DE3044971A1 - 4,4'''-Di:deoxy-paromycin antibiotic - active against gram-negative and positive bacteria and protoza e.g. has superior activity to paromycin against Staphylococcus eptdermidis - Google Patents

Abstract

4',4"'-Dideoxy-paromycin of formula (5) and its salts are new. Used as antibiotics active against gram-negative and gram- positive bacteria and protozoa.

Description

The invention relates to the new compound 4 ', 4' '' -dideoxyparomomycin, which is effective as an antibacterial agent against gram-positive, gram-negative bacteria and against protozoa.

The manufacturing process includes the reaction of the well-known 6,3´, 2´´, 5´´, 3´´´, 4´´´-Hexa-O-acetyl-6´-O-benzoyl-penta-N-benzyloxycarbonylparomomycin with a large excess of carbon disulfide and sodium hydroxide and the subsequent treatment of the reaction mixture with methyl iodide, whereby 6,3´, 2´´, 5´´, 3´´´-Penta-O-acetyl-6´-O-benzoyl-4´, 4 "" -di-O- (methylthio-thiocarbonyl) -penta-N-benzyloxycarbonylparomomycin is obtained. The latter is subjected to a deoxygenation process by reduction with tributyltin hydride, suitably in toluene and in the presence of a catalytic amount of azobisisobutyronitrile, whereby 6,3 ', 2' ', 5' ', 3' '' -penta-O-acetyl-6 ' -O-benzoyl-4 ', 4' '' -dideoxy-penta-N-benzyloxycarbonylparomomycin is obtained.

De-O-acylation of this intermediate gives 4´, 4´´´-dideoxy-penta-N-benzyloxycarbonylparomomycin, from which the desired 4´, 4 ´´´-Dideoxyparomomycin is obtained and optionally isolated as sulfate.

The invention relates to paromomycin derivatives and processes for their preparation.

The invention relates in particular to compounds of the general formula:

in which R represents a hydrogen atom or a group of the formula -O-CS-SCH [deep] 3, X represents a hydrogen atom or an acyl group having 2 to 5 carbon atoms or a benzoyl group, Y represents a hydrogen atom or a benzoyl group and Z represents Represents hydrogen atom or a benzyloxycarbonyl group.

The invention further relates to processes for the preparation of the compounds according to the invention. The processes are illustrated by the following reaction scheme, in which A represents an acyl group having 2 to 5 carbon atoms or a benzoyl group, Bz represents a benzyl group, and Ph represents a phenyl group.

The starting material, a 6'-O-benzoyl-6,3 ', 2' ', 5' ', 3' '', 4 '' '-acyl- or -benzoyl-penta-N-benzyloxycarbonylparomomycin (1), can from paromomycin, a natural aminoglycoside antibiotic (US Pat. Nos. 2,916,485 and 3,065,147), according to the procedures of GB-PA 7,919,778. The compounds (1) can be prepared from the same precursor using benzoylimidazole in chloroform with a shorter reaction time and with a comparable yield. The reaction of compound (1) with a large excess of carbon disulfide and sodium hydroxide and the subsequent treatment of the reaction mixture with methyl iodide leads to the key intermediate (2), the O- (methylthio-thiocarbonyl) groups in 4´ and 4´´´ Positions. The deoxygenation process can be obtained by reducing the 4 ', 4' '' bis (S-methyldithiocarbonate) (2) with tributyltin hydride, suitably in toluene in the presence of a catalytic amount of azobisisobutyronitrile, whereby the 4 ', 4' '' -Dideoxy derivative (3) is obtained. De-O-acylation of compound (3) gives 4´, 4´´´-dideoxy-penta-N-benzyloxycarbonylparomomycin (4), which is converted into 4´, 4´´ by catalytic transfer hydrogenolysis in the presence of 10% palladium on charcoal ´-Dideoxyparomomycin (5) can be converted. The compound (5) is suitably purified by ion exchange column chromatography and converted into the sulfate form.

The mass spectrometric values (field desorption) indicate through fragmentation that the deoxygenation sites are present in rings A and D. The [high] 13C-NMR spectroscopy helps to determine the positions of deoxygenation in the compound (5). On the basis of the spectra of paromomycin and 4´-deoxyparomomycin and the known effect on the chemical shifts during the change from a hydroxymethylene group to a methylene group, considerations of the chemical shifts in dideoxyparomomycin strongly suggest that the deoxygenation sites are in 4 'and 4' '' positions. In fact, a change in the shielding was found at C-5´, C-6´ and C-3´, at C-5´´´, C-6´´´ and C-3´´´, while this was found for C -2´ and C-2´´´ is negligible.

