- Preparation method of 2-amino-3-methyl-5-chlorobenzoic acid
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The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 2-amino-3-methyl-5-chlorobenzoic acid. The preparation method provided by the invention comprises the steps of mixing m-toluic acid and nitric acid, and carrying out nitration reaction to obtain 2-nitro-3-methyl benzoic acid, wherein the mass concentration of the nitric acid is 60-75%; mixing the 2-nitro-3-methyl benzoic acid, a hydrogenation reduction reaction solvent and a hydrogenation catalyst, and carrying out hydrogenation reduction reaction in a hydrogen atmosphere to obtain 2-amino-3-methyl benzoic acid; and mixing the 2-amino-3-methyl benzoic acid, a chlorination reagent, benzoyl peroxide and a chlorination reaction solvent, and carrying out a chlorination reaction to obtain the 2-amino-3-methyl-5-chlorobenzoic acid. The preparation method provided by the invention has the advantages of cheap and easily available reaction raw materials, high product yield and high purity, and is easy for industrial production.
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Paragraph 0056-0057; 0062-0063; 0067-0068; 0072-0073; 0077
(2021/05/12)
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- PROCESS FOR THE PREPARATION OF CHLORANTRANILIPROLE
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The present invention relates to two novel, efficient and one-pot methods for synthesizing chlorantraniliprole. In the first scheme, Chlorantraniliprole is prepared by a novel telescopic process starting from 3-Bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxylic acid a key raw material-A (Key RM-A). In the second scheme, starting from Key RM-A, the process steps use of a novel variant of anthranilic acid (Methyl 2-amino-5-chloro-3-methylbenzoate), to get Chlorantraniliprole. Furthermore, the present invention also relates to the synthesis of key starting material for the synthesizing chlorantraniliprole in-situ. All the in-situ steps of the disclosed synthesis methods obtain good yield, without using any expensive reagent or base or harsh reaction conditions, which makes the process simple, environment friendly and more cost effective. With this process the production cost of chlorantraniliprole and its intermediates is substantially reduced; fewer by-products are formed during its synthesis and since it's a one-pot reaction, isolation and purification are easy to achieve.
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Page/Page column 9; 15-17
(2021/02/26)
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- Method for synthesizing 2-nitro-3-methylbenzoic acid
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The invention discloses a method for synthesizing 2-nitro-3-methylbenzoic acid. The method comprises that powdery meta-methylbenzoic acid and nitric acid undergo a reaction at -30 to -15 DEG C to produce a nitrification reaction solution, and the nitrification reaction solution is separated and purified to form a 2-nitro-3-methylbenzoic acid product. The method has simple processes, is easy to operate, has a high conversion rate of m-methylbenzoic acid, has high selectivity of 2-nitro-3-methylbenzoic acid, and has obvious environmental protection effects and significant economic benefits.
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Paragraph 0043; 0045; 0047; 0049; 0051; 0053; 0058-0059
(2018/07/06)
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- Preparation method of highly selective 3-methyl-2-nitrobenzoic acid
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The invention discloses a preparation method of 3-methyl-2-nitrobenzoic acid. 3-methylbenzoic acid alkyl ester is used as raw material in nitrification, two-grade selectivity and high yield are realized, and the amount of waste acid was reduced. In nitrification product, only 3-methyl 2-nitrobenzoic acid alkyl ester and 3-methyl-4-nitrobenzoic acid alkyl ester are hydrolyzed after separation to obtain 3-methyl 2-Nitrobenzoic acid and 3-methyl-4-nitrobenzoic acid. The process is simple, and suitable for industrial production.
