- Nitration of deactivated aromatic compounds via mechanochemical reaction
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A variety of deactivated arenes were nitrated to their corresponding nitro derivatives in excellent yields under high-speed ball milling condition using Fe(NO3)3·9H2O/P2O5 as nitrating reagent. A radical involved mechanism was proposed for this facial, eco-friendly, safe, and effective nitration reaction.
- Wu, Jian-Wei,Zhang, Pu,Guo, Zhi-Xin
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supporting information
(2021/05/05)
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- Synthesis and Electronic Properties of Novel 5,7-Diazapentacene Derivatives
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A route to the synthesis of novel 5,7-diazapentacenes and some preliminary studies on their properties is reported. A single crystal X-ray diffraction study of the dihexyl derivative showed it had formed a dimer during the analysis. The materials possess lower lying frontier orbitals than pentacene and may have potential applications in organic electronic devices. This synthetic method may be applicable to the synthesis of other azaacenes.
- Lunchev, Andrey V.,Morris, Samuel A.,Ganguly, Rakesh,Grimsdale, Andrew C.
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p. 1819 - 1823
(2019/01/14)
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- A 4, 6 - dinitro resorcinol preparation method
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The present invention provides a 4, 6 - dinitro resorcinol preparation method, comprising: under the action of a catalyst, the reaction raw material in the water to perform hydrolysis reaction, thereby obtaining a reaction product; the reaction product of extraction, the organic solution; to the organic solution to the nitration reaction, to obtain the 4, 6 - dinitroresorcinol resorcinol. This invention uses the methylacetylene comprising diflufenican in the synthesis of by-product as the raw material, by-product effective resource, high yield high-quality synthesis of 4, 6 - dinitroresorcinol resorcinol. The method of the invention the synthesis step is simple, easy to operate, potential safety hazards are reduced; not only can be valuable, but the synthetic route is simple easy to implement very high industrial value.
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Paragraph 0035-0038
(2019/07/04)
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- Synthesis and Detonation Properties of 5-Amino-2,4,6-trinitro-1,3-dihydroxy-benzene
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5-Amino-4,6-dinitro-1,3-dihydroxy-benzene (6) was synthesized through the ring-opening reaction of macrocyclic compound 4 with the aid of VNS (vicarious nucleophilic substitution of hydrogen) reaction conditions. The mechanism of ring opening of macrocyclic compound 4 was studied. 5-Amino-2,4,6-trinitro-1,3-dihydroxy-benzene (8) was obtained after the nitration of 6 in KNO3 and concentrated sulfuric acid. The thermal stability, sensitivity, and other detonation performances of 6 or 8 were compared to commercially used 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) or 1,3,5-trinitrotriazacyclohexane (RDX), respectively. All target compounds were characterized by using single-crystal X-ray diffraction, NMR spectroscopy, elemental analysis, and differential scanning calorimetry. The sensitivities were determined by using BAM methods (drop-hammer and friction tests). Performance parameters, including heats of formation and detonation properties, were calculated by using Gaussian 03 and EXPLO5 v6.01 programs, respectively. It is worth pointing out that compound 8 has a remarkable measured density of 2.078 g cm?3 at 298 K. In addition, compound 8 is more insensitive than RDX (compound 8: IS=11 J; RDX: IS=7 J; IS is the impact sensitivity).
- Zhang, Xingcheng,Xiong, Hualin,Yang, Hongwei,Cheng, Guangbin
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p. 447 - 451
(2017/06/23)
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- 4 - [6 - (methylthio) benzo [1,2-d:5,4-d '] b [1,3] oxazole-2-yl] benzoic acid and its preparation method
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The invention discloses 4-[6-(methylthio) benzo [1, 2-d: 5, 4-d']-di-[1, 3] oxaxole-2-yl] benzoic acid and a preparation method thereof. The preparation method comprises the steps as follows: resorcinol is taken as a raw material and subjected to sulfonation, nitration, hydrolysis and reduction to obtain 4-amino-6-nitroresorcinol hydrochloride; ANR*HCl and p-methoxycarbonyl benzoyl chloride (MBC) are subjected to condensation, cyclization and dehydration to obtain 4-(6-hydroxy-5-nitrobenzo[d]oxazole-2-yl) methyl benzoate; NHABE is subjected to hydrogenation reduction under the action of a Pd/C catalyst to obtain 4-(6-hydroxy-5-aminobenzo[d]oxazole-2-yl) methyl benzoate; AHABE and CS2 are subjected to cyclization under the alkaline condition to obtain 4-(6-(mercapto)benzo[1, 2-d:5, 4-d']-di-(oxazole)-2-yl) benzoic acid; and dimethyl methyl sulfate is compounded to the target compound 4-[6-(methylthio) benzo [1, 2-d: 5, 4-d']-di-[1, 3] oxaxole-2-yl] benzoic acid. According to the invention, a novel compound is obtained, the method is simple and convenient, and the product yield is high.
