6 results about "Methoxyamine" patented technology

The invention provides a preparation process for co-production of methoxyamine hydrochloride and N, O-dimethyl hydroxylamine hydrochloride. Comprising the steps of aminolysis, methylation reaction, extraction separation, primary hydrolysis, distillation, dehydration and recrystallization of a first product, secondary hydrolysis, dehydration and recrystallization of a second product and the like. According to the invention, methoxyamine hydrochloride and N, O-dimethyl hydroxylamine hydrochloride can be prepared at the same time, and reaction conditions can be greatly widened, so that high-efficiency and high-yield production is realized, and meanwhile, the product purity is greatly improved; through the coproduction design, the equipment utilization rate is high, the cost is greatly reduced, the recovery rate of solution substances such as methyl acetate, dichloromethane, toluene, methanol and isopropanol is greater than or equal to 90%, the wastewater is circulated and zero discharged after being treated, only a small amount of common industrial waste salt is used as solid waste, the hazardous waste amount is greatly reduced, and the effect of environmental protection is achieved.

The invention discloses a method for synthesizing methoxyamine hydrochloride, which comprises the following steps of: adding sodium nitrite into acetylacetone under an acidic condition to synthesize 2, 3, 4-pentanetrione oxime; adjusting the reaction liquid to be alkaline, and adding a phase transfer catalyst and a methylation reagent to synthesize 3-(O-methyl oxime)-2, 3, 4-pentanetrione; and adjusting the reaction liquid to be strongly acidic, hydrolyzing, and rectifying to recover pentane-2, 3, 4-triketone, thereby obtaining the methoxyamine hydrochloride. According to the method, acetylacetone is adopted as a synthesis raw material, only an organic solvent is used for extracting an intermediate product before rectification, inorganic salt in reaction liquid is separated, the problem of recovery of difficult-to-recover substances such as ethyl alcohol and acetic acid is solved, the synthesis route is simple, operation is easy and convenient, aftertreatment is convenient, few hazardous waste is generated, investment cost is low, and labor cost and energy consumption are reduced; meanwhile, side reactions in the hydrolysis process can be reduced, and the yield of the product is improved.

This invention relates to a method for synthesizing the sitafloxacin intermediate 5-benzyl-7(S)-tert-butoxycarbonylamino-5-azaspiro[2,4]heptane. The method uses 1-benzylmethylpyrrolidine-2,4-dione as the starting material and proceeds through five steps: cyclization, oxime formation, chiral asymmetric reduction, salt formation, and amino protection to obtain the target product. Specifically, the cyclization reaction uses an alkylating agent and a base to construct a spirocyclic structure; the oxime reaction introduces a methoxyimino group via methoxyamine hydrochloride; the chiral asymmetric reduction uses a catalytic system composed of a chiral ligand and a boron reagent to construct the chiral center, followed by purification via maleic acid salt formation; and finally, the amino group is protected with di-tert-butyl dicarbonate to obtain the target product. This invention offers high atom economy, good process scalability, simple operation, controllable cost, and high product purity, providing a reliable intermediate synthesis scheme for the efficient preparation of sitafloxacin active pharmaceutical ingredient.

The application discloses a method for cleaning the surface pollution of a polyamide composite membrane and simultaneously repairing the water flux and salt retention rate of the polyamide composite membrane, and the method comprises the following steps: step 1, under normal temperature conditions, immersing a polyamide composite membrane damaged by oxidation of active chlorine substances into a repairing solution, wherein the repairing solution is composed of a methoxyamine salt and a metal catalyst; the methoxyamine salt is one or a combination of two or more of methoxyamine hydrochloride, methoxyamine sulfate, methoxyamine phosphate, methoxyamine acetate, methoxyamine trifluoroacetate, methoxyamine formate, methoxyamine methanesulfonate, methoxyamine trifluoromethanesulfonate and methoxyamine p-toluenesulfonate; and step 2, after 2-5 hours of repairing, taking out the polyamide composite membrane and washing away the residual repairing solution with water. The method can clean and remove the inorganic scaling, organic matter and other pollutants on the surface of the polyamide composite membrane while repairing the water flux and salt retention rate of the polyamide membrane damaged by sodium hypochlorite oxidation.

The application provides a synthesis method of relugolix, comprising the following steps: reacting compound 2 with di-tert-butyl dicarbonate to obtain compound 3; reacting compound 3 with dibromohydantoin to obtain compound 4; reacting compound 4 with dimethylamine hydrochloride to obtain compound 5; hydrolyzing compound 5 to obtain compound 6; condensing compound 6 with 6-methoxy-3-aminopyridazine to obtain compound 7; deprotecting the amino group of compound 7 to obtain compound 8; performing reductive amination on compound 8 with 2,6-difluorobenzaldehyde to obtain compound 9; performing nitro reduction on compound 9 to obtain compound 10; and reacting compound 10 in the presence of carbonyldiimidazole and methoxyamine hydrochloride to obtain relugolix. The synthesis method is more efficient than prior art, avoids potential genotoxic impurities in the prior art, has mild process conditions, high reaction yield in each step, effectively reduces industrial production cost and safety risk, and is suitable for industrial production.

This invention relates to the field of organic synthesis technology and discloses a high-yield synthesis method for benzofuran-2,3-dione 3-(O-methyloxime)2-oxime. The method uses o-hydroxyacetophenone as the starting material and includes the following steps: Step 1, the starting material is refluxed with N,N-dimethylformamide dimethyl acetal in an aromatic hydrocarbon solvent to obtain an enamine ketone intermediate; Step 2, the enamine ketone intermediate is nitrosated and oxidatively cyclized using sodium nitrite and tert-butyl nitrite in a ketone solvent; Step 3, the cyclized product is reacted with methoxyamine hydrochloride in an alcohol solvent to obtain the target product. This invention avoids the use of hazardous reagents such as sodium hydride and concentrated nitric acid by constructing an enamine ketone intermediate and employing a mild two-component nitrosation system. The reaction conditions are mild, and post-processing only requires solid-liquid separation. This method has the advantages of high yield, good purity, high safety, and simple operation, making it suitable for industrial production.