DE1011417B - Process for the production of anhydrodesdimethylaminochlortetracycline or anhydrodesdimethylaminotetracycline - Google Patents

Description

Process for the preparation of anhydrodesdimethylaminochlortetracycline or Anhydrodesdimethylaminotetracycline The invention relates to a method for Conversion of antimicrobiologically active substances of the tetracycline series into the corresponding ones Anhydro compounds by splitting off a molecule of water.

It is known that chlortetracycline (»Aureomycina), tetracycline, Oxytetracycline ("Terramycin") and Desdimethylaminooxytetracycline are affected by the action let hydrochloric acid be converted into the corresponding anhydro compounds. The education of anhydrotetracycline and anhydrodesdimethylaminooxytetracycline takes place according to the Literature data based on the action of concentrated hydrochloric acid in methanol on tetracycline or desdimethylaminooxytetracycline, while dehydration performed from oxytetracycline with anhydrous hydrogen chloride in anhydrous acetone was, whereby an addition product of anhydrooxytetracycline to acetone was formed, from which by dissolving in water and adjusting a pH value of 5 the anhydrooxytetracycline was recovered as precipitate.

It has now been found that not only the above-mentioned compounds, but also desdimethylaminochlortetracycline and desdimethylaminotetracycline in in an analogous manner by splitting off water with the aid of acids into the corresponding Anhydro compounds can be transferred. It is noteworthy that the antimicrobiological Spectrum of these new anhydro compounds compared to that of the starting materials is noticeably changed. This change in the nature of the spectrum can be on a characteristic Change in the structure of the product compared to that of the starting materials.

The anhydro compounds prepared according to the invention are likely to have the following structure: Anhydrodesdimethylaminochlortetracycline Anhydrodesdimethylaminotetracycline Dehydration can be effected with a large number of dehydrating agents, in particular acidic compounds, and is explained using the following formula scheme for the conversion of desdimethylaminotetracycline into anhydrodesdimethylaminotetracycline In this reaction not only one molecule of water is removed, but there is obviously a rearrangement of a hydrogen atom on the tetracycline ring to the 0 atom which is bound to the permanent carbon atom of the ring. For unknown reasons, this gives rise to the new compounds, which have a markedly different activity against microorganisms than the starting compounds. This change in activity is not purely quantitative, but the new product is effective against organisms that are little or not at all attacked by the starting compound. Furthermore, the dehydrated compounds have somewhat different chemical properties than the starting materials. In particular, the stability of the new compounds is often higher than that of the starting compounds.

The particular value of the method according to the invention is that the new anhydro compounds obtained afterwards have a considerably higher activity to resistant staphylococcal species show than the previously known tetracycline compounds. It has also been found that the anhydrodesdimethylaminotetracycline compounds are less hygroscopic than the other anhydro compounds, which is why they are better suited for dust. They are also more stable in air. the end for these reasons they are better suited for external application. In view of the absence of the tetravalent dimethylamino group, these compounds are not subject to epimerization. It is believed that this contributes to the stability of the desdimethylamino compounds.

To carry out the dehydration according to the invention are below a variety of acids are effective. These include mineral acids such as sulfur, Hydrochloric, hydrobromic, phosphoric acid and various anhydrides of these compounds. Acid salts such as potassium bisulfate, sodium bisulfate and monosodium phosphate are also included effective. It has been found that the process also works with certain organic acids can be carried out. These include strong organic acids such as benzenesulfonic acid, Toluenesulfonic acid and chloroacetic acid. The reaction can be carried out in aqueous solutions The presence of the various acidic dehydrating agents are carried out; it however, it is often preferable to use only a smaller amount of water or at all to work without water. The use of a stable one is particularly useful polar organic solvent when working with acidic dehydrating agents. Preferred combinations include anhydrous hydrogen chloride in methanol, anhydrous hydrogen chloride in acetone, concentrated sulfuric acid in dimethylformamide and hydrogen chloride in acetic acid. The reaction must be carried out carefully, extensive decomposition of the reaction product after dehydration to avoid; so must the proportion of concentrated sulfuric acid in a solvent be chosen accordingly. The most suitable for a given remedy Conditions can be determined relatively easily. Generally works preferably not above about 50 °. More degrading when used Acids are often advisable at considerably lower temperatures. In some cases you can boiling dilute solutions of mineral acids in water or a solvent be used.

