cas 573-56-8, 2,6-DINITROPHENOL | Articles data

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Method for synthesizing benzoxazole compound by using nitration by-products of aromatic hydrocarbon and application of benzoxazole compound
The invention discloses a method for synthesizing a benzoxazole compound by using nitration by-products of aromatic hydrocarbon and application of the benzoxazole compound. The method comprises the main process: performing step-by-step crystallization on nitration products of a 2,4-dinitrochlorobenzene production enterprise so as to obtain 2,4-dinitrochlorobenzene, 2,6-dinitrochlorobenzene (I) anda small amount of residues, adopting the obtained 2,6-dinitrochlorobenzene (I) as the main starting material, and performing hydrolysis, selective catalytic hydrogenation reduction, cyclization, halogenation, carbon-carbon coupling and other processes so as to synthesize the benzoxazole compound, wherein the obtained compound can be used as a main raw material to synthesize a series of chemical intermediates with important application, and the chemical intermediates include o-aminophenol, 2-amino-4-nitrophenol, 2-amino-5-nitrophenol and hydrochloride of o-aminophenol, 2-amino-4-nitrophenol, 2-amino-5-nitrophenol. Through the method, the industrial by-products are converted into high value-added aromatic aminophenol products, industrial hazardous waste of the 2,4-dinitrochlorobenzene production enterprise is reduced, the scope of products of the enterprise is widened, and the economic benefits of enterprise are increased.
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Paragraph 0043-0045; 0059-0061

(2019/09/14)

Magnetically recyclable Pd/Fe3O4/g-C3N4 as efficient catalyst for the reduction of nitrophenol and suzuki-miyaura reaction at room temperature
Herein, we present the design and synthesis of a novel magnetic stable and recyclable catalyst Pd/Fe3O4/g-C3N4 with approachable active palladium nanoparticles (Pd NPs) based on the platelet-like graphitic carbon nitrides (g-C3N4). The Pd NPs, g-C3N4 and magnetic particles (Fe3O4) are tightly connected through non-covalent interactions owing to the layered structure of g-C3N4 with abundant nitrogen atoms, facilitating the stability of Pd/Fe3O4/g-C3N4 and activating the Pd NPs at the same time. The Pd/Fe3O4/g-C3N4 catalyst with a narrow particle size distribution (2.55 nm) of Pd NPs displayed the maintenance of the planar structure of g-C3N4. The activity parameter of the catalyst turned out to be excellent (12.4 s11￠mM11) by fitting the curves derived from the reduction of nitrophenol. Meanwhile, the Suzuki-Miyaura coupling reaction at room temperature processed smoothly with the Pd/Fe3O4/g-C3N4 catalyst. It is meaningful to stress that 2-bromobenzonitrile and p-tolylboronic acid could afford the medical intermediate sartanbiphenyl at total conversion without side reactions in 25 min. Furthermore, the nanocatalyst owes the properties of easy recycling using a powerful magnet as well as high turnover frequency (at least 5 runs) with retention of high catalytic activity.
Yang, Yingwei,Tang, Ruiren
supporting information
p. 544 - 547
(2018/04/09)

Nitrogen Oxides and Nitric Acid Enable the Sustainable Hydroxylation and Nitrohydroxylation of Benzenes under Visible Light Irradiation
A new type of waste recycling strategy is described in which nitrogen oxides or nitric acid are directly employed in photocatalyzed hydroxylations and nitrohydroxylations of benzenes. Through these transformations, otherwise costly denitrification can be combined with the synthesis of valuable compounds for various applications.
Hofmann, Laura Elena,Mach, Leonard,Heinrich, Markus R.
supporting information
p. 431 - 436
(2017/12/15)

Microwave assisted synthesis of nitro phenols from the reaction of phenols with urea nitrate under acid-free conditions
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.
p. 1320 - 1322
(2014/03/21)

A facile demethylation of ortho substituted aryl methyl ethers promoted by AlCl3
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
experimental part
p. 222 - 227
(2010/08/04)

