JPH0570636B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to novel erythromycin derivatives useful as antibacterial agents. [Prior art] The antibiotic erythromycin is widely used clinically and is an excellent antibacterial agent, but it is unstable to acids [Experientia 27 (4), 362
(1971)]. In addition, erythromycin A cyclic 11,12-carbonate has been proposed as a derivative with stronger antibacterial activity than erythromycin A, but its stability against acids has not been significantly improved [J. Antibiotics, 29(9), 907-914 ( 1976)]. [Problems to be solved by the invention] As mentioned above, it would be medically useful to find a derivative that has various properties superior to that of erythromycin. In particular, it has stronger antibacterial activity than erythromycin, is stable against acids, and is effective against hyperemia. It is important to search for erythromycin derivatives that exhibit intermediate concentrations. [Means for Solving the Problems] Under these circumstances, the present inventors synthesized various erythromycin A derivatives and studied their effects. As a result, they found that they have antibacterial activity superior to erythromycin, and that The present invention was completed by discovering a new derivative that is also effective against resistant bacteria (group C bacteria). That is, the present invention provides the formula

The present invention provides a compound represented by the following formula (wherein R represents a lower alkanoyl group) or a salt thereof. The above salts are pharmaceutically acceptable salts.
Such suitable salts include salts with inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, propionic acid, butyric acid, tartaric acid, glycolic acid, citric acid, gluconic acid, succinic acid, malic acid, mandelic acid, Examples include salts with organic acids such as stearic acid, palmitic acid, aspartic acid, glutamic acid, methanesulfonic acid, p-toluenesulfonic acid, but are not limited thereto, and other non-toxic salts are also included. Next, the method for producing the object compound [1] of the present invention will be explained, and the formula excluding substituents at the 6-, 9-, 2'- and 4'-positions that can be converted during the production process is

[ka] simply the expression

[Formula] (The numbers in the formula indicate the position numbers of the substituents) and the chemical structural formula below is abbreviated. The object compound [1] of the present invention is an erythromycin A cyclic 11,12-carbonate [2].
Protecting the 2′-hydroxyl group with a lower alkanoyl group
2'-O-protected-erythromycin A cycle
11,12-carbonate [3] was obtained, and this compound was
The hydroxyl group at the 4'' position was protected with a silyl group to obtain 2'-O-protected-4''-O-silyl-erythromycin A cyclic 11,12-carbonate [4], which was protected at the 9-position with _NaBH4 in a lower alcohol. 9-dihydro-2'-O-protected-4''-O-silyl-erythromycin A cyclic 11,12-carbonate [5] was obtained by reducing the ketone group of Protect 9-O-Protect-9-
Dihydro-2'-O-protected-4''-O-silyl-erythromycin A cyclic 11,12-carbonate [6] was obtained, and the hydroxyl group at position 6 was removed in the presence of a tertiary organic amine in an inert organic solvent. Acylation with lower alkanoyl halide under heating yields 6-O-acyl-9-O-protected-9-dihydro-2'-O-protected-
4″-O-silyl-erythromycin A cyclic 11,12-carbonate [7] was obtained, and this was treated with aqueous alkali carbonate in a lower alcohol to remove the protecting group of the hydroxyl group at the 9-position and form 6-O-acyl. -9-dihydro-2'-O-protected-4''-O-silyl-erythromycin A cyclic 11,12-
Carbonate [8] was obtained, and the hydroxyl group at position 9 was oxidized to give 6-O-acyl-2'-O-protected-4''-O-silyl-erythromycin A cyclic 11,12-carbonate.

[9] was obtained, which was desilylated by treatment with acidic water to give 6-O-acyl-
2'-O-protected-erythromycin A cycle
11,12 carbonate [10] is obtained by heat treatment in a lower alcohol to remove the protecting group of the hydroxyl group at the 2' position. The reaction formula for the above manufacturing process is as follows.

