9results about How to "Three wastes less" patented technology

The application belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 4-bromopyrazole [3,4-D] -pyrimidine, and the specific steps are as follows: under the condition of anhydrous and anaerobic, 4-chloro-1H-pyrazolo [3,4-d] pyrimidine is reacted with a brominating reagent in an aprotic solvent to obtain 4-bromopyrazole [3,4-D] -pyrimidine. The preparation method provided by the application has the advantages of simple process route, clear steps, high yield of the target product, low cost, suitability for industrial production, considerable economic benefits, mild reaction condition and environmental protection.

This invention provides a simple and environmentally friendly method for synthesizing 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid ester. Unlike the conventional method of first converting excess carboxylic acid to the corresponding acyl chloride using thionyl chloride, removing the excess thionyl chloride, adding fresh solvent, and then adding the corresponding alcohol to form the ester, this method uses the following order of addition: thionyl chloride → ethylene glycol monomethyl ether → thionyl chloride → ethylene glycol monomethyl ether. The thionyl chloride and ethylene glycol monomethyl ether are added alternately. Under a certain amount of solvent, the generated ester is cleverly utilized to promote the dissolution of the acyl chloride, while simultaneously reducing the absolute content of the acyl chloride in the solution. This allows the reaction mixture to form a solution state, promoting complete conversion of the carboxylic acid and driving the reaction forward. This avoids the defect of the carboxylic acid raw material being encapsulated due to the poor solubility of the intermediate, resulting in incomplete reaction.

This invention discloses a method for synthesizing geranialdehyde, comprising the following steps: Citral undergoes an isomerization reaction under the action of a catalyst; after the reaction, a post-treatment is performed to obtain a product rich in geranialdehyde; the catalyst includes a noble metal catalyst and an organophosphorus ligand; the noble metal catalyst is a palladium salt. This preparation method can effectively realize the conversion of nerol to geranialdehyde, and the reaction process generates relatively little waste, is environmentally friendly, fully utilizes the raw materials, and produces no waste gas.

This invention relates to a method for preparing 2',4-dichloro-2-aminodiphenyl ether, belonging to the field of chemical synthesis technology. The preparation method is as follows: S1, m-dinitrobenzene undergoes selective hydrogenation to obtain m-nitroaniline; S2, in a solvent, m-nitroaniline reacts with N-chlorosuccinimide to obtain 2-chloro-5-nitroaniline; S3, 2-chloro-5-nitroaniline, o-nitrophenol, a base, and a solvent undergo a co-heated reaction to obtain 2',4-dinitro-2-aminodiphenyl ether; S4, 2',4-dinitro-2-aminodiphenyl ether is dissolved in a solvent, and FeCl3 solution, sodium chloride, and Oxone are added. The reaction is catalyzed under ultraviolet light to obtain 2',4-dichloro-2-aminodiphenyl ether. The preparation method of this invention uses readily available raw materials, has good reaction efficiency, produces less waste, is cleaner and more environmentally friendly, and has a high conversion rate, making it suitable for industrial application.

The application discloses a preparation method of N1,N2-dimethyl benzene-1,2-diamine and belongs to the technical field of medical intermediate preparation. The method comprises the following steps: taking o-phenylenediamine as a raw material, reacting with ethyl formate, then adopting dimethyl sulfate to perform a nitrogen-methylation reaction, and finally removing a formyl group under the action of an acid to obtain N1,N2-dimethyl benzene-1,2-diamine. In the method, all raw materials can be conveniently purchased on the market, the process of each reaction is simple, there is no expensive catalyst, the yield is high, and the industrialized production is easy.

The application discloses a one-pot preparation method of 3,4,5-trifluorobromobenzene. In an organic solvent, 2,6-difluoroaniline is used as raw material to obtain the product 3,4,5-trifluorobromobenzene through three steps of bromination, diazotization and fluorination at a certain temperature. The method has the advantages of multiple raw material sources, obvious cost advantage, safety and convenience, high total yield, less waste and the like, and is beneficial to industrialization.

This invention relates to a continuous flow synthesis method for hydroquinone, a chemical and pharmaceutical intermediate, belonging to the field of chemical intermediate synthesis. The method for preparing hydroquinone uses phenol as a starting material, which undergoes oxidation to obtain p-benzoquinone, followed by hydrogenation reduction to obtain hydroquinone. Both steps are performed in a microreactor system. The synthesis method includes the following steps: (1) Phenol, catalyst 1, and organic solvent are prepared as component A, and an oxidant is used as component B. A and B react in a microchannel reactor 1 to obtain intermediate I benzoquinone; (2) Intermediate I benzoquinone is mixed with an organic solvent and reacted with hydrogen in a microchannel reactor 2 under the action of catalyst 2 to obtain hydroquinone. This invention utilizes a microreactor system with excellent heat and mass transfer performance, significantly shortening the reaction time. Both steps are completed within 50 minutes, and the reaction efficiency is high, energy consumption is low, safety is high, automation is high, and the environment is environmentally friendly.

The process described in this application uses ethyl N-Cbz-4-oxo-3-pyrrolidinecarboxylate and Wittig reagent ethyltriphenylphosphine iodide as the starting points for synthesis. First, ethyl N-Cbz-4-oxo-3-pyrrolidinecarboxylate undergoes a nucleophilic addition reaction with Wittig reagent ethyltriphenylphosphine iodide to generate an olefin. Then, it undergoes a hydrolysis reaction under alkaline conditions to generate an acid, followed by a double bond reduction reaction under catalytic hydrogen conditions. The process is reasonable, has high yield, is simple to operate, and has low production cost, which is conducive to large-scale industrial production and fills a technological gap in related fields.

This application discloses a method for synthesizing thiazolinyl dithioalkyl sulfonate, relating to the field of chemical synthesis. The method includes the following steps: mixing 2-mercaptothiazoline, polydithioalkyl sulfonate, and a solvent to obtain a mixture; adding an alkaline catalyst to the mixture; reacting and then separating and purifying to obtain the thiazolinyl dithioalkyl sulfonate; the general structural formula of the polydithioalkyl sulfonate is: ; where M is an alkali metal ion and n is an integer from 1 to 5. This invention uses 2-mercaptothiazoline and polydithioalkyl sulfonate as raw materials, and performs an alkaline-catalyzed thiol / disulfide exchange reaction. Through a precipitation-crystallization purification process, it is beneficial to improve the yield (≥90%) and purity (≥98%) of the synthesized thiazolinyl dithioalkyl sulfonate. It has advantages such as convenient process, good safety, low waste, high atom economy efficiency, and ease of scale-up production.