HU209450B - Process for preparing adriamycin and its hydrochloride salt - Google Patents

Abstract

During improved prepn. of adriamycin and its hydrochloride, daunomyci hydrogen halides are brominated in methanol and dioxane (1:1) solvents to obtain a mixt. of mostly 14-halide-daunomycin- 13-dimethyl-ketal-hydrogen-halide(s) and 14-daunomycin-hydrogen-hali de. The mixt. is salted out by diisopropyl ether and treated by hydrogen-bromide in an aq.-acetone soln. to remove ketal gps. 14-halide-daunomycin freed from ketal gps. and aq. alkali-formate yield adriamycin. This is isolated as a free base or its acid salt. Daunomycin-hydrogen-halides are brominated in the presence of agents capable of removing free hydrogen-halides and water. These agents are added in stages. - Removal of ketal gps. from phased out 14-halogen-daunomycin- and 14-daunomycin-13-di:methyl-ketal-hydrogen-halide salt mixts. proceeds to completion in acetone with 0.5N aq. hydrogen-halide, at room temp. Acetone and apolar byprods. are removed by organic solvents and the prepd. 14 daunomycin-hydrogen-halides react with alkali formate in aq. soln. at acid pH. The pH of the opt. water diluted reaction mix is set to pH 7.5-8.5. The adriamycin base is extracted by chloroform, opt. with added methanol. The extract is concentrated and contaminants are removed by filtration. Adriamycin is phased out from the filtrate and opt. its hydrochloride is formed. Conversely adriamycin-hydrochloride is formed. Conversely, adriamycin-hydrochloride is phased out directly by an (opt. max. 10%) excess of alcoholic hydrochloric acid. Acid addn. is followed immediately by addn. of 2-3C alkylene oxide.

Description

precipitating and, if desired, converting it to a hydrochloric acid salt in a known manner, or, if appropriate, separating adriamycin hydrochloride directly with alcoholic hydrochloride by using an excess of the acid, preferably up to 10%, and adding the acid to the solution. to give a C2-C3 alkylene oxide.

The present invention relates to an improved process for the preparation of the salt of adriamycin and its hydrogen halide starting from daunomycin hydrogen halide.

Of the anthracycline-type antibiotics used in medicine, chemotherapy for the treatment of cancer is primarily adriamycin / (8S-10S) -10 [(3-amino-2,3,6-trideoxy-a-L-lyxo-hexopyranosyl) -oxy] -7.8, 9,10-tetrahydro-6,8,11-trihydroxy-8-acetyl-1-methoxy-5,12-naphthacenedione hydrogen halide.

Most preferably, adriamycin is produced by fermentation with daunomycin / (8S-10S) -10 [(3-amino-2,3,6-trideoxy-α-L -hexo-hexopyranosyl) -oxy] -7,8,9,10-tetrahydro-6,8, 11-trihydroxy-8-acetyl-1-methoxy-5,12-naphthacenedione) / by chemical conversion can be obtained by converting the 8-acetyl group of the molecule into a hydroxyacetyl (i.e., 14-hydroxy) group. Fermentation technology for the production of adriamycin is also known, but its efficiency is still less than that of semi-synthesis. In the literature, the formation of the 14-hydroxyl group of adriamycin is, in principle, accomplished by first converting daunomycin into a 14-halogen derivative and then converting it to a hydroxyl group. There are a number of possible ways to accomplish this reaction sequence.

No. 1,217,133. according to one method of the British patent, daunomycin and daunomycin hydrochloride are brominated in anhydrous methanolic dioxane solution with elemental bromine in chloroform and the resulting 14-bromo-daunomycin is hydrolyzed with an alkali metal hydroxide solution; alternatively, by converting 14-bromo-daunomycin to 14-acetoxy-daunomycin and then subjecting it to hydrolysis; another possibility is described in the above description, according to which the synthesis is carried out via 14-iodine-daunomycin but the amino group of daunomycin must first be protected for iodination.

