Preparation method of eszopiclone
A technology of eszopiclone and zopiclone, applied in the direction of organic chemistry, etc., can solve the problems of long reaction period, harsh reaction conditions, unsuitable for large-scale production and the like
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Embodiment 1
[0050] a. Salt formation and resolution: Mix 2.33kg racemic zopiclone, 0.81kg D-(+)-malic acid, 13.98kg methanol and 23.3kg acetone, heat to reflux, and react for 30 minutes to dissolve all the solids; The solution was cooled down to room temperature, allowed to stand for 8-24 hours, crystallized, filtered, washed with 0.93-3.5kg acetone, filtered, and dried to obtain 1.42kg crude product of D-(+)-malic acid S-zopiclone; The yield is 45.3%, and the optical purity is 96.6%.
[0051] b. Demalate: Add the D-(+)-malic acid S-zopiclone obtained in the previous step to 5.68kg water and 19.88kg ethyl acetate, add 0.43kg anhydrous K 2 CO 3 , reflux reaction for 30 minutes, use test paper to measure the pH of the water layer > 7, let stand to separate the liquid, wash the organic phase with saturated aqueous sodium chloride solution, then add 3.55kg ethyl acetate to wash the container wall, combine the organic phases, and evaporate under reduced pressure Part of ethyl acetate, the re...
Embodiment 2
[0053] a. Salt formation and resolution: Mix 2.33kg racemic zopiclone, 0.81kg D-(+)-malic acid, 15kg methanol and 24.5kg acetone, heat to reflux, and react for 30 minutes to dissolve all the solids; Cool the solution down to room temperature, let stand for 8-24 hours, crystallize, filter, and wash with 1-3.5kg acetone, filter to obtain the crude product of D-(+)-malic acid S-zopiclone; by weight of zopiclone , add 14kg of acetone and 9.4kg of methanol to this crude product, heat to reflux, stop heating after dissolving, drop to room temperature, let stand for 8-24 hours, crystallize, filter, wash with 1-3.5kg of acetone, filter, and dry to obtain D -(+)-malic acid S-zopiclone 1.27kg; molar yield 40.5%, optical purity 98.5%.
[0054] b. Demalate: add the D-(+)-malic acid S-zopiclone obtained in the previous step to 5.8kg water and 20kg ethyl acetate, add 0.38kg anhydrous K 2 CO 3 , reflux reaction for 30 minutes, use test paper to measure the pH of the water layer > 7, let st...
Embodiment 3
[0056] a. Salt formation and resolution: Mix 2.33kg racemic zopiclone, 0.81kg D-(+)-malic acid, 14.4kg methanol and 24.5kg acetone, heat to reflux, and react for 30 minutes to dissolve all the solids; The solution was cooled down to room temperature, left standing for 8-24 hours, crystallized, filtered, washed with 1-3.5kg acetone, filtered to obtain the crude product of D-(+)-malic acid S-zopiclone; Add 14.6kg of acetone and 10kg of methanol to this crude product, heat to reflux, stop heating after dissolving, drop to room temperature, let it stand for 8-24 hours, crystallize, filter, wash with 1-3.5kg of acetone, filter, and dry to obtain D-(+)-malic acid S-zopiclone 1.25kg; molar yield 39.9%, optical purity 98.8%.
[0057] b. Demalate: Add the D-(+)-malic acid S-zopiclone obtained in the previous step to 5.25kg of water and 18kg of ethyl acetate, and add 0.375kg of anhydrous K 2 CO 3 , reflux for 30 minutes, use test paper to measure the pH of the water layer > 7, let stand...
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