DE1493253C - - Google Patents

Description

Chromomycin-Aj is a valuable commercially available antibiotic that inhibits the growth of inhibits malignant tumor cells and gram-positive bacteria. However, it is sparingly soluble in water, so that it is difficult to use the antibiotic in pharmaceutical preparations in the form of solutions use parenteral application. ,

Chromomycin-Aa has the formula (Merck Index [1968], 8th edition, p. 258):

OCH

HO

CH,

OH

It contains many functional groups including alcoholic hydroxyl groups and phenolic hydroxyl groups in its molecule. Numerous attempts have been made to introduce hydrophilic groups into these functional groups in the molecule of Chromomycin-A ₃ . However, the attempts were unsuccessful: in some cases the derivatives obtained were not water-soluble to the extent desired for practical purposes, and in other cases the derivatives obtained lost the antibiotic activity of chromomycin A ₃ despite their water solubility.

It has now been found that the problem described above can be solved by partial esterification of chromomycin A ₃ with succinic acid or its reactive derivatives and that the product, chromomycin A ₃ hemisuccinate or its alkali, alkaline earth and ammonium salts, is sufficiently water-soluble and the antibiotic activity of Chromomycin-Aj is sufficiently preserved.

The invention relates to a mixture of chromomycin A ₃ hemisuccinates, which is characterized in that in the formula of chromomycin A ₃ no more than 3 hydrogen atoms of the alcoholic hydroxyl groups are represented by the corresponding number of groups of the formula

- CO - CH ₂

CH ₂ - COOH

are replaced, as well as their ammonium, alkali and alkaline earth salts.

The esters of chromomycin-A ₃ , which are formed between the phenolic hydroxyl group of chromomycin-A ₃ and the carboxyl group of succinic acid, on the other hand, have little or no _{antibiotic activity of chromomycin-A 3.}

The products according to the invention are valuable medicaments for parenteral or oral treatment, since it allows the growth of malignant tumor cells and of gram-positive bacteria with low toxicity inhibit and are water soluble.

The invention also relates to a process for the preparation of chromomycin A ^ hemisuccinates, which is characterized in that chromomycin A ₃ with succinic anhydride in a solvent, in particular in pyridine, at temperatures from -5 to +10 ⁰ C in per se known Way is implemented.

The temperature ^{is expediently below 0 °} C. The process is expediently carried out in the presence of a basic substance such as pyridine or quinoline. _{The chromomycin A 3} hemisuccinates formed in this way in the reaction mixture are made using the properties of chromomycin A 1 hemisuccinate, e.g. B. the differences between chromomycin A ₃ hemisuccinate and the impurities in the solubility, in the partition coefficient in liquid phases, in the adsorption capacity or in the ion coherence isolated.

Chromomycin-Aj-hemisuccinate can contain the corresponding alkali, alkaline earth and ammonium salts on the carboxyl group of the chromomycin A ^ hemisuccinate form. These salts are generally more soluble in water than the corresponding free chromomycin A ^ hemisuccinate. From these salts the alkali salts are preferably used because they are easily soluble in water and in the usual way, z. B. by reacting the chromomycin A ^ hemisuccinate with alkali compounds such as sodium hydrogen carbonate or potassium hydrogen carbonate.

_{In the chromomycin A 3} hemisuccinates prepared according to the invention there are no more than 3 hydrogen atoms of alcoholic hydroxyl groups of the chromomycin A ₃ by the corresponding number of groups of the formula

-COCH ₂ CH ₂ COOH

replaced. The phenolic hydroxyl groups of chromomycin-A ₃ are not esterified. In general, chromomycin A ₃ hemisuccinates in which two alcoholic hydroxyl groups of chromomycin A _{3 are} esterified are obtained in high yield.

As already mentioned, chromomycin A ₃ hemisuccinates and their water-soluble salts, e.g. B. the alkali, alkaline earth and ammonium salts, the antibiotic activity of chromomycin-A ₃ . _{Compared to Chromomycin-A 3, the} compounds according to the invention are also more readily soluble in water and less toxic. They are valuable tools for the therapy of malignant tumors and of diseases caused by Bacillus subtilis and Staphylococcus aureus.

example

A small amount of granular sodium hydroxide is dissolved in 98 cm ^{3 of} pyridine. 14 g of purified chromomycin-A _{3 are dissolved} in the solution at a temperature between 0 and -5 "C. 28 g of succinic anhydride are added to the resulting solution, whereupon the mixture is stirred at a temperature between 0 and -5" C for 40 hours. The reaction mixture is ^{poured into about 250 cm 3 of} cold water and the reaction product is extracted ^{with 300 cm 3 of ethyl acetate.} The ethyl acetate layer is washed with water and then shaken with a 5-10% aqueous solution of formic acid to completely remove the pyridine from the ethyl acetate layer. To remove excess formic acid from the ethyl acetate layer, it is washed with water and shaken twice with an approximately 0.5% strength aqueous sodium hydrogen carbonate solution. The yellowish aqueous layer is isolated. 2 to 3 times the volume of water is added to this aqueous solution in order to reduce the concentration of sodium hydrogen carbonate. The aqueous solution is extracted several times with ethyl acetate until the yellowish color of the ethyl acetate layer disappears.

