UA74874C2 - A method for purifying 20(s) camptothecin - Google Patents

Abstract

The invention relates to a method for purifying 20(S) camptothecin by transforming the lactone ring of the 20(S) camptothecin into a carboxylate salt with the help of an aqueous base, hydrogenating the mixture that is obtained in the presence of a transition metal catalyst, acidifying the aqueous phase to form camptothecin crystals, adding a polar aprotic solvent, optionally heating and cooling the mixture and separating the camptothecin crystals.

Description

Description of the invention

The present invention relates to a method for the purification of 20(5)-camptothecin, which contains as an impurity vinyl derivative 2 of camptothecin.

Prerequisites for the creation of the invention 29(5)-camptothecin further 20(5)-KPT) is an alkaloid of natural origin of the formula (I) ()

Same about

M

--her

M H y o ono () o 25 . oh where V! means ethyl. 20(5)-KPT and its derivatives are topoisomerase inhibitors inhibitory effect on tumors | see, for example, V.S. Siomape and others, Sapseg Kezeagsp 51 (1991), pp. 302-355, applications ER 0074256, ER 0088642, v. patents 05 4473692, OB 4545880, 05 4604463 and UMO application 92/05785). so 20(5)-KOT can be obtained as a raw product, in particular from the Chinese tree Satrioyesa asitipaya (Muzzaseae) | see M. UmMai! etc., Assoc. At. Spent boss. 88 (1966), pp. 3888-3890)|) or from the Indian tree « z5 MoiParodubez Toeida (pittopiapa) (former name Marrie Toeida Miege (|see T.K. Somipdasraghi and others, cha

Rpuyuspetizigu 11 (1972), pp. 3529-35311.

These raw products, which are primarily obtained from Moi(parodouiez Toeida), contain 20(5)-CPT with admixture

KPtT-derivative of formula (I), where B! means vinyl (hereinafter 20-vinyl-CPT). Usually, such crude products have to be purified by expensive chromatography methods or by transferring camptothecin into the aqueous phase and removing impurities by extraction with water-insoluble solvents (see, for example, UUO application 94/19353). However, it should be noted that such an impurity as 20-vinyl-CPT cannot be completely and effectively removed by the specified methods. "» Based on the above, the basis of this invention was the task of developing a method that would allow the purification of the initial product 20(5)-KPT without the need to use expensive chromatography methods for these purposes. -I During the creation of the invention, it was established that 20-vinyl impurities -CPTs, which are present in 20(5)-CPTs, can surprisingly be almost completely removed by treating the starting material first with an aqueous base, then by t-hydrogenation and subsequent acidification, after which the product can be isolated. o The object of the invention accordingly is a method purification of 20(5)-camptothecin, which consists in the fact that a) the aqueous base and the starting material containing 20(5)-camptothecin are loaded together, while the lactone ring of 20(5)-camptothecin is converted into a carboxylate salt,

GT" b) the resulting mixture is hydrogenated in the presence of a catalyst based on a transition metal, c) the aqueous phase is acidified to form camptothecin crystals, d) at least one polar aprotic solvent is added and e) the formed camptothecin crystals are isolated. Another object of the invention is a method of obtaining 20(5)-camptothecin of formula (I), where B! means ethyl, from 20-vinyl-camptothecin of formula (I), where B! means vinyl, which consists in having) a) the aqueous base and the starting material containing 20-vinyl-camptothecin are loaded together, with the formation of the compound of formula (II) 60 b5

- 0; and Mr. ON

M m Y ;

Ome

Aly 7 ono (I) where B means vinyl and Mei means metal, b) the resulting mixture is hydrogenated in the presence of a catalyst based on a transition metal, c) the aqueous phase is acidified to form camptothecin crystals, d) at least one polar aprotic solvent is added, and e) isolate the formed crystals of camptothecin. with

As used above and in the following, the term "starting material containing camptothecin" means d) impurity material containing 20(5)-CPT, crude camptothecin, plant extracts containing camptothecin, synthetic camptothecin, camptothecin derivatives, described, for example, in the UMO application 92/05785), or the products of the corresponding reactions, which contain camptothecin.