[Table] [8]

【table】
heating


〔Ten〕

Erythromycin A cyclic 11,12-carbonate [2] used in the present invention is a known substance, which is obtained by heating and refluxing erythromycin A with ethylene carbonate in the presence of an alkali carbonate in benzene (US Pat. No. 3,417,077). . In order to obtain the target compound [1] from the above compound [2], the hydroxyl groups at the 2′ and 4″ positions of the compound [2] are protected, and then the hydroxyl group at the 6th position is acylated to obtain the desired 6-O -Acyl derivatives cannot be obtained because if erythromycin is treated with acid, 8,9-anhydroerythromycin A6,9-
This is because a hemiketal form is obtained [Experientia 27 (4), 362 (1971)]. Therefore, the target compound [1] cannot be produced by conventional methods,
This method could only be synthesized through the manufacturing process discovered by the present inventors, and should be considered a pioneering method as a 6-O-acylation method. In the present invention, first, the hydroxyl group at the 2' position of erythromycin A cyclic 11,12-carbonate is protected with an appropriate protecting group. The above-mentioned protection of the 2'-position hydroxyl group is carried out by reacting compound [2] with a lower fatty acid anhydride in an inert organic solvent, and since an acetyl group is most preferred, acetic anhydride is usually used. Preferred inert organic solvents include dichloromethane, chloroform, dichloroethane, and acetone. The above reaction proceeds sufficiently at room temperature, and the progress of the reaction can be tracked by thin layer chromatography (TLC) using silica gel, high performance liquid chromatography (HPLC), etc., so that the maximum amount of product [3] is produced. The reaction can be terminated as appropriate by waiting for this to occur. The reaction time is usually 30 to 60 minutes. To collect product [3] from the reaction solution, pour the reaction solution into water and adjust the pH to about 9 with an alkali such as aqueous ammonia, and then add a non-hydrophilic organic solvent such as chloroform, dichloromethane, dichloroethane, ethyl acetate, or acetic acid. Obtained by extraction with butyl etc., washing and concentration. Next, the hydroxyl group at the 4″ position of the product [3] is protected.
This reaction is carried out by reacting a silylating agent in the presence of an organic amine. As an inert organic solvent,
Examples include organic solvents similar to those used for 2'-O-acetylation. As the tertiary organic amine, a known tertiary organic amine is used.
Usually, pyridine, diethylaniline, etc. are used. As the silylating agent, it is preferred to use a tri-lower alkyl-silyl halide such as trimethylsilyl halide. The reaction proceeds satisfactorily even at around 0°C. Since the progress of the reaction can be tracked by TLC, HPLC, etc., the reaction can be appropriately terminated after waiting for the maximum amount of product [4] to be produced. Usually it takes 30 minutes to 2 hours. Product [4] can be collected from the reaction solution in the same manner as described above. Next, the product [4] was dissolved in a lower alcohol.
The 9-dihydro compound [5] is obtained by reduction with NaBH ₄ . Methanol may be used as the lower alcohol, but since the silyl group may be eliminated, ethanol or propanol is usually used. The reaction proceeds satisfactorily at room temperature. Since the progress of the reaction can be monitored by TLC and HPLC, the reaction can be appropriately terminated after waiting for the maximum amount of product [5] to be produced. Usually it takes about 4 to 8 hours. The product [5] can be collected from the reaction solution in the same manner as described above. Next, the hydroxyl group at the 9-position of the product [5] is protected.
It is carried out by reacting a halogenated acetyl halide in the presence of an organic amine. Examples of the inert organic solvent include organic solvents similar to those used for 2'-O-acetylation. Examples of the tertiary organic amine include the same amines as the tertiary amine used in the silylation. Examples of the halogenated acetyl halide include chloroacetyl chloride, dichloroacetyl chloride, trichloroacetyl chloride, trifluoroacetyl chloride, and the like. The reaction proceeds satisfactorily even at around 0°C. The reaction progress was TLC,
Since it can be traced by HPLC etc., the product [6]
It is sufficient to wait until the maximum amount of is generated and then terminate the reaction as appropriate. Usually it takes 30 minutes to 2 hours. The product [6] can be collected from the reaction solution in the same manner as described above. If further purification is required, separation and purification can be carried out by column chromatography using a carrier such as silica gel. Next, the hydroxyl group at the 6-position of the product [6] is acylated, and the product [6] is acylated with a lower alkanoyl halide in the presence of a tertiary organic amine in an inert organic solvent under heating. This is done by Examples of inert organic solvents include organic solvents similar to those used in 2'-O-acetylation, but since the acylation reaction is carried out under heating, organic solvents with higher boiling points, such as dichloroethane, are recommended. Preferred are solvents such as As the tertiary organic amine, a known tertiary organic amine is used,
Tribenzylamine, diethylaniline and the like are preferred. Examples of lower alkanoyl halides include acetyl chloride and propionyl chloride. The above acylation reaction is performed under heating. The heating temperature is selected within the range of 60 to 80°C. Since the progress of the reaction can be monitored by TLC, HPLC, etc., the reaction can be appropriately terminated after waiting for the maximum amount of 6-O-acylated [7] to be produced.
Usually it takes 1 to 4 days. Product from reaction solution [7]
To collect it, you can do it in the same way as above. If further purification is required, separation and purification can be carried out by column chromatography using a carrier such as silica gel. Next, the protecting group for the hydroxyl group at the 9-position of the product [7] is removed by treating the product [7] with an aqueous alkali carbonate in a lower alcohol. As the lower alcohol, methanol, ethanol, etc. are preferable. Examples of the alkali carbonate include sodium carbonate and potassium carbonate. The reaction proceeds satisfactorily at around 0°C. Since the progress of the reaction can be monitored by TLC, HPLC, etc., the reaction can be appropriately terminated after waiting until the maximum amount of product [8] is produced. Usually it takes 30 minutes to 2 hours. Product [8] can be collected from the reaction solution in the same manner as described above. Next, the product [8] is subjected to Moffat oxidation to convert the hydroxyl group at the 9-position into a keto group, which is carried out by treating the product [8] with a Moffat oxidizing agent. Examples of the moat oxidizing agent include a mixed reagent of dimethyl sulfoxide and acetic anhydride, N,N'-dicyclohexylcarbodiimide (DCC), or trifluoroacetic anhydride. The reaction proceeds satisfactorily at room temperature. The reaction progress was TLC,
The product can be traced by HPLC etc.