Reactivity of α-amino acids in the N-acylation with benzoic acid esters in aqueous dioxane
The effect of the nitro group as a substituent in the phenoxide part of phenyl benzoate on the rate of N-acylation of glycine, L-proline,and L-valine in the water (40 wt %)-dioxane solvent was studied. The activation parameters of glycine reactions with the esters were measured. The existence of compensation effect and the linear relation of the logarithms of the acylation constants to the Hammett constants were revealed. The energy of the LUMO of esters can serve as the descriptors of the easters reactivity. Pleiades Publishing, Ltd., 2010.
Ishkulova,Oparina,Kochetova,Kustova,Kalinina,Kuritsin
experimental part
p. 964 - 967
(2011/01/07)

From N-(dinitrophenyl) amino acids to benzimidazole N-oxides. Synthesis, kinetics and mechanism
Several benzimidazole N-oxide derivatives were synthesized in very good yields by heating under reflux the corresponding N-(2,4- or 2,6-dinitrophenyl) amino acid derivative with NaOH in 60% 1,4-dioxane-H2O. The N-oxides obtained from glycine and α- and β-alanine derivatives lost the carboxylic group. The observed rate constant for the reaction of N-(2,4-dinitrophenyl) glycine (2a) in 10% 1,4-dioxane-H2O to give 5-nitro-1H-benzimidazole-3-oxide (4a) is first order on [NaOH]; the second-order rate constant is kN=1.7 × 10-3 M-1 S-1. The mechanism proposed includes the formation of an N-alkylidene 2-nitrosoaniline-type intermediate as the rate-determining step. Copyright
Bujan, Elba I.,Salum, Maria Laura
p. 187 - 195
(2007/10/03)

Nitrophenol derivatives oxidized by cerium(IV) ammonium nitrate (CAN) and their cytotoxicity
Oxidation of a series of phenols with cerium(IV) ammonium nitrate (CAN) in acetonitrile undermild conditions yields the mixture of corresponding nitrophenols. In the cases of methylphenols and hydroxy-carboxylic acids, the steric effect may reduce the nitration reaction. Compounds 3 a and 4b showed selective activities to Hep 3B and Hep G2 cancer cell lines, respectively. Compound 2c showed selective activities to Hep G2 and MDA-MB-231 cancer cell lines. Further more, com pound 10b showed selective activities to Hep G2, Hep 3B, MCF-7 and MDA-MB-231 cancer cell lines.
Pan, Wen-Bin,Wei, Li-Mei,Wei, Li-Lan,Wu, Chin-Chung,Chang, Fang-Rong,Wu, Yang-Chang
p. 581 - 588
(2007/10/03)

Leaving group effects on the mechanism of aromatic nucleophilic substitution (SnAr) reactions of some phenyl 2,4,6-trinitrophenyl ethers with aniline in acetonitrile
Kinetic studies are reported for the reactions with aniline in acetonitrile of a series of X-phenyl 2,4,6trinitrophenyl ethers [X = H, 2-, 3-, 4-CH3,2,4-, 2,6-(CH3)2,2-, 3-, 4-NO 2,2,4-, 2,6-(NO2)2]. X-ray crystal structures for X = H, 2,6-(CH3)2 and 2,6-(NO2) 2 are reported and provide evidence for steric crowding around the 1-position of these molecules. Nevertheless, the kinetic data show that increasing substitution does not sterically inhibit nucleophilic attack by aniline and an 'early' transition state is likely. In general, the reactions are base catalysed; interpreted as rate-limiting deprotonation of the zwitterionic intermediates. Only with the dinitro derivatives is an uncatalysed reaction involving intramolecular proton transfer observed and when X = 2,6-(NO2)2 this pathway takes all the reaction flux. Copyright
Crampton, Michael R.,Emokpae, Thomas A.,Howard, Judith A.K.,Isanbor, Chukwuemeka,Mondal, Raju
p. 65 - 70
(2007/10/03)

Clay supported ammonium nitrate "clayan": A new reagent for selective nitration of arenes
The nitration of activated, deactivated and highly functionalized arenes is described using clay-supported ammonium nitrate in the presence of perchloric acid.
Meshram,Ganesh,Madhavi,Eshwaraiah,Yadav,Gunasekar
p. 2497 - 2503
(2007/10/03)