The preferred starting material is a raw product of natural origin, obtained primarily from -

Moiparoduiez ioeyda. As a rule, this product is a mixture of the compound of the formula (I), where B" means ethyl, and rch - the compound of the formula (I), where EK! means vinyl. The composition of the mixture contains, as a rule, 0.9-1.5 mass .9o, preferably 1.0-1.4 wt.9o vinyl compound. However, the starting material may also contain other camptothecin derivatives, such as, for example, 9U-methoxy-KPT, 10-methoxy-KPT, 11-methoxy- CPT, 10-Hydroxy-CPT, and 11-Hydroxy-CPT As a rule, the starting material contains up to Mwt.b5 of one or more of these additional CPT derivatives, primarily 0.2-0.8wt.9o 9-methoxy-CPT. -

The concept of "aqueous base", which is used above and in the following in stage a) of the method of purification proposed in the invention, refers to a base which in an aqueous environment, preferably in pure water, forms a sufficient amount of hydroxide ions necessary for the complete conversion of the lactone group of camptothecin derivatives, which are contained in the starting material, into the corresponding hydroxycarboxylates. Metal hydroxides are preferred, primarily alkali or alkaline earth metal hydroxides, such as lithium hydroxide, sodium hydroxide, potassium hydroxide or calcium hydroxide. The most preferred of them is sodium hydroxide. It is advisable to use metal hydroxide in the form of a diluted aqueous solution, preferably in the form of a 1-2596, primarily 3-1095 aqueous solution. As a rule, metal hydroxide is used in the amount required for complete dissolution of camptothecin derivatives; preferably per mole of starting material - 75 use 1-20 moles, especially preferably 5-15 moles, primarily 7.5-12.5 moles of metal hydroxide.

A catalyst based on a transition metal, preferably a heterogeneous catalyst based on a transition metal, such as platinum, platinum oxide, nickel, palladium or rhodium on a carrier such as activated carbon or oxide is added to the mixture obtained in this way in stage b) aluminum Preferred from the list of named palladium on activated carbon, where its content is from 1 to 15 wt.95, preferably from 2 -| 50 to 1Omas.9o, primarily of the order of 5os.9o.

T» The amount of the catalyst based on the transition metal is chosen in such a way as to ensure complete hydrogenation of the vinyl derivative of camptothecin. At the same time, it is preferable to use 0.01-0.5O0 parts by mass, primarily 0.02-0.1O parts by mass of the specified catalyst (including the carrier) per mass part of the starting material. and with. and

The mixture obtained in this way preferably at a temperature in the range from -20 to -1002C, primarily from 10 (F) to 402C, most preferably at about room temperature, is treated with gaseous hydrogen.

GI Hydrogen pressure does not play a significant role, it is advisable to carry out hydrogenation at normal or slightly increased pressure, primarily at a pressure from 0.9 to 5.0 bar, most preferably at a pressure of approximately 1 bar. If the specified conditions are observed, the hydrogenation process is usually completely completed after 1-20 hours, preferably 4-15 hours, primarily 6-1 hours.

After the completion of the hydrogenation process, the catalyst based on the transition metal is preferably removed by filtration, and then the resulting reaction mixture is acidified in stage c). Such acidification can be carried out using an inorganic or organic acid. Preferred for these purposes are mineral acids, such as NOCI, 65 НВг, НУ, НМО3, НзРО,Х, НЗО,, or aliphatic carboxylic acids, such as acetic acid or trifluoroacetic acid, or mixtures of said acids, primarily, however, concentrated hydrochloric acid . With the help of the acid used in each case, the pH value is set at 3.0-6.0, preferably at 3.5-5.0, primarily at about 4.0-4.5. The interaction with the acid is carried out, as a rule, at a temperature in the range from

О to 1002С, mainly from ЗО to 802С, primarily at 50-6090.

According to one of the preferred embodiments of the invention, 2 to 20 parts by weight, preferably from 4 to OU parts by weight, and primarily 6 parts by weight of concentrated hydrochloric acid are used for acidification per T part by weight of the starting material.

