- A practical synthesis of 2,4-dichloro-3-methyl-6-nitrophenol
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2,4-Dichloro-3-methyl-6-nitrophenol 2 was prepared by KOH/H2O hydrolysis of a product mixture obtained from chlorination of p-nitrotoluene in the presence of a phase transfer catalyst. A 95-99% yield of 2 based on 2,3,6-trichloro-4-nitrotoluene, 4 (major chlorination product) was achieved in >95% purity.
- Ran,Pittman Jr.
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- Novel preparation method of mosapride
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The invention discloses a novel preparation method of mosapride.Cheap 2-chlorotoluene is used as an initial raw material is subjected to nitration, nucleophilic substitution, free radical bromination, chlorination, alkylation, nitro reduction and oxidative amidation to synthesize mosapride. According to the scheme, raw materials are easy to obtain, dangerous processes and highly toxic reagents are avoided, the method is green and environment-friendly, oxidation amidation is adopted, selectivity is achieved, formation of aromatic amide by-products is avoided, and the yield is high.
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Paragraph 0033-0036
(2021/08/07)
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- 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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- Method for catalytic nitration of o-chlorotoluene by using modified beta zeolite
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The invention discloses a method for catalytic nitration of o-chlorotoluene by using modified beta zeolite. The method comprises the following steps: while stirring, adding a solvent into a container,then sequentially adding o-chlorotoluene, acetic anhydride, fuming nitric acid, a modified beta zeolite molecular sieve catalyst and silicon dioxide loaded perfluorinated sulfonic acid resin; performing heating reflux for 1-9h before terminating the reaction. According to the method disclosed by the invention, acetic anhydride is applied to a nitration process of o-chlorotoluene; compared with anitration process of o-chlorotoluene using nitric-sulfuric acid, the use of strong acid sulfuric acid is avoided, and the treatment amount of waste acid is reduced; meanwhile, the silicon dioxide loaded perfluorinated sulfonic acid resin is adopted, with the perfluorinated sulfonic acid resin dispersed in a SiO2 network or pore channel; since the effective surface area is greatly increased, the acid site of the perfluorinated sulfonic acid resin is fully exposed, the potential of the resin catalyst is totally played, and the conversion rate and yield are increased; moreover, the modified zeolite molecular sieve catalyst Bibeta provides an acid center and a pore channel structure as well as shape selecting catalysis, the reaction selectivity is improved, the yield reaches 85.4%, and the selectivity of 2-chloro-4-nitrotoluene is up to 84.6%; the method is easy to operate and control and is a green and environment-friendly o-chlorotoluene nitration method.
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Paragraph 0024-0043
(2018/11/03)
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- O-chlorotoluene catalytic nitration method by using microwaves for assisting zeolite
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The invention discloses an o-chlorotoluene catalytic nitration method by using microwaves for assisting zeolite. The method comprises the following steps of adding solvents into a container; sequentially adding o-chlorotoluene, acetic anhydride, nitrosonitric acid, modified zeolite molecular sieve catalysts and silicon dioxide loaded perfluorinated sulfonic acid resin; performing microwave temperature rise for 4 to 12min; performing heat insulation for 8 to 10min; terminating the reaction. The microwave technology is applied to the o-chlorotoluene nitration process; the reaction progress is greatly accelerated; meanwhile, silicon dioxide is used for loading perfluorinated sulfonic acid resin; the perfluorinated sulfonic acid resin is dispersed into SiO2 networks or pore passages; the effective surface area is greatly increased, so that the acid positions of the perfluorinated sulfonic acid resin are sufficiently exposed, so that the potential of the resin catalyst is achieved; the conversion rate and the yield are improved; in addition, the modified zeolite molecular sieve catalyst Bibeta provides acid centers and pore passage structures; the shape selection catalyst effect is provided; the reaction selectivity is improved; the yield is as high as 80.9 percent; the selectivity of the 2-chloro-4-nitrotoluene is as high as 84.1 percent. The method has the advantages that the operation is easy; the energy is saved; the efficiency is high; the control is easy; the method belongs to a green and environmental-friendly o-chlorotoluene nitration method.