Selective nitration of aromatic compounds with bismuth subnitrate and thionyl chloride
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.
p. 593 - 598
(2007/10/03)

Amines as leaving groups in nucleophilic aromatic substitution reactions. Part 5. Substitution vs. N-oxide formation in the reaction of N-n-butyl-2,6-dinitroaniline with hydroxide ions
A kinetic study of the reaction of N-n-butyl-2,6-dinitroaniline 1 with NaOH was carried out in 10% 1,4-dioxane-water at 25 °C, giving 2,6-dinitrophenol 2 and 7-nitro-2-n-propyl-1 H-benzimidazole 3-oxide 3 in ratios depending on the HO- concentration. The rate constant for the formation of 2 is second order in HO- concentration while that of 3 is first order then, the relative amount of 2 : 3 formed increases with HO-. A mechanism involving the formation of a σ complex by addition of HO to an unsubstituted position of the aromatic ring is proposed for 2,6-dinitrophenol formation. The mechanism suggested for the formation of the N-oxide requires the deprotonation of the substrate.
Bujan, Elba I.,Canas, A. Irene,De Rossi, Rita H.
p. 1973 - 1977
(2007/10/03)

Vanadium(v) oxytrinitrate, VO(NO3)3. A powerful reagent for the nitration of aromatic compounds at room temperature under non-acidic conditions
Vanadium(v) oxytrinitrate is an easy to handle reagent which can be used to nitrate a range of substituted aromatic compounds in dichloromethane at room temperature, leading to >99% yields of nitration products in most cases.
Dove, Michael F. A.,Manz, Berthold,Montgomery, John,Pattenden, Gerald,Wood, Simon A.
p. 1589 - 1590
(2007/10/03)

From N-n-butyl-2,6-dinitroaniline to a fused heterocyclic N-oxide
The reaction of N-n-butyl-2,6-dinitroaniline with NaOH in 60% dioxane-water at reflux gives 7-nitro-2-n-propylbenzimidazole-3-oxide quantitatively.
De Vargas, Elba Bujan,Canas, A. Irene
p. 767 - 770
(2007/10/03)

The Anomalous Reactions of Some Fluoronitrobenzenes with Some N,N-Dialkylamines
The reactions of 1-fluoro-2,4,- and -2,6-dinitrobenzene with certain N,N-dilkylamines in dimethyl sulfoxide solution in the presence of potassium carbonate give the corresponding dinitrophenyl N,N-dialkylcarbamates as well as corresponding N,N-dialkyldinitroanilines.The extent of carbamate formation is governed by steric factors.The corresponding reactions of 1-fluoro-4-nitrobenzene with diisopropylamine and di-s-butylamine give poor yields of the corresponding 4-nitrophenyl N,N-dialkylcarbamates but none of the corresponding N,N-dialkyl-4-nitroanilines; in these reactions, the major product is 4,4'-dinitrodiphenyl ether.The 1H and 13C n.m.r. spectra of the 2,4- and 2,6-dinitrophenyl N,N-dialkylcarbamates reveal that their aliphatic protons and carbon atoms are magnetically non-equivalent.
Gale, Douglas J.,Rosevear, Judi,Wilshire, John F. K.
p. 997 - 1008
(2007/10/02)

Associative and Dissociative Pathways in the Alkaline Hydrolysis of Aryl 2-Hydroxycinnamates
Aryl 2-hydroxycinnamate esters hydrolyze in alkaline solutions (20percent dioxane-water v/v) obeying the rate law kobs = ka + kb/(1 + aH/Ka), where Ka is the ionization constant of the hydroxy group of the ester and kb is the second-order rate constant for the attack of hydroxide ion on the ionized ester.Kinetic data and activation parameters for the hydrolysis of the 2,4-dinitrophenyl ester show that the mechanism giving rise to the ka term cannot be a simple BAc2 type process and suggest the occurrence of a E1cB mechanism involving an "extended" o-oxoketene intermediate.The Broensted plot of the apparent second-order rate constante (kaKa/kw) versus the pK of the leaving group indicates that the reaction mechanism changes from E1cB to BAc2 for esters with leaving groups having pK higher than about 6.
Cevasco, Giorgio,Thea, Sergio
p. 70 - 73
(2007/10/02)