If the specified conditions are observed, the process of lactonization with the formation of CPT, as a rule, is completely completed after 10-180 minutes, preferably 15-60 minutes, primarily after the end of about 30 minutes. 70 The reaction mixture obtained as a result of acidification is, as a rule, a pure suspension. For more effective crystallization at stage d), this suspension is mixed with one or more polar aprotic solvents. Among others, sulfoxides, such as, for example, dimethyl sulfoxide (DMSO), or amides and urea derivatives of the formula IV are suitable as such.

In M

I rent in" her 0; from c to

B2 means hydrogen or a C.-C. alkyl group, primarily hydrogen or methyl, (o)

BZ and E7 each independently means a C.-C/alkyl group, primarily methyl, or 22 and C together form the group -"СНо)т or -МЕЗ-(СНо)н, while

BZ means a C.i.sub.alkyl group, "I" means C or 4, preferably C, and C means 2 or 3, preferably solvents selected from the group consisting of M,M-dimethylformamide (DMF), M,M- dimethylacetamide (ge) (DMA), M-methylpyrrolidone (M-MP), M,M-dimethylethyleneurea (DMEM) and M,M-dimethylpropyleneurea (DMPM) " or mixtures of these solvents, the most preferred of which is DMF.

As a rule, 10 to 10 parts by mass of the used starting material are used, preferably from 20 to 8 parts by mass, primarily from 30 to 5 parts by mass of a polar aprotic solvent.

Treatment with a polar aprotic solvent can be carried out at any temperature. It is preferable to stir the reaction mixture at a temperature in the range from 30 to 1202C, primarily from 80 to 1009C, and then slowly cool to room temperature.

The CPT crystals obtained in this way can then be separated from the liquid phase without problems at stage d) - c preferably separated by decantation, centrifugation, the dedentate method, by squeezing "" or by filtration, primarily by filtration. As a rule, the obtained CPT crystals the crystals are washed with alcohol, preferably methanol, ethanol or isopropanol, primarily methanol, and finally dried.

The advantage of the method proposed in the invention is that it provides a high yield per unit time per unit volume, as well as high yields and purity of the obtained 20(5)-camptothecin practically without the presence in it of impurities containing vinyl groups , and without the use of chromatographic purification for their removal.

The examples presented below serve only to illustrate and explain in more detail some possible options for the method of purifying camptothecin, which do not limit the scope of the invention. -I 20 Example 1 10.45 g of a crude product containing camptothecin obtained from Moiparoduges Toeiida with a 1.3395% content of 20-vinyl-CPT and a 0.4796% content of 9U-methoxy-CPT is dissolved in 26 ml of 2N. caustic sodium and mix with 0.bg of palladium (590o) on activated carbon. Then the mixture for 8 hours. treated at room temperature and a pressure of 1 bar with hydrogen. After that, the reaction mixture is filtered and at 50-60 is mixed with 25 ml of concentrated hydrochloric acid and the pH value is set to 4.0-4.5. Add 400 ml of DMF to the resulting suspension and mix

F! within 2.5 hours. at 90-100 C. Then the obtained suspension is slowly cooled to room temperature and filtered. The obtained KPT crystals are washed with 100 ml of methanol and dried under vacuum at 55920. In this way, 9.85 g (94.295 from the starting material) of 20(5)-camptothecin containing less than 0.0590 20-vinyl-CPT and 0.1195 9 -methoxy-KPT. bo Example 2 10.45 g of a crude product containing camptothecin obtained from Moiparoduges Toeiida with 1.3395% content of 20-vinyl-CPT and 0.4796% content of 9U-methoxy-CPT is dissolved in 26 bOml of 2n. caustic sodium and mix with 0.bg of palladium (590o) on activated carbon. Then the mixture for 8 hours. treated at room temperature and a pressure of 1 bar with hydrogen. After that, the reaction mixture is filtered and at 50-602С it is mixed with ZOO ml of 1095% sulfuric acid 65 | the pH value is set to 4.0-4.5. X0O0 ml of DMF is added to the resulting suspension and stirred continuously

2.5 hours at 90-1002С7. Next, the resulting suspension is slowly cooled to room temperature and filtered.

