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Preparation of 6-substituted-4-chromanone-2-carboxylic acid
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A technology of chromanone and formic acid, applied in the direction of organic chemistry, can solve the problems of consumption, unfavorable industrialization, high price, etc., and achieve the effect of optimizing the process
Inactive Publication Date: 2011-07-27
ZHEJIANG NORMAL UNIVERSITY
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[0005] But this technology only describes the preparation of 6-fluorochromanone-2-carboxylic acid, but does not mention other 6-substituted chromanone-2-carboxylic acids, and the problem that this method also exists is: this method Use 6-fluoroanisole as a raw material, which is generally obtained by methylating 6-fluorophenol through a methylating reagent, and general methylating reagents are more toxic and expensive, and the use of maleic di The direct acylation reaction of acid anhydride with 6-fluoroanisole relatively consumes more catalyst aluminum trichloride, which causes more troubles for post-processing and is not conducive to industrialization
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Embodiment 1
[0038] Embodiment 1, a kind of preparation method of 4-chromanone-2-formic acid, carries out following steps successively:
[0039] 1), phenolic esterification:
[0040] Add 4.0g of phenol and 50ml of 1mol / L sodiumhydroxide solution into a round-bottomed flask, stir and add 2.40g of maleic anhydride at room temperature for reaction, TLC traces until the reaction of the raw materials is complete, and the reaction time is 1h.
[0041] Pour the resulting reaction mixture into a mixed system of hydrochloric acid and ice (composed of 1mol / L100ml hydrochloric acid and ice), filter, wash the resulting filtrate with water, and dry it under an infrared lamp to obtain a white solid, that is, 3-phenyl- 3-oxo-2-butenoic acid 4.4 g.
[0042] 2), carboxyl esterification:
[0043] Put the obtained product of step 1) and p-toluenesulfonic acid 3g, 12ml benzene, and 4ml ethanol into a round-bottomed flask, and install an oil-water separation device on the round-bottomed flask; The organic ...
Embodiment 2
[0049] Embodiment 2, a kind of preparation method of 4-chromanone-2-formic acid,
[0050] Change 2.40g maleic anhydride into 3.53g in the step 1) of embodiment 1, change 1mol / L sodiumhydroxide 50ml into 75ml, and other reaction conditions are all equal to embodiment 1 (therefore, the mole between all the other raw materials Than relation is with embodiment 1).
[0051] 2.77 g of the product 4-chromanone-2-carboxylic acid was obtained with a purity of 100% and a yield of 40.1%.
Embodiment 3
[0052] Embodiment 3, a kind of preparation method of 4-chromanone-2-formic acid,
[0053] The 2.40g maleic anhydride in the embodiment 1 step 1) is changed into 4.00g, and 1mol / L sodium hydroxide 50ml is changed into 90ml, and other reaction conditions are all equal to embodiment 1.
[0054] 2.73 g of the product 4-chromanone-2-carboxylic acid was obtained with a purity of 98.0% and a yield of 34.2%.
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Abstract
The invention discloses a method for preparing a 6-substituted-4-chromanone-2-methanoic acid. The method uses phenol or derivatives thereof, and maleic anhydride as raw materials. The method comprises the following steps: 1) phenol esterification, in which, the phenol or the derivatives thereof react with the maleic anhydride under base catalysis; 2) carboxyl esterification, in which, 3-(4-substituted phenyl)-3-keto-2-crotonic acid is dissolved in an organic solvent I, and an esterification catalyst and ethanol are added to the mixed solvent to react; 3) Fries recomposition, in which, the 3-(4-substituted phenyl)-3-keto-2-crotonic acid and aluminum trichloride are mixed to react; and 4) Michael addition, in which, the 3-(4-substituted phenyl)-3-keto-2-crotonic acid reacts with a sodiumbicarbonate solution. The method for preparing the 6-substituted-4-chromanone-2-methanoic acid has the characteristics of simple and safe operation and low production cost.
Description
technical field [0001] The invention relates to a preparation method of 6-substituted-4-chromanone-2-carboxylic acid. Background technique [0002] 4-chromanone derivatives are an important class of organic heterocyclic compounds, which have important physiological activities such as anti-stunt, anti-allergic, hypoglycemic, anti-inflammatory and antibacterial, and have important roles in medicine, pesticides and biology. Applications. 6-substituted-4-chromanone-2-carboxylic acid, especially 6-fluoro-4-chromanone-2-carboxylic acid is one of the key intermediates for the synthesis of anti-stress drugs with chroman structural units. It has a wider range of uses in synthesis and is an important intermediate. Therefore, exploring its better synthetic methods has broad application prospects. [0003] The preparation method of 6-substituting-4-chromanone-2-carboxylic acid has multiple, wherein easier industrial method is the method (Kurono M .and Baba Y.[P].JP6092956,1994), the...
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