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Novel synthesis method and intermediate for 2-ethoxy-4-amino-5-chlorobenzoic acid

A technology of p-aminosalicylic acid and ethylation, applied in directions such as organic chemistry, can solve the problems of long preparation steps, high cost of raw materials, and high pollution, achieve high total yield, improve total yield, and shorten reaction steps. Effect

Active Publication Date: 2009-09-23
四川弘远药业有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In order to solve the problems of high raw material cost, long preparation steps, high pollution and high energy consumption in the preparation of the compound of formula (I) in the prior art, the present invention provides a new preparation method of the compound of formula (I) and two new intermediates body

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  • Novel synthesis method and intermediate for 2-ethoxy-4-amino-5-chlorobenzoic acid
  • Novel synthesis method and intermediate for 2-ethoxy-4-amino-5-chlorobenzoic acid
  • Novel synthesis method and intermediate for 2-ethoxy-4-amino-5-chlorobenzoic acid

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Embodiment 1

[0027] Steps: Preparation of acetamidosalicylic acid: Sodium p-aminosalicylate (52.54g, 0.3mol), water (260mL) and acetic anhydride (30.6g, 0.3mol) were added to the reaction flask, stirred and heated, and reacted at 50°C After 2 hours, the pH was adjusted to acidic after the reaction, filtered, washed with water, and dried to obtain p-acetamidosalicylic acid (47.73 g, 81.5%) as a white solid. mp 232°C. 1 H-NMR (400MHz, d 6 -DMSO): δ 2.07 (s, 3H), 7.02 (dd, J 1 =8.4Hz,J 2 =8.4Hz, 1H), 7.34(d, J=1.6Hz, 1H), 7.69(d, J=4.8Hz, 1H), 10.20(s, 1H), 11.35(br, 1H), 13.67(br, 1H ).

[0028] Step 2 Preparation of ethyl 2-ethoxy-4-acetamidobenzoate: p-acetamidosalicylic acid (46.84g, 0.24mol), DMF (500mL), potassium carbonate (66.34g, 0.48mol) and Ethyl bromide (65.38g, 0.6mol) was put into a reaction bottle, stirred and heated, reacted at 100°C for 8 hours, poured into water and stirred for crystallization, filtered, washed with water, dried to obtain a white solid 2-ethoxy-4-acetam...

Embodiment 2

[0032] Preparation of p-acetamidosalicylic acid: p-aminosalicylic acid (4.60g, 0.03mol), water (46mL) and acetic anhydride (3.07g, 0.03mol) were added to the reaction flask, stirred and heated, and reacted at 60°C for 4 hours, Cool, filter, wash with water, and dry to obtain white solid p-acetamidosalicylic acid (4.70 g, 80.2%).

Embodiment 3

[0034] Preparation of p-acetamidosalicylic acid: Potassium p-aminosalicylate (5.74g, 0.03mol), water (29mL) and acetic anhydride (3.07g, 0.03mol) were added to the reaction flask, stirred and heated, and reacted at 50°C for 2 hours , cooled, adjusted the pH to acidic, filtered, washed with water, and dried to obtain white solid p-acetamidosalicylic acid (4.76g, 81.3%).

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Abstract

The invention provides a preparation method for synthesizing an important mosapride intermediate 2-ethoxy-4-amino-5-chlorobenzoic acid. The method comprises the following steps: carrying out the four-step reaction of acetylation, biethylation, chlorination and hydrolysis for aminosalicylic acid or corresponding sodium salt and kali salt compounds thereof, and obtaining a product. The method has cheap and easily obtained raw materials, short synthesis steps, moderate reaction conditions, easy control, simple operation, lower pollution, high total yield, low cost and good and stable product quality, and is easily used for the industrialized production.

Description

technical field [0001] The invention provides a preparation method of 2-ethoxy-4-amino-5-chlorobenzoic acid, an important intermediate for synthesizing mosapride citrate, and belongs to the field of pharmaceutical synthesis. Background technique [0002] Mosapride citrate is a selective 5-hydroxytryptamine 4 (5-HT4) receptor agonist, which stimulates the 5-HT4 receptors of cholinergic interneurons and myenteric plexuses in the gastrointestinal tract to promote acetylcholine release, thereby enhancing the motility of the gastrointestinal tract, improving the gastrointestinal symptoms of patients with functional dyspepsia, without affecting the secretion of gastric acid. Mosapride citrate has no affinity with dopamine D2, 5-HT1, and 5-HT2 receptors on the synaptic membrane of the brain, so there is no extrapyramidal side effect caused by these receptor blockade, and it has receptor selectivity Strong, good pharmacokinetics, selective effect on the digestive tract, small doses...

Claims

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Application Information

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IPC IPC(8): C07C229/64C07C233/54
Inventor 陈书明秦欣荣
Owner 四川弘远药业有限公司
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