FLUORINE-CONTAINING MACROLIDE COMPOUNDS, PHARMACEUTICAL COMPOSITIONS COMPRISING THE SAME AND THEIR USE FOR THE MANUFACTURE OF MEDICAMENTS

Abstract: A fluorine-containing macrolide compound of the formula: wherein R¹ is hydroxy or -OR (wherein R is C₁-C₅ alkyl), R² is hydrogen or hydroxy, or R¹ and R² together form a cyclic residue of the formula: (wherein R′ und R″ are independently hydrogen or C₁-C₅ alkyl), when R⁴ is hydrogen or C₁-C₅ alkyl, or (wherein Ph is phenyl), R⁵ is hydrogen or C₁-C₅ alkyl, and R⁶ is hydrogen or methyl and a pharmaceutical composition comprising the fluorine-­ containing macrolide compound (I) as an effective component; and the use of the fluorine-containing macrolide compounds for the manufacture of medicaments.

Description: FIELD OF THE INVENTION The present invention relates to a novel fluorine-containing macrolide compound which can be used as for example antimicrobial agent. BACKGROUND OF THE INVENTION Erythromycin A, which is one of macrolide antibiotics having antimicrobial activity, is widely clinically used. However, it is difficult to increase the blood concentration of erythromycin A since it is easily decomposed by an acid in stomach when it is orally administered due to its chemical unstability under an acidic condition. As a result of investigation to improve chemical stability of erythromycin A, a fluorine-containing compound, 8-fluoroerythromycin A was developed (cf. Japanese Patent Kokai Publication No. 140779/1982). EP-A-0 158 102 describes (8S)-8-fluoroerythromycin derivatives which may be employed as active ingredients of pharmaceutical compositions for anti-bacterial use suitable for administration. SUMMARY OF THE INVENTION From the viewpoint that, when an erythoromycin A derivative contains fluorine atom, it has high chemical stability under the acidic condition, further improved derivatives have been searched and it has been found that an erythromycin derivative having fluorine atoms in 8- and 9-positions has excellent chemical stability. An object of the present invention is to provide a novel fluorine-containing macrolide compound which has antimicrobial activity against, for example, aerobic and anaerobic bacteria and has improved chemical stability. DETAILED DESCRIPTION OF THE INVENTION According to the present invention, there is provided a fluorine-containing macrolide compound of the formula: wherein R¹ is hydroxy or -OR (wherein R is C₁-C₅ alkyl), R² is hydrogen or hydroxy, or R¹ and R² together form a cyclic residue of the formula: (wherein R′ and R″ are independently hydrogen or C₁-C₅ alkyl), when R⁴ is hydrogen or C₁-C₅ alkyl, or (wherein Ph is phenyl), R⁵ is hydrogen or C₁-C₅ alkyl, and R⁶ is hydrogen or methyl. The invention also comprises a pharmaceutical composition containing the fluorine containing macrolide compound (I) as an effective component. Included is also said pharmaceutical composition for use as an anti-microbial agent and the use of the compound (I) for the manufacture of a medicament for use as an anti-microbial agent. The fluorine-containing macrolide compound of the present invention can be prepared for example by the following series of reactions (1) and (2) from a known erythromycin derivative which is comparatively easily obtainable: (1) An erythromycin derivative of the following formula: wherein R¹, R², R³, R⁴, R⁵ and R⁶ are the same as defined above is reacted with acetic acid to prepare a compound of the following formula: wherein R¹, R², R³, R⁴, R⁵ and R⁶ are the same as defined above. (2) The compound obtained by the reaction (1) is reacted with fluorine (F₂) to give a present compound of the following formula: wherein R¹, R², R³, R⁴, R⁵ and R⁶ are the same as defined above. The reaction (1) of an erythromycin derivative with acetic acid has been known and described for example in Experimentia, 27 , (1971) 362. In the above-mentioned fluorination reaction (2), although fluorine may be used as such, it is usually diluted with an inert gas such as