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- PROCESS TO PREPARE 3-METHYL-2-NITROBENZOIC ACID BY AIR OXIDATION
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A method for preparing 3-methyl-2-nitrobenzoic acid is disclosed wherein 1, 3 -dimethyl-2-nitrobenzene is combined with an oxidation catalayst in the presence of an oxygen source and an initiator, provided that less than 99% of the 1,3 -dimethyl-2- nitrobenzene is oxidized. A method for preparing compounds of Formula 7 and Formula 11 is also disclosed wherein the method is characterized by using 3-methyl-2-nitrobenzoic acid as prepared by the method disclosed above. wherein R1 is C1-C7 alkyl, C3-C6 cycloalkyl or C4-C7 alkylcycloalkyl
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Page/Page column 40; 41; 42
(2016/01/30)
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- An "ortho effect" in electrophilic aromatic nitrations: Theoretical analysis and experimental validation
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Usually, a π-donor substituent acts as an ortho/para directing group in an electrophilic aromatic substitution reaction, and a π-acceptor substituent acts as a meta directing group. Interestingly, when a π-acceptor substituent is meta to a π-donor substituent, certain electrophilic aromatic nitration occurs ortho to the π-acceptor substituent rather than para . The "ortho effect", highlighted in various textbooks, has been tentatively analyzed here based on ab initio calculations. The reliability of the calculations was verified by the corresponding experimental data, including a newly-designed electrophilic aromatic nitration that also gave reasonable product distributions.
- Li, Hui-Jing,Wu, Yan-Chao,Dai, Jian-Hong,Song, Yan,Cheng, Runjiao,Qiao, Yuanyuan
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p. 1307 - 1312
(2015/02/05)
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- A significant improvement in enantioselectivity, yield, and reactivity for the copper-bi-o-tolyl bisoxazoline-catalyzed asymmetric allylic oxidation of cyclic olefins using recoverable SBA-15 mesoporous silica material
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A series of chiral bi-o-tolyl bisoxazoline ligands 1 and 2 were conveniently synthesized on a gram scale from inexpensive and commercially available 3-methyl benzoic acid in eight steps. The catalytic and induced asymmetric effects of the chiral copper (I) complexes of these ligands on the asymmetric allylic oxidation of cycloolefins were investigated in the presence of various nano-sized additives. When SBA-15 mesoporous silica was used in conjunction with these ligands very highly enantioselectivities (up to 97% ee) and excellent yields (up to 99%) of the corresponding chiral allylic esters were obtained in a reasonably short period of time.
- Samadi, Saadi,Nazari, Saber,Arvinnezhad, Hamid,Jadidi, Khosrow,Notash, Behrouz
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p. 6679 - 6686
(2013/07/26)
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- Regioselectivity nitration of aromatics with N2O5 in PEG-based dicationic ionic liquid
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Regioselective mononitration of simple aromatic compounds has been investigated with N2O5 as nitrating agent and a new PEG200-based dicationic acidic ionic liquid (PEG200-DAIL) as catalyst. The results of experiments show that this nitration system can significantly improve the para-selectivity of alkyl-benzenes and the ortho-selectivity of halogenated-benzenes. The PEG200-DAIL exhibits recyclable temperature-dependant phase behavior in CCl4 solvent, and it can be recycled without apparent loss of catalytic activity, and only 5% loss of weight is observed after six times recycling.
- Wang, Peng-Cheng,Lu, Ming
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supporting information; experimental part
p. 1452 - 1455
(2011/05/16)
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- INHIBITORS OF STEAROYL-COA DESATURASE
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Provided herein are compounds of the formula (I): as well as pharmaceutically acceptable salts thereof, wherein the substituents are as those disclosed in the specification. These compounds, and the pharmaceutical compositions containing them, are useful for the treatment of diseases such as, for example, obesity.
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- Aromatic nitration using nitroguanidine and EGDN
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Acid catalyzed nitration has been examined using a variety of novel nitration agents: guanidine nitrate (GN) and nitroguanidine (NQ) as well as the simple nitrate ester, ethylene glycol dinitrate (EGDN). Reactions with either activated or deactivated aromatic substrates proceed rapidly and in high yield. Regioselectivity was similar for all nitrating agents examined. The synthetic advantages of liquid EGDN include high solubility in organic solvents, strong nitration activity and ease of preparation.