4´, 4´´´-Dideoxyparomomycin (5) can be used as an antibacterial agent against gram-positive and gram-negative bacteria as well as against protozoa.

The invention therefore further provides a medicament which contains 4 ', 4' '' -dideoxyparomomycin or its pharmaceutically acceptable salt in admixture with a pharmaceutically acceptable diluent or carrier.

The in vitro antibacterial activity of 4´, 4´´´-Dideoxyparomomycin (5) is shown in the following table. The in vitro tests were carried out using the serial dilution method in a liquid medium (Difco nutrient broth). The minimum inhibitory concentration (MIC) was determined 24 hours after the incubation at 37 ° C.

Tabel

MIC values (Mcg / ml) of 4 ', 4' '' -dideoxyparomomycin (sulfate form) compared to paromomycin sulfate.

The invention is illustrated in the examples.

example 1

6,3 ', 2' ', 5' ', 3' '' -penta-O-acetyl-6 '-O-benzoyl-4', 4 '' '-di-O- (methylthio-thiocarbonyl) -penta -N-benzyloxycarbonylparomomycin (2)

15 g 6,3 ', 2' ', 5' ', 3' '' -hexa-O-acetyl-6 '-O-benzoyl-penta-N-benzyloxycarbonylparomomycin, prepared according to GB-PA 7 919 778, and 30 ml of carbon disulfide was dissolved in 250 ml of dimethyl sulfoxide. A 5N sodium hydroxide solution (24 ml) was added dropwise to the ice-cold solution. The mixture was stirred at 0 ° C for 30 min. Then 73 ml of methyl iodide was added with cooling and the reaction mixture was stirred at room temperature for 3 hours. Excess volatile reagents were removed under reduced pressure. After adding salt water, the solution was extracted with ethyl acetate. The extracts were washed with salt water and then with water, dried and evaporated. Precipitation from chloroform / diethyl ether / hexane gave a mixture which mainly consisted of a compound with an Rf value of 0.42 on TLC analysis (silica gel) in the solvent system toluene / ethyl acetate (volume ratio 1: 1). The crude product was purified by preparative HPLC analysis on a silica gel column, eluting with toluene / ethyl acetate (volume ratio 6: 4). In this way 6 g of the title compound were obtained with a yield of 37%.

Mp 110-115 ° C. [small alpha] [low] D [high] 25 + 42.9 (c 1.024 CHCl [low] 3). Nuclear Magnetic Resonance Spectrum (60 MHz, CDCI [low] 3) small delta: 2.53 and 2.48 (3 H each, s, -SCH [low] 3).

Elemental analysis:

Calculated for C [deep] 84H [deep] 93N [deep] 5O [deep] 30S [deep] 4:

C% 56.64 H% 5.26 N% 3.93 S% 7.20

Found: 56.49 5.37 3.79 7.72.

Example 2

6,3 ', 2' ', 5' ', 3' '' -penta-O-acetyl-6 '-O-benzoyl-4', 4 '' '-di-O-dideoxy-penta-N-benzyloxycarbonylparomomycin (3)

To a refluxing solution of 5.55 g of the compound prepared in Example 1 in 350 ml of dry toluene under a nitrogen atmosphere, 12 ml of tributyltin hydride in 12 ml of toluene and 300 mg of azobisisobutyronitrile were added. After refluxing for 2.5 hours, the solvent was removed under reduced pressure and the residue was washed with n-hexane, dissolved in chloroform and added to a mixture of diethyl ether and n-hexane to give 4.6 g of the title mentioned compound were precipitated (yield 95%). TLC analysis (silica gel): Rf value 0.29 in the solvent system toluene / ethyl acetate (volume ratio 1: 1). Mp 110-115 ° C. [small alpha] [low] D [high] 25 + 30.1 (c 0.915 CHCl [low] 3).

Elemental analysis:

Calculated for C [deep] 80H [deep] 89N [deep] 5O [deep] 28:

C% 61.25 H% 5.72 N% 4.46

Found: 60.99 5.94 4.12.

Example 3

4´, 4´´´-dideoxy-penta-N-benzyloxycarbonylparomomycin (4)

4.5 g of the compound prepared in Example 2 were dissolved in 180 ml of a 0.025N methanolic sodium methoxide solution dissolved and the mixture was stirred at room temperature for 3 hours. Solid carbon dioxide and water were added and the solution was evaporated to dryness. Water was added to the residue and the mixture was extracted several times with ethyl acetate. The extracts were washed with water and evaporated to dryness to give 3.9 g of crude product. Purification is carried out by preparative HPLC analysis on a silica gel column with the solvent system chloroform / ethyl acetate / methanol (volume ratio 40: 25: 9) as the eluent, giving 2.36 g of the compound named in the title (yield 65%) in pure form became. The product had an Rf of 0.27 by TLC analysis in the same solvent system. M.p. 115 to 120 ° C.

