- Preparation method of tizanidine hydrochloride
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The invention discloses a preparation method of tizanidine hydrochloride, and belongs to the field of medicine preparation. According to the preparation method, 5-chloro-4-amino-2,1,3-benzothiadiazole and 1-acetyl-2-imidazolinone are taken as raw materials, and condensation, alcoholysis and salification are performed, further refining can be performed; then the tizanidine hydrochloride can be prepared. The operation is simpler, more convenient and safer, and the preparation method is more suitable for industrial production. The tizanidine hydrochloride prepared by the method is higher in yield, the obtained tizanidine hydrochloride is also higher in purity; the method has important industrial value, and can protect the supply of the bulk drug tizanidine hydrochloride and benefit the public.
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- Preparation method of imidazoline derivative
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The invention discloses a preparation method of an imidazoline derivative, and particularly relates to a preparation method of tizanidine hydrochloride. The preparation method of the imidazoline derivative comprises the following steps: A, taking a compound II and a compound III, reacting the compound II and the compound III in an organic solvent in the presence of a dehydrating agent, alkalizingand filtering the reaction product to obtain a compound IV; B, hydrolyzing the compound IV obtained in the step A as a raw material to obtain tizanidine shown by formula V; and C, preparing the tizanidine hydrochloride shown in formula I from the tizanidine obtained in the step B as a raw material. The method has high yield and purity simultaneously, is simple and convenient to operate, high in production efficiency, environmentally friendly and safe, is suitable for industrial mass production, and has wide market application prospect.
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- Preparation method for benzothiadiazole derivative
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The invention discloses a preparation method for a benzothiadiazole derivative, and specifically relates to a preparation method for tizanidine hydrochloride. The preparation method includes the following steps: (a) taking a compound II and a compound III or a salt thereof, performing reaction in an organic solvent in the presence of an acid-binding agent, and obtaining an intermediate IV throughalkalization, filtration and refining; and (b) preparing tizanidine hydrochloride shown as a formula I by taking the intermediate IV obtained by step (a) as a raw material. The method is high in yieldand purity, simple in operation, high in production efficiency, environmentally friendly, safe and suitable for industrial mass production, and has wide market application prospects. The preparationsteps are shown in the description.
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Paragraph 0012; 0042; 0044-0045; 0047-0048; 0050-0051; 0053
(2019/04/10)
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- Preparation method of novel central skeletal muscle relaxant
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The invention discloses a preparation method of a novel central skeletal muscle relaxant, and particularly relates to a preparation method of tizanidine hydrochloride. The method includes the following steps that firstly, organic acid A, a compound S1 and a compound S2 serve as raw materials react in an organic solvent X to remove a solvent, and a tizanidine organic acid salt S3 crude product is obtained; secondly, the crude product obtained in the first step is added into organic acid A and an organic solvent Y and dissolved at 50-120 DEG C; thirdly, the temperature is reduced by 50-75 DEG C,heat preservation and crystallization are kept for 2-10 hours, then the temperature is cooled again by 10-30 DEG C, heat preservation is conducted, crystallization continues for 3-10 hours, and tizanidine organic acid salt S3 is obtained; fourthly, the tizanidine organic acid salt S3 obtained in the third step serves as the raw material to prepare tizanidine hydrochloride. According to the method, the yield and purity are high, and the method is easy to operate, high in production efficiency, environmentally friendly, safe and suitable for industrial mass production and has wide market application prospects. The molecular formula is as shown in the description.
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Paragraph 0046-0048; 0055-0060
(2018/03/24)
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- Preparation method of central alpha 2 adrenergic receptor agonist
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The invention relates to a preparation method of a central alpha 2 adrenergic receptor agonist. The invention discloses a preparation method of tizanidine hydrochloride, which comprises the followingsteps of: (1) taking organic acid A, a compound S1 as shown in the specification and a compound S2 as shown in the specification as raw materials for reaction in an organic solvent, separating out a solid to form tizanidine organic acid salt S3 as shown in the specification, and (2) preparing tizanidine hydrochloride by taking the tizanidine organic acid salt S3 obtained in step (1) as a raw material, wherein the organic acid A is formic acid, dichloroacetic acid, glycolic acid, maleic acid, fumaric acid, tartaric acid, caproic acid or benzoic acid; R1 is hydrogen, methyl, acetyl, propionyl, benzoyl, tertiary butyl methyl carbonyl or COOR2; and R2 is methyl, ethyl, allyl, benzyl, tertiary butyl or phenyl. The method achieves higher productivity and purity, is easy and simple to operate, high in production efficiency, environment-friendly, safe and applicable to industrial mass production and has broad market application prospects.
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- Decolorizing method of tizanidine
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The invention relates to a decolorizing method of tizanidine, and belongs to the field of pharmaceutical chemistry. The brand new decolorizing method of tizanidine is provided to solve the problem of poor solubility of tizanidine and tizanidine hydrochloride. The method is characterized in that tizanidine reacts with an organic acid to form a corresponding organic salt compound in order to improve the solubility of the compound. The method concretely comprises the following steps: 1, adding tizanidine into a solvent, adding the organic acid, and carrying out a reaction to obtain a crude organic acid salt of tizanidine; and 2, adding the obtained crude organic acid salt of tizanidine into the solvent, adding the organic acid and a hydrochloric acid solution, carrying out a reaction, carrying out cooling crystallization, and filtering obtained crystals to obtain tizanidine hydrochloride. The decolorizing method avoids the problem of difficult purification of tizanidine and tizanidine hydrochloride because of the poor solubility, allows recrystallization to be carried out through forming a new substance with good solubility by changing the acid form, so the tizanidine hydrochloride with high yield and high purity is obtained, and the use amount of the solvent is significantly reduced.
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Paragraph 0038-0040; 0041-0043; 0044-0046
(2017/08/31)
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