CH621797A5 - Process for the preparation of 6''-deoxykanamycin B and 6''-deoxytobramycin - Google Patents

Description

The invention relates to the production of semisynthetic, where R is hydrogen or OH, and non-toxic, pharmaceutically acceptable acid addition salts thereof.

In the present application, the term “non-toxic, pharmaceutically acceptable acid addition salts” means a mono-, di-, tri-, tetra- or pentasalt which can be obtained by reacting 1 molecule of 6 // - deoxykanamycin B or 6 "-deoxytobramycin with 1 up to 5 moles of a non-toxic,

pharmaceutically acceptable acid is formed. These acids include acetic acid, hydrochloric acid, sulfuric acid, maleic acid, phosphoric acid, nitric acid, hydrobromic acid, ascorbic acid, malic acid and citric acid, as well as all other acids that are commonly used to form salts of amine-containing pharmaceuticals.

According to the invention, these connections are produced according to the following schematic diagram:

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(2) Compound 2

p-toluenesulfonyl chloride.

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6

(3) Compound 3 sodium iodide

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and

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: h2nh2

It should be noted that in the schematic diagram, stage 5 shows the production of 6 "-deoxytobramycin. The exact mechanism by which 6" -deoxykanamycin B is also obtained is not known, since one would expect from the previous stages that only 6 "-deoxytobramy-cin would be obtained. However, it is hypothesized that in stage 2 some 6 / y-monotosylate of penta-N-acetylkanamycin B can be obtained, in which case some 6" -iodo-penta- N-acetylkanamycin B in step 3 and some penta-N-acetyl-6 "-deoxykanamycin B in step 4. However, the analytical data do not confirm the presence of such derivatives in these steps.

The object of the present invention is achieved by the inventive creation of the process for the preparation of 6 "-deoxytobramycin and 6 // - deoxykanamycin B or a non-toxic, pharmaceutically acceptable acid addition salt thereof; the process comprises the following, successive stages:

(A) Kanamycin B is treated with a large molar excess of an acetylating agent, for example acetic hydride in a low alkanol or with acetyl chloride in combination with a base to take up the free HCl, such as triethylamine or pyridine. The term “lower alkanol” means an alkanol having up to 4 carbon atoms, for example methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol and tert-butyl alcohol.

Preferably, at least 5.1 moles of acetylene agent are used per mole of kanamycin B and the reaction is carried out at a temperature below 25 ° C., and preferably at about room temperature. The product obtained by treating kanamycin B with the acetylating agent is penta-N-acetylkanamycin B.

(B) Penta-N-acetylkanamycin B is treated with p-toluenesulfonyl chloride in the presence of a tertiary amine such as pyridine, triethylamine or dimethylaniline. Preferably, at least 2.0 moles of p-toluenesulfonyl chloride are used per mole of penta-N-acetylkanamycin B and the reaction is carried out in a

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Temperature below 25 ° C and more preferably at about room temperature.

(C) The tosylate derivative obtained in step (B) is reacted with a halide which is selected from sodium iodide, lithium iodide, sodium bromide or lithium bromide in a suitable solvent system. The solvent is a compound selected from N, N-dimethylformamide or a ketone of the formula

O

II

R'-C-R "

wherein R 'and R "are the same or different and each represents an alkyl group containing up to 6 carbon atoms. Examples of such ketones include acetone, methyl isobutyl ketone and methyl ethyl ketone. An alternative solvent system is hexamethyl phosphorus triamide in an aromatic hydrocarbon, which is selected toluene, benzene, xylene, or mixtures thereof using reflux temperatures of approximately 1.1 moles of hexamethylphosphoric triamide per mole of sodium iodide, lithium iodide, sodium bromide or lithium bromide in this system, preferably at least 6 moles of halide per mole of tosylate derivative and the reaction is carried out at a temperature above 80 ° C, and more preferably at a temperature from 100 to 125 ° C.

(D) An aqueous solution of the product obtained in step (C) is hydrogenated in the presence of a known hydrogenation catalyst, for example Raney nickel, palladium, platinum, rhodium or ruthenium. The hydrogenation reaction is preferably carried out at about room temperature.

(E) An aqueous solution of the product obtained in step (D) is heated in the presence of a strong base, for example sodium hydroxide, lithium hydroxide, potassium hydroxide or barium hydroxide, to provide a mixture of 6 "-deoxykanamycin B and 6 // - deoxytobramycin.

