catalytic nitration reaction for phenolic compounds.
- -
-
Paragraph 0041-0042
(2017/06/19)
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- On the performance and mechanisms of toluene removal by FeOx/SBA-15-assisted non-thermal plasma at atmospheric pressure and room temperature
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FeOx/SBA-15 catalysts were prepared via impregnation and utilized for toluene removal in dielectric barrier discharge (DBD) plasma at atmospheric pressure and room temperature. Toluene removal was investigated in the environment of various mixed N2/O2 plasmas, showing that toluene removal efficiency and COx selectivity were greatly increased by FeOx/SBA-15 and that the organic intermediates were greatly reduced by catalysts. In pure N2 plasma, the bulk oxygen in the catalyst was involved in the toluene oxidation, and the 3%FeOx/SBA-15 catalyst showed the optimal toluene oxidation activity. The catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), N2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR) and O2 temperature-programmed desorption (O2-TPD), showing that toluene oxidation was closely related to the highly dispersed nature of iron on the SBA-15 surface, the reduction temperature of Fe2+ and the oxygen adsorption ability of the catalyst. The pathways of toluene decomposition in the combination of FeOx/SBA-15 with a non-thermal plasma (NTP) system were proposed based on the identified intermediates.
- Lu, Meijuan,Huang, Rong,Wu, Junliang,Fu, Mingli,Chen, Limin,Ye, Daiqi
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p. 274 - 286
(2015/02/19)
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- Regioselective nitration of phenols and phenyl ethers using aluminium nitrate on silica as a nitrating system
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Silica supported aluminum nitrate (Al(NO3)3·9H2O) was found to be an excellent reagent for the nitration of phenols and phenyl ethers. This procedure works efficiently on most of the examples at room temperature yielding nitro derivatives in fair to good yields with high regioselectivity. The present methodology evidenced a considerable enhancement in the reaction rate along with high o-selectivity, excellent yields, ease of handling and the simplicity in work up.
- Patil, Mahadeo R.,Mohite, Pravinkumar H.,Shisodia, Suresh,Keri, Rangappa S.
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p. 129 - 135
(2015/06/23)
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- N-methyl-2-chloropyridinium iodide/NaNO2/Wet SiO2: Neutral reagent system for the nitration of activated aromatic compounds under very mild conditions
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Mononitration of activated aromatic compounds using N-methyl-2-chloro-pyridinium iodide (Mukaiyama reagent)/NaNO2/wet SiO2 reagent system under neutral, very mild and environmentally safer reaction condition has been developed. Various structurally diverse aromatic rings are subjected in this condition and the corresponding nitro-aromatic compounds are prepared in moderately high yields.
- Azadi, Roya,Nazari-Far, Zahra
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p. 136 - 140
(2015/06/22)
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- Biomimetic Nitration of Phenols Using Metalloporphyrins/H2O2/NO2 -
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An efficient metalloporphyrins/H2O2/NO2 - nitration of phenols has been developed. The total yield of nitrophenol could reach up to 55.1 %, which is about 4 and sixfold higher than that of horse radish peroxidase catalysis and peroxynitrite nitration, respectively. Furthermore, the nitration system attained an enhanced regioselectivity of 1.0 o/p ratio, and exhibited a good substrate scope of monophenols. This protocol is environmentally friendly compared with HNO3/H2SO4 nitration, and stable, inexpensive and organic solvent tolerant compared with enzyme catalytic nitration and peroxynitrite nitration reaction. Graphical Abstract: [Figure not available: see fulltext.]
- Sun, Weizhi,Liu, Yaojie,Zhang, Haibo,Xian, Mo,Liu, Huizhou
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p. 1991 - 1999
(2015/12/24)
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- A phenacrylate scaffold for tunable thiol activation and release
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A thiol-selective 2-methyl-3-phenacrylate scaffold with spatiotemporal control over delivery of a cargo is reported. The half-lives of decomposition could be tuned from 30 min to 1 day and the scaffold's utility in thiol-inducible fluorophore release in cell-free as well as within cells is demonstrated.