[9]
It is sufficient to wait until the maximum amount of is generated and then terminate the reaction as appropriate. Usually 10-20 hours. Product from reaction solution

[9] can be collected in the same manner as described above. If further purification is required, separation and purification can be carried out by column chromatography using a carrier such as silica gel. then the product

The protecting group for the hydroxyl group at the 4″ position in [9] is eliminated, but the product

This is carried out by treating [9] with acidic water. Examples of acidic water include hydrous organic solvents of acids such as acetic acid, trifluoroacetic acid, and hydrochloric acid. Examples of the organic solvent include inert hydrophilic organic solvents such as acetonitrile and tetrahydrofuran. The elimination reaction proceeds satisfactorily at room temperature. Since the progress of the reaction can be tracked by TLC, HPLC, etc., it is sufficient to wait until the maximum amount of product [10] is produced and then terminate the reaction appropriately. Usually it takes 30 minutes to 3 hours. Product from reaction solution [10]
To collect it, you can do it in the same way as above. Next, the protecting group for the hydroxyl group at the 2' position of the product [10] is removed, which is carried out by heating the product [10] in a lower alcohol. Examples of lower alcohols include methanol and ethanol, but methanol is preferred. The heating temperature is usually around the boiling point of the lower alcohol. Since the progress of the reaction can be monitored by TLC, HPLC, etc., the reaction can be appropriately terminated after waiting for the maximum amount of the desired target compound [1] to be produced. The target compound [1] thus obtained can be obtained by distilling off the lower alcohol from the reaction product, but if further purification is required, an adsorbent such as silica gel, activated alumina, or adsorption resin may be used. It can be purified by column chromatography using. [Effect] Next, Table 1 shows the results of measuring the minimum inhibitory concentration (MIC) of the target compound [1] of the present invention for microbial growth. Invention product; 6-O-acetylerythromycin A cyclic 11,12-carbonate EM; Erythromycin A *; EM-resistant bacteria