ίο The aqueous solution is acidified to a pH of about 4 to 4.5 by adding a 5% aqueous formic acid solution and then ^{extracted with 300 cm 3 of} ethyl acetate. The extract is washed several times with water to remove the formic acid. The ethyl acetate solution is dried with anhydrous sodium sulfate and then concentrated under reduced pressure at low temperature. Petroleum ether is added to the residue, about 6.5 g of a yellowish precipitate being obtained

20: will. This precipitate is dissolved in about 30 cm ^{3 of} ethyl acetate. ^{About 120 cm 3 of} diethyl ether are added to the solution, a yellowish precipitate being obtained. This is washed with diethyl ether and then with petroleum ether, about 5.3 g of chromomycin A ^ hemisuccinate being obtained in the form of a homogeneous yellowish powder.

_{The chromomycin A 3} hemisuccinate mixture formed in this way has the following physico-chemical and biological properties:

1. elemental analysis after drying at 6O ⁰ C: 55.74% C, 6.86% H, 4.89% OCH _3.

2. Specific rotation after drying at 6O ⁰ C: [„] * ° = -45 ± 10 ° (C = 1, absolute ethanol). [,,] » ^ü = -31 ± 7 ° (C = 1, absolute methanol).

3. Absorption spectrum: The ultraviolet absorption spectrum measured in ethanol is in FIG. 2 shown. The maximum absorption bands are as follows:

/, "(Ηΐμ) 230, 280.5, 305, 319, 333, 418;
E ^ _n , 186, 362, shoulder 63,2, 52, 68.

The infrared absorption spectrum measured by the potassium bromide method is shown in FIG. 1 shown. The following essential absorption bands (in, «) are present in the spectrum:

2.9 (strong)
3.4 (medium)

3.65 to 3.8 (weak, broad)

5.75 (strong)

6.1 (strong)

6.3 (weak)
6.6 (weak)

7.0 (shoulder) '

7.28 (medium)

7.56 (weak)

7.7 (weak)
8.1 (medium)

8.5 (medium)
8.9 (weak)
9.35 (strong)

9.6 (shoulder)
10.6 (weak)

11.1 (medium)
12.3 (weak)
13.15 (weak)

4. Melting point: the product will be at 162 bis 165 ° C soft and melts at 190 to 193 ° C with decomposition.

5. Appearance: Yellowish powder.

6. Color reaction: The compound turns blue with Barton's reagent. This reagent exists from equal parts of a 1% aqueous iron (III) chloride solution and a 1 percent aqueous potassium ferricyanide solution. The compound is colored with an alkali hydrogen peroxide solution briefly red and reduces the Fehling's reagent.

7. Solubility: The compound is soluble in chloroform, Ethyl acetate, dioxane, tetrahydrofuran, acetone, ethanol and methanol, poorly soluble in Diethyl ether, insoluble in cyclohexane and petroleum ether and easily soluble in aqueous sodium hydrogen carbonate solution, in which the sodium hydrogen carbonate is equivalent to the free carboxyl groups.

8. Thin-layer chromatography: A homogeneous mixture of 30 g of silica gel G Merck and 60 cm ^{3 of} theoretical buffer solution (pH 2.3; 0.07 μ) is painted as a 0.2 mm thick layer on a glass plate, which is then kept at 100 ^{° for 1 hour} C is dried. A solution of Chromomycin-Aj and a solution of Chromomycin-Aj-hemisuccinate in ethyl acetate is applied in the form of spots on the thin layer. After drying, the stains are developed with a mixture of benzene, chloroform and methanol (volume ratio 1: 2: 1). The Rf value is 0.67 ± 0.1 for chromomycin A ₃ and 0.40 ± 0.1 for chromomycin A ₃ hemisuccinate.

9. Acute toxicity: The mean lethal dose (LD ₅₀ ) for mice is 11.78 ± 0.56 mg / kg body weight for iv injection and 14.64 ± 0.60 mg / kg for intraperitoneal injection.

10. Local toxicity: The maximum tolerated doses and the minimum harmful doses of Chromomycin Aj hemisuccinate and Chromomycin Aj are given in the table below in micrograms / cm ³ / rabbit.

Chromomycin-A] Chromomycin-A ₃ -
hemisuccinate Harmful
Minimum dose ..
Maximum
tolerable
dose 2
1.5 200
150

As the values in this table show, Chromomycin A ₃ hemisuccinate has only 1/100 of the local toxicity of Chromomycin A ₃ .
11. Antiulcer effect: rats were inoculated with Yoshida sarcoma on the peritoneum. After 24 hours chromomycin-A ₃ was hemisuccinate intraperitoneally at a dose of 40 micrograms / rat / day for a period administered 2 weeks. Compared to the control animals, the lifespan was increased by at least 1.5 times.

12. Antibacterial effectiveness: The antibacterial effectiveness corresponds to 1500 to 2000 units per milligram against Staphylococcus aureus and 3500 to 7500 units per milligram against Bacillus subtilis, measured by the Waksman dilution method.

Claims (2)

Patent claims: 1. Mixture of Chromomycin Arhemisuccinates. characterized in that in the formula of chromomycin-A ₃ not more than 3 hydrogen atoms of the alcoholic hydroxyl groups by the corresponding number of groups of the formula -CO-CH ₂ -CH ₂ -COOH are replaced, as well as their ammonium, alkali and alkaline earth salts. · 2. A process for the preparation of chromomycin A ₃ hemisuccinates, characterized in that chromomycin A _{3 is} reacted with succinic anhydride in a solvent, in particular in pyridine, at temperatures from -5 to +10 C in a manner known per se. 35 1 sheet of drawings