It has been found that those already responsible for the elimination of water from oxytetracycline known combination of acetone and anhydrous hydrogen chloride for the production the anhydro compounds is particularly effective. The formed product can always be can be isolated in good yield, and new intermediate compounds are formed. They consist of a molecule of acetone, which - with - the anhydrous compound connected is. The anhydro compounds can be in the form of their acetone derivatives isolate very easily with high purity. You can easily get into the free anhydro compounds can be converted by treating them with aqueous acid. It is advisable that Reaction mixture after completion of the reaction, preferably at a moderate temperature, constrict in a vacuum. In this way, the crystalline acetone derivative becomes direct obtained from the concentrated reaction mixture. Also other acids that are less Volatile as hydrogen chloride, acetone can be used to make the anhydro compounds to produce in the form of their acetone derivatives; however, these acids do not have the advantage the high volatility, which is their easy evaporation and the isolation of the acetone derivatives allowed in very pure form.

When carrying out the process, a dilute solution, e.g. B. of 0.1 g of the tetracycline compound per 100 cm3 of solution. If desired,' Concentrations can be up to about 2001, on the other hand even below 0.1 g / 100 cm3 be used. In general, at least 1 mole of acid is used per mole Tetracycline compound.

The anhydro product can often be isolated by changing the reaction mixture diluted with water and neutralized the acidic dehydrating agent used. One can also neutralize the acid and the solid when it is in the reaction medium is insoluble, separate. If the product is soluble, the solvent can be removed be e.g. By evaporation to recover the solid product. The anhydro compounds are at a pH slightly below the neutral point, i. H. between about 4 and 7, limited solubility in water. However, if the product is not out of the Solution separates, the neutralized solution can be concentrated, preferably at moderate or low temperature, d. H. at not above about 50 ° to the product to be deposited. A second method of obtaining a dry product is by freezing the aqueous solution and drying it in vacuo. For extraction the products from the aqueous solution, especially at an approximately neutral pH value, certain solvents can be used. These include polar organic ones Solvents such as water-immiscible aliphatic alcohols, e.g. B. butanol, Amyl alcohol or benzyl alcohol. The solvent extract can then be concentrated or evaporated to dryness. An aqueous concentrate can also be obtained by extracting the alcohol solution with a small volume of dilute acid. The aqueous concentrate is then adjusted to approximately neutral pH precipitate the product. The products can be dehydrated with acid in the form of the salts, or they can be isolated from the amphoteric compounds and a suitable strong acid, e.g. B. hydrochloric acid or sulfuric acid will. Furthermore, one can use salts from the amphoeterous compounds with strong bases, such as alkali and alkaline earth hydroxides.

Provide the products obtained by the process according to the invention new compounds. They are solid, yellow in color and often crystalline. You can from lower alcohols or from a mixture of lower alcohols with water or ether are recrystallized.

The following values were determined for the microbiological activity of the anhydrodesdimethylaminochlorotetracycline Minimum inhibition concentrations in gs / cm3 Aerobacter aerogenes (AC 2) ....... 50.0 (MT 2) ....... 1.56 *) Starting line 100.0 Escherichia coli ................... 100.0 Proteus .......................... 100.0 Pseudomonas sp. .................. 100.0 Candida alicans ................... 100.0 Salmonella typhosa ................ 100.0 Klebsiella pneumoniae ....... ... .. 50.0 Salmonella paratyphi A ............. 100.0 Salmonella paratyphi B .... . .... .. 100.0 Staphylococcus aureus ......... ... 0.19 Streptococcus faecalis .............. 0.19 Brucella bronchiseptica ...... . ... . 0.78 Brucella subtillis .................. 0.19 Pseudomonas aeruginosa ........... - Mycobacterium ranae .............. 0.39 *) Partial inhibition Minimum inhibition concentrations in gG / cm3 Mycobacterium smegmatis .... ... . . 0.19 Mycobacterium phlei .............. 0.19 Mycobacterium No. 607 ............. 0.19 Mycobacterium berolinense .......... 0.78 *) Mycobacterium butyricum. . . . . . . . . . 0.78 *) *) Partial inhibition In-vitro comparative experiments were carried out to demonstrate the above-mentioned, particularly high activity of the compounds prepared according to the invention against resistant staphylococcal species. For this purpose, bacterial cultures isolated from clinical cases were used that showed resistance to oxytetracycline, tetracycline and chlortetracycline. The corresponding activities against these three antibiotics were also measured. The values are given in the table below: Activities of anhydrous derivatives of the tetracycline series against resistant staphylococci (Minimum inhibitory concentration in ge / cm3) Anhydro- @ @ o Anhydro- desdi- desdi- anhydro- Chloromethyl anhydro anhydro Oxytetra- tetra- methyl- methyl- chlorine- Organism tetra- amino- oxytetra- tetra- cyclin cyclin cyclin ammo-chlorocyclin aminocyclin tetra- tetra-tetra-oxytetra-cyclin Cyclin cyclin cyclin Mikrococcuspyogenes var. aureus 5 (normal) ......... 0.19 0.19 0.39 12.5 0.78 6.25 100 3.12 1.56 Resistant to antibiotics Strains of micrococcus pyogenes var. aureus 376 .................... 100 -100 100 100 0.78 100 100 6.25 3.12 Y-1 .................... 100 100 100 100 0.39 100 100 3.12 3.12 Mayo 2866 ............. 100 100 100 50 0.78 100 100 6.25 3.12 Mayo 2868 ............. 100 100 100 25 0.78 100 100 6.25 12.5 Mayo 2869 ............. 100 100 100 50 1.56 100 100 3.12 3.12 In the laboratory posed, against oxy- tetracycline more resistant Trunk ....... ........ 100 100 100 12.5 0.78 100 100 6.25 6.25 Koch M 1 .............. 100 100 25 3.12 0.78 100 100 6.25 3.12 Koch M 2 .............. 50 100 25 *) 3.12 1.56 100 100 6.25 3.12 Koch M 3 .............. 50 100 25 3.12 1.56 100 100 6.25 3.12 Koch M 4 .............. 100 100 50 1.56 0.39 100 100 6.25 3.12 Koch M 5 .............. 100 100 100 3.12 1.56 100 100 6.25 3.12 *) Partial inhibition As can be seen from the table, anhydrodesdimethylaminochlorotetracycline shows by far the strongest activity against these resistant strains of microorganisms. It is much more effective against resistant microorganisms than all previously known tetracycline derivatives.

