- Preparation method of 4-chloro-2, 5-dimethoxyaniline
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The invention relates to the technical field of organic synthesis, and particularly discloses a preparation method of 4-chloro-2, 5-dimethoxyaniline. The preparation method comprises the following steps that in the presence of a supported nickel catalyst, ethyl alcohol serves as a solvent, 4-chloro-2, 5-dimethoxynitrobenzene reacts with hydrazine hydrate, the 4-chloro-2, 5-dimethoxyaniline is obtained through separation from reaction liquid, and a carrier of the supported nickel catalyst is a TiO2-Al2O3 composite carrier. According to the preparation method of the 4-chloro-2, 5-dimethoxyaniline, provided by the invention, the use of a dehalogenation inhibitor and hydrogen can be effectively avoided, the process is simple, the operation is convenient, the preparation method is green and environment-friendly, safe and reliable, the cost is relatively low, and the product yield is greater than or equal to 95%.
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Paragraph 0022; 0025-0026; 0029-0030; 0033-0040
(2020/02/14)
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- A process for preparing 2, 5 - dimethoxy - 4 - chloroaniline method
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The invention provides a method for preparing 2, 5-dimethoxy-4-chloroaniline. The method comprises the following steps: in the presence of a nickel-based amorphous alloy catalyst, contacting 2, 5-dimethoxy-4-chloronitrobenzene with hydrogen-containing gas to obtain a mixture and separating 2, 5-dimethoxy-4-chloroaniline from the contacted mixture. By the method provided by the invention, the conversion rate of 2, 5-dimethoxy-4-chloronitrobenzene is high, and 2, 5-dimethoxy-4-chloroaniline is high in selectivity and is environment friendly and has very good industrial application prospects.
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Paragraph 0070; 0071; 0072; 0073; 0074; 0075; 0076-0085
(2017/11/22)
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- Method for continuous hydrogenation production of 4-chloro-2,5-dimethoxyaniline
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The invention discloses a method for industrial continuous hydrogenation synthesis of 4-chloro-2,5-dimethoxyaniline. According to the method, 4-chloro-2,5-dimethoxy nitrobenzene and hydrogen are taken as raw materials, methyl alcohol is used as reaction solvent, methyl alcohol and a catalyst are added into a reduction kettle, and the raw materials 4-chloro-2,5-dimethoxy nitrobenzene and hydrogen are added too for reduction reaction; reaction of reaction liquid continues in a second reduction kettle and a third reduction kettle till conversion rate reaches 100%, and then the reaction liquid is crystallized to obtain the product. Reduction reaction is achieved through the three reduction kettles connected in sequence, raw material contact time is long, and raw material conversion rate can reach 100%; the obtained product is white powder, chromatographic purity is 99% or more, content is 99% or more and yield is 97% or more.
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Paragraph 0021; 0022; 0023; 0024; 0025; 0026
(2016/12/16)
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- Method for synthesizing 2,5-dimethoxy-4-chloroaniline
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The invention relates to a method for synthesizing 2,5-dimethoxy-4-chloroaniline. The method comprises the steps: in the presence of carbon oxide and water, performing the reaction in an organic solvent under a high temperature and high pressure by adopting 2,5-dimethoxy-4-chloro-nitrobenzene as a raw material, selenium as a catalyst and organic alkali or inorganic alkali as an assistant catalyst, and reducing the nitro to amino to synthesize the 2,5-dimethoxy-4-chloroaniline. The method adopts high-pressure reaction and one-pot reaction, so that less equipment investment is needed, the operation is simple and convenient, and a product is relatively easy to separate and purify.
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Paragraph 0010; 0020; 0021; 0022; 0023; 0024
(2016/11/21)
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- A hydrazine hydrate and catalytic reduction process for preparing 4 - chloro - 2, 5 - two-anisidine production process (by machine translation)
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A hydrazine hydrate and catalytic reduction process for preparing 4 - chloro - 2, 5 - two-anisidine production process, the reaction vessel is sequentially added in the water, FeCl3·6H2OandFeSO4·7H2O, adding activated carbon, dropping NaOH solution to adjust pH value, for filtering and washing the filter cake to make theFe (OH) 3clay, crushing and drying to obtain the catalyst; sequentially added to the reaction kettle in ethanol solvent, 4 - nitro - 2, 5 - dimethoxy chlorobenzene and the catalyst, uniform drop water [...] solution, for HPLC detection reaction process, until the 4 - nitro - 2, 5 - dimethoxy chlorobenzene is completely reduce the hydrazine hydrate, the temperature of the filter when the system, separate out the target product 4 - chloro - 2, 5 - two-anisidine, filtering the solution of catalyst to continue to apply the filter residue; the production of the catalyst are cheap, high catalytic efficiency, stable catalytic activity, environmental protection and pollution-free, the produced 4 - chloro - 2, 5 - two-anisidine high yield, high purity, and the quality is stable. (by machine translation)
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Paragraph 0033; 0034
(2017/06/19)
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- Synthetic studies on lactonamycins: Synthesis of the model BCDEF aglycon
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The lactonamycin model aglycon 4 was synthesized from the trihalogenated benzene derivative 10. Ethynyltetraol 6 was prepared from 10 via carbon elongations, oxidative demethylation, a cycloaddition reaction with the diene derived from homophthalic anhydride, and dihydroxylation. Final E- and F-ring constructions from 6 were realized via a palladium-catalyzed cyclization-methoxycarbonylation, a stereoselective methanol addition, and lactonization, leading to the production of 4.
- Watanabe, Kana,Iwata, Yusuke,Adachi, Satoshi,Nishikawa, Tomoyuki,Yoshida, Yuko,Kameda, Shunsuke,Ide, Mitsuaki,Saikawa, Yoko,Nakata, Masaya
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supporting information; experimental part
p. 5573 - 5579
(2010/11/05)
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- Synthesis of quinones from hydroquinone dimethyl ethers. Oxidative demethylation with cobalt(III) fluoride
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The oxidative demethylation of 1,4-dimethoxynaphthalene and 1,4- dimethoxybenzene derivatives with cobalt(III) fluoride proceeded in good to excellent yield to afford the corresponding naphthoquinone and benzoquinone derivatives.
- Tomatsu, Ayumi,Takemura, Syunji,Hashimoto, Kimiko,Nakata, Masaya
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p. 1474 - 1476
(2007/10/03)
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- A concise total synthesis of (±)-A80915G, a member of the napyradiomycin family of antibiotics
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(±)-A80915G, a member of the napyradiomycin family of antibiotics, has been synthesized from 1-amino-2,5-dimethoxy-4-nitrobenzene via the sequential palladium-catalyzed cross-coupling reactions (the Stille reaction) of aryl halides with allyltins and the Diels-Alder reaction of the chloroquinone with the Danishefsky-Brassard diene.
- Takemura, Shunji,Hirayama, Aya,Tokunaga, Junko,Kawamura, Fumie,Inagaki, Kyoko,Hashimoto, Kimiko,Nakata, Masaya
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p. 7501 - 7505
(2007/10/03)
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