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- Design and synthesis of urea-linked aromatic oligomers-a route towards convoluted foldamers
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Herein we report the design and synthesis of crescent-shaped and helical urea-based foldamers, the curvature of which is controlled by varying the constituent building blocks and their connectivity. These oligomers are comprised of two, three or five alternating aromatic heterocycles (pyridazine, pyrimidine or pyrazine) and methyl-substituted aromatic carbocycles (tolyl, o-xylyl or m-xylyl) connected together through urea linkages. A crescent-shaped conformational preference is encoded within these π-conjugated urea-linked oligomers based on intramolecular hydrogen bonding and steric interactions; the degree of curvature is tuned by the urea connectivity to the heterocycles and the aryl groups. NMR characterization of these foldamers confirms the intramolecular hydrogen-bonded conformation expected (Z,E configuration of the urea bond) in both the pyridazyl and pyrimidyl foldamers in solution. An X-ray crystal structure of the N3,N6-diisobutylpyridazine-4,6- diamine-o-tolyl urea-linked foldamer (4) confirms the presence of N-H...N hydrogen bonds between the heterocyclic nitrogen atom and the free hydrogen of the urea linkage. Additionally, the tolyl methyl group interacts unfavourably with the urea carbonyl oxygen, thus destabilising the alternate planar conformation.
- Mousseau, James J.,Xing, Liyan,Tang, Nathalie,Cuccia, Louis A.
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supporting information; experimental part
p. 10030 - 10038
(2010/06/15)
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- An efficient synthesis of 2,6-disubstituted benzobisoxazoles: New building blocks for organic semiconductors
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(Chemical Equation Presented) 2,6-Disubstituted benzobisoxazoles have been synthesized by a highly efficient reaction of diaminobenzene diols with various orthoesters. The scope of this new reaction for the synthesis of substituted benzobisoxazoles has been investigated using four different orthoesters. The utility of these compounds as building blocks for the synthesis of conjugated polymers is demonstrated.
- Mike, Jared F.,Makowski, Andrew J.,Jeffries-El, Malika
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supporting information; experimental part
p. 4915 - 4918
(2009/05/31)
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- Aromatic oligoureas: Enforced folding and assisted cyclization
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Aromatic oligoureas are forced into well-defined conformation by incorporated intramolecular hydrogen bonds. Shape-persistent tetraureas macrocycles were obtained in a one-step [2 + 2] reaction in good yields.
- Zhang, Aimin,Han, Yaohua,Yamato, Kazuhiro,Zeng, Xiao Cheng,Gong, Bing
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p. 803 - 806
(2007/10/03)
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- Synthesis and characterization of 2,7-bis(2-pyridyl)-1,8-diazaanthraquinone - A redox-active ligand designed for the construction of supramolecular grids
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Double condensation of 2-acetylpyridine with 1,3-diaminobenzene-4,6- dicarboxaldehyde affords 2,7-bis(2-pyridyl)-1,8-diazaanthracene, which was subsequently oxidized to the corresponding quinone. Electrochemical studies indicate two reversible reduction processes corresponding to semiquinone and hydroquinonate formation. Electron-withdrawing pyridine groups and the nitrogen atoms make this somewhat more easily reduced than anthraquinone. This compound is redox-active and can be reduced to its radical anion, a potential spin-bearing ligand for the construction of [2 x 2] metallo-grid structures.
- Jain, Rajsapan,Caldwell, Sharon L.,Louie, Anika S.,Hicks, Robin G.
