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Process for preparing candesartan cilexetil C-form crystal

A technology for candesartan cilexetil and crystals is applied in the field of preparation of organic compound crystals, and can solve the problems of low one-time yield, small difference in boiling point, large loss of raw materials and the like

Active Publication Date: 2006-01-04
CHONGQING SHENGHUAXI PHARMA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Facts have shown that this single lower alcohol, or the water-containing mixed solvent based on lower alcohol or acetone (lower alcohol or acetone is 1-4 times of water), directly mixes the candesartan cilexetil raw material in its weight Dissolve in 2-30 times the amount of solvent and then make it to crystallize and then precipitate the crystalline product. Even if necessary, it is necessary to add a little C-type crystal as a seed crystal to promote crystallization. First of all, it shows that this method is effective in realizing the crystallization. The process of converting non-C-type crystals into C-type crystals and crystallizing out is more difficult
Test result also proves, when preparing candesartan cilexetil C-type crystal with this method, the one-time yield is lower, generally only about 80%, and the loss of raw material is larger
On the other hand, when using the mixed solvent of lower alcohol / water or acetone / water mentioned in the above-mentioned documents, because they are all binary azeotropic systems with little difference in boiling point, the lower alcohol in the mixed solution used after the crystal is prepared Or recovery of acetone is difficult

Method used

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  • Process for preparing candesartan cilexetil C-form crystal
  • Process for preparing candesartan cilexetil C-form crystal

Examples

Experimental program
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Effect test

Embodiment 1

[0020] Add 10g of candesartan cilexetil non-C-type crystal powder into 20ml of dimethylformamide aqueous solution, stir at room temperature to dissolve, then add 100ml of water dropwise to the organic solution under continuous stirring, stir for 1 to 5 hours, and precipitate crystals , suction filtration, and vacuum drying to obtain 10 g of the product. The HPLC method measures its content to be 99.4%, and melting point is 164 ℃~166 ℃, and the X-ray diffraction pattern of gained crystal is as follows: figure 1 Shown; The infrared spectrogram of the obtained crystal is shown in image 3 shown. The corresponding X-ray diffraction pattern and the infrared spectrogram of the candesartan cilexetil C-type crystal reported by aforementioned CN1058966C are as follows respectively Figure 4 and Figure 5 shown. The X-ray diffraction contrast pattern of the non-C-type crystal powder of candesartan cilexetil as raw material used in the present invention is as follows figure 2 shown...

Embodiment 2

[0022] Add 10 g of candesartan cilexetil non-C-form crystal into 20 ml of diethylene glycol dimethyl ether aqueous solution, stir and dissolve at room temperature, add 150 ml of water dropwise under stirring, continue stirring for 1 to 5 hours and lower the temperature to 5°C to 10°C, Crystals were precipitated, filtered by suction, and dried in vacuo to obtain 10 g of the product. The HPLC method determines its content to be 99.5%, and its melting point is 160°C to 163°C.

Embodiment 3

[0024] Add 10 g of candesartan cilexetil non-C-form crystal into 30 ml of acetonitrile aqueous solution, stir and dissolve at room temperature, add 350 ml of water dropwise under continuous stirring and lower the temperature to below 40°C, keep stirring for 1 to 5 hours, precipitate crystals, filter with suction, Drying in vacuo yielded 9.8 g of product. As determined by HPLC method, its content is 99.2%, and its melting point is 158°C-163°C.

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Abstract

Type-C candesartan cilexetil crystal is prepared through dissolving corresponding non-type C crystal material organic solvent capable of consoluting with water except C1-C3 lower alcohol and acetone, adding water to the solution while stirring to separate out crystal, and collecting the separated crystal as the type-C candesartan cilexetil. The said process is simple, low in organic solvent consumption, type-C candesartan cilexetil yield near the theoretical value, high crystal purity, high crystal quality and environment friendly.

Description

technical field [0001] The present invention relates to a method for preparing organic compound crystals, in particular to a method for preparing candesartan cilexetil C-type crystals. Background technique [0002] Candesartan cilexetil, chemical name 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]benzimidazole-7-carboxylic acid-1-( Cyclohexyloxycarbonyloxy)ethyl ester is an ideal pharmaceutical compound with potent antihypertensive and potent angiotensin II antagonistic activities. The compound is prepared according to an appropriate synthesis method reported in the current literature and purified by silica gel column chromatography to obtain its amorphous powder product. However, the amorphous product is unstable to heat, and it is difficult to meet the subsequent processing requirements. It has been reported in the literature that the thermal stability of the amorphous product can be significantly improved after it is converted into C-type crystal. The Chinese patent ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D403/10C07D257/04C07D235/26
Inventor 姜维平贾春荣王宗玉
Owner CHONGQING SHENGHUAXI PHARMA CO LTD
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