No. 190,382. U.S. Patent No. 4,198,123 to Horsham discloses an improved process for the preparation of the hydrogen halide salts of adriamycin which comprises bromination in the presence of anhydrous methanol / dioxane in a ratio of 1: 2 to 5 in the presence of a C 1 -C 5 orthoalkanoate or C 1 -C 5 is carried out over a relatively long reaction time (3-30 hours), and the "cyclic bromo ketal" (the above structure of which is not supported by any data) as described herein is first reacted with acetone, aqueous hydrogen bromide and then with aqueous alkaline formate. . The base of adriamycin is then extracted at an alkaline pH to form the hydrochloride salt. (Note that this process is the same as that described in Belgian Patent No. 841,266 for the preparation of epiradriamycin.)

No. 00 39 060. European Patent Publication No. 14,123,125 discloses the preparation of adriamycin and C-4 'ether derivatives starting from 14-halo daunomycin or its hydrochloric acid salt. The target products are obtained by hydrolysis of the above compounds or their C-4 'ether derivatives in lower alcohols or aqueous acetone. According to the disclosure, the starting 14-halo-daunomycin is prepared by brominating daunomycin hydrochloride in anhydrous methanol-dioxane (1: 2) solution of elemental bromine in dichloromethane in the presence of ortho-acetic acid methyl ester at 25 ° C for 40 minutes.

The preparation of 14-halo-daunomycins is described in U.S. Pat. European publication. The authors of this specification prepare 14-chloro-daunomycin by reacting daunomycin hydrochloride in anhydrous methanolic dioxane (1: 1) in the presence of an ortho-acetic acid alkyl ester at 10-15 ° C for 1 hour. The 14-bromo-daunomycin-13-dimethyl ketal formed by the reaction is decanted with acetone hydrobromic acid to give 14-bromo-daunomycin hydrobromide, which is then converted to 14-chloro-daunomycin hydrochloride with an aqueous solution of alkali chloride. The procedures described were reproduced and, according to our experimental data, following the methods described in the literature, in contrast to 30-40% yield, only 20-30% of the yield of daunomycin to adriamycin can be achieved. The resulting product is highly contaminated, containing only about 80-85% of adriamycin, which is only a very low yield of pharmacologically pure adriamycin hydrochloride. According to our studies, the low yields are due to the fact that daunomycin, 14-bromo-daunomycin and adriamycin are hydrolysed to different degrees during the known processes (daunomycin, 14-bromo-daunomycin, adriamycinone and α-methyl-daunomycin) other significant degradation occurs under the alkaline conditions of the final step; finally, the extraction of the adriamycin base present does not proceed completely as described in the literature. Consequently, the adriamycin formed must be recovered from the by-products in excess thereof. Thus, none of the known processes are suitable for the industrial production of adriamycin.

According to the procedure described in Hungarian Patent Application Publication No. T / 525166, the authors obtained from 14-Bromo-daunomycin and the like. starting from their dimethyl ketal, which is hydrolyzed with dicarboxylic acid in the aqueous medium through their supposed ester to the adriamycin dicarboxylic acid salt.

Of which, the hydrochloric acid salt is either ion exchange chromatography or preperative high performance liquid chromatography2

HU 209 450 Β is recovered and cleaned using a coaxial procedure. The above process variant does not allow for the preparation of a good quality final product due to the decomposition of high volumes of solvent, whereas high pressure liquid chromatography is not suitable for large quantities of material.

According to the procedure described in Hungarian Patent Application Publication No. T / 52108, 14-trifluoromethanesulfonyloxy-daunomycin is first prepared from pure 14-bromo-daunomycin, which is optionally hydrolyzed to adriamycin under acidic conditions without isolation. The disadvantage of this process is that it is based on pure 14-bromo-daunomycin, which can only be obtained by acid hydrolysis from the 14-halo-daunomycin-13-dimethylketal formed by the bromination of daunomycin, and on the other hand, the preparation of 14-bromo meshate, which is a very expensive reagent and is not industrially applicable. Although other salts are mentioned as being useful herein, they cannot be used for halogen exchange, since the insoluble silver salt is the driving force behind the reaction. Because of the extremely high value of the starting daunomycin, we aimed to develop a commercially available version of the known conceptual reaction (daunomycin hydrogen halide -> 14-halo-daunomycin - »adriamycin - hydrogen chloride) so that the unavoidable by-products on the one hand, and, on the other hand, a process for the easy and efficient removal of contaminants.