nitrogen or helium. The concentration of fluorine is at least 1 % by volume, preferably from 2 to 20 % by volume. The reaction temperature in the fluorination is generally from -120 to +50 °C, preferably from -80 to 0 °C. The reaction is usually carried out in an inert solvent which is liquid at reaction temperature. Specific examples of the solvent are 1,1,2-trichloro-1,2,2-trifluoroethane, trichlorofluoromethane, dichloromethane, trichloromethane, tetrahydrofuran, dioxane, dichloromethane, trichloromethane, tetrahydrofuran, dioxane, acetonitrile, formic acid, acetic acid, 2,2,3,3-tetrafluoropropanol and a mixture thereof. Further, the present compound may be converted into a pharmaceutically acceptable derivative such as ester, salt-ester or salt by esterification of hydroxy in the 2′-position and/or neutralization of dimethylamino or N-oxide in the 3′-position according to known methods (cf. Japanese Patent Kokai Publication No. 140779/1982). The fluorine-containing macrolide compound of the present invention may be blended with usual additives such as excipients, vehicles and fillers and may be orally or intravenously administered in the form of a tablet, capsule, suspension, solution and the like (cf. Japanese Patent Kokai Publication No. 140779/82). The fluorine-containing macrolide compound of the present invention has higher chemical stability than erythromycin A under an acidic condition. In addition, the antimicrobial activity of the present compound against aerobic and anaerobic bacteria corresponds to that of erythromycin A. The present invention will be hereinafter explained further in detail by following examples. Example 1 Preparation of 8,9-difluoroerythromycin A 6,9-epoxide Glacial acetic acid (9.0 ml, 157 mmol) was added to erythromycin A (3.0 g, 4.1 mmol) and stirred for two hours at 25 °C. To the mixture, sodium acetate trihydrate (1.1g, 8.1 mmol) was added and stirred for ten minutes. Then, chloroform (100 ml) was added and stirred until the mixture became homogeneous. The obtained solution was cooled to -50°C and then fluorine gas (6.7 mmol) diluted with nitrogen gas to 10 % by volume was bubbled in the solution at a flow rate of 50 ml/min. with vigorously stirring. Then, the temperature of the reaction mixture was raised to about 0 °C. After adding sodium sulfite (100 mg) and calcium carbonate (2.0 g) and stirring, solid materials were filtered off. After concentration of the filtrate, the residue was dissolved in methylene chloride (50 ml) and washed with saturated aqueous sodium bicarbonate solution. The organic phase was dried on magnesium sulfate and concentrated. The concentrate was purified by means of a silica gel column with using a mixture of choloroform/methanol/triethylamine (volume ratio, 200/20/1) as an eluent and further purified by recrystallization from ethanol to give 8,9-difluoroerythromycin 6,9-epoxide (884 mg). Yield 28.7 %. Melting point: 194.0 to 195.5 °C. Elemental analysis: Calculated: C 57.57 %; H 8.75 %; N 1.81 %; F 4.92 %. Found: C 57.80 %; H 8.81 %; N 1.83 %; F 4.62 %. Mass spectra: 754 (M+N), 734 (M+H-HF), 596 (M+H-C₅ bound sugar) and 576 (M+H-C₅ bound sugar-HF) ¹H-NMR (solvent: CDCl₃): δ = 0.96 (3H, t, -C₂H₅, J = 7 Hz), 2.37 (6H, s, -N(CH₃)₂) and 3.36 (3H, s, -OCH₃). ¹⁹F-NMR (external standard: trifluoroacetic acid; solvent: CDCl₃): δ = 39.8 (1F, dd, F₉, J F8 = 8 Hz, J H10 = 27 Hz) and 72.5 (1F, quint. d, F₈, J F9 = 8 Hz, J CH3,H7 = 23 Hz). IR (cm⁻¹): 3450, 2980, 2920, 1730, 1455 and 1165. Example 2 Preparation of 8,9-difluoroerythromycin A 6,9-epoxide 11,12-carbonate To a solution of 8,9-difluoroerythromycin 6,9-epoxide (200 mg, 0.27 mmol) in benzene (10.0 ml), anhydrous potassium carbonate (100 mg, 0.73 mmol) was added and the mixture was refluxed with stirring. Then, ethylene carbonate (180 mg, 2.18 mmol) dissolved in benzene (10.0 ml) was droppwise added to the mixture and refluxed for a day. The completion of reaction was confirmed by means of silica gel thin layer chromatography with using