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Synthesis process of 2,4-dichloro-5-sulfonyl benzoic acid

A technology of sulfonamidobenzoic acid and synthetic method, applied in 2 fields, can solve problems such as high cost, low yield, large dosage, etc., and achieve the effect of reducing the cost of raw materials

Inactive Publication Date: 2009-08-05
江苏天泽新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This process is because the reaction raw material is 2,4-dichlorobenzoic acid, so the cost is higher; in the refining process, because 2,4-dichloro-5-sulfonamidobenzoic acid is less soluble in water, the consumption of water is very large , so the consumption of energy is large, the utilization rate of equipment space is poor; the yield is low, only 49.5%

Method used

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  • Synthesis process of 2,4-dichloro-5-sulfonyl benzoic acid
  • Synthesis process of 2,4-dichloro-5-sulfonyl benzoic acid
  • Synthesis process of 2,4-dichloro-5-sulfonyl benzoic acid

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Experimental program
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Effect test

Embodiment 1

[0019] A) Compound II is prepared from compound I, specifically: in a 250ml three-necked reaction flask, drop into 2,4-dichlorotrichlorobenzyl 30g (0.11mol), chlorosulfonic acid 100g (0.86mol), catalyst as compound I Concentrated sulfuric acid 8g (0.08mol), slowly heated to 135°C, reacted for 4h, cooled down to room temperature, added the reactant dropwise into 400g of ice water to decompose, and controlled the temperature of deglaciation below 2°C. temperature) and stirred for 5h, then suction filtered to obtain a white solid, and washed the filter cake with water to neutrality to obtain compound II, namely 2,4-dichloro-5-sulfonyl chloride benzoic acid;

[0020] B) Compound III is prepared from compound II, and the compound II obtained in step A) is added in batches to 70 g of 20% (0.4 mol) ammonia water, and the reaction temperature is controlled below 10° C. % hydrochloric acid was added dropwise to pH 1-2, the temperature of hydrochloric acid was added dropwise below 10°C,...

Embodiment 2

[0023] Only change the chlorosulfonic acid in step A) from 100 g to 64 g (0.55 mol) to obtain 15.6 g of finished product (HPLC>99%). All the other are the same as the description of embodiment 1.

Embodiment 3

[0025] Only change the chlorosulfonic acid in step A) from 100g to 116.5g (1.0mol), and the ice water from 400g to 600g to obtain 20g of finished product (HPLC>99%). All the other are the same as the description to embodiment 1.

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Abstract

The invention discloses a method for synthesizing 2,4-dichloro-5-sulfonamidobenzoic acid, which belongs to the technical field of synthesizing pharmaceutical intermediates. The method comprises the following steps: using compound I to prepare compound II, in the presence of a catalyst, reacting compound I (2,4-dichlorotrichlorobenzyl) with chlorosulfonic acid, adding the reactant to ice water to freeze after the reaction, After the ice-lysis is completed, keep warm, then filter and wash with water to obtain compound II (2,4-dichloro-5-sulfonyl chloride benzoic acid); compound III is prepared from compound II, and compound II is subjected to ammonolysis and acidification to obtain the crude compound III (2,4-dichloro-5-sulfonamidobenzoic acid); the crude compound III was dissolved in an aqueous alcohol solution, decolorized, and recrystallized to obtain the finished product of 2,4-dichloro-5-sulfonamidobenzoic acid. Advantages: It not only reduces the cost of raw materials, but also increases the yield of 2,4-dichloro-5-sulfonamidobenzoic acid. The yield is 70%, the melting point is 232-234°C, and the content is over 99%. Guaranteed.

Description

Technical field: [0001] The invention relates to a synthesis method of 2,4-dichloro-5-sulfonamidobenzoic acid, belonging to the technical field of synthesis of pharmaceutical intermediates. Background technique: [0002] 2,4-Dichloro-5-sulfonamidobenzoic acid is an important pharmaceutical intermediate and an important raw material for the synthesis of furosemide, furosemide and other drugs. Its structural formula is as follows: [0003] [0004] At present, the traditional process of synthesizing 2,4-dichloro-5-sulfonamidobenzoic acid is to use 2,4-dichlorobenzoic acid as a raw material, and there are journal reports (Shanghai No. 6 Pharmaceutical Factory, trial production of new diuretic-furosemide Method, Chinese Journal of Pharmaceutical Industry, 1973 (01), 25-26), after the raw material is reacted with chlorosulfonic acid, it is ice-lyzed in ice water, then ammonolyzed in ammonia water, and the crude product is obtained through acidification, and then the crude pro...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C311/16
Inventor 谭建平
Owner 江苏天泽新材料有限公司