During our experiments it was found that the amount of water present in the reaction mixture essentially influences the production of bromination, the reaction time, the composition of the final product and the extent of the most significant secondary reaction (hydrolysis). It has also been found that although it is advisable to use a strictly anhydrous medium for bromination and subsequent ketal formation, it is not necessary to create absolute anhydrous conditions at the beginning of the bromination reaction. In fact, during the formation of acetal, additional water is released into the system, slowing down the reaction and reducing production. Therefore, in order to eliminate this, bromination must be carried out in the presence of reagents that are capable of irreversibly binding water, but also for the bromination reaction. However, in the presence of these reagents, a maximum of 1 molar equivalent of water, initially calculated per daunomycin hydrochloride reacted, may be present in the system. Certain organometallic compounds such as tetraethoxysilane, dimethyl diethoxysilane, etc., and various substituted and unsubstituted aliphatic orthoesters, such as tri (2-chloroethyl) orthoformate, trimethyl- orthoformate or triethyl orthoformate.

It has also been found that if the bromination reaction is carried out in sufficiently concentrated solutions, the halogenated products can be precipitated directly from the reaction mixture without evaporation of the mixture. This circumstance is of great importance in that, in this way, unlike in the known processes, the inevitable decomposition during evaporation can be prevented.

Hydrogen bromide is formed in the bromination reaction, which can cause or enhance the hydrolysis of the compounds present in the reaction mixture. On the other hand, a certain concentration of hydrogen bromide must be present in the system, otherwise bromination will not occur. It has been found that if an acid binder is used in the bromination reaction and added to the reaction mixture in portions to maintain the optimal concentration of hydrogen bromide formed, the hydrolysis during the bromination reaction can be significantly reduced.

According to our studies, for example, various epoxides such as styrene oxide, epoxypropanol or propylene oxide are used as acid scavengers; and ion-exchange resins and potassium fluoride.

(Note that although propylene oxide is used as an acid scavenger in Example 1 of European Patent Application 0295 119, it is added in one portion only one hour after the addition of bromine, prior to concentration. The acid scavenging is carried out in this way. acid hydrolysis during the bromination reaction cannot be prevented.)

It has been found that the bromination reaction starting from daunomycin hydrochloride gives a very good yield of a salt mixture consisting mainly of the hydrochloride and hydrobromide salts of 14-halo-daunomycins and 14-halo-daunomycin-13-dimethyl ketals. This salt mixture is a well-processed crystalline product which can be stored for a long time without decomposition and used directly to produce adriamycin.

It is further recognized that the decalcification of the 14-halo-daunomycin13-dimethyl ketal components of the salt mixture resulting from the bromination must be perfectly accomplished because, under mild conditions, only the 14-halo-daunomycin can be converted to adriamycin and the and can only be removed by high-performance chromatography.

There are several known methods for converting 14-halo-daunomycin to adriamycin. The most preferred of these was the reaction with alkali formate. The known processes employ the reaction in an anhydrous solvent (e.g. dimethylsulfoxide) or a solvent-water system (e.g. aqueous acetone). We have found it advantageous to carry out the reaction in water only, in a pH of 4-5 acidic medium, since at this pH, a perfect conversion is achieved and the formation of by-product is negligible as opposed to the processes employing the above solutions. In this way, the hydrolysis end-point results in an aqueous solution of a very pure adriamycin + salt mixture in which only 1-2% of anthracycline skeletal impurities are detected.

It has been found that the pure adriamycin from the aqueous reaction mixture can advantageously be obtained by adjusting the aqueous solution to pH 7.5 to 8.5.

EN 209 450 Β and extracted several times with chloroform, optionally containing methanol, and the extracts are concentrated to a content of 1.5-3.0% adriamycin base, followed by solids precipitated from a solution which is a mixture of impurities of unknown structure formed during synthesis. removed by filtration. Finally, the adriamycin base is precipitated from the filtrate in a manner known per se and optionally converted to the hydrochloric acid salt or, if desired, to the hydrochloric acid adriamycin, by the addition of a small excess of up to 10% of the acid and addition of hydrogen chloride. propylene oxide is also added to the solution to prevent hydrolysis.