The compounds obtainable according to the invention are valuable

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full of antibacterial agents, supplementary feed in animal feed, therapeutic agents for poultry and animals and humans, and they are particularly valuable in the treatment of infectious diseases caused by gram-negative bacteria. They are effective in treating systemic bacterial infections when administered parenterally in the dose range of about 250 mg to about 3000 mg per day in divided doses three or four times a day. In general, the compounds are effective when administered at a dose of approximately 5.0 to 7.5 mg / kg body weight every 12 hours.

example

step 1

Penta-N-acetylkanamycin B (2)

117.2 ml (1.24 mol) of acetic anhydride are added dropwise to a stirred suspension of 40.0 g (0.0827 mol) of kanamycin B in 800 ml of methanol. A clear solution is obtained before all of the acetic anhydride is added, but the formation of a precipitate begins almost immediately thereafter. After the addition of the acetic anhydride has ended, the mixture is stirred for a further 16 hours. During this time, the reaction mixture solidifies and several 100 ml of methanol are added in order to obtain a filterable mixture. The wet solids are suspended in 800 ml of fresh methanol and the suspension is stirred for 1 hour. The solids are collected by filtration and then stirred for 1.5 hours with 800 ml of methylene chloride. The product is then collected by filtration, rinsed with methylene chloride and dried thoroughly, giving 44.4 g (yield 77.4%) of compound (2) in the form of a crystalline solid with a melting point of 340 to 343 ° C.

Analysis for C28H47N5O15:

C H N

Calculated: 48.87% 6.84% 10.09%

Found *: 48.62% 6.83% 10.13%

* Corrected for 1.37% water found

The infrared and NMR spectra are consistent with structure 2.

Level 2

Penta-N-acetylkanamycin B-3 /, 6 "-ditosylate (3)

A mixture of 1,000 g of penta-N-acetylkanamycin B (1,442 mmol) and 1,645 g of p-toluenesulfonyl chloride (8,649 mmol) in 10 ml of anhydrous pyridine is stirred at room temperature for 23 hours. The reactants slowly dissolve and are completely dissolved after 5 hours. After 5 hours the solution has an orange color and this color does not change during the further reaction. The reaction mixture is poured into 200 ml of methylene chloride and the precipitated cream-white product obtained is dried thoroughly. Then it is suspended in 30 ml of methylene chloride and heated to reflux for 2 minutes. The insoluble solid is collected by filtration from the hot solvent and dried thoroughly over P2O5, yielding 1.043 g (yield 72.2%) of compound 3. The infrared spectrum shows typical tosylate bands at 1180 and 1220 cm-]. A sample of the product is subjected to liquid chromatography by injecting 35 microliters of a suspension of 1 ml of the product per ml of a solution consisting of 30% water and 70% methanol onto a series of four 0.38 cm columns 1/8 in.) X60.96 cm (2 it.). The columns are loaded with Cis / CORASIL I, a monomolecular layer of octadecyl-trichlorosilane, which is chemically bound to a porous silicon dioxide layer on a solid core made of glass beads. It is found that the product consists of a very minor component with a retention time of 1672 minutes and a main component with a retention time of 193A minutes.

Analysis for C42H59N5O19S2:

C H N S

Calculated: 50.34% 5.93% 6.99% 6.40%

Found *: 48.67% 5.64% 6.83% 5.87%

* Corrected for 2.66% moisture found

level 3

Penta-N-acetyl-3,6 "-dijodkanamycin B (4)

A mixture of 834 mg of the product obtained in Example 2 (0.832 mmol), which was dried in vacuo over P2O5 at room temperature and 1.998 g of sodium iodide (13.3 mmol), which was in an oven in air at 110 ° C. for 20 hours dried, in 1.5 ml of N, N-dimethylformamide is placed in a 60 ml thick-walled glass ampoule, which is rinsed with N2 and heated to 100 ° C. for 23 hours. Then you open the ampoule, cool and fill with ether. After several hours, the ether is decanted and the residue is heated on a steam bath until a thick syrup has formed. The ampoule is then filled with dioxane, heated to 90 ° C. and the insoluble solids, which include the desired product, are collected by filtration, rinsed with ether and dried in vacuo over P2O5. The solids obtained are desalted by dispersing them in 15 ml of water and then removing the water-insoluble solids by filtration over a bed of diatomaceous earth. The filtrate is passed through an 800 ml column with Sephadex G10, a cross-linked dextran with a molecular weight retention of up to approximately 700. The column is pumped at 1 ml / min and 27 ml fractions are collected. It is found that the product is in tubes 11 to 21. The components of these tubes are combined, reduced to a volume of 20 ml by evaporation at 50 ° C. and the product, 504 mg of compound 4 (yield 66.3%), is obtained therefrom by lyophilization. This product is used directly without further cleaning in the example below.

Level 4

Penta-N-acetyl-6 'deoxytobramycin (5)

An aqueous solution of 388 mg of the product obtained in Example 3 (0.425 mmol) in 60 ml of water is hydrogenated for 21 hours in the presence of approximately 4 g of Raney nickel catalyst at room temperature and a hydrogen pressure of 3.09 kg / cm 2 (44 psi) . Then the catalyst is filtered off and washed thoroughly with water. The combined filtrates are evaporated to dryness at 50 ° C. and dried over P2O5 in vacuo to give 180 mg (yield 63.1%) of compound 5.

