Preparation method of benzimidazole compound
A technology of benzimidazoles and compounds, applied in the field of pharmaceutical chemical synthesis, can solve the problems of reducing the yield of benzimidazoles, increasing the cost of purification, and long process time, so as to reduce the production of impurities, improve the yield, and improve the process. simple effect
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[0034] The invention provides a kind of preparation method of benzimidazole compound, such as figure 1 As shown, the benzimidazole compound has the structural formula VIII, and the preparation method comprises the following steps: (1) oxidizing the compound A of the structural formula V into the compound C of the structural formula VI; (2) compound C and the compound D of the structural formula IV A condensation reaction occurs to obtain a compound E with a structural formula of VII; (3) oxidizing the sulfide group of the compound E to obtain a compound with a structural formula of VIII, that is, a benzimidazole compound; wherein, the structural formula V is Structural formula Ⅵ is Structural formula IV is Structural formula VII is Structural formula VIII is wherein Y is a halogen substituent. Preferably, the halogen substituent is chlorine.
[0035] By first oxidizing the pyridyl group in compound A (2-chloromethyl-3,5-dimethyl-4-methoxypyridine), the compound C obt...
Embodiment 1
[0041]1) Preparation of 2-chloromethyl-3,5-dimethyl-4-methoxypyridine nitrogen oxide
[0042] Take 2-chloromethyl-3,5-dimethyl-4-methoxypyridine hydrochloride (2.2g, 0.01mol) and add to sodium carbonate (1.3g, 0.012mol) aqueous solution and dichloromethane (2.0g ), then add m-chloroperoxybenzoic acid (1.9g, 0.011mol), stir at room temperature for 2h, separate liquids, extract the water layer, combine the organic phases, dry, filter, and spin the solvent to obtain 2-chloroform 2.0 g of the crude product of 3,5-dimethyl-4-methoxypyridine nitroxide.
[0043] 2) Preparation of 5-methoxy-2-(4-methoxy-3,5-dimethylpyridine nitrogen oxide-2-yl)methylthio-1H-benzimidazole
[0044] 2-Chloromethyl-3,5-dimethyl-4-methoxypyridine nitroxide (2.0g, 0.01mol) and 5-methoxy-2-mercapto-1H-benzimidazole (1.8g0 .01mol) was dissolved in methanol, 5ml of sodium hydroxide (0.44g, 0.011mol) aqueous solution was added, stirred at room temperature for 4h, concentrated, the aqueous solution was extract...
Embodiment 2
[0048] 1) Preparation of 2-chloromethyl-3,5-dimethyl-4-methoxypyridine nitrogen oxide
[0049] The 2-chloromethyl-3,5-dimethyl-4-methoxypyridine hydrochloride (0.022mol) was added to the mixed solution formed by 2.6g of sodium hydroxide solution and 4.3g of dichloromethane , then add hydrogen peroxide (0.02mol), stir for 3h, separate the layers, extract the water layer, combine the organic phases, dry, filter, and spin the solvent to obtain 2-chloromethyl-3,5-dimethyl-4-methoxy 4.0 g of crude pyridine nitrogen oxide.
[0050] 2) Preparation of 5-methoxy-2-(4-methoxy-3,5-dimethylpyridine nitrogen oxide-2-yl)methylthio-1H-benzimidazole
[0051] 2-Chloromethyl-3,5-dimethyl-4-methoxypyridine nitroxide (4.0g, 0.02mol) and 5-methoxy-2-mercapto-1H-benzimidazole (10.8g , 0.06mol) was dissolved in 40ml of methanol, added 5ml of sodium hydroxide aqueous solution (containing 0.86g of sodium hydroxide solid), stirred at room temperature for 6h, concentrated, extracted the aqueous soluti...
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