SUMMARY OF THE INVENTION The present invention relates to a process for the preparation of adriamycin and its hydrochloride salt by bromination of a daunomycin hydrogen halide in a methanol-dioxane (1: 1) mixture in the presence of water and halohydride binding reagents, mainly 14-halo-daunomycin-13 precipitation of a salt mixture of ketal hydrogen halide (s) and 14-halo-daunomycin hydrogen halide (s) and treatment with hydrogen bromide in aqueous acetone solution at room temperature with the decalcified 14-halo-daunomycin salt formate by reacting the resulting adriamycin in the form of a base or its hydrochloride salt, which comprises using tri (2-chloroethyl) orthoformate or tetraethoxysilane as the water scavenger in bromination of the daunomycin hydrohalide halides, and adding the free -hydroxylamine deoxygenated reagent, and after bromination, the precipitated mixture of 14-halo-daunomycin and 14-halo-daunomycin, 13-dimethyl-ketal-hydrogen halide, was decanted with 0.5 N aqueous hydrobromic acid, The hydrogen halide salts of the resulting 14-halo-daunomycins are reacted with the alkali formate in aqueous solution and the pH of the acid solution is adjusted to pH 7.5 to 8.5 by extraction in a known manner. Concentrate to 1.5-3.01% adriamycin base, filter off precipitated impurities from the concentrated solution, precipitate the adriamycin base from the filtrate in a known manner and, if desired, convert to the hydrochloric acid salt or, optionally, directly with alcoholic hydrogen chloride. adriamycin hydrochloride is isolated so that the acid is purified by the method described in Art is used in an excess, preferably up to 10%, and after the addition of the acid, a C2-C3 alkylene oxide is added.

In a preferred embodiment of the process of the invention, the adriamycin and its hydrochloride salt are prepared starting from daunomycin hydrochloride. In this case, during the bromination step, 14-bromo-daunomycin-13-dimethyl-ketal forms 14-chloro-daunomycin-13-dimethyl-ketal and 14-bromo-daunomycin in the form of a mixture of its hydrochloride and hydrobromic acid salts. This salt mixture can be directly decalcified and converted to adriamycin with sodium formate.

The hydrochloride salt of adriamycin is used in medicine by intravenous treatment. To do this, a 1: 5 aqueous solution of adriamycin salt and lactose is lyophilized and reconstituted in water when used; One lio ampoule contains most often 10 mg of adriamycin hydrochloric acid salt and 50 mg of lactose. An aqueous injection containing adriamycin hydrochloride salt may also be prepared.

Main advantages of the process of the invention.

- The conversion of daunomycin to adriamycin is achieved in approximately 50% higher yields (30-42% versus 55-65%) compared to prior art processes;

- whereas the literature processes yield only "crude" (75-90% purity) product, the process of the present invention can provide pharmaceutical grade adriamycin;

- the process is safe, can be easily followed by analytical methods at all stages and is suitable for industrial implementation.

The process of the invention is illustrated in detail by the following embodiment:

Example

Preparation of Adriamycin p, bromination of Daunomycin hydrochloride

Method A.

Dissolve 112.8 g (0.2 mol) of daunomycin hydrochloride in 560 ml of anhydrous dioxane and 560 ml of anhydrous methanol, add 120 ml (0.72 mol) of triethyl orthoformate and cool to 15 ° C. Bromine (2 mL, 0.72 mol) was added dropwise over about 3 minutes.

While maintaining the temperature at 14-16 ° C, propylene oxide (4 ml) was added over 10 minutes, an additional 4 ml (20 minutes) and 12 ml (45 minutes). The solution was poured into 10 L of diisopropyl ether with stirring. The precipitated red product is filtered off, washed with diisopropyl ether, and air dried under vacuum. This gives 125-126 g of the product which is a mixture of 14-bromo-daunomycin-13-dimethyl ketal (72%) 14-chloro-daunomycin-13-dimethyl ketal (7%) 14-bromo-daunomycin (12%) ) and adriamycin (3-8%); these compounds are formed as a mixture of their hydrochloride and hydrobromide salts.

