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Method for synthesizing 1,4-benzdioxan-2-carboxylic acid

A technology of benzodioxane and synthesis method, which is applied in the field of synthesis of 1,4-benzodioxane-2-carboxylic acid, can solve the problems of high price, environmental pollution, etc. Simple processing and overcoming the effect of unstable performance

Inactive Publication Date: 2011-07-20
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] In the above two methods, 2,3-dibromopropionitrile and 2-chloroacrylonitrile are respectively used as raw materials, the price is higher, and 2-chloroacrylonitrile has high toxicity, in addition, in the reaction, bromine-containing A by-product of chlorine, which has certain pollution to the environment

Method used

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  • Method for synthesizing 1,4-benzdioxan-2-carboxylic acid
  • Method for synthesizing 1,4-benzdioxan-2-carboxylic acid

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Experimental program
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Embodiment 1

[0025] Embodiment 1, a kind of synthetic method of 1,4-benzodioxane-2-carboxylic acid, carry out following steps successively:

[0026] 1) Dissolve ethyl glycine hydrochloride (28g, 0.2mol) in 30mL of water, add 100mL of dichloroethane, cool down to -15°C, add dropwise sodium nitrite (15.2g, 0.22mol) in 20mL of water After 30 minutes of dripping, add hydrochloric acid solution with a mass concentration of 15% to adjust to pH = 4, continue to react at -15°C for 2 hours, add saturated sodium carbonate solution to adjust to pH = 6, let stand to separate the liquid, and take The organic phase located in the lower layer is cooled for use; the organic phase is the dichloroethane solution of ethyl diazoacetate.

[0027] 2) Dissolve 1,2-methylenedioxybenzene (8.13g, 0.067mol) in 40mL of dichloroethane, then add 0.5g of cuprous chloride, heat to 60°C, add dropwise the obtained product in step 1) Dichloroethane solution of ethyl diazoacetate (containing 0.14 mol of ethyl diazoacetate) ...

Embodiment 2

[0029] Embodiment 2, a kind of synthetic method of 1,4-benzodioxane-2-carboxylic acid, carries out following steps successively:

[0030] 1), with embodiment 1.

[0031] 2) Dissolve 1,2-methylenedioxybenzene (8.13g, 0.067mol) in 40mL of dichloroethane, add 0.5g of copper acetate, heat to 90°C, and dropwise add dichloromethane of ethyl diazoacetate Ethane solution (containing ethyl diazoacetate 0.08mol), 3h drop complete. After dripping, continue to react at 90°C for 1 hour, cool to room temperature, remove the solvent dichloroethane, and collect the distillate at 100°C-110°C under reduced pressure at 30 Pa, that is, 1,4-benzodioxane- 2-Carboxylic acid ethyl ester.

[0032] 3) Add all the ethyl 1,4-benzodioxane-2-carboxylate prepared above to the solution obtained by dissolving NaOH (8g, 0.2mol) in 50mL water, heat up to 60°C and react for 3h , adjusted to pH = 6 with a 15% hydrochloric acid solution and filtered, and recrystallized the obtained brown-yellow solid in ethanol...

Embodiment 3

[0033] Embodiment 3, a kind of synthetic method of 1,4-benzodioxane-2-carboxylic acid, carries out following steps successively:

[0034] 1), with embodiment 1.

[0035] 2) Dissolve 1,2-methylenedioxybenzene (8.13g, 0.067mol) in 40mL of dichloroethane, add 0.5g of copper sulfate, heat to 90°C, add dichloroethyl diazoacetate dropwise Ethane solution (containing ethyl diazoacetate 0.14mol), 6h drop. After dripping, continue to react at 90°C for 1 hour, cool to room temperature, remove the solvent dichloroethane, and collect the distillate at 100°C-110°C under reduced pressure at 30 Pa, that is, 1,4-benzodioxane- 2-Carboxylic acid ethyl ester.

[0036] 3) Add all the ethyl 1,4-benzodioxane-2-carboxylate prepared above to the solution obtained by dissolving NaOH (5.2g, 0.13mol) in 50mL water, and raise the temperature to 100°C for 1h Finally, adjust the pH to 6 with a hydrochloric acid solution with a mass concentration of 15% and filter, and recrystallize the resulting brown-y...

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Abstract

The invention discloses a method for synthesizing 1,4-benzdioxan-2-carboxylic acid. The method comprises the following steps of: (1) dripping a dichloroethane solution of ethyl diazoacetate into a dichloroethane solution into which 1,2-methylenedioxy benzene and a copper catalyst are dissolved at the temperature of between 60 DEG C and 90 DEG C for undergoing an insertion reaction, removing dichloroethane and distilling under reduced pressure in turn and collecting fractions at the temperature of between 100 DEG C and 110 DEG C to obtain 1,4-benzdioxan-2-carboxylic acid ethyl ester; and (2) hydrolyzing 1,4-benzdioxan-2-carboxylic acid ethyl ester in a NaOH solution, adjusting the pH value of the obtained hydrolysis product to 5.5-6.5, filtering and recrystallizing the obtained claybank solid in an organic solvent to obtain the white solid 1,4-benzdioxan-2-carboxylic acid. The 1,4-benzdioxan-2-carboxylic acid synthesized by adopting the method has the characteristics of low toxicity ofraw materials, simple post-treatment and low emission of three wastes.

Description

technical field [0001] The invention relates to a synthesis method of 1,4-benzodioxane-2-carboxylic acid. Background technique [0002] 1,4-Benzodioxane-2-carboxylic acid, molecular formula: C 9 h 8 o 4 , molecular weight: 180.16, CAS number: 3663-80-7, melting point 125-128 ° C, is an important intermediate for the synthesis of doxazosin drugs, and its structural formula is shown in formula 1. [0003] [0004] Formula 1 . [0005] The methods for the synthesis of 1,4-benzodioxane-2-carboxylic acid reported at home and abroad mainly contain the following: [0006] 1. With catechol as raw material and 2,3-dibromopropionitrile as raw material, 1,4-benzodioxane-2-carbonitrile is generated through intermolecular elimination reaction under alkaline conditions, and then 1,4-benzodioxane-2-carboxylic acid was hydrolyzed under conditions (Journal of Medicinal Chemistry, 1989, 32(8), 1988-1996, yield 83.3%; Chinese Journal of Medicinal Chemistry, 2006, 16(6 ), 336-341, w...

Claims

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Application Information

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IPC IPC(8): C07D319/20
Inventor 陈新志曹长辉钱超
Owner ZHEJIANG UNIV