【table】

[Stability against acids]

The test product was dissolved in Clark Lubs buffer (PH2.0) and left for 0 minutes, 15 minutes, 30 minutes, and 60 minutes, respectively, and the residual activity was measured by bioassay using Staph.aureus 209P.The results are as follows. It is as shown in Table 2. Table 2 Residual antibacterial activity (%) Time Inventive product EM 0 min 100 100 15 min 100 61.2 30 min 100 23.0 60 min 92 5.2 From the above results, the compound of the present invention has significantly better acid stability than erythromycin. I understand that. [Effects of the Invention] The compound [1] of the present invention exhibits antibacterial activity superior to erythromycin, is effective against erythromycin-resistant bacteria (group C bacteria), and is stable against acids. It is a clinically useful antibacterial substance. [Example] Next, production examples of the present invention will be specifically described with reference to Examples. Note that the Rf values in the examples were measured by TLC using the following carrier and developing solvent, unless otherwise specified. Carrier: DC-Fertigplatten Kiesel manufactured by Merck & Co.
gel 60F ₂₅₄ , Art5715 Developing solvent; a; benzene-acetone (2:1) b; chloroform-methanol (4:1) Example 1 6-O-acetylerythromycin A cyclic 11,12-carbonate 1 2'-O- Production of acetyl erythromycin A cyclic 11,12-carbonate (2) 1.69 g (2.23 mmol) of erythromycin A cyclic 11,12-carbonate was dissolved in 8.5 ml of dry dichloromethane, and 0.557 ml (2.5 mmol) of acetic anhydride was dissolved in this.
After stirring at room temperature for 30 minutes, the reaction solution was poured into diluted aqueous ammonia and extracted with chloroform. Separate the chloroform layer, wash with water,
After dehydration using Whatman 1PS, the residue was concentrated under reduced pressure to obtain 1.78 g of the title compound (2) as a white foam. Mass (CI) m/z; 802 (MH ⁺ ), 784 (MH ⁺ −
18), 758 (MH ⁺ -CO ₂ ), 200 TLC; Rfa = 0.27 2 2'-O-acetyl-4''-O-trimethylsilyl-erythromycin A cyclic 11,12-
Production of carbonate (3) Dissolve 1.78 g of compound (2) in 17 ml of dichloromethane, add 0.892 ml of pyridine (5 times the mole) and 1.132 ml of trimethylchlorosilane (4 times the mole).
After stirring for 45 minutes under ice-cooling at 0 to 5°C, the reaction solution was poured into diluted aqueous ammonia and extracted with chloroform. The chloroform layer was separated, washed with saturated saline, dehydrated using Whatman 1PS, and concentrated under reduced pressure. Benzene-ethanol was added to the residue, pyridine was removed by azeotropy, and the residue was dried under reduced pressure to obtain 1.92 g of the title compound (3). Mass (CI) m/z; 874 (MH ⁺ ), 830 (MH ⁺ −
CO ₂ ), 200 TLC; Rfa = 0.51 3 2′-O-acetyl-9-dihydro-4″-O-
Production of trimethylsilyl-erythromycin A cyclic 11,12-carbonate (4) 1.92 g of compound (3) was dissolved in 17 ml of ethanol, 337 mg (4 times the mole) of NaBH ₄ was added thereto under ice cooling, and the mixture was stirred at room temperature for 7.5 hours. did. Add the reaction solution to 170% water.