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p. 1263 - 1267
(2008/01/27)
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- Overcoming regioselectivity issues inherent in bis-Troeger's base preparation
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(Figure Presented) Bis-Troeger's base derivatives are a new family of molecular tweezers. A major drawback to their study is a lack of commercially available precursors, ortho-nitrocarboxylic acids. A reverse synthetic strategy starting from known dinitrodicarboxylic acids, which circumvents this problem, is presented. Via this methodology regioisomeric bis-TB derivatives can be prepared selectively, using only common aromatic amines that are typically commercially available.
- Havlik, Martin,Kral, Vladimir,Dolensky, Bohumil
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p. 4867 - 4870
(2007/10/03)
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- Production method of 4,6-diaminoresorcin
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The present invention relates to a novel production method of 4,6-diaminoresorcin, and to 2-sulfonic acid-4,6-dinitroresorcin as its intermediate and salts thereof. The target compound is obtained by (R1) sulfonating resorcin (A) to obtain resorcin 2,4,6-trisulfonate (B), (R2) nitrating the compound (B) to obtain 2-sulfonic acid-4,6-dinitroresorcin (C), (R3) hydrolyzing the compound (C) to obtain 4,6-dinitroresorcin (D), and finally (R4) reducing the compound (D) to obtain 4,6-diaminoresorcin (E):
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Page column 12,13,15
(2010/01/31)
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- Intramolecular Hydrogen Bonding and Molecular Geometry of 4,6-Dinitroresorcinol from Gas-Phase Electron Diffraction
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The molecular geometry of 4,6-dinitroresorcinol has been determined by gas-phase electron diffraction.The resonance-assisted intramolecular hydrogen bonding is accompanied by pronounced bond length changes as compared with the parent molecules phenol and nitrobenzene.The molecular geometry is characterized by the following bond lengths (rg) and bond angles: (C-H)mean, 1.086 +/- 0.015 Angstroem; (C-C)mean, 1.402 +/- 0.003 Angstroem; C3-C4, 1.424 +/- 0.005 Angstroem; C-O, 1.341 +/- 0.004 Angstroem; O-H, 1.002 +/- 0.009 Angstroem; C-N, 1.461 +/- 0.004 Angstroem; (N-O)mean, 1.233 Angstroem; C1-C2-C3, 120.3 +/- 0.4 deg; C2-C3-C4, 119.3 +/- 0.3 deg; C3-C4-C5, 121.6 +/- 0.3 deg; C4-C5-C6, 118.0 +/- 0.4 deg; C4-C3-O, 123.4 +/- 0.3 deg; C-O-H, 104.5 +/- 1.4 deg; C3-C4-N, 121.0 +/- 0.2 deg; (C-N-O)mean, 118.1 +/- 0.1 deg; O-N-O, 123.7 +/- 0.2 deg.The effective angle of nitro group torsion from electron diffraction is 14.4 +/- 1.3 deg.If it is assumed that this effective angle of torsion emerges as a consequence of torsional vibrations about the planar equilibrium conformation, then a barrier to internal rotation of 18 +/- 3 kJ/mol may be estimated, the same as in nitrobenzene, the planarity of which is consistent with microwave spectroscopic results.
- Borisenko, Konstantin B.,Zauer, Karoly,Hargittai, Istvan
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p. 13808 - 13813
(2007/10/02)
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- Cleaving arylethers
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The present invention relates to a method of cleaving arylethers such as arylethers represented by the formula: STR1 wherein R is hydrogen, C1 -C6 alkyl, cycloalkyl, phenyl, substituted phenyl or CH=CH2 ; each A is independently NO2, hydroxy, halo, or methoxy; n is an integer from 0 to 5; and x is 1 or 2, comprising contacting the arylether with an amide hydrohalide salt under conditions sufficient to cleave the ether group(s) of the arylether and form a phenol or substituted phenol. The present invention also relates to a method of preparing 4,6-diaminoresorcinol, which is a monomer used for making polybenzoxazoles (PBO).
