Method for synthesizing 2-methoxy-4-amino-5-ethylsulfonyl benzoic acid
A technology of ethylsulfone benzoic acid and methyl acetaminobenzoate, which is applied in the field of preparation of pharmaceutical intermediates, can solve problems such as low yield, long process route, and poor product quality, and achieve high product yield and process route Simple, good product quality effect
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Embodiment 1
[0024] Slowly add 150g (0.67mol) of methyl 2-methoxy-4-acetamidobenzoate into a 1000mL four-necked reaction flask containing 391g (3.36mol) of chlorosulfonic acid below 10°C with a chlorination absorption system, and add The process is controlled below 10°C, after the feeding is completed, the reaction is carried out at 5-10°C for 5 hours. After the reaction was completed, the reaction solution was poured into 1000 ml of ice water, solids were precipitated, and suction filtration gave 220.6 g of a wet product of methyl 2-methoxy-4-acetylamino-5-sulfonyl chloride benzoate, with a water content of 12.4%. The dry product is 193.2g (0.60mol), and the molar yield is 89.6%. Add the wet product of methyl 2-methoxy-4-acetylamino-5-sulfonyl chloride benzoate in batches to 2000 ml of 800 mL aqueous solution containing 302.5 g (2.4 mol) of sodium sulfite at 75-80 °C with a reflux condenser In the four-necked reaction flask, keep warm for 1 hour after feeding. Then cool to 35-40°C, and ...
Embodiment 2
[0026] Slowly add 100.5g (0.45mol) of methyl 2-methoxy-4-acetamidobenzoate into a 1000mL four-necked reaction flask containing 262g (2.25mol) of chlorosulfonic acid with a chlorination absorption system below 10°C, The feeding process is controlled below 10°C. After the feeding is completed, the reaction is carried out at 5-10°C for 8 hours. After the reaction was completed, the reaction solution was poured into 800 ml of ice water, solids were precipitated, and suction filtration gave 144.6 g of a wet product of methyl 2-methoxy-4-acetylamino-5-sulfonylchloride benzoate, a water content of 13.2%. The dry product was 125.5g (0.39mol), and the molar yield was 86.4%. Add the wet product of methyl 2-methoxy-4-acetylamino-5-sulfonylchloride benzoate in batches to 2000 ml of 600 mL aqueous solution containing 245.8 g (1.95 mol) of sodium sulfite at 75 to 80 ° C with a reflux condenser In the four-necked reaction flask, keep warm for 1 hour after feeding. Then cool to 35-40°C, and...
Embodiment 3
[0028] Slowly add 201g (0.9mol) of methyl 2-methoxy-4-acetamidobenzoate into a 1000mL four-necked reaction flask containing 839g (7.2mol) of chlorosulfonic acid below 10°C and equipped with a chlorination absorption system. The process is controlled below 10°C, after the feeding is completed, the reaction is carried out at 5-10°C for 6 hours. After the reaction was completed, the reaction solution was poured into 1500 ml of ice water, solids were precipitated, and suction filtration gave 277 g of a wet product of methyl 2-methoxy-4-acetylamino-5-sulfonyl chloride benzoate, with a water content of 10.6%. The product was 247.7g (0.77mol), and the molar yield was 85.6%. Add the wet product of methyl 2-methoxy-4-acetamido-5-sulfonylchloride benzoate in batches to 2000 ml four- In a reaction bottle, keep the temperature for 1 hour after the addition. Then cool to 35-40°C, and slowly add 355.7 g (2.3 mol) of diethyl sulfate dropwise at this temperature. After the dropwise addition...
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