JPS6152839B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to erythromycin derivatives, and more particularly to erythromycin derivatives that are acid resistant and exhibit excellent in vivo activity. Erythromycin A is an extremely useful macrolide antibiotic that has a strong antibacterial effect against Gram-positive bacteria, but when administered orally, it rapidly loses its antibacterial activity due to acid in the stomach, resulting in a low blood concentration. The disadvantage is that it does not rise. As a result of various studies, the present inventors discovered that an erythromycin derivative in which the hydroxyl group at the 6-position of the erythronolide ring is methylated does not lose its antibacterial activity even when administered orally, and has completed the present invention. did. The target compound of the present invention has the formula It is an erythromycin derivative (hereinafter referred to as a compound) represented by (hereinafter referred to as a compound) or a salt thereof. In the present invention, salts refer to pharmacologically acceptable salts, such as salts with organic acids such as tartaric acid, citric acid, stearic acid, and succinic acid; salts with methanesulfonic acid; and salts with aminoethanesulfonic acid. Salt: Examples include salts with amino acids such as aspartic acid and glutamic acid. The compound can be produced, for example, by the following method. Namely, E.H. Flynn (EH
Flynn et al. [Journal of the American Chemical Society]
General formula synthesized according to the method of American Chemical Society, Volume 77, Page 3104 (1955)] (In the formula, R represents -COOCH ₂ C ₆ H _5. ) A suitable base (for example, lithium hydride, sodium hydride, potassium hydride, etc.) is added to the compound (hereinafter referred to as the compound). The hydroxyl group at the 6-position of the erythronolide ring is methylated by the action of methyl iodide in the presence of an alkali metal amide such as lithium amide, sodium amide, potassium amide; butyl lithium; lithium diisopropyl amide, etc.). So, the general formula (In the formula, R has the same meaning as above.) A compound (hereinafter referred to as a compound) is prepared, and after post-treatment by a conventional method, it is purified and isolated by silica gel column chromatography. This isolated compound was described above in E.H.
According to the method of Flynn et al., the protecting group R is removed by catalytic reduction, and then N-methylation is performed by catalytic reduction in the presence of excess formaldehyde to obtain a compound. It is also possible to simultaneously remove the protective group R of a compound and N-methylate it to form a compound.In the reaction for obtaining a compound from a compound, 5 to 10 moles of methyl iodide and 1 to 10 moles of base are used per mole of the compound. Using 2 mol, -78°C to room temperature, preferably -
The reaction is carried out between 15°C and 5°C. As the solvent, polar aprotic solvents such as N·N-dimethylformamide, N·N-dimethylacetamide, dimethylsulfoxide, and hexamethylphosphoramide can be used, but preferably dimethylsulfoxide or dimethylsulfoxide and tetrahydrofuran are used. A mixed solvent system is used. The target compound of the present invention is a novel compound that has not been described in any literature, and its blood concentration and in vivo activity are significantly higher than that of erythromycin A when administered orally, and its antibacterial activity is similar to that of erythromycin A. It is superior and useful as a medicine. Next, the present invention will be specifically explained with reference to test examples demonstrating that the compound is excellent in acid stability, antibacterial properties, and in vivo activity, and examples showing production examples of the compound. Test Example 1 (Acid stability) Using erythromycin A as a control, the compound was kept in PH2 (Clark-Lubs buffer) for a certain period of time, and its residual activity was determined using Staphylococcus aureus FDA209P strain. It was measured by the method. The results are shown in Table 1.

[Table] Test Example 2 (Antibacterial Spectrum) Using erythromycin A as a control, the compound was subjected to an antibacterial test against various bacteria by the agar plate method. The results are calculated using the MIC value (minimum inhibitory concentration mcg/
ml) and are shown in Table 2.

[Table] Test Example 3 (In vivo activity) A group of 14 male ddY mice (weight 18 to 22 g) was used to test Staphylococcus aureus Smith.
No.4 was inoculated. Using erythromycin A as a control, the compound was orally administered 1 hour after inoculation, and the number of surviving mice 7 days after administration was determined to examine its in vivo activity. The result is
It is shown in Table 3.