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- Thermal Stability Studies on a Homologous Series of Nitroarenes
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The thermal stabilities of a number of nitroarenes were examined in solution and in condensed phase.In general, increasing the number of nitro groups decreased thermal stability.Changing the substituent on 1-X-2,4,6-trinitrobenzene from X = H to NH2 to CH3 to OH accelerated decomposition; this effect was attributed to increased ease of intramolecular proton transfer to an ortho nitro group, thus weakening the carbon-nitrogen bond.In solution, the effect of increasing substitution from n = 1 to n = 3 on Xn(NO2)3C6H3-n was uniformly that of decreasing the thermal stability of the species.However, in condensed phase, results suggested that crystal habit may be more important than molecular structure; for X = Br, CH3, and NH2, the more substituted species was the more stable.
- Oxley, Jimmie C.,Smith, James L.,Ye, Hong,McKenney, Robert L.,Bolduc, Paul R.
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p. 9593 - 9602
(2007/10/02)
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- Ozone-mediated Nitration of Alkylbenzenes and Related Compounds with Nitrogen Dioxide
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In the presence of ozone, nitrogen dioxide exhibits a strong nitrating ability for alkylbenzenes at low temperatures, converting them into the corresponding nitro derivatives in high yield.The addition of a protonic acid as catalyst enhances considerably the ability of this nitrating system and leads to a good yield of polynitro compounds.The reaction is clean and proceeds rapidly without any accompanying side-chain substitution or aryl-aryl coupling.It shows no kinetic dependence on the concentration of substrates and, as far as can be judged from relative reactivities and isomer distributions of products, it gives the appearance of being an electrophilic aromatic process.A possible role for nitrogen trioxide has been suggested as the initial electrophilic agent for the nitration of alkylbenzenes.
- Suzuki, Hitomi,Murashima, Takashi,Kozai, Iku,Mori, Tadashi
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p. 1591 - 1598
(2007/10/02)
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- 1,3-bis(alkylcarbonato)-nitrobenzenes
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High purity amino-1,3-benzenediols are prepared by (a) contacting a 1,3-bis(alkylcarbonato)benzene with a nitrating agent under rection conditions such that a 1,3-bis(alkylcarbonato)nitrobenzene is formed, (b) contacting the 1,3-bis(alkylcarbonato)nitrobenzene with a hydrolyzing agent under conditions such that a nitro-1,3-benzenediol is produced, and (c) contacting the nitro-1,3-benzenediol with a reducing agent under conditions such that an amino-1,3-benzenediol is produced. Of the amino-1,3-benzenediols, 4,6-diamino-1,3-benzenediol is particularly useful in the preparation of high molecular weight polybenzoxazoles.
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- Synthesis and Reactions of Some Pyridoquinolines (1,8-Diazaanthracenes)
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The pyridoquinolines 1b, c, and e are synthesized for the first time directly by Friedlaender condensation from 4,6-diaminoisophthalic aldehyde (6) and ketones.Copper(I)-catalyzed decarboxylation of the 2,8-dicarboxylic acid 1e occurs in diethylene glycol monoethyl ether at temperatures as low as 165 deg C affording the parent compound 1a in high yield.Despite steric hindrance by a tert-butyl group methyllithium adds to position 2 of the 2,8-di-tert-butyl compound 1c producing the 1,2-dihydropyridoquinoline 9.Dehydrogenation of the octahydroquinoacridine 7 using palladium on carbon at 250 deg C yields the 1,2,3,4,7,12-hexahydro- (10) and the 5,14-dihydroquinoacridine (11).
- Quast, Helmut,Schoen, Norbert
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p. 133 - 146
(2007/10/02)
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- Cycloarenes, a New Class of Aromatic Compounds, I. Synthesis of Kekulene
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Definition and nomenclature of cycloarenes, a new class of aromatic compounds, are discussed.Cyclododecakisbenzene ("kekulene", 1) has been synthesized as the first representative of cycloarenes. - From the dithiaphane 11 by double sulfur extrusion, either photochemically or by pyrolysis of disulfone 12, the carbocyclic system 13 was formed which by dehydrogenation yielded 14.By Stevens rearrangement of 11 followed by elimination the phanediene 15 was obtained which was dehydrogenated to 18.From 15 by photo-cyclodehydrogenation in excellent yield the octahydrokekulene 19 was obtained.The different reactivity of 15 and 18 in the photo-cyclodehydrogenation is discussed in terms of electronic and steric effects.Dehydrogenation of 19 yielded 1.
- Staab, Heinz A.,Diederich, Francois
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p. 3487 - 3503
(2007/10/02)
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