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Synthetic method of piroxicam drug intermediate 3-oxo-1,2-benzisothiazole-1,1-dioxo-2-ethyl acetate

A technology of benzisothiazole and piroxicam, applied in the direction of organic chemistry, can solve problems such as many adverse reactions in the gastrointestinal tract, and achieve the effects of reducing reaction temperature and reaction time, reducing intermediate links and improving reaction yield

Inactive Publication Date: 2016-04-06
CHENGDU KA DI FU TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, because the concentration required for this product to inhibit cyclooxygenase-2 is higher than that required to inhibit cyclooxygenase-1, there are more adverse reactions in the gastrointestinal tract

Method used

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  • Synthetic method of piroxicam drug intermediate 3-oxo-1,2-benzisothiazole-1,1-dioxo-2-ethyl acetate

Examples

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Effect test

example 1

[0012] In the reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, and thermometer, add 2.16mol of saccharinamine (2), 2.1L of nitromethane, control the stirring speed at 160rpm, raise the solution temperature to 110°C, Slowly add 2.3 mol of ethyl acetate (3), continue to stir for 11 hours after the addition is complete, steam most of the nitromethane, pour the reactant into a 15% potassium chloride solution by mass fraction, and filter with suction to obtain a white solid. 900ml of 80% acrylonitrile was recrystallized, the temperature of the solution was lowered to 3°C, allowed to stand for 30 hours, suction filtered, washed with 90% toluene, and dehydrated with anhydrous calcium sulfate to obtain 3-oxo-1,2-benzene Ethyl isothiazole-1,1-dioxo-2-acetate 418.35g, yield 72%.

example 2

[0014] In the reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, and thermometer, add 2.16mol of saccharinamine (2), 2.2L of nitromethane, control the stirring speed at 170rpm, raise the solution temperature to 112°C, Slowly add 2.4 mol of ethyl acetate (3), continue to stir for 112 hours after the addition is complete, steam most of the nitromethane, pour the reactant into a 17% potassium chloride solution by mass fraction, and filter with suction to obtain a white solid. 900ml of 82% acrylonitrile was recrystallized, lowered the temperature of the solution to 4°C, allowed to stand for 32 hours, filtered with suction, washed with 92% toluene, and dehydrated with activated alumina to obtain 3-oxo-1,2-benzo Isothiazole-1,1-dioxo-2-ethyl acetate 435.78g, yield 75%.

example 3

[0016] In the reaction vessel equipped with a stirrer, reflux condenser, dropping funnel, and thermometer, add 2.16mol of saccharinamine (2), 2.3L of nitromethane, control the stirring speed at 190rpm, raise the solution temperature to 115°C, Slowly add 2.5 mol of ethyl acetate (3), continue to stir for 13 hours after the addition is complete, evaporate most of the nitromethane, pour the reactant into a 20% potassium chloride solution by mass fraction, and filter with suction to obtain a white solid. 900ml of 85% acrylonitrile was recrystallized, the temperature of the solution was lowered to 5°C, allowed to stand for 36 hours, filtered with suction, washed with 95% toluene, and dehydrated with anhydrous calcium sulfate to obtain 3-oxo-1,2-benzene Ethyl isothiazole-1,1-dioxo-2-acetate 470.64g, yield 81%.

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Abstract

A synthetic method of a piroxicam drug intermediate 3-oxo-1,2-benzisothiazole-1,1-dioxo-2-ethyl acetate comprises the following steps: adding 2.16mol of saccharin amine and 2.1-2.3L of nitromethane into a reaction container provided with a stirrer, a reflux condenser, a dropping funnel and a thermometer, controlling a stirring speed to be 160-190rpm, rising the temperature of a solution to 110-115 DEG C, slowly adding 2.3-2.5mol of ethyl acetate, after adding continuously stirring for 11-13h, distilling off most of the nitromethane, pouring a reactant into a potassium chloride solution, performing suction filtration to obtain a white solid, recrystallizing by using 900ml of propionitrile, reducing the temperature of a solution to 3-5 DEG C, standing for 30-36h, performing suction filtration, washing by using methylbenzene, and dehydrating by a dehydrating agent, thus obtaining the 3-oxo-1,2-benzisothiazole-1,1-dioxo-2-ethyl acetate, wherein the mass fraction of the potassium chloride solution is 15-20 percent, and the mass fraction of the propionitrile is 80-85 percent.

Description

technical field [0001] The invention relates to a method for synthesizing piroxicam drug intermediate 3-oxo-1,2-benzisothiazole-1,1-dioxo-2-acetic acid ethyl ester. Background technique [0002] Piroxicam drug has analgesic, anti-inflammatory and antipyretic effects. This product plays a pharmacological role by inhibiting cyclooxygenase to reduce the synthesis of prostaglandins in local tissues and inhibiting the chemotaxis of leukocytes and the release of lysosomal enzymes. The analgesic and swelling effects of this product are similar to those of indomethacin, aspirin and naproxen in the treatment of arthritis. However, since the concentration required for this product to inhibit cyclooxygenase-2 is higher than the concentration required to inhibit cyclooxygenase-1, there are more adverse reactions in the gastrointestinal tract. Food can reduce the rate of absorption, but does not affect the total amount absorbed. Plasma protein binding rate as high as 90%. Metabolized...

Claims

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Application Information

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IPC IPC(8): C07D275/06
CPCC07D275/06
Inventor 廖如佴
Owner CHENGDU KA DI FU TECH
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