3- alkoxy -4-carbalkoxyphenylacetate and 3-alkoxy-4-carbalkoxyphenylacetic acid synthesis method
A technology of alkoxycarbonyl phenylacetate and synthesis method, which is applied in the direction of carboxylate preparation, chemical instruments and methods, carboxylate/lactone preparation, etc., and can solve the problem of long production cycle, high total cost and many steps, etc. problems, to achieve the effect of short synthetic route, easy operation and high reaction yield
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Embodiment 1
[0024] The synthesis of embodiment 1 3-ethoxy-4-methylbenzoic acid ethyl ester
[0025] Put 30.4g (0.2mol) of 4-methylsalicylic acid, 92.5g (0.6mol) of diethyl sulfate and 2g of tetrabutylammonium bromide in a mixed solution of 500mL of dichloromethane and 500mL of water, at room temperature (25°C ) was stirred for 20h, and the dichloromethane layer was separated after the reaction was completed, and the aqueous layer was extracted with dichloromethane (150mL×2), the organic phases were combined, washed with water, and concentrated to obtain the product 3-ethoxy-4-methylbenzoic acid ethyl 36 g of ester, yield 86.5%. The next reaction was carried out without purification.
Embodiment 2
[0026] Example 2 Synthesis of 3-ethoxyl-4-ethoxycarbonylphenylacetic acid ethyl ester
[0027] Under the protection of nitrogen, add 9.7g (0.095mol) of diisopropylamine into 80mL of tetrahydrofuran, stir, and after the system drops to -80°C, add 60mL (0.096mol) of n-hexane solution of butyllithium, stir for 30min, add dropwise 1 The tetrahydrofuran solution of 10 g (0.048 mol) of the obtained 3-ethoxy-4-methylbenzoic acid crude product was stirred for 30 min, then the tetrahydrofuran solution of 7.8 g (0.071 mol) of ethyl chloroformate was added, and after stirring for 3 h, added 5% ammonium chloride solution, raised to room temperature, adjusted to pH = 7 with 2N HCl, separated the organic layer, washed with water and saturated brine successively, dried over anhydrous sodium sulfate, concentrated to obtain the product 3-ethoxy-4-ethane 22 g of ethyl oxycarbonyl phenylacetate, the product was directly carried out to the next step without purification.
Embodiment 3
[0028] Example 3 Synthesis of 3-ethoxyl-4-ethoxycarbonylphenylacetic acid
[0029] Dissolve 16 g of the crude ethyl 3-ethoxy-4-ethoxycarbonylphenylacetate obtained in Example 2 in 80 mL of 95% ethanol, lower the reaction solution to 5-10 °C, and then add 2N sodium hydroxide solution in batches to pH Until the value no longer changes, control the reaction temperature at 5-15°C. After the reaction was completed, the reaction solution was adjusted to neutral with 6N hydrochloric acid, concentrated ethanol, then added 50ml of water, extracted with dichloromethane (25 mL×2), separated the water layer, and adjusted the pH to 3.5-4 with 6N HCl under ice bath. , the aqueous layer with CH 2 Cl 2 Extraction (30mL×2), the organic layer was successively washed with water (30mL×2), saturated brine (30mL×2), dried over anhydrous sodium sulfate, and concentrated to obtain a yellow solid, which was decolorized and recrystallized with toluene to obtain 6.0 g of a white solid . The overall ...
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