Method B.

0.56 g (0.001 mol) of daunomycin hydrochloride was dissolved in 2.8 ml of anhydrous dioxane and 2.8 ml of anhydrous methanol at room temperature. The solution was cooled to 16 ° C and 0.6 ml (0.003 mol) of tri (2-chloroethyl) -orthoformate and 0.07 ml (0.0013 mol) of bromine were added with stirring. Propylene oxide (0.02 ml) was added over 15 minutes after the addition of bromine, another 0.02 ml (20 minutes), and 0.05 ml (0.05 ml) at the end of the reaction (~ 35 minutes). The solution was washed with stirring with diisopropyl ether (56 mL) and dried in vacuo. The product weighed 0.62 g and had the same composition as in method A.

HU 209 450 B

Method C.

0.56 g (0.001 mol) of daunomycin hydrochloride

Dissolve in a mixture of 2.8 ml of anhydrous dioxane and 2.8 ml of anhydrous methanol at room temperature. To the solution was added tetraethoxysilane (0.8 mL, 0.003 mol) followed by bromine (0.08 mL, 0.0015 mol). The reaction was carried out as described in Method B to give 0.64 g of the brominated product having the same composition as in Method A.

Method D.

0.56 g (0.001 mol) of daunomycin hydrochloride was dissolved in 2.8 ml of anhydrous dioxane and 2.8 ml of anhydrous methanol at room temperature. 0.6 ml (0.003 mol) of tri (2-chloroethyl) orthoformate and 0.07 ml (0.0013 mol) of bromine are added with stirring. The solution was stirred at 25 ° C. Within 15 minutes of the bromine addition, 1 ml of AGI-X2 (OH-) anion exchange resin (0.2 N capacity) was added to the reaction mixture, which was repeated at 20 minutes and an additional 3 ml of resin was added at 30 minutes. After stirring for a further 10 minutes, the resin was filtered, washed with dioxane-methanol 1: 1, and the filtrate was poured into 60 ml of diisopropyl ether. Filter, wash with diisopropyl ether, and dry. Weight of product: 0.6 g has the same composition as described above.

_2. Daunomycin hydrobromide Bromination

6.89 g (0.01 mol) of daunomycin hydrobromide salt were dissolved in a mixture of 30 ml of dioxane and 30 ml of methanol at room temperature, followed by 6 ml (0.03 mol) of tri (2-chloroethyl) -orthoformate and 0.7 ml. Bromine (0.013 mol) was added to the solution. Propylene oxide (0.19-0.19-0.52 ml) was added to the stirred reaction mixture at 20 ° C at the times described in (j). The reaction mixture was poured into 600 ml of diisopropyl ether, and the precipitate was filtered off, washed, dried. Weight: 6.73 g. The product is a 3: 1 mixture of the hydrobromic salts of 14-bromo-daunomycin-13-dimethyl ketal and 14-bromo-daunomycin.

bj., 14-Bromo-daunomycin hydrobromide

The product (6.73 g) obtained in ₂ was dissolved in a mixture of 120 ml of acetone and 120 ml of 0.5 N aqueous hydrogen bromide and stirred for 6 hours at 20 ° C until complete hydrolysis of the ketal group. The reaction was monitored by thin layer chromatography. (Adsorbent: silica gel, mixture chloroform-methanol-formic acid (80: 20: 2); _Rf values: 14-bromo-daunomycin dimetilketál 0.65, 14-bromo-daunomycin 0.55.) The reaction mixture was 120 diluted with water (3 ml) and extracted with chloroform (3 x 50 ml). The aqueous phase is extracted with three 150 ml portions of n-butanol and the n-butanol solution is concentrated to 100 ml in vacuo. During evaporation, crystalline precipitation of the product begins. The suspension was cooled to 0 ° C for 5 hours, the crystals were collected, washed with 10 ml of acetone and dried. 4.5 g of product are thus obtained. Mp 184-185 ° C; impurity (as measured by HPLC): 1%.

