Method for preparing lansoprazole midbody
A technology for lansoprazole and an intermediate is applied in the application field of potassium trifluoroethoxide in the preparation of lansoprazole raw materials, and can solve the problems of difficulty in recycling trifluoroethanol, being unsuitable for large-scale production, difficult to separate, and the like , to achieve the effect of less side reactions, high safety and simplified process
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Embodiment 1
[0017] The bottom is equipped with a 50L stainless steel interlayer reaction kettle with magnetic stirring. It is pre-dried thoroughly. Add 10 liters of hexane and 1.5kg of metal potassium blocks that have been cut in advance. Trifluoroethanol 15L, the rate of addition depends on the severity of the reaction, and the potassium trifluoroethoxide / trifluoroethanol solution generated by the reaction is released from the bottom of the reaction kettle in batches and stored in a sealed container.
Embodiment 2
[0019] Add 6 L of trifluoroethanol to the dry reaction kettle, add 5.0 kg of 2,3-dimethyl-4-nitropyridine-N-oxide and stir to dissolve completely, then add the potassium trifluoroethoxide / Trifluoroethanol solution, heated up to 85-90°C, stirred and reacted for 40 hours, recovered excess trifluoroethanol under reduced pressure, after completion, cooled to room temperature, added water, extracted with chloroform for 4 times, combined chloroform extract and washed with water twice, The chloroform layer was dried over anhydrous sodium sulfate, and the chloroform was evaporated under reduced pressure to obtain 6.2 kg of solid residue, which was directly dissolved by adding 20 L of acetic anhydride and 300 ml of concentrated sulfuric acid, stirred and dissolved, heated to 95-100°C, reacted for 6.0 hours, and the excess was evaporated under reduced pressure Acetic anhydride, add a mixture of methanol, water, and sodium hydroxide (30L: 7.0L: 3.0kg) to make the pH of the solution alkal...
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