a mixture of choloroform/methanol/triethylamine (volume ratio, 100/30/1) as a developer. Then, at room temperature, the reaction mixture was washed with water and dried on anhydrous sodium sulfate. After concentration under a reduced pressure, the concentrate was purified by means of a silica gel column with using a mixture of chloroform/ methanol/triethylamine (volume ratio, 200/20/1) as an eluent to give 8,9-difluoroerythromycin A 6,9-epoxide 11,12-carbonate (130 mg). Yield 63 %. IR (KBr, cm⁻¹): 3450, 2980, 1805 and 1740. ¹H-NMR (solvent: CDCl₃): δ = 0.92 (3H, t, -C₂H₅, J = 7.1 Hz), 2.32 (6H, s, -N(CH₃)₂) and 3.31 (3H, s, -OCH₃). ¹⁹F-NMR (external standard: trifluoroacetic acid; solvent: CDCl₃): δ = 44.0 (1F, dd, F₉, J F8 = 12 Hz, J H10 = 27 Hz) and 75.2 (1F, quint. d, F₈, J F9 = 12 Hz, J Me ,H₇ = 20 Hz). ¹³C-NMR (solvent: CDCl₃): δ = 153.3 (carbonate carbonyl) and 177.2 (lactone carbonyl). Example 3 Preparation of 8,9-difluoroerythromycin A 6,9-epoxide 11,12-(N,N-dimethylacetamide) acetal To a solution of 8,9-difluoroerythromycin 6,9-epoxide (180 mg, 0.24 mmol) in benzene (3.0 ml), N,N-dimethylacetamide dimethylacetal (1.0 ml, 910 mg, 6.84 mmol) was added and the mixture was stirred for two days at room temperature in a nitrogen atmosphere. After confirmation of disappearance of the spot of the starting substances by silica gel thin-layer chromatography with using a mixture of choloroform/methanol/triethylamine (volume ratio, 100/30/1) as a developer, the mixture was concentrated under a reduced pressure. The residue was purified by means of a silica gel column with using a mixture of choloroform/triethylamine (volume ratio, 200/1) as an eluent to give 8,9-difluoroerythromycin A 6,9-epoxide 11,12-(N,N-dimethylacetamide) acetal (120 mg). Yield 65 %. IR (KBr, cm⁻¹): 3450, 2950 and 1735. ¹H-NMR (solvent: CDCl₃): δ = 2.28 (s, 6H, N(CH₃)₂), 2.32 (s, 6H, N(CH₃)₂) and 3,34 (s, 3H, -OCH₃). ¹⁹F-NMR (external standard: trifluoroacetic acid; solvent: CDCl₃): δ = 44.4 (1F, dd, F₉, J F8 = 14 Hz, J H10 = 30 Hz) and 75.4 (1F, quint. d, F₈, J F9 = 14 Hz, J Me,H7 = 19 Hz). Example 4 Preparation of 8,9-difluoroerythromycin A 6,9-epoxide 11,12-sulfite To a solution of 8,9-difluoroerythromycin 6,9-epoxide (400 mg, 0.54 mmol) in absolute methanol (6.0 ml), anhydrous potassium carbonate (500 mg, 3.65 mmol) was added and the mixture was stirred. Then, ethylene sulfate (1.0 ml, 1.46 g, 13.18 mmol) dissolved in absolute methanol (1.0 ml) was gradually added to the reaction suspension and stirred for three days. After confirmation of completion of reaction by a silica gel thin-layer chromatography with using a mixture of choloroform/methanol/triethylamine (volume ratio, 100/30/1) as a developer, the reaction mixture was poured into water (10.0 ml) and extracted with ethyl acetate (12.0 ml) for three times. The combined organic phase was dried on anhydrous magnesium sulfate, concentrated under a reduced pressure and purified by means of a silica gel column with using a mixture of choloroform/triethylamine (volume ratio, 200/1) as an eluent to give 8,9-difluoroerythromycin A 6,9-epoxide 11,12-sulfite (200 mg). Yield 48 %. IR (KBr, cm⁻¹): 3370, 2950 and 1730. ¹H-NMR (solvent: CDCl₃): δ = 0.91 (t, 3H, -C₂H₅, J = 7.1 Hz), 2.47 (s, 6H, -N(CH₃)₂) and 3.29 (s, 3H, -OCH₃). ¹⁹F-NMR (external standard: trifluoroacetic acid; solvent: CDCl₃): δ = 44.4 (1F, dd, F₉, J F8 = 13 Hz, J H10 = 27 Hz) and 75.3 (1F, quint. d, F₈, J F9 = 13 Hz, J Me,H7 = 22 Hz). Example 5 Preparation of 8,9-difluoroerythromycin A 6,9-epoxide acetate To a mixture of sodium bicarbonate (3760 g), acetone (30 ml) and 8,9-difluoroerythromycin A 6,9-epoxide (7.520 g, 10 mmol), anhydrous acetic acid (1.23 ml, 13 mmol) was added and the mixture was stirred for two hours at 25 °C and then poured into iced water. After two hours, the mixture was extracted three times with chloroform. The organic phase was washed with a saturated aqueous sodium bicarbonate solution and then water, and dried on anhydrous sodium