ml and extracted with chloroform. After separating the chloroform layer and washing with saturated saline,
It was dehydrated using Whatman 1PS and dried under reduced pressure to obtain 1.9 g of the title compound (4). Mass (CI) m/z; 876 (MH ⁺ ), 200 TLC; Rfa = 0.44 4 2'-O-acetyl-9-O-dichloroacetyl-9-dihydro-4''-O-trimethylsilyl-erythromycin A cyclic 11 , 12-carbonate (5) 1.9 g of compound (4) was added to 10 ml of dry dichloromethane.
To this, add 0.535 ml of pyridine (3 times the mole) and 0.536 ml of dichloroacetyl chloride under ice-cooling.
ml (2.5 times the mole) was added, and the mixture was stirred for 45 minutes. The reaction solution was poured into diluted aqueous ammonia and extracted with chloroform. The chloroform layer was separated, washed with saturated saline, and dehydrated using Whatman 1PS.
It was concentrated under reduced pressure. The residue was charged to a 50 g column of silica gel and purified by column chromatography eluting with benzene-acetone (8:1), the same mixed solvent (6:1), and the same mixed solvent (4:1) in this order. Detection was performed using sulfuric acid color development, and fractions around Rfa=0.49 were collected and dried under reduced pressure to obtain 1.068 g of the title compound (5). PMR (100MHz, CDCL ₃ ) δ ^TMS _ppn ; 0.14 (s,
9H), 1.47 (s, 3H), 2.03 (s, 3H), 2.28 (s,
6H), 3.34 (s, 3H), 6.04 (s, 1H) CMR (CDCl ₃ ) δ ^TMS _ppn ; 176.0, 169.6, 153.1,
99.4, 95.7, 85.0, 84.4, 82.5, 80.4, 79.5, 77.7,
76.1, 74.0, 73.2, 71.8, 68.2, 65.5, 64.4, 62.4,
49.0, 44.2, 43.5, 40.6, 37.6, 35.1, 33.6, 32.3,
31.1, 24.6, 22.8, 22.5, 21.4, 21.2, 18.9, 17.7,
14.0, 13.4, 13.3, 10.7, 8.9 5 6,2'-di-O-acetyl-9-O-dichloroacetyl-9-dihydro-4''-O-trimethylsilyl-erythromycin A cyclic
Production of 11,12-carbonate (6) 1.068 g of compound (5) was dissolved in dry dichloroethane 5
ml, add 3.42 g of tribenzylamine and 0.77 ml of acetyl chloride, and incubate at 70°C for 30 minutes.
The mixture was heated and stirred for several days. The reaction solution was poured into dilute ammonia water and extracted with 50 ml of chloroform. The chloroform layer was separated, washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was charged to a column of 40 g of silica gel, and benzene-
Purified by column chromatography eluting with acetone (6:1 to 5:1 gradient).
Fractions around Rfa=0.44 were collected and dried under reduced pressure to obtain 350 mg of the title compound (6). Mass (CI) m/z; 1032, 1030, 1028 (MH ⁺ ),
988, 986, 984 (MH ⁺ −CO ₂ ), 200 PMR (100 MHz, CDCl ₃ ) δ ^TMS _ppn ; 0.14 (s, 9H),
1.48 (s, 3H), 1.53 (s, 3H), 2.02 (s, 3H×
2), 2.27 (s, 6H), 3.33 (s, 3H), 6.12 (s,
1H) 6 6,2'-di-O-acetyl-9-dihydro-
Production of 4″-O-trimethylsilyl-erythromycin A cyclic 11,12-carbonate (7) Dissolve 350 g of compound (6) in 6 ml of methanol,
To this was added 0.6 ml of 10% potassium carbonate aqueous solution, and the mixture was stirred for 2 hours under ice cooling. The reaction solution was poured into water and extracted with chloroform. The chloroform layer was separated, washed with saturated saline, dehydrated through Whatman 1PS, and dried under reduced pressure to obtain 310 g of the title compound (7). Mass (CI) m/z; 918 (MH ⁺ ), 858, 626,
