- Preparation method of methoxamine hydrochloride degradation impurities
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The invention discloses a preparation method of a methoxamine hydrochloride degradation impurity, and the method comprises the following steps: 1, adding a methoxamine hydrochloride impurity into a reaction flask, and adding a hydrolysis reagent, an alkylation reagent, a protective agent, a deprotection reagent and a nitric acid reagent; 2, performing reacting at 40-60 DEG C for 1-3 hours, and adding 100ml of extracting agent for extracting; 3, carrying out the organic layer concentration drying and column chromatography, and obtaining the treated impurities. According to the preparation method, 2-hydroxy-5-methoxyacetone is taken as a raw material and is subjected to multiple process treatments of alkylation, acylation, oximation and hydrolysis, so that the stability of an intermediate of the obtained methoxamine hydrochloride is improved, and impurities of the methoxamine hydrochloride can be degraded.
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Paragraph 0014; 0026-0027
(2021/05/08)
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- A salt structure the armor oxygen is bright erythro method for the preparation of acid
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A disclosed preparation method for erythro-structure methoxamine hydrochloride comprises the following steps: (1) dissolving an initial raw material 2,5-dimethylpropiophenone in an organic solvent, under the condition of introducing dry hydrogen chloride gas, dropwise adding a 1-butyl nitrite solution to perform an oximation reaction, so as to obtain an intermediate I; (2) under the acidic condition, taking a methanol solution as a solvent, take palladium on activated carbon as a catalyst, employing hydrogen to reduce the oximido group in the intermediate I, so as to obtain an intermediate II; and (3) performing hydrogenation reduction reaction on the intermediate II to obtain the erythro-structure methoxamine hydrochloride. The method provided by the invention is simple in operation, economic, environment-friendly, mild in reaction conditions, excellent in product quality and high in yield, and can help to obtain the single erythro-structure methoxamine hydrochloride.
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Paragraph 0038; 0039; 0040
(2017/03/28)
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