- Oxley, Jimmie C.,Smith, James L.,Moran, Jesse S.,Canino, Jonathan N.,Almog, Joseph
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p. 4449 - 4451
(2008/12/21)
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- Urea nitrate and nitrourea: powerful and regioselective aromatic nitration agents
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Urea nitrate (UN) and nitrourea (NU), easily prepared from urea and nitric acid, convert deactivated aromatic compounds to the corresponding nitrated derivatives with a high yield and a high regioselectivity under very mild conditions. The performance of the two reagents is quite similar indicating that NU is an intermediate in the UN nitration process.
- Almog, Joseph,Klein, Asne,Sokol, Anat,Sasson, Yoel,Sonenfeld, Dana,Tamiri, Tsippy
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p. 8651 - 8652
(2007/10/03)
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- Synthesis, Resolution, and Applications of 1,16-Dihydroxytetraphenylene as a Novel Building Block in Molecular Recognition and Assembly
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This paper concerns the synthesis of 1,16-dihydroxytetraphenylene (DHTP) (2) by employing a novel NBS bromination route. (±)-DHTP 2 was successfully resolved into its optical antipodes and converted to (±)-1,16-bis(diphenylphosphino)tetraphenylene (BPTP) (26), whose platinum complex BPTP-PtCl2 (27) was also obtained. As a hydrogen bond donor, racemic and optically active DHTP 2 was allowed to assemble with 4,4′-bipyridine to form single crystals of good quality. X-ray Diffraction studies of these crystals revealed that the crystallographic packing of the hydrogen bonded complex between (±)-2 and 4,4′-bipyridine was different from the one formed from (S)-2 and 4,4′-bipyridine. It was found that an infinite zigzag chain with alternate chirality was formed in the assembly of (±)-2 and 4,4′-bipyridine, while (S)-2 and 4,4′-bipyridine failed to show the same assembly pattern. The reason (±)-2 formed an alternate and zigzag chain with 4,4′-bipyridine was most likely due to the inherent stability of this supramolecular assembly. The chiral recognition between 2 and optically active BINAP under the direction of platinum(II) has also been examined. 1H and 31P NMR spectroscopic studies demonstrated that there was an obvious discrimination of 2 between the enantiomers of BINAP-PtCO3.
- Wen, Jian-Feng,Hong, Wei,Yuan, Ke,Mak, Thomas C. W.,Wong, Henry N. C.
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p. 8918 - 8931
(2007/10/03)
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- Practical Method for the Synthesis and Optical Resolution of Axially Dissymmetric 6,6'-Dimethylbiphenyl-2,2'-dicarboxylic Acid
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Racemic 6,6'-dimethylbiphenyl-2,2'-dicarboxylic acid (1) could be conveniently synthesized and efficiently resolved by the recrystallization of the brucine salts in satisfactory yields.Each enantiomer, thus obtained, was confirmed to be optically pure from a high-performance liquid chromatographic (HPLC) analysis on an optically active column.
- Kanoh, Shigeyoshi,Muramoto, Hiroki,Kobayashi, Natsumi,Motoi, Masatoshi,Suda, Hiroshi
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p. 3659 - 3662
(2007/10/02)
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- Kinetics of Electron Transfer from Nitroaromatic Radical Anions in Aqueous solutions. Effects of Temperature and Steric Configuration
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Rate constants for electron transfer from various nitroaromatic radical anions to other nitroaromatic compounds in aqueous solutions have been determined by kinetic spectrophotometric pulse radiolysis.The rate constants were found to increase from ca. 105 to ca. 108 M-1 s-1 upon increase in driving force (ΔE) from 0 to ca. 300mV, while the activation energies decrease from ca. 6 to ca 3 kcal/mol.Nitro compounds with ortho substituents exhibit lower reduction potentials due to rotation of the nitro group away from the ring plane.Anion radicals of such compounds transfer their electrons much more slowly (k down to ca. 106 M-1 s-1) despite the apparent increase in ΔE (to ca. 550 mV).This behavior is rationalized by an increase in solvent reorganization energies around these radical anions caused by localization of the charge.In general, nitroaromatic radical anions donate electrons much more slowly than other radical anions, in reactions with similar driving forces, due to low self-exchange rates for ArNO2/ArNO-..The kinetics show no anomalies in supercooled solutions.