Preparation of b. ₂ , 14-halo-daunomycin hydrobromic acid and a salt mixture

All proceed as in bj., But starting from the 14-halo-daunomycin mixture prepared in j. Starting from 47 g of the salt mixture, 35 g of 14-halo-daunomycin are obtained, which is a mixture of 85% of the hydrobromic acid salt of 14-bromo-daunomycin and 15% of 14-chloro-daunomycin.

c., Preparation of Adriamycin

The product (125 g) obtained in (j) is dissolved in a mixture of 2400 ml of acetone and 2400 ml of 0.5 N aqueous hydrobromic acid with stirring at 26 ° C. The end point of the de-scaling reaction was determined by the TLC assay described in bj. complete conversion occurs within 5-6 hours. The solution was diluted with water (2400 mL) and the acetone and by-product were extracted with 3 x 2 L chloroform. A solution of 360 g of sodium formate in 1400 ml of water is added dropwise to the aqueous solution with stirring. In 1 hour. The dark solution was stirred at 26 ° C for 20 hours. The gel-like reaction mixture was diluted to 28 L with water and then basified to pH 7.6-8 with 5% aqueous sodium bicarbonate. Extract the mixture several times with chloroform containing methanol, concentrate the organic phase containing adriamycin to 3 liters, filter off solid precipitated by-products from the dilute suspension, add 5% methanolic hydrochloric acid to the clear solution and add 5.6 ml of propylene oxide. The crystal slurry was cooled to 0 ° C for 24 hours, washed with chloroform and acetone and finally dried in vacuo. 64 g of adriamycin hydrochloride are thus obtained.

The impurity of the product as measured by HPLC is 1%. An additional 5.8 g of adriamycin hydrochloride of the above quality is obtained from the mother liquor by liberating the base after evaporation and salt formation. Yield: 60.2% (based on daunomycin hydrochloride).

Claims (5)

PATENT CLAIMS A process for the preparation of adriamycin and its hydrochloride salt by bromination of a daunomycin hydrogen halide in a 1: 1 volume ratio of methanol in the presence of water and halogenated hydrogenating reagents, mainly 14-halo-daunomycin-13-dimethyl ketal. precipitation of a mixture of halide (s) and 14-halo-daunomycin hydrogen halide (s) with diisopropyl ether and treatment with hydrogen bromide in aqueous acetone solution at room temperature, reacting the decalcified 14-halo-daunomycin salt with an alkaline formate separating the resulting adriamycin in the form of a base or its hydrochloride salt which comprises using tri (2-chloroethyl) orthoformate or tetraethoxysilane as the water scavenger in brominating the daunomycin hydrogen halides and adding the free mixture in several portions to the reaction mixture. for the bonding of halohydrogen apple reagent, After the bromination, the precipitated 14-halo-daunomycin and 14-halo-daunomycin-13-dimethyl-ketal-hydrogen halide salt precipitate from the reaction mixture was decanted with 0.5 N aqueous hydrobromic acid. the hydrogen halide salts of the resulting 14-halo-daunomycins are reacted with alkaline formate in aqueous solution and the pH of the acid solution is adjusted to pH 7.5 to 8.5 by extraction of the adriamycin base in a known manner, concentrating the extractant to a content of 1.5-3.0% by weight of adriamycin base, filtering out the impurities from the concentrated solution, precipitating the adriamycin base from the filtrate in a known manner and converting it, if desired, to a hydrochloric acid salt in a known manner; adriamycin hydrochloride is directly precipitated with alcoholic hydrogen chloride in such a way that the acid is in an excess, preferably up to 10%, and after the addition of the acid, a C2-C3 alkylene oxide is added. Process according to claim 1, characterized in that the bromination is carried out by linking the free halohydrogen acid with propylene oxide or an anion exchange resin. Process according to claim 1 or 2, characterized in that the excess acid is trapped with propylene oxide during the removal of the adriamycin hydrochloride. 4. A process according to any one of claims 1 to 3, characterized in that daunomycin hydrochloride is used as starting material. 5. A process according to any one of claims 1 to 3, characterized in that daunomycin hydrobromide is used as starting material.