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Process for preparing high purity letrozole

A technology for letrozole and a compound is applied in the field of preparation of high-purity letrozole, can solve the problems of no effective refining intermediate, complicated and tedious operation, and high production cost, and achieves the operation of avoiding column chromatography and multiple recrystallizations Effect

Active Publication Date: 2009-11-18
AVENTIS PHARMA HAINAN
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0010] In the patent EP0236940, it is reported that column chromatography and multiple recrystallization methods are used to remove isomers, but this method is complicated and cumbersome to operate, and the refining yield is low, which leads to low production efficiency and high production cost
[0011] In the patent EP0236940 and other published reports on the preparation of letrozole, there is no mention of using an economical and effective method to prepare high-purity letrozole, and there is no report on the method of effectively refining the intermediate

Method used

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  • Process for preparing high purity letrozole
  • Process for preparing high purity letrozole
  • Process for preparing high purity letrozole

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Embodiment 1

[0022] The preparation of embodiment 1 high-purity letrozole

[0023] Add 1 liter of chloroform into a 2-liter reaction flask, add 60 grams of p-cyanobenzyl bromide and 90 grams of 1,2,4-triazole under stirring, and heat to reflux for 20 hours. Cool, wash with 5% sodium bicarbonate solution, and dry the organic phase. After filtration, the filtrate was evaporated to dryness under reduced pressure to obtain about 82 grams of a mixture of the intermediate compound of formula I and its isomer compound of formula II.

[0024] 82 g of the mixture obtained above (the ratio of the compound of formula I to the compound of formula II is about 2:1) was dissolved in 500 ml of ethanol, and about 30 ml of concentrated hydrochloric acid was slowly added dropwise with stirring, and the precipitate was removed by filtration. Continue to add concentrated hydrochloric acid to the filtrate until no more precipitates are formed. Filtration yielded 74 g of the hydrochloride salt of the compound ...

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Abstract

The invention relates to a process for preparing letrozole with high degree of purity.

Description

field of invention [0001] The invention relates to a preparation method of high-purity letrozole. Background of the invention [0002] Letrozole (Letrozole) is a new generation of aromatase inhibitors, which can reduce the level of estrogen by inhibiting aromatase, thereby eliminating the stimulating effect of estrogen on tumor growth. Its structural formula is shown in the figure below: [0003] [0004] Letrozole [0005] Studies have shown that compared with the first-generation aromatase inhibitor aminolute, letrozole has much stronger activity in vivo and in vitro than aminolute, and has high selectivity, no potential toxicity, and good tolerance , strong pharmacological effects, no significant effect on the formation of adrenal gland substances, etc., so its anti-tumor effect is stronger, it is the first choice drug for the treatment of advanced breast cancer, and it can completely replace Anlut and megestrol . There are many female breast cancer patients in our...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D249/08
Inventor 刘昆杨利民
Owner AVENTIS PHARMA HAINAN
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