200 TLC; Rfa=0.40 7 6,2′-di-O-acetyl-4″-O-trimethylsilyl-erythromycin A cyclic
Production of 11,12-carbonate (7) 310g of compound (7) was dissolved in dimethyl sulfoxide.
The mixture was dissolved in 1.8 ml, 1.2 ml of acetic anhydride was added thereto, and the mixture was stirred at room temperature overnight. Add 50ml of diluted ammonia water to the reaction solution.
The resulting precipitate was collected and dissolved in chloroform. Wash this with saturated saline,
Dehydrated through Whatman 1PS and concentrated under reduced pressure.
The residue was charged to a column containing 10 g of silica gel, and benzene-acetone (8:1) and the same mixed solvent (6:1) were charged.
It was purified by column chromatography eluting in the order of 1). Fractions around Rfa=0.45 were collected and dried under reduced pressure to obtain 100 mg of the title compound (8) as a crystalline powder. Mass (CI) m/z; 916 (MH ⁺ ), 872 (MH ⁺ −
CO ₂ ), 812,200 PMR (100MHz, CDCl ₃ ) δ ^TMS _ppn ; 0.13 (s, 9H),
1.48 (s, 3H), 1.65 (s, 3H), 1.88 (s, 3H),
2.04 (s, 3H), 2.27 (s, 6H), 3.33 (s, 3H) TLC; Rfa = 0.45 8 6,2'-di-O-acetyl-erythromycin A cyclic 11,12-carbonate (8)
Production of Compound (8) 100 mg was dissolved in 1.5 ml of acetonitrile-water (2:1) mixed solvent, and 21.1 μm (2.5 times the mole) of trifluoroacetic acid was added thereto, followed by stirring at room temperature for 1 hour. Dilute ammonia water was added to the reaction solution to adjust the pH to approximately 9.5, followed by extraction with chloroform. The chloroform layer was separated, washed with saturated saline, dehydrated through Whatman 1PS, and then dried under reduced pressure to obtain the title compound (9). Mass (CI) m/z; 844 (MH ⁺ ), 800 (MH ⁺ −
_CO2 ), 740,200 TLC; Rfa=0.10 9 Production of 6-O-acetylerythromycin A cyclic 11,12-carbonate (1) Dissolve the compound (9) in 5 ml of methanol,
Heated at 65°C for 16 hours. After the reaction solution was concentrated under reduced pressure and distilled off into methanol, the residue was charged to a 4 g column of silica gel and purified by column chromatography eluting with chloroform-methanol (concentration gradient of 60:1 to 40:1). Rfa=0.5)
Nearby fractions were collected and dried under reduced pressure to obtain 59.6 mg of the title compound (1) as a white crystalline powder. Mass (CI) m/z; 802 (MH ⁺ ), 758 (MH ⁺ −
_CO2 ), 158 TLC; Rfa=0.51 PMR (100MHz, _CDCl3 ) δ ^TMS _ppn ; 0.87 (t, 3H),
1.48 (s, 3H), 1.69 (s, 3H), 1.91 (s, 3H, 6
−OAc), 227 (s, 6H), 3.31 (s, 3H, OCH ₃ ),
4.59 (d, 1H), 4.94 (dd, 1H), 5.07 (dd, 1H) CMR (CDCl ₃ ) δ ^TMS _ppn ; 212.3 (s), 175.4 (s),
170.4(s), 153.7(s), 101.9(d), 96.0(d)
，
84.9 (s), 84.6 (s), 80.3, 79.2, 78.2, 77.7,
75.2, 73.1 (s), 71.2, 68.6, 66.5, 65.6, 49.3
(q), 45.3, 45.0, 40.4, 38.8, 38.1, 35.3 (t),
28.8(t), 22.4, 21.9, 21.6, 21.5, 21.3, 19.1,
17.8, 16.5, 12.8, 10.1, 9.6.

Claims (1)

[Scope of Claims] 1. A compound represented by the formula: (wherein R represents a lower alkanoyl group) or a salt thereof. 2. The compound or salt thereof according to claim 1, wherein the lower alkanoyl group is an acetyl or propionyl group.