Elemental analysis:

Calculated for C [deep] 63H [deep] 75N [deep] 5O [deep] 22:

C% 60.32 H% 6.02 N% 5.58

Found: 59.54 5.85 3.57.

Example 4

4´, 4´´´-Dideoxyparomomycin (5)

17 ml of cyclohexane and 3.7 g of 10% palladium on charcoal were added to a solution of 2.2 g of the compound prepared in Example 3 in 250 ml of 80% strength ethanol. The reaction mixture was refluxed for half an hour and then filtered. The catalyst was washed with water. The filtrate was evaporated in vacuo to give 950 mg of residue. The crude product was purified on a column of Amberlite CC 50 (NH [low] 4 [high] + - form; 150 to 75 µm), washed with water and with increasing concentration trations of ammonia (0.05-0.3N) eluted, whereby 480 mg of the compound named in the title (yield 47%) were obtained in pure form. The product (free base) was converted into the sulfate by adding 0.2M sulfuric acid - at a pH of 6.4. Mp 250 ° C (decomposition) (sulphate form).

[small alpha] [low] D [high] 25 + 51.0 (c 1.170 H [low] 2O) (sulfate form).

Elemental analysis (sulphate form):

Calculated for C [deep] 23H [deep] 45N [deep] 5O [deep] 12.2 1 / 2H [deep] 2SO [deep] 4.3H [deep] 2O:

C% 31.29 H% 6.35 N% 7.93 S% 9.07

Found: 31.17 6.54 7.68 7.38.

The mass spectrum (field desorption) (free base) showed peaks at m / e 584 (MH [high] +) and fragments at 439 and 440 indicating that the deoxygenation sites are in the A and D rings. [high] 13C NMR (D [low] 2O) (free base): 100.3 (C-1 '), 57.2 (C-2'), 67.9 (C-3 '), 34.7 (C-4´), 70.1 (C-5´), 64.1 (C-6´), 99.1 (C-1´´´), 52.4 (C-2´´´) , 72.2 (C-3 ″ ″), 29.7 (C-4 ″ ″), 68.6 (C-5 ″ ″), 44.7 (C-6 ″ ″).

Claims (3)

1. 4 ', 4' '' -dideoxyparomomycin of the formula: 2. Process for the production of 4 ', 4''' -dideoxyparomomycin of the formula (5) according to claim 1, characterized in that the known 6,3 ', 2'',5'',3''', 4 ´´´-Hexa-O-acetyl-6´-O-benzoyl-penta-N-benzyloxycarbonylparomomycin of the formula: in which A stands for an acyl group (acetyl), Bz stands for a benzyl group and Ph stands for a phenyl group, in dimethyl sulfoxide solution with a large excess of carbon disulfide and 5N sodium hydroxide solution at 0 ° C. for 30 minutes, so that the reaction mixture is then reacted with Methyl iodide treated to 6,3´, 2´´, 5´´, 3´´´-Penta-O-acetyl-6´-O-benzoyl-4´, 4´´´-di-O- (methylthio- thiocarbonyl) penta-N-benzyloxycarbonylparomomycin of the formula: in which A, Bz and Ph have the meanings given above, to obtain that this product is then treated in toluene solution at reflux temperature and under a nitrogen atmosphere with tributyltin hydride in the presence of azobisisobutyronitrile as a catalyst to 6,3 ', 2'',5' ´, 3´´´-Penta-O-acetyl-6´-O-benzoyl-4´, 4´´´-dideoxy-penta-N-benzyloxycarbonylparomomycin of the formula: in which A, Bz and Ph have the meanings given above, to obtain that 4 ', 4''' -dideoxy-penta-N-benzyloxycarbonylparomomycin der from this compound by treatment for 3 hours with 0.025N-methanolic sodium methoxide solution at room temperature Formula: obtained, and that this compound is then converted by catalytic transfer hydrogenolysis in the presence of 10% palladium on charcoal and cyclohexene into the desired 4´, 4´´´-dideoxyparomomycin of the formula (5) and this after purification by ion exchange chromatography on Amberlite CG 50 ( NH [high] + [low] 4-form; 150 to 75 µm), increasing concentrations of ammonia (0.05 to 0.3N) being used as eluant, optionally isolated as the sulfate form. 3. Medicament, characterized in that it contains 4 ', 4' '' -dideoxyparomomycin or a pharmaceutically acceptable salt thereof in admixture with a pharmaceutically acceptable diluent or carrier.