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Synthetic method of piroxicam

A technology of piroxicam and a synthesis method, applied in the direction of organic chemistry and the like, can solve the problems of many impurities, difficult to control reaction, low yield and the like, and achieves the effects of good repeatability, simple operation and production cost saving

Active Publication Date: 2018-10-09
ZHENGZHOU MINGZE MEDICAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] 3-oxo-1,2-benzisothiazoline-2-acetic acid methyl ester-1,1 dioxide is mostly obtained by 2-methylation to obtain 2-methyl-3,4-dioxo-4-oxo -2H-1,2-benzothiazine-3-carboxylic acid methyl ester-1,1-dioxide, the yield is low and there are many impurities, and the reaction is difficult to control

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A synthetic method of piroxicam, comprising the following steps:

[0027] Step 1: Synthesis of 3-oxo-1,2-benzisothiazoline-2-acetic acid methyl ester-1,1 dioxide

[0028] Add 400mL of N-methylpyrrolidone (NMP) and 160g of sodium saccharin dihydrate to a 1000mL reaction bottle, add 129g of ethyl chloroacetate dropwise at 105°C, and react at 110-120°C for 4 hours after the dropwise addition , After the reaction, the NMP was distilled off under reduced pressure to obtain a concentrated solution and cooled to 80°C for use.

[0029] Step 2: Synthesis of 2-methyl-3,4-dioxo-4-oxide-2H-1,2-benzothiazine-3-carboxylic acid methyl ester-1,1-dioxide

[0030] Add 384g of 28% sodium methoxide, 11g of potassium iodide and 400mL of methanol to the concentrated solution obtained in the above step 1, gradually raise the temperature to 65°C during the stirring process, react at 65°C for 2 hours, distill the methanol under reduced pressure, and cool down to 30°C ;Pour 600mL of pure water...

Embodiment 2

[0036] Step 1: Synthesis of 3-oxo-1,2-benzisothiazoline-2-acetic acid methyl ester-1,1 dioxide

[0037] Add 400mL of N,N-dimethylformamide (DMF) and 160g of sodium saccharin dihydrate to a 1000mL reaction bottle, and add 89.5g of ethyl chloroacetate dropwise at 105°C The reaction was carried out under the same conditions for 4 hours. After the reaction, the DMF was distilled off under reduced pressure to obtain a concentrated solution which was cooled to 80°C for use.

[0038] Step 2: Synthesis of 2-methyl-3,4-dioxo-4-oxide-2H-1,2-benzothiazine-3-carboxylic acid methyl ester-1,1-dioxide

[0039] Add 767g of 28% sodium methoxide, 27.5g of potassium iodide and 400mL of methanol to the concentrated solution obtained in the above step 1, and gradually heat up to 65°C during the stirring process. After reacting at 65°C for 3 hours, the methanol is evaporated under reduced pressure, and the temperature is lowered to 30°C; Pour 600mL of pure water into the above product, lower the t...

Embodiment 3

[0045] A synthetic method of piroxicam, comprising the following steps:

[0046] Step 1: Synthesis of 3-oxo-1,2-benzisothiazoline-2-acetic acid methyl ester-1,1 dioxide

[0047] Add 400mL of N-methylpyrrolidone (NMP) and 160g of sodium saccharin dihydrate to a 1000mL reaction bottle, add 110g of ethyl chloroacetate dropwise at 105°C, and react at 110-120°C for 4 hours after the dropwise addition , After the reaction, the NMP was distilled off under reduced pressure to obtain a concentrated solution and cooled to 80°C for use.

[0048] Step 2: Synthesis of 2-methyl-3,4-dioxo-4-oxide-2H-1,2-benzothiazine-3-carboxylic acid methyl ester-1,1-dioxide

[0049]Add 576g of 28% sodium methoxide, 29.3g of potassium iodide and 400mL of methanol to the concentrated solution obtained in the above step 1, gradually heat up to 65°C during the stirring process, react at 70°C for 2 hours, then distill out the methanol under reduced pressure, and cool down to 30°C ℃; Pour 600mL of pure water i...

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Abstract

The invention belongs to the field of chemical synthesis, and more specifically relates to a synthetic method of piroxicam. The synthetic method of piroxicam comprises following steps: 1, sodium saccharin and ethyl chloroacetate are taken as initial raw materials, and condensation reaction is carried out so as to obtain 3-oxo-1,2-benzoisothiazoline-2-methyl acetate-1,1-dioxide; 2, sodium methylateis added into the product in step 1, reaction is carried out under catalytic effect of potassium iodide, and 2-methyl-3,4- dioxo-4-oxo-2H-1,-2- benzothiazine-3-carboxylic acid methyl ester-1, 1-dioxide is obtained under the effect of DMSO; 3, the above product is reacted with 2-aminopyridine at 130 DEG C for 10h so as to obtain a high purity finished product. According to the synthetic method, potassium iodide is taken as a catalyst to increase the reaction conversion rate of step 2 obviously, impurity content is controlled effectively; and the total yield is increased to 69%.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, and in particular relates to a synthetic method of piroxicam. Background technique [0002] Piroxicam chemical name: 4-hydroxy-2-methyl-N-2-pyridyl-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide, a non-steroid Anti-inflammatory analgesic. In June 1982, Pfizer went public under the trade name of Feldene and Toyama Chemical Industry under the trade name of Baxo. Piroxicam has analgesic, anti-inflammatory and antipyretic effects, and 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. [0003] 3-oxo-1,2-benzisothiazoline-2-acetic acid methyl ester-1,1 dioxide is mostly obtained by 2-methylation to obtain 2-methyl-3,4-dioxo-4-oxo -2H-1,2-benzothiazine-3-carboxylic acid methyl ester-1,1-dioxide, the yield is low and there are more impurities, and the re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D417/12
CPCC07D417/12
Inventor 赵波徐元杜岭川郭海波李海剑谢芝丽
Owner ZHENGZHOU MINGZE MEDICAL TECH
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