[Table] Example (1) O・N-dibenzyloxycarbonyl-des-N-methyl 30 g of erythromycin A and 18 ml of methyl iodide were dissolved in a mixed solvent of 50 ml of dry dimethyl sulfoxide and 100 ml of dry tetrahydrofuran, and the mixture was heated at -12°C in a nitrogen stream. While cooling to -10°C and stirring, 2.4 g of 55-65% oily sodium hydride was added little by little, and stirring was continued for an additional hour.
After the reaction was completed, 50 ml of triethylamine was added while stirring under ice cooling, and the precipitate was separated. The obtained solid was thoroughly washed with ethyl acetate, and the washing solution and mother liquor were mixed together, washed with saturated brine, and dried over anhydrous magnesium sulfate. The crude product obtained by evaporating the solvent was placed on a silica gel dry column (manufactured by A.Merck Darmschat; silica gel 60 pore column chromatography, 70-230 mesh) (Φ5.4 x 60 cm). The mixture was developed with a mixed solvent of ethyl acetate and N-hexane (1:1), and 15 ml aliquots were collected. Each classification was confirmed using silica gel thin-layer chromatography (manufactured by A.Merck Darmschat; pre-coated thin-layer chromatography plate silica gel 60 F254; developing solvent: ethyl acetate-n-hexane (1:1) mixed solvent. , Rf value
0.16 (Rf value of starting material 0.07) was collected and the solvent was distilled off under reduced pressure to obtain a colorless and transparent glassy substance.
12.2g was obtained. (2) 10 g of the glassy substance obtained in the previous section (1) was dissolved in a mixed solvent consisting of 1.32 g of sodium acetate, 0.8 ml of acetic acid, 40 ml of water and 200 ml of ethanol, 1.0 g of palladium black was added thereto, and the mixture was heated at normal pressure. Catalytic reduction was carried out for 5 hours under a weak hydrogen stream at room temperature.
Next, add 37% formaldehyde aqueous solution 32 to this.
ml was added and the catalytic reduction was further continued for 7 hours. After the reaction was completed, the catalyst was separated, and the liquid was concentrated under reduced pressure to about 1/4 of the liquid volume. To this, 100 ml of water was added and the pH was adjusted to about 10 with sodium carbonate water. This was thoroughly extracted with chloroform, washed with water, dried, and the solvent was distilled off. The resulting residue was recrystallized from chloroform-ether to obtain 6 g of crystals. After stirring this in 500 ml of ether for 5 hours, it was filtered, the liquid was concentrated to dryness, and the obtained crystals were recrystallized from chloroform-ether.
4.5 g of 6-O-methylerythromycin A was obtained as colorless columnar crystals. (3) Dissolve 1 g of the crystals obtained in the previous section (2) in chloroform and adsorb onto 5 g of reversed-phase silica gel (manufactured by A.Merck Darmschat, Silica Gel 60 Silanized Foor Column Chromatography, 70-230 mesh) and reduce the pressure. The solvent was evaporated at the bottom. This was placed on a column (Φ5.0 x 40cm) packed with the above-mentioned reversed phase silica gel, developed with a mixed solvent of methanol and 0.1M phosphate buffer (PH7.0) (3:2), and separated into 15ml portions. did. Each section was analyzed using thin-layer chromatography (manufactured by A.Merck-Dharmschitut; thin-layer chromatography plate Silica gel 60, silanized precoated, 0.25 mm thick; developing solvent: methanol-0.1M phosphate buffer (PH7.0). ) (3:2)
The mixture was confirmed by Rf value 0.42 (Rf value 0.46 for erythromycin A), and most of the methanol was distilled off under reduced pressure, then made alkaline with sodium carbonate, and extracted with chloroform. The chloroform layer was washed with water, dried, concentrated under reduced pressure, and the obtained crystals were recrystallized from a mixed solvent of chloroform-isopropyl ether (1:2) to obtain 700 mg of pure 6-O-methylerythromycin A as colorless columnar crystals. Obtained. mp 217-220℃ (decomposition) Elemental analysis value (as C ₃₈ H ₆₉ NO ₁₃ ) Theoretical value (%): C61.02, H9.30, N1.87 Measured value (%): C60.37, H9.18 , N1.71 MS m/e: 747 (M ⁺ ) IRν ^CHCl3 _nax cm ^-1 : 3500, 1730, 1690 ¹ H-NMR
(CDCl ₃ ) δ=0.84 (dd.3H), 1.40 (s, 3H), 2.28 (s,
6H), 3.03 (s, 3H), 3.33 (s, 3H), 4.44
(d, 1H), 4.93 (dd.1H), 5.06 (dd, 1H) UVλ ^CHCl3 _nax nm (ε): 288 (27.9)

Claims (1)

[Claims] 1 formula An erythromycin derivative or a salt thereof.