MICELLAR CATALYSIS OF ORGANIC REACTIONS. PART 36. NUCLEOPHILIC AROMATIC SUBSTITUTION REACTIONS IN HYDROXY FUNCTIONALIZED MICELLES WITH BULKY HEAD GROUPS
The reaction of several nitro activated aromatic halides with hydroxide ions was studied in the presence of hydroxy functionalized micelles containing bulky head groups, e.g.C16H33N+R2CH2CH2OH Br-, where R = Me, Et, Bu.In a biphasic reaction, the aryl halide is first converted into an aryl micellar ether which subsequently reacts with hydroxide ions to form the phenolic product.Despite the increased nucleophilicity of hydroxide ions as water is squeezed away from the micelle surface by the bulky head groups, no direct reaction of the aromatic substrate with hydroxide ion is detectable.In the second phase of reaction, the breakdown of the aryl micellar ether to form the phenolic product, the order of reactivity in the different micelles is dependent on the steric interactions between substituents ortho to the reaction centre and the head group of the micelle.For compounds having one substituent ortho to the reaction centre, the order of reactivity is Bu > Me > Et, whereas for 2-chloro-1,3-dinitrobenzene, which has two substituents ortho to the reaction centre, the order is Me > Et > Bu.
Broxton, Trevor J.,Lucas, Mathew
p. 442 - 447
(2007/10/02)

Participation of an Extended p-Oxo Ketene Intermediate in the Dissociative Alkaline Hydrolysis of Aryl 4-Hydroxycinnamates
The alkaline hydrolysis of 4-hydroxycinnamate esters of acidic phenols follows an E1cB mechanism and involves the participation of an "extended" p-oxo ketene intermediate.The apparent bimolecular rate constant (kaKa/Kw) for the hydrolysis of the 2,4-dinitrophenyl ester is some 2500-fold larger than that determined from the Hammett relationship for the BAc2 alkaline hydrolysis of substituted 2,4-dinitrophenyl cinnamates.The positive value of entropy of activation for the hydrolysis of 2,4-dinitrophenyl 4'-hydroxycinnamate and trapping experiments with nitrogen nucleophiles are consistent with the dissociative pathway.A change from a E1cB to a BAc2 mechanism is expected for esters with leaving groups having pKa higher than ca. 6.7.The higher E1cB reactivity of 2,4-dinitrophenyl 4'-hydroxycinnamate compared to that of the corresponding 4'-hydroxybenzoate is due to the vinylene group that further favors the dissociative route, probably increasing the stability of the unsaturated intermediate.
Cevasco, Giorgio,Thea, Sergio
p. 6274 - 6278
(2007/10/02)

Photochemical Nitration by Tetranitromethane. XV. Formation of Adducts and their Secondary Products in the Photochemical Reaction between Benzene and Tetranitromethane
Photolysis of benzene/tetranitromethane in dichloromethane or acetonitrile with light of λ>435 nm gives four main product categories, namely, in dichloromethane at +20 deg C (relative yield, products): adducts 1 of hydroxy/trinitromethyl type (total 54percent, see below), nitro substitution products (total 8percent, nitrobenzene, 1,3-dinitrobenzene and 1,3,5-trinitrobenzene), trinitromethyl substitution products (26percent, trinitromethylbenzene, 1-nitro-4-trinitromethylbenzene, 1,3-dinitro-5-trinitromethylbenzene) and phenols (total 12percent, 2,4- and 2,6-dinitrophenol, 2,4,6-trinitrophenol). In acetonitrile at +20 deg C the same product groups comprised 15, 24, 39 and 18percent, respectively, and, in addition, a low yield (1.7percent) of what is formally a cycloaddition product between 4-nitrobenzonitrile N-oxide and acetonitrile, 5-methyl-3-(4-nitrophenyl)-1,2,4-oxadiazole 2. The structure of 2 was determined by single crystal X-ray analysis. The main adducts were assigned the structures of a cis/trans pair of 1-hydroxy-4-trinitromethylcyclohexa-2,5-diene (NMR). Their formation in both dichloromethane and acetonitrile shows that adduct formation from photolysis of tetranitromethane/aromatics is not only confined to polycyclic aromatics but can occur with a maximally resonance-stabilized system, like benzene itself. The high complexity of the product mixture can be explained partly by elimination reactions of adducts, combined with further thermal and photochemical transformations.
Eberson, Lennart,Calvert, Jane L.,Hartshorn, Michael P.,Robinson, Ward T.
p. 347 - 355
(2007/10/02)

