New preparation method of febuxostat
A febuxostat and new process technology, which is applied in the field of febuxostat's new process preparation method, can solve the problems of high factory equipment requirements, difficult wastewater treatment, high risk, shorten production cycle, increase cost, The effect of short reaction time
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Embodiment 1
[0041] The preparation of embodiment 1 3-formyl-4-hydroxyl thiobenzamide
[0042] Sodium hydrosulfide (67g, content 70%, 0.84mol) and magnesium chloride hexahydrate (85g, 0.42mol) were added to a 2L three-necked flask, and DMF (420ml) was added to dissolve under stirring. Then 2-hydroxy-5-cyano-benzaldehyde (61.80 g, 0.42 mol) was added, heated and heated for 1 h under stirring according to the conditions in Table 1, and detected by TLC. When the reaction was almost complete, 800 mL of purified water was added. Under stirring, the pH was adjusted to 3 with concentrated hydrochloric acid. Then extract with ethyl acetate, 400ml ethyl acetate each time, extract 3 times. Separate the layers and combine the organic layers. The organic layer was washed 3 times with saturated brine, 200ml each time. The organic layer was washed with purified water three times, 2000 ml each time. After the organic layer was separated, it was dried over anhydrous magnesium sulfate (100 g). After ...
Embodiment 2
[0048] Example 2 Preparation of 2-(3-formyl-4-hydroxyphenyl)-4-methyl-5-ethoxycarbonylthiazole
[0049] Add the product of step 1 (63.96, 0.35mol) into a 1L three-necked flask, add 600mL of absolute ethanol, and dissolve completely under stirring. Added ethyl 2-chloroacetoacetate (61.02g, 0.37mol) and then added 1g of KI, and heated to reflux for 6h. After the reaction was completed, the heating was removed, and the temperature was naturally cooled to room temperature, and solids were precipitated. Filter and dry the filter cake to obtain 64.24 g of light yellow-green solid with a yield of 63.0%.
[0050] MS (m / z): 292.0 [M+H]
[0051] HPLC purity: 99.0%.
Embodiment 3
[0052] Example 3 Preparation of 2-(3-cyano-4-hydroxyphenyl)-4-methyl-5-ethoxycarbonylthiazole
[0053] The product of step 2 (37.87g, 0.13mol) was added to a 500mL three-necked flask, formic acid (88%, 200ml) was added, and then hydroxylamine hydrochloride (10.51g, 0.15mol) and sodium formate dihydrate (21.0g, 0.20mol) were added. Stirring and heating, warming to reflux. Insulation and reflux reaction for 6h. TLC followed the reaction. After the reaction was finished, cool and crystallize naturally, and filter. The filter cake was dispersed with water, and the pH was adjusted to 9 with 10% potassium hydroxide. Then adjust the pH to 3 with 10% dilute hydrochloric acid. A pale yellow solid precipitated out. Dry to obtain 31.90 g of light yellow powder solid, yield 85.1%.
[0054] MS (m / z): 289.1 [M+H]
[0055] HPLC purity: 97.5%.
[0056] TLC detection reaction. Developing agent: petroleum ether / ethyl acetate=3:1
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