4-methoxy methyl acetoacetate preparation method
A technology of methyl methoxyacetoacetate and methyl acetate, which is applied in the field of preparation of methyl 4-methoxyacetoacetate, can solve problems such as unfavorable industrialized large-scale production, achieve safe use, reduce impurity content, reduce The effect of the introduction of impurities
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Embodiment 1
[0019] In a 2L reaction flask, add 250ml of solvent tetrahydrofuran (AR) in advance, and start stirring under the protection of argon. At this time, the temperature in the kettle is 25°C, and add 30g (0.75mol) of industrial sodium hydride (containing 40wt% mineral oil) in batches. And 53g (0.75mol) of potassium methylate, after the addition, continue to add 450ml of solvent tetrahydrofuran; slowly drop the mixed solution of 30g of methanol and 100g (0.68mol) of methyl 4-chloroacetoacetate at the temperature of 20°C in the kettle, and stir for 4h , raise the temperature in the kettle to 25°C and stir for 5 hours. TLC detects that the reaction is complete, and the system begins to cool down. The color of the solution is earthy yellow and a large amount of solids are suspended. to 0-5°C) until the pH of the system = 5; stand for stratification, after separation, the upper layer is concentrated and spin-dried to remove the solvent tetrahydrofuran, and the resulting residue is added...
Embodiment 2
[0021] In a 2L reaction flask, add 250ml of solvent tetrahydrofuran (AR) in advance, and start stirring under the protection of argon. At this time, the temperature in the kettle is 15°C, and add 30g (0.75mol) of industrial sodium hydride (containing 40wt% mineral oil) in batches. and 40.5g (0.75mol) sodium methoxide, after the addition, continue to add 450ml of solvent tetrahydrofuran; slowly add a mixed solution of 30g methanol and 100g (0.68mol) methyl 4-chloroacetoacetate dropwise at a temperature of 15°C in the kettle, and stir the reaction 6h, raise the temperature in the kettle to 20°C and stir for 15h, TLC detects that the reaction is complete, the system begins to cool down, the color of the solution is earthy yellow and a large amount of solids are suspended, when the temperature in the kettle drops to 10°C, slowly add 2M hydrochloric acid solution (pre- Cool to 0-5°C) until the pH of the system is 7; stand and separate the layers, concentrate the upper layer and spin...
Embodiment 3
[0023] In a 2L reaction flask, add 250ml of solvent tetrahydrofuran (AR) in advance, and start stirring under the protection of argon. At this time, the temperature in the kettle is 20°C, and add 30g (0.75mol) of industrial sodium hydride (containing 40wt% mineral oil) in batches. and 51g (0.75mol) sodium ethoxide, after the addition, continue to add 450ml of solvent tetrahydrofuran; slowly add dropwise a mixed solution of 30g methanol and 100g (0.68mol) methyl 4-chloroacetoacetate at a temperature of 5°C in the kettle, and stir for 5h , raise the temperature in the kettle to 25°C and stir for 4 hours. TLC detects that the reaction is complete, and the system begins to cool down. The color of the solution is earthy yellow and a large amount of solids are suspended. to 0-5°C) until the pH of the system = 6; stand for stratification, and after separation, the upper layer is concentrated and spin-dried to remove the solvent tetrahydrofuran, and the resulting residue is added with ...
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