Example 1 Anhydrodesdimethylaminochlortetracycline 1.5 g of pure desdimethylaminochlortetracychn in 60 cm3 of 5011111 dioxane-methanol are mixed with 60 cm3 of a saturated solution of hydrogen chloride in methanol, carefully filtered and left to stand overnight in the refrigerator. Long orange needles separate from analytically pure anhydrodesdimethylaminochlortetracycline. This material decomposes without melting at about 240 °. For analysis, it is dried at 100 ° in a vacuum. Mole- Analysis for kular CzoHis ' N T07Cl CHN Cl weight Calculated ......... 57.49 3.85 3.35 8.49 418 Found .......... 57.13 4.04 3.17 8.70 421 (titr.) The optical rotation of the anhydrodesdimethylaminochlorotetracycline is [a] ö ° _ - 228.7 ° (dimethylformamide). The UV absorption spectrum can be made to coincide with that of anhydrochlortetracycline.

Example 2 Anhydrodesdimethylaminotetracycline A solution of 0.5 g of desdimethylaminotetracycline in 10 cm3 of methanol and 1 cm3 of concentrated hydrochloric acid is heated to boiling temperature for 1 minute. The product crystallizes directly from the acid-methanol solvent mixture in the form of yellow prismatic needles in about 80% yield. This material has a biological effectiveness of 26 oxytetracycline units per mg against Klebsiella pneumoniae. The UV absorption spectrum, which is practically identical to that of anhydrodesdimethylaminooxytetracycline, has maxima at 270 mp. (log Z = 2.06) and 425 m # t (log 1 = 1.29). Example 3 Samples of 15 g each of desdimethylaminochlortetracycline and desdimethylaminotetracycline are mixed individually with a solution, each cooled to -5 ', of 15.2 g of anhydrous hydrogen chloride in 600 cm3 of pure acetone. The temperature of the solutions is allowed to rise to about 5 ° and is kept at this temperature for several hours, after which the solutions are concentrated in vacuo. Once a small volume is reached, the solid acetone derivatives of anhydrodesdimethylaminochlortetracychn and anhydrodesdimethylaminotetracychn separate as solid yellow products. These products are isolated and identified on the basis of their characteristic properties, such as the UV absorption spectrum. It has been found that by treatment with aqueous acid, each of these acetone derivatives is easily converted into the corresponding anhydro compound, ie into anhydrodesdimethylaminochlorotetracycline or anhydrodesdimethylaminotetracycline, respectively. These compounds have been identified on the basis of their characteristic properties.

Claims (3)

PATENT CLAIMS: 1. Process for the preparation of anhydrodesdimethylaminochlortetracycline or anhydrodesdimethylaminotetracycline, characterized in; that 'from 1 Mol desdimethylaminochlortetracycline @ '°' or desdimethylaminotetracycline in an known = ter way with an acidic dehydrating agent; expedient in the present a stable polar organic solvent, at a temperature not exceeding 50 ° splits off 1 mol of water and the anhydro compounds from the reaction mixture; preferably via their addition compounds to the organic solvent used, like the acetone addition compound. 2. The method according to claim 1, characterized characterized in that a 'mineral acid, such as hydrochloric acid, is used as the dehydrating agent or a single strong organic acid is used. 3. The method according to claim 1, characterized characterized in that the starting material in a concentration of no more than about 20 percent by weight. References considered: J. Am. Chem. Soc., Vol. 74, 1952, pp. 4981, 4982; Vol. 75, 1953, pp. 4621, 4622; P. 5455 to 5475.