Aromatic Nitro-group Displacement Reactions. Part 4. The Action of Cyanide and Halide Ions on Compounds containing Strongly Activated Nitro-groups
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Gorvin, John H.
p. 1831 - 1851
(2007/10/02)

The Rearrangement of Aromatic Nitro Compounds. Part 2. The Rearrangement os Substituted Nitrophenols in Trifluoromethanesulphonic Acid
o-Nitrophenols with an additional substituent (Y = NO2, Cl, or Me) in the 3-position rearrange in trifluoromethanesulphonic acid at 100 deg C to give mainly the product with the nitro group in the opposite ortho position; no more than 1-4percent of other products are formed.The reactions give first-order kinetics, are acid-catalysed and (at least when Y = NO2) are intramolecular.The rate of rearrangement varies with the 3-substituent in the order Me > Cl > NO2.The results are discussed in terms of a rate-determining migration of the nitro group in the Wheland intermediate formed by protonation at the 2-position.A much slower rearrangement occurs with 3,4-dinitrophenol under the same conditions to give a small yield of 2,5-dinitrophenol accompanied by decomposition of the substrate.
Bullen, John V.,Ridd, John H.
p. 1675 - 1679
(2007/10/02)

The Stabilities of Meisenheimer Complexes. Part 41. Kinetic Studies of Adduct Formation and Nucleophilic Substitution in the Reactions of Hydroxide Ions with 1-X-3,5-Dinitrobenzenes and with 1-X-4-Chloro-3,5-dinitrobenzenes (X = H, CF3, CO2-) in Water-Dimethyl Sulphoxide Mixtures. T...
Kinetic and equilibrium measurements are compared for the reactions of (1) and (4) (X = CF3, CO2-, H) with hydroxide ions in dimethyl sulphoxide-water mixtures.The aducts (3), formed from (1), have higher thermodynamic stabilities than their isomers (2) although there is little kinetic discrimination in the rates of hydroxide attack at the three unsubstituted positions.The presence in (4) of the chlorine atom results in a general reduction in the rate of nucleophilic attack, the effect being particularly large for ipso-reaction (attack at the 4-position).Hence the reaction of (4) with base results in the initial formation of adducts (5).Contrary to a recent report the intermediates (6) on the reaction pathway to the phenols (7) are not sufficiently stable to allow spectrophotometric detection.
Crampton, Michael R.,Greenhalgh, Colin
p. 187 - 192
(2007/10/02)

Base Catalysis in Nucleophilic Aromatic Substitution Reactions: Evidence for Cyclic Transition State Mechanism over the Dimer Mechanism in a Non-polar Aprotic Solvent
The reactions of X-phenyl 2,4,6-trinitrophenyl ethers with aniline in benzene display three distinct mechanisms even though all except the 2,6-dinitrophenyl ether are base catalysed.The catalysis of the mononitro-substituted ethers involves two aniline molecules and proceeds at a temperature-independent rate in the temperature range 5 - 35 deg C while that of the dinitro-substituted ones involves only one aniline molecule and proceeds at a temperature-dependent rate over the same temperature range.The results are interpreted in terms of a cyclic mechanism involving four-, six-, and eight-membered rings in the transition state.
Banjoko, Olayinka,Ezeani, Chike
p. 531 - 536
(2007/10/02)