- Meot-Ner, Michael,Neta, P.
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p. 4648 - 4650
(2007/10/02)
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- Conformational Behaviour of Medium-sized Rings. Part 12. Tri-3-methyltrianthranilide
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The stepwise synthesis of the N,N'-di- and N,N',N''-tri-substituted tri-3-methyltrianthranilides (13)-(19) are described.The amino-acid derivatives (34), (38), and (45), which are the key acyclic precursors in the synthesis of the tri-3-methyltrianthranilides, were all prepared from 2-amino-m-toluic acid (22) and 2-nitro-m-toluoyl chloride as starting materials.Tri-3-methyltrianthranilide derivatives with three equivalent N,N',N''-substituents can exist in either propeller or helical conformations.The N,N',N''-trimethyl derivative (14) adopts enantiomeric helical conformations in solution and the barrier to ring inversion is 26.8 kcal mol-1.The N,N',N''-tribenzyl derivative (19) populates both propeller and helical conformations in solution: these two conformational diastereoisomers have been separated by chromatography and isolated as crystalline compounds.Tri-3-methyltrianthranilide derivatives with two or three non-equivalent N,N',N''-substituents can, in principle, exist in either propeller or three different helical conformations.One of these three helical conformations is specifically populated in deuteriochloroform solution by compounds (13) and (15)-(17).The N,N'-dibenzyl derivative (18) populates the propeller and one helical conformation in solution: two conformational diastereoisomers have been isolated, one as an oil and the other as a crystalline compound.The N,N'-dimethyl-N''-benzyl derivative (15) undergoes spontaneous resolution when it crystallises as a 1:1 adduct from toluene.The N-methyl-N'-benzyl derivative (16) also forms a 1:1 inclusion compound on crystallisation from toluene.Although this derivative exists as only one conformational diastereoisomer of the helical type in deuteriochloroform solution, two different diastereoisomeric conformations undergo equilibration in hexadeuteriodimethyl sulphoxide with a barrier to interconversion of 16.1 kcal mol-1.
- Edge, Simon J.,Ollis, W. David,Stephanatou, Julia Stephanidou,Stoddart, J. Fraser
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p. 1701 - 1714
(2007/10/02)
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- Conformational Behaviour of Medium-sized Rings. Part 10. Dithiosalicylides and Trithiosalicylides
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The trithiosalicylide derivatives (8)-(11) have been synthesised and shown by temperature-dependent 1H n.m.r. spectroscopy to exist in solution as ring inverting (35a)(35b) enantiomeric helical conformations with trans-thioester linkages.The free energies of activation for these conformational changes are ca. 10 kcal mol-1 higher than those for the similar process in the corresponding trisalicylides.In contrast with the trisalicylides, the trithiosalicylides can only ring invert between enantiomeric helical conformations via intermediates containing a cis-thioester linkage.The dithiosalicylide derivatives (3)-(7) have been synthesised; the temperature dependence of the 1H n.m.r. spectrum of di-o-thiothymotide (7) has been interpreted in terms of ring inversion (40a)(40b) between enantiomeric boat conformations.Comparison of the ΔG value of 24.6 kcal mol-1 for this conformational change with that of 17.7 kcal mol-1 previously obtained for di-o-thymotide (41) suggests that cis-thioester linkages are subject to more resonance stabilisation than are cis-ester linkages.
- Guise, G. Bruce,Ollis, W. David,Peacock, Judith A.,Stephanatou, Julia Stephanidou,Stoddart, J. Fraser
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p. 1637 - 1648
(2007/10/02)
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- Process for the production of nitro derivatives of aromatic compounds
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Nitroderivates of aromatic compounds which are difficult to nitrate, can readily be obtained by nitration providing that the aromatic compound is treated with nitric acid or another nitrating agent in the presence of aliphatic or cycloaliphatic hydrocarbons monosubstituted or polysubstituted by halogen, the nitro group or an alkyl sulphonyl group, and the nitro derivative formed subsequently isolated.
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