- Sankar, Rathinam K.,Kumbhare, Rohan S.,Dharmaraja, Allimuthu T.,Chakrapani, Harinath
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supporting information
p. 15323 - 15326
(2015/01/09)
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- Ultrasonic and microwave-assisted synthesis of β-nitro styrenes and nitro phenols with tertiary butyl nitrite under acid-free conditions
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Tertiary butyl nitrite (TBN) is an acid-free and safe nitrating agent that provides preferentially β-nitrostyrenes with cinnamic acids and corresponding nitro derivatives with phenols in good yields under classical conditions. However, ultrasonic and microwave-assisted reactions reduced the reaction times substantially and enhanced the yields from good to excellent. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Kumar, M. Satish,Rajanna,Reddy, K. Rajendar,Venkateswarlu,Venkanna
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supporting information
p. 2672 - 2677
(2013/07/26)
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- Oxalylchloride/DMF as an efficient reagent for nitration of aromatic compounds and nitro decarboxylation of cinnamic acids in presence of KNO 3 or NaNO2 under conventional and nonconventional conditions
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Nitration of aromatic compounds and cinnamic acids with oxalylchloride/DMF afforded the corresponding nitro derivatives in the presence of KNO3 or NaNO2 under conventional and nonconventional (ultrasonic and microwave) conditions. The present methodology offers several benefits such as excellent yields, simple work-up procedure, and short reaction times. The yields obtained under present methodology are comparable with those obtained from (POCl3/DMF/KNO3 or NaNO2) and (SOCl 2/DMF/KNO3 or NaNO2) systems followed by shorter reaction times. The reaction times of sonication and microwave conditions are very shorter than those of the conventional conditions.
- Kumar, M. Satish,Reddy, K. Rajendar,Rajanna,Venkanna,Krishnaiah
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p. 977 - 983
(2013/06/05)
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- Nitration of aromatic compounds under neutral conditions using the Ph 2PCl/I2/AgNO3 reagent system
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Aromatic compounds were nitrated efficiently under essentially neutral conditions by employing Ph2PCl in the presence of I2 and AgNO3. This method minimizes waste products compared to traditional methods and gives the corresponding mononitro derivatives in good to excellent yields in dichloromethane at room temperature.
- Nowrouzi, Najmeh,Zareh Jonaghani, Mohammad
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experimental part
p. 5081 - 5082
(2011/10/09)
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- Highly efficient nitration of phenolic compounds using some nitrates and oxalic acid under solvent-free conditions
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Nitrophenols can be obtained by direct nitration of phenols with some nitrates and oxalic acid at room temperature in moderate to high yields under solvent-free conditions. A small amount of water proved to be important in the initial period of the reaction.
- Ji, Li,Qian, Chao,Liu, Mei-Xin,Chen, Xin-Zhi
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experimental part
p. 101 - 103
(2011/07/29)
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- A mild procedure for the preparation of o-nitrophenols by nitro urea or ammonium nitrate in the presence of silica sulfuric acid (SiO 2-OSO3H)
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A mixture of ammonium nitrate or nitro urea and silica sulfuric acid was found to be efficient and environmentally friendly nitrating media for the preparation of orto-nitro phenols in dichloromethane at room temperature. A mixture of ammonium nitrate or nitro urea and silica sulfuric acid was found to be efficient and environmentally friendly nitrating media for the preparation of orto-nitro phenols in dichloromethane at room temperature.
- Ghorbani-Choghamarani, Arash,Nikoorazm, Mohsen,Goudarziafshar, Hamid,Naserifar, Zahra,Zamani, Parisa
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experimental part
p. 731 - 734
(2011/11/12)
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- Non-steroidal dissociated glucocorticoid agonists: Indoles as A-ring mimetics and function-regulating pharmacophores
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We report a SAR of non-steroidal glucocorticoid mimetics that utilize indoles as A-ring mimetics. Detailed SAR is discussed with a focus on improving PR and MR selectivity, GR agonism, and in vitro dissociation profile. SAR analysis led to compound (R)-33 which showed high PR and MR selectivity, potent agonist activity, and reduced transactivation activity in the MMTV and aromatase assays. The compound is equipotent to prednisolone in the LPS-TNF model of inflammation. In mouse CIA, at 30 mg/kg compound (R)-33 inhibited disease progression with an efficacy similar to the 3 mg/kg dose of prednisolone.
- Betageri, Raj,Gilmore, Thomas,Kuzmich, Daniel,Kirrane, Thomas M.,Bentzien, J?rg,Wiedenmayer, Dieter,Bekkali, Younes,Regan, John,Berry, Angela,Latli, Bachir,Kukulka, Alison J.,Fadra, Tazmeen N.,Nelson, Richard M.,Goldrick, Susan,Zuvela-Jelaska, Ljiljana,Souza, Don,Pelletier, Josephine,Dinallo, Roger,Panzenbeck, Mark,Torcellini, Carol,Lee, Heewon,Pack, Edward,Harcken, Christian,Nabozny, Gerald,Thomson, David S.
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scheme or table
p. 6842 - 6851
(2011/12/22)
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- A facile demethylation of ortho substituted aryl methyl ethers promoted by AlCl3
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An efficient and practical demethylation of ortho substituted aryl methyl ethers using AlCl3 has been developed. This method gives a high conversion, is simple to operate and is cost-effective. A mechanism involving the complexation of AlCl3 with the OMe and the adjacent electron withdrawing group is proposed. Many functional groups can be tolerated in the demethylation process, and 29 examples gave a demethylated product in a yield of 90-98%.
- Du, Zhen-Ting,Lu, Jing,Yu, Hong-Rui,Xu, Yan,Li, An-Pai
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experimental part
p. 222 - 227
(2010/08/04)
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- Fast and efficient nitration of salicylic acid and some other aromatic compounds over H3PO4/TiO2-ZrO2 using nitric acid
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TiO2-ZrO2 (1/1)-surf with Ti and Zr molar ratio of 1/1 was prepared with surfactant through a sol-gel method. The optimum experimental condition was investigated for nitration of salicylic acid. Then, a number of nitration reactions were carried out with a variety of aromatic compounds in the optimum condition. The 25 wt% H3PO4/TiO2-ZrO2 (1/1)-surf catalyst showed good selectivity and yield in a short time for the nitration of salicylic acid and some other aromatic compounds.
- Kalbasi, Roozbeh Javad,Massah, Ahmad Reza,Zamani, Farzad,Hamid, Javaherian Naghash
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experimental part
p. 397 - 403
(2010/10/20)
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- Amino-acetone-bridged cyclodextrins - Artificial alcohol oxidases
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A new series of α-and β-cyclodextrin derivatives containing a substituted amino-acetone bridge attached to the 6A and 6D positions of the cyclodextrin are reported. The synthesis starts from the known α-or β-cyclodextrin A,D-diols, which were either oxidized to α-or β-cyclodextrin A,D-dicarbaldehydes and then coupled with 1,3-diamino-2-propanol by a reductive amination reaction and further modified to give the final 6A,6D-diamino-6A,6 D-dideoxy-N,N'-(2-oxopropa-1,3-dienyl)-N,N'-acetyl-α-or-β- cyclodextrin or the cyclodextrindiol was substituted with azide then reduced and after a few alkylation steps the final 6A,6D-dideoxy-N, N'-(2-oxopropa-1,3-dienyl)-6A,6D-(N,N,N'N'- tetramethyldiammonio)-α-cyclodextrin dibromide was obtained. The new compounds display very good enzymatic catalytic properties in the oxidation of benzyl alcohols with a rate increase of up to 18500 but only appreciable catalysis for aniline oxidations. Thus, unlike previously studied cyclodextrin ketones, these new amino-acetone-bridged cyclodextrins have high substrate selectivity and also exhibit stereoselectivity in the oxidation of different enantiomers.