Level 5

6 "-Desoxytobramycin (6) and 6" -Desoxykanamycin B (7) A mixture of 180 mg of the product obtained in Example 4 (0.272 mmol), 2.55 g Ba (OH) 2 • 8H2O (8.08 mmol) and 10.2 ml of water is heated to reflux for 17 hours. The reaction mixture is then diluted to 35 ml by adding water and solid carbon dioxide is added until the pH has dropped to 7.0. The BaCÛ3 obtained is removed by filtration through a fine filter paper and washed with a few ml of water. The combined filtrates are evaporated to 10 ml and then lyophilized. The raw product weighs

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170 mg. The product is dissolved in 2.00 ml of water for analysis by thin layer chromatography on a column with silica gel S110 using the solvent system HzO-.CHsOH-.konz. NlfcOHiCHCls (1: 4: 2: 1). The analysis shows that kanamycin B has an Rf value of 0.52, while the two main ninhydrin-positive components of the product mix have an Rf of 0.47 and an Rf of 0.61. If one covers a corresponding plate with an agar plate sown with Bacillus subtilis at a pH of 8 and incubates overnight at 37 ° C., large zones of inhibition are obtained at Rf = 0.47 and Rf = 0.61. A 0.100 ml aliquot of the 2.00 ml solution of the crude product is diluted with 0.1 N phosphate buffer with a pH of 8.0 bus 5.00 ml and subjected to a differential biological test for tobramycin-like and kanamycin-B-like activities . From the bioassay data it follows that the yield of 6 // - deoxytobramycin is approximately 7.1% and the yield of 6 "-deoxykanamycin B is calculated from the bioassay data to approximately 1.5% io.

B

Claims (3)

621797 2. The method according to claim 1, characterized in that ss The invention relates to a process for the production of two new semisynthetic derivatives of kanamycin B, namely 6 "-deoxykanamycin B and 6" -deoxytobramycin, which are highly active antibiotics with a broad spectrum of activity. These compounds are made by dehydroxylation of the 6 "and 3 ', 6' / positions of kanamycin B. Kanamycin B is a known antibiotic, which is described in the Merck Index, 8th edition, pages 597-598. Kanamy-6s a B is a compound of the formula: 2nd PATENT CLAIMS 1. Process for the preparation of 6 "-Desoxykanamycin B and 6" -Desoxytobramycin of the formula in which R is hydrogen or OH, or of pharmaceutically acceptable acid addition salts thereof, from Kanamycin B, characterized in that in successive stages : (A) treating kanamycin B with a large molar excess of an acetylating agent selected from acetane hydride in a lower alkanol and acetyl chloride in conjunction with a base to take up the free HCl, forming penta-N-acetylkanamycin B; (B) treating the penta-N-acetylkanamycin B with p-toluenesulfonylchloride in the presence of a tertiary amine which is selected from pyridine, triethylamine and dimethylaniline, the 3 ', 6 // - di-tosylate derivative thereof being formed; (C) the ditosylate derivative with a compound selected from sodium iodide, lithium iodide, sodium bromide and lithium bromide in a solvent system consisting of: 45 (I) a compound selected from N, N-dimethylformamide and a ketone of the formula O so that triethylamine or pyridine is used as the base for taking up the free HCl in stage (A). 3. The method according to claim 1, characterized in that in step (A) a lower alkanol is used, which is selected from methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol and tert .-Butyl alcohol. 4. The method according to claim 1, characterized in that in step (C) a ketone is used, which is selected from acetone, methyl isobutyl ketone and methyl ethyl ketone. 5. The method according to claim 1, characterized in that the hexamethylphosphoric triamide in step (C) is present in an amount of approximately 1.1 mol per mol of sodium iodide, lithium iodide, sodium bromide or lithium bromide. 6. The method according to claim 1, characterized in that the 3 ', 6 "-diodide or 3', 6'-dibromide obtained in stage (C) is isolated in the form of an aqueous solution. 7. The method according to claim 1, characterized in that one uses a hydrogenation catalyst which is selected from Raney nickel, palladium, platinum, rhodium and ruthenium. R'-C-R " wherein R 'and R "are the same or different and each represents an alkyl group containing up to 6 carbon atoms, or (II) hexamethylphosphoric triamide in an aromatic hydrocarbon selected from toluene, benzene, xylene and mixtures thereof, reacted at reflux temperature; (D) hydrogenating the 3 ', 6 // - diiodo or 3 /, 6 // - dibromo derivative obtained in step (C) in the presence of a hydrogenation catalyst; and (E) hydrolyzing the product obtained in step (D) to form 6 "-deoxykanamycin B and 6" -deoxytobramycin. 3rd 621797 Tobramycin is also a known antibiotic known as chemically 3'-deoxykanamycin B bial Agents And Chemotherapy, pages 309-313 (1970). This ver according to the formula: bond is by K. F. Koch and J. A. Rhoades in Antimicro- 621797 The compounds of the formula: .2nh2 h2n in which R is hydrogen or OH, or the non-toxic derivatives of kanamycin B, these compounds being 6 "- Pharmaceutically acceptable acid addition salts thereof, called deoxykanamycin B and 6 "-deoxytobramycin are valuable antibacterial agents. 25 and the formula: