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Preparation method of dibazol hydrochloride
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A technology of dimethazole hydrochloride and phenylacetic acid, applied in the direction of organic chemistry, can solve the problems of equipment corrosion, low reaction yield, high production cost, etc., to save production cost, increase reaction rate, and avoid high corrosiveness Effect
Inactive Publication Date: 2012-07-25
ZHEJIANG MEDICINE CO LTD XINCHANG PHAMACEUTICAL FACTORY
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[0005] The disadvantages of this process are as follows: during the condensation reaction, the temperature rises to dehydrate, the temperature is high, the acidity is strong, and the equipment is corroded seriously, so there are serious safety hazards; Large pollution; low reaction yield, high energy consumption and high production cost
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Embodiment 1
[0020] Embodiment 1: the preparation of dimethazole hydrochloride (1)
[0021] Put o-phenylenediamine (2) (108g, 1mol), phenylacetic acid (3) (136g, 1mol), DCC (408g, 2mol) and ethylene glycol (108mL) into a 1000mL three-necked flask, heat up to 120°C, and keep warm React for 1.5 hours. After completion of the reaction, cool, filter with suction, and recover the solvent ethylene glycol (90 mL) from the filtrate. Add the residue to deionized water (1000mL) to dissolve, adjust the pH to 4.6-4.8 with hydrochloric acid, add activated carbon, decolorize and filter at 70-80°C, and cool the filtrate to crystallize and dry to obtain dimethazole hydrochloride (1), 215.4g, yield 88%. mp: 172-176°C.
Embodiment 2
[0022] Embodiment 2: the preparation of dimethazole hydrochloride (1)
[0023] Put o-phenylenediamine (2) (10.8g, 0.1mol), phenylacetic acid (3) (16.3g, 0.12mol), EDC.HCl (38.3g, 0.2mol) and 1,2-propanediol in a 500mL three-necked flask (216mL), the temperature was raised to 100°C, and the reaction was incubated for 1 hour. After completion of the reaction, cool and filter with suction, and recover the solvent 1,2-propanediol (180 mL) from the filtrate. Add the residue to deionized water (100mL) to dissolve, adjust the pH to 4.6-4.8 with hydrochloric acid, add activated carbon, decolorize and filter at 70-80°C, and cool the filtrate to crystallize and dry to obtain dimethazole hydrochloride (1), 22g, yield 89.9 %. mp: 172-176°C.
Embodiment 3
[0024] Embodiment 3: the preparation of dimethazole hydrochloride (1)
[0025] In a 1000mL three-necked flask, drop into o-phenylenediamine (2) (108g, 1mol), phenylacetic acid (3) (149.6g, 1.1mol), CDI (324.3g, 2mol) and glycerol (150mL), and heat up to 100 °C, keep the reaction for 2 hours. After completion of the reaction, cool and filter with suction, and recover the solvent glycerol (120 mL) from the filtrate. The residue was dissolved in deionized water (1000mL), adjusted to pH 4.6-4.8 with hydrochloric acid, added activated carbon, decolorized and filtered at 70-80°C, and the filtrate was cooled, crystallized and dried to obtain dimethazole hydrochloride (1), 195.6g, yield 80%. mp: 172-176°C.
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Abstract
The invention provides a preparation method of dibazol hydrochloride, comprising the following steps of: dissolving o-phenylenediamine and phenylacetic acid into an alcoholic solvent, adding a dehydrating agent, increasing the temperature to 100-130 DEG C, and keeping the temperature for reaction; cooling a reaction solution to room temperature, filtering, decompressing filter liquor, and recovering the solvent till drying; adding water to dissolve, regulating pH, adding active carbon to decolor and filter, and cooling, crystallizing and drying the filter liquor to obtain the dibazol hydrochlorides, wherein the dehydrating agent is dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylamino propyl) carbon diimide hydrochloride, N, N-carbonyl diimidazole and n-propyl phosphoric anhydride. The invention uses the alcoholic solvent as a catalyst and a solvent of condensation reaction and adopts the low-cost dehydrating agent, thereby preventing high corrosion of strong acid used as the catalyst,greatly reducing the temperature of the reaction, enhancing the reaction rate and shortening the reaction time; and in addition, the reaction solvent can be recycled, thus the production cost is saved.
Description
technical field [0001] The invention belongs to the field of organic chemistry, in particular to a preparation method of dimethazole hydrochloride. Background technique [0002] The chemical name of dimethazole hydrochloride is 2-benzylbenzimidazole hydrochloride, and its structural formula is: It is white crystalline powder, odorless, soluble in hot water and ethanol. Slightly soluble in water and acetone, almost insoluble in chloroform and benzene. As a smooth muscle relaxant, it has a direct relaxation effect on vascular smooth muscle and is used for hypertension, angina pectoris and cerebral vasospasm; it is also used for neuropoliomyelitis, peripheral facial paralysis, mononeuritis and multiple neuritis. [0003] At present, the production process of domestic manufacturers is to use o-phenylenediamine and phenylacetic acid as raw materials, and hydrochloric acid as a catalyst to condense to obtain dimethazole hydrochloride (compilation of national raw material drug p...
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Patent Type & Authority Patents(China)
IPC IPC(8): C07D235/08
Inventor 曹瑞伟陈文霞陈建辉
Owner ZHEJIANG MEDICINE CO LTD XINCHANG PHAMACEUTICAL FACTORY
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