- Marinescu, Lavinia G.,Doyagueez, Elisa G.,Petrillo, Marta,Fernandez-Mayoralas, Alfonso,Bols, Mikael
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scheme or table
p. 157 - 167
(2010/03/26)
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- Cyclodextrin ketones as oxidation catalysts: Investigation of bridged derivatives
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A series of α-cyclodextrin derivatives containing a 3, 4 or 5 membered ether-linked bridge between the 6A and 6D oxygen atoms, with and without a ketone, were prepared. The synthesis used perbenzylated α-cyclodextrin A,D-diol as a starting material upon which O-alkylation and further modifications led to the di-O-(buta-1,4-diyl), the di-O-(penta-1,5- diyl) and the di-O-(buta-2-on-1,4-diyl) derivatives, which were debenzylated, and compared with the previously reported di-O-(propa-2-on-1,3-diyl) derivative. Permethylated derivatives of the di-O-(propa-2-on-1,3-diyl) and the buta-1,4-diyl derivatives were also made. The 6A,6D-di-O-(propa-2-on-1,3-diyl)- 6C,6F-di-O-methyl and di-O-pivaloyl derivatives were also prepared. The new compounds were analysed for catalysis of the oxidation of amines and alcohols.
- Fenger, Thomas Hauch,Marinescu, Lavinia G.,Bols, Mikael
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experimental part
p. 933 - 943
(2009/05/30)
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- Aluminum nitrate and silica sulfuric acid as efficient nitrating media for the mononitration of phenols under mild and heterogeneous conditions
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A variety of phenol derivatives were successfully nitrated via combination of Al(NO3)3-9H2O and silica sulfuric acid in the presence of wet SiO2 (50% w/w) in dichloromethane at room temperature with moderate-to-good yields.
- Ghorbani-Choghamarani, Arash,Goudarziafshar, Hamid,Nikoorazm, Mohsen,Yousefi, Somaieh
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experimental part
p. 1144 - 1147
(2009/10/23)
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- Zeolite H-Y-supported copper(II) nitrate: A simple and effective solid-supported reagent for nitration of phenols and their derivatives
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Highly regiospecific mononitration of phenols and substituted phenols is accomplished by employing copper(II) nitrate supported on a catalytic amount of zeolite H-Y in a solid state. Copyright Taylor & Francis Group, LLC.
- Lalitha,Sivakumar
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p. 1745 - 1752
(2008/09/20)
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- PEG-N2O4: An efficient nitrating agent for the selective mono- and dinitration of phenols under mild conditions
-
N2O4 was easily impregnated on polyethyleneglycol to give a stable reagent. The polyethyleneglycol-N2O4 (PEG-N2O4) system was used as an effective nitrating agent for the nitration of phenols. Mono- and dinitrophenols can be obtained via direct nitration of phenols in the presence of PEG-N2O4 at room temperature in moderate to high yields. Copyright Taylor & Francis Group, LLC.
- Zolfigol, Mohammad Ali,Madrakian, Elaheh,Ghaemi, Ezat,Niknam, Khodabakhsh
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p. 3366 - 3374
(2008/12/22)
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- Tribromoisocyanuric acid/NaNO2: A new reagent for mononitration of phenols under mild and heterogeneous conditions
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Nitrophenols can be obtained via direct nitration of phenols with tribromoisocyanuric acid, NaNO2 and wet SiO2 at room temperature in good to high yields.
- Niknam, Khodabakhsh,Zolfigol, Mohammad Ali,Madrakian, Elaheh,Ghaemi, Ezat
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p. 109 - 112
(2008/09/17)
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- 1,3-Dihalo-5,5-dimethylhydantoin or citric acid/NaNO2 as a heterogeneous system for the selective mononitration of phenols under mild conditions
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Direct nitration of phenols was performed using 1,3-dichloro-5,5- dimethylhydantoin, 1,3-dibromo-5,5-dimethylhydantoin or citric acid/NaNO 2 in the presence of wet SiO2 at room temperature.
- Zolfigol, Mohammad A.,Ghaemi, Ezat,Madrakian, Elaheh,Choghamarani, Arash G.
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