The resulting CPT crystals are washed with 1000 ml of methanol and dried under vacuum at 5520. In this way, 9.67 g (92.695 from the starting material) of 20(5)-camptothecin containing 0.0995 9-methoxy-CPT, the content of 20-vinyl- At the same time, the CPT is below the detection limits.

Claims (10)

The formula of the invention 70 1. The method of purification of 20(5)-camptothecin, which consists in the fact that a) the aqueous base and the starting material containing 20(5)-camptothecin are loaded together, while the lactone ring of 20(5)-camptothecin is converted into a carboxylate salt, b) the resulting mixture is hydrogenated in the presence of a catalyst based on a transition metal, c) the aqueous phase is acidified to form camptothecin crystals, d) at least one polar aprotic solvent is added, and e) the formed camptothecin crystals are isolated. 2. The method of purifying 20(5)-camptothecin according to claim 1, which is characterized in that the starting material containing 29(5)-camptothecin is a plant product of natural origin. 3. The method of purifying 20(5)-camptothecin according to claim 1 or 2, which is characterized by the fact that the starting material containing 20(5)-camptothecin is mainly a mixture of compounds of the formula (I) in: m - M x n s I h o) Eh! Sh p an de V! means ethyl or vinyl. - 4. The method of purifying 20(5)-camptothecin according to any of the previous clauses, which differs in that the base used in stage a) is sodium hydroxide. 5. The method of purifying 20(5)-camptothecin according to any of the previous items, which is characterized by the fact that the mixture obtained in stage a) is hydrogenated in the presence of a palladium catalyst at a temperature in the range from 0 °C to 1009 and at a pressure of 0, 5 to 5.0 bar. Zo 6. The method of purifying 20(5)-camptothecin according to any of the previous items, which is characterized by the fact that - the aqueous phase obtained in stage b) is treated with an acid selected from the group that includes NOSI, НВг, НУ, НМО з, НзРО ,, HBO,, acetic acid and trifluoroacetic acid, or mixtures of these acids at a temperature in the range from 30 to 802C. " 7. The method of purifying 20(5)-camptothecin according to any of the previous points, which differs in that the aqueous phase obtained in stage c) is treated at a temperature in the range from 30 to 1202C with one or more polar aprotic solvents of the formula; » in, Shk M to tri 7 o i de Go) V? means hydrogen or a C.-Sulalkyl group, BZ and E7 each independently means a C.-Sulalkyl group or they B2 and Z together form the group -"СНо)т or -МЕ?2-(СНо)я, when in this case, VZ stands for C.i-Alalkyl group, t stands for Z or 4, and n stands for 2 or 3. oo 8. The method for purifying 20(5)-camptothecin according to claim 7, which is characterized by the fact that the polar aprotic solvent is selected from the group that includes M,M-dimethylformamide (DMF), M,M-dimethylacetamide (DMA), M-methylpyrrolidone (M-MP), M,M-dimethylethylene urea (DMES) and M,M-dimethylpropylene urea (DMIPS) or mixtures of these solvents. 9. The method for purifying 20(5)-camptothecin according to any of the previous items, which is characterized by the fact that 60 crystals of 29(5)-camptothecin, which are formed in step d), are separated by filtration. 10. The method of obtaining 20(5)-camptothecin of the formula (I), where B! means ethyl, from 20-vinylcamptothecin of formula (I), where B! means vinyl, which consists in the fact that a) the aqueous base and the starting material containing 20-vinylcamptothecin are loaded together, with the formation and at the same time the compound of formula (II) I), then (1) M-th r is still an kh OomMei "Z , an where B! means vinyl, and Mei means metal, b) the resulting mixture is hydrogenated in the presence of a catalyst based on a transition metal, c) the aqueous phase is acidified with formation of camptothecin crystals, d) adding at least one polar aprotic solvent and e) separating the formed camptothecin crystals. s o "yich-s" and - shi s z -I sh» (ee) - 50 s» F) name) 60 b5