sulfate. After evaporating off chloroform, the resulting solid was recrystallized from a mixture of ethyl ether and n-hexane to give 8,9-difluoroerythromycin A 6,9-epoxide acetate (6.325 g, 7.95 mmol). IR (cm⁻¹): 3480, 1740, 1455, 1370, 1340, 1280, 1235, 1160, 1110, 1085, 1050, 1030, 1010, 995, 975 and 955. Example 6 Preparation of 8,9-difluoroerythromycin A 6,9-epoxide ethylsuccinate By the same way as Example 5, but using ethylsuccinyl chloride in place of anhydrous acetic acid, 8,9-difluoroerythromycin A 6,9-epoxide ethylsuccinate was prepared. IR (cm⁻¹): 3480, 1735, 1450, 1370, 1345, 1190, 1160, 1050, 1030, 1010, 995, 975, 955, 890 and 800. Example 7 Preparation of 8,9-difluoroerythromycin A 6,9-epoxide succinate To a mixture of acetone (37.5 ml) and 8,9-difluoroerythromycin A 6,9-epoxide (7.520 g, 10 mmol), anhydrous succinic acid (1 g, 10 mmol) was added and the mixture was stirred for 15 minutes at 80 °C and then cooled to room temperature. After two hours, by the same way as Example 5, the mixture was extracted, dried and recrystallized to give 8,9-difluoroerythromycin A 6,9-epoxide succinate (450 g, 7.55 mmol). IR (cm⁻¹): 3450, 1730, 1575, 1455, 1370, 1340, 1190, 1160, 1050, 990, 975 and 950. Example 8 Preparation of 8,9-difluoroerythromycin A 6,9-epoxide stearate To a mixture of acetone (20 ml) and 8,9-difluoroerythromycin A 6,9-epoxide (7.520 g, 10 mmol), a solution of stearic acid (2.85 g, 10 mmol) in a mixture of acetone and distilled water (volume ratio, 1:1) was added. The solvents were evaporated off from the solution and the residue was recrystallized from a mixture of acetone and n-hexane to give 8,9-difluoroerythromycin A 6,9-epoxide stearate (10.2 g, 10.1 mmol). IR (cm⁻¹): 3470, 1730, 1455, 1375, 1340, 1150, 1105, 1030, 1010, 990, 975, 950, 930, 890, 830 and 800. Example 9 The antimicrobial activities of 8,9-difluoroerythromycin 6,9-epoxide (Example 1), 8,9-difluoroerythromycin 6,9-epoxide 11,12-carbonate (Example 2) and 8,9-difluoroerythromcyin 6,9-epoxide 11,12-sulfite (Example 4) were examined by an ager streak method and expressed in terms of minimal inhibitory concentrations (MIC, µg/ml) against the following bacteria. The results are shown in Tables 1 to 3. Example 10 A certain amount of 8,9-difluoroerythromcyin-6,9-epoxide or erythromycin A was dissolved in an aqueous solution (pH 2.97) of disodium citrate (0.1 M) and hydrochloric acid (0.1 M) (volume ratio, 4:6). Then, at certain intervals of time, the antimicrobial activities of the solutions were examined by a serial dilution method. The half-life period of the antimicrobial activity of 8,9-difluoroerythromycin (6,9-epoxide was three days and that of erythromycin A was ten minutes.

Claims: A fluorine-containing macrolide compound of the formula: wherein R¹ is hydroxy or -OR (wherein R is C₁-C₅ alkyl), R² is hydrogen or hydroxy, or R¹ and R² together form a cyclic residue of the formula: (wherein R′ und R″ are independently hydrogen or C₁-C₅ alkyl), when R⁴ is hydrogen or C₁-C₅ alkyl, or (wherein Ph is phenyl), R⁵ is hydrogen or C₁-C₅ alkyl, and R⁶ is hydrogen or methyl. A pharmaceutical composition comprising as an effective component, a fluorine-containing macrolide compound of the formula: wherein R¹ is hydroxy or -OR (wherein R is C₁-C₅ alkyl), R² is hydrogen or hydroxy, or R¹ and R² together form a cyclic residue of the formula: (wherein R′ and R″ are independently hydrogen or C₁-C₅ alkyl), when R⁴ is hydrogen or C₁-C₅ alkyl, or (wherein Ph is phenyl), R⁵ is hydrogen or C₁-C₅ alkyl, and R⁶ is hydrogen or methyl, and a pharmaceutically acceptable carrier. A pharmaceutical composition according to claim 2 for use as an antimicrobial agent. The use of a compound according to claim 1 for the manufacture of a medicament for use as an antimicrobial agent.

Inventors: HISANAGA, YORISATO, KAWANO, TOSHIHIKO, SHIMOKAWA, KAZUHIRO, SUITA, YASUNORI, YAMASHITA, TSUNEO
Applicants: DAIKIN INDUSTRIES, LIMITED
Application year: 1987
Main classification: C07H17
IPC codes: C07H17