A Novel Dissociative Mechanism in Acyl Group Transfer from Aryl 4-Hydroxybenzoate in Aqueous Solvents.
The hydrolysis of ary 4-hydroxybenzoates esters exibits the kinetic rate law kobsd=(ka+kb->/(1++>/Ka) where kb is the second-order rate constant for hydroxide ion attack on the ionized ester and Ka is the ionization constant.The apparent second-order rate constant for the hydrolysis of the 2,4-dinitrophenyl ester (kaKa/Kw) is some 340-fold larger than that determined from the Hammett correlation for the alkaline hydrolysis of substituted 2,4-dinitrophenyl benzoates known to possess a BAc2 mechanism.A slightly positive entropy of activation for ka and aniline trapping experiments for the 2,4-dinitrophenyl ester are consistent with a mechanism where a p-oxo ketene intermediate takes the reaction flux. Correlation of kaKa/Kw with the pK of the leaving phenol fits the equation kaKa/Kw-10(-1.33pK+9.57)+10(-0.35pK+3.51) which favors the BAc2 mechanism for poor leaving groups and the E1cB pathway for good leaving groups.There is no reason to postulate a borderline concerted displacement process in this case.
Cevasco, Georgio,Guanti, Giuseppe,Hopkins, Andrew R.,Thea, Sergio,Williams, Andrew
p. 479 - 484
(2007/10/02)

REACTIONS OF NITROANISOLES. PART 6. REACTION OF 2,6-DINITROANISOLE WITH CYCLOHEXYLAMINE IN MIXED SOLVENTS. SOLVENT EVIDENCE FOR THE 'DIMER' MECHANISM
The reaction of 2,6-dinitroanisole with cyclohexylamine in methanol and benzene-methanol was studied at several amine concentrations.Althrough the reaction rate in methanol is higher than in benzene, addition of small amounts of methanol to the benzene solution diminishes the rate of reaction (which is of third order in amine), reaching a minimum value at nearly 30percent methanol, after which the rate increases almost linearly with the methanol content.These and other results, here described, are satisfactorily explained by a previously proposed reaction scheme, in which the dimer of the amine is operating.
Nudelman, Sbarbati N.,Palleros, Daniel
p. 1277 - 1280
(2007/10/02)

Evidence for a Single Transition State in the Intermolecular Transfer of a Sulfonyl Group between Oxyanion Donor and Acceptors
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D'Rozario, Peter,Smyth, Richard L.,Williams, Andrew
p. 5027 - 5028
(2007/10/02)

Decarboxylative Nitration of Some Simple Hydroxybenzoic Acids Using Cerium(IV) Ammonium Nitrate
The mechanistic pathways proposed earlier in the Ce(IV) induced decarboxylation of aromatic acids have been examined in the light of new observations made.A simple, non-explosive, easy to control substitute to Bechman and Biermann's decarboxylative nitration is described and a plausible mechanism suggested.
Chawla, H. Mohindra,Mittal, Ram S.
p. 1129 - 1131
(2007/10/02)

Reactions of Nitroanisoles. Part 2. Reactions of 2,4- and 2,6-Dinitroanisole with Piperidines in Benzene
The reactions of 2,4- (I) and 2,6-dinitroanisole (VIII) with piperidine (II) and N-methylpiperidine (NMP) in benzene have been studied.It was found that (I) and (VIII) react with (II) to give not only the expected aromatic nucleophilic substitution (a.n.s.) products, but also the corresponding dinitrophenols, generated by an SN2 reaction.The rate for each reaction and the overall rates were measured and it was observed that compound (I) has similar rate coefficients for the a.n.s. as well as for the SN2 reaction.Mild acceleration by base was found for the a.n.s.reaction.When (VIII) reacts with (II) the rate of reaction to form 2,6-dinitrophenol is greater than the rate for the a.n.s.In the reaction with NMP only an SN2 reaction was observed.Furthermore, the rates of reaction of (VIII) with (II) and with NMP are ca. 1000 and 300 times, respectively, the rate of reaction of (I) with these amines.A field effect is proposed for the increase in rate.
Nudelman, N. Sbarbati,Palleros, Daniel
p. 995 - 999
(2007/10/02)