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Paragraph 0024-0045
(2018/11/03)
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- Reaction of dimethyldioxirane with aniline hydrohalides
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Oxidation of aromatic amine hydrohalides (aniline hydrochloride, hydrobromide, and hydrofluoride; 4-methylaniline hydrochloride and hydrobromide; 3-methylaniline and N,N-diethylaniline hydrochlorides) with dimethyldioxirane was studied. The product composition was analyzed in relation to the reactant ratio.
- Ivanova,Grabovskii,Kabal'nova,Shereshovets
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p. 2101 - 2105
(2007/10/03)
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- Palladium-catalyzed cross-methylation of aryl chlorides by stabilized dimethylaluminium and -gallium reagents
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Two methods for palladium-catalyzed cross-methylation of aryl chlorides by intramolecularly stabilized dialkylaluminium and -gallium complexes 6-13 have been studied. In one method, in which either tetrakis(triphenylphosphine)palladium (1) or dichloro- bis(triphenylphosphine)palladium (2) is used as the catalyst at 80-90°C, the activation of the chlorine atom is affected by introduction of strong electron-withdrawing groups into the aromatic moiety. The second method is based on the application of either [1,3- bis(diisopropylphosphino)propane)]palladium (4) or homologous electron-rich palladium complexes as catalysts. Although 4 promotes smooth cross-alkylation of aryl chlorides it fails to activate simple aryl bromides.
- Blum, Jochanan,Berlin, Olga,Milstein, David,Ben-David, Yehoshua,Wassermann, Birgit C.,Schutte, Stefan,Schumann, Herbert
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p. 571 - 575
(2007/10/03)
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- A novel method for the nitration of simple aromatic compounds
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Simple aromatic compounds such as benzene, alkylbenzenes, halogenobenzenes, and some disubstituted benzenes are nitrated in excellent yields with high regioselectivity under mild conditions using zeolite β as a catalyst and a stoichiometric quantity of nitric acid and acetic anhydride. The zeolite can be recycled, and the only byproduct is acetic acid, which can be separated easily from the nitration product by distillation; the process is inexpensive and represents an attractive method for the clean synthesis of a range of nitroaromatic compounds. For example, nitration of toluene gives a quantitative yield of mononitrotoluenes, of which 79% is 4-nitrotoluene; fluorobenzene gives a quantitative yield of mononitro compounds, of which 94% is 4-nitrofluorobenzene; and 2-fluorotoluene gives a 96% yield of mononitro products, of which 90% is the 5-nitro isomer and 10% is the 4-nitro isomer.
- Smith, Keith,Musson, Adam,DeBoos, Gareth A.
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p. 8448 - 8454
(2007/10/03)
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- Process for the preparation of 2-chloro-4-nitro-alkylbenzene
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In the preparation of 2-chloro-4-nitro-alkylbenzene by reaction of 4-nitro-alkylbenzene with elemental chlorine or chlorine-releasing compounds in the presence of a Friedel-Crafts catalyst in the liquid phase, particularly high selectivities in respect of the target compounds chlorinated exclusively in the 2-position are achieved if a dibenzo-condensed sulphur heterocycle of the formula STR1 having the meanings given in the description for R1 to R8, X and n, is used as co-catalyst.
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- Synthesis of 4-Aminobenzoic Aldehydes.
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In the reported research program, studies have been carried out on the reaction of oxidation-reduction of 4-nitrotoluene (NT) and 2-chloro-4-nitrotoluene (CNT) resulting in aminobenzaldehydes and toluidines, respectively. The optimum conditions have been elaborated (the ratio of S:Na//2S and Na//2S//x:nitrotoluene) of carrying on the processes enumerated. It has been established that introduction of a halide in ortho position of methyl group in 4-nitrotoluene brings about a considerable acceleration of the oxidation-reduction reaction leading to aminoaldehyde, but without any influence of the rate of reduction in the result of which toluidine is obtained.
- Witek,Bielawski,Bielawska
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p. 243 - 246,244, 245
(2007/10/16)
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- 2-Aryl-3,4-diphenylisoxazolin-5-ones
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Contacting of appropriately substituted nitrosobenzene with diphenylcyclopropenone under reflux conditions yields novel 2-aryl-3,4-diphenylisoxazolin-5-ones, which are useful as pharmacological agents in view of their serum triglyceride and cholesterol lowering properties.
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