Environment-friendly method for preparing phenylbutazone
A kind of phenylbutazone, green technology, applied in the field of medicine and chemical industry, can solve the problems of inadequate control, incomplete reaction, too long reaction time, etc., to achieve the effect of reducing raw material cost, stable yield and qualified purity
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Embodiment 1
[0016] Add 80g of sodium methoxide methanol solution into a dry and clean 500mL four-neck flask, distill to dryness, add 68.8g of diethyl n-butylmalonate, stir until the sodium methoxide is completely dissolved, add 50g of hydroazobenzene, heat up, Control the internal temperature at 130°C, react for 3-4 hours, and take samples for HPLC control. If the relative content of hydroazobenzene is ≤0.5%, the reaction is complete. Recover A and ethanol until no alcohol is evaporated, add 250g of 95% ethanol to dissolve, then transfer to a 1L four-necked bottle, cool down to below 20°C and slowly add ethanol solution of hydrochloric acid (mixed solution of 150g of ethanol and 45g of 36% hydrochloric acid) Adjust the pH to 6, a large amount of white solids are precipitated, heated in a water bath to 65°C, the solids are completely dissolved, decolorized once with activated carbon, the decolorization time is 15min, filtered while it is hot, cooled to 0-5°C to crystallize, and obtained cru...
Embodiment 2
[0018] Add 80g of sodium methoxide methanol solution into a dry and clean 500mL four-neck flask, distill to dryness, add 68.8g of diethyl n-butylmalonate, stir until the sodium methoxide is completely dissolved, add 50g of hydroazobenzene, heat up, Control the internal temperature at 130°C, react for 3-4 hours, and take samples for HPLC control. If the relative content of hydroazobenzene is ≤0.5%, the reaction is complete. Recover methanol and ethanol until no alcohol is evaporated, add 200g of methanol and ethanol mixed solution (methanol content 18.7%) to dissolve, transfer it to a 1L four-necked bottle, cool down to below 20°C and slowly add hydrochloric acid solution of methanol and ethanol (70g of methanol, Ethanol and 45g of 36% hydrochloric acid mixed solution) to adjust the pH to 6, a large amount of white solids precipitated, heated to 65°C in a water bath, the solids were completely dissolved, decolorized once with activated carbon, the decolorization time was 15min, ...
Embodiment 3
[0020] Add 80g of sodium methoxide methanol solution into a dry and clean 500mL four-neck flask, distill to dryness, add 68.8g of diethyl n-butylmalonate, stir until the sodium methoxide is completely dissolved, add 50g of hydroazobenzene, heat up, Control the internal temperature at 130°C, react for 3-4 hours, and take samples for HPLC control. If the relative content of hydroazobenzene is ≤0.5%, the reaction is complete. Recover formazan and ethanol until no alcohol is evaporated, add 200g of recovered formazan and ethanol to dissolve, transfer to a 1L four-necked bottle, cool down to below 20°C and slowly add hydrochloric acid formazan and ethanol solution dropwise (70g recovered formazan, ethanol and 45g 36% hydrochloric acid mixed solution) to adjust the pH to 6, a large amount of white solids were precipitated, heated in a water bath to 65°C, the solids were completely dissolved, decolorized once with activated carbon, the decolorization time was 15min, filtered while it ...
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