CS219308B2 - Process for the production of new pleuromutilins - Google Patents

Abstract

The subject of the invention is a method for producing acylated derivatives of pleuromutilins, which are obtained by reacting pleuromutilins with an acylating agent and optionally converting the derivatives obtained into acid addition salts or quaternary salts. The new pleuromutilins according to the invention are antibacterial substances, useful in particular against Mycoplasmas, both directly in the form of drugs and as disinfectants, or as an additive to drinking water.

Description

The invention relates to a method for producing novel pleuromutilins of general formula I,

íl) where means

Ri is an ethyl or vinyl group and Rz is an acyloxyalkyl of 2 to 5 carbon atoms in the acyloxy group and 1 to 4 carbon atoms in the alkyl group or benzoyloxyalkyl of up to 4 carbon atoms in the alkyl part, and their acid addition salts as well as quaternary salts, characterized in that the compound of the general formula Ia,

where

R1 has the above meaning and

R2 ¹ denotes hydroxyalkyl of 1 to 4 carbon atoms, which, in reaction with an acylating agent of general formula III,

R4—C—B

II about

(III), where

B is an alkoxy group of 1 to 4 carbon atoms, a bromine atom, a chlorine atom, or a group —O—C—R4 and

II about

R4 is alkyl of 1 to 4 carbon atoms or phenyl, and the obtained pleuromutilins of general formula I are optionally converted into their acid addition salts or quaternary salts.

The process can be carried out, for example, by allowing a compound of the formula Ia to react in a solvent for a certain period of time with an acid derivative of the formula III. The acid derivative can preferably be used alone as a solvent or in a mixture with an inert solvent, for example a chlorinated hydrocarbon such as dichloromethane. The reaction product can be isolated from the reaction mixture by known methods and optionally purified.

Compounds of general formula I can be converted into their acid addition salts and vice versa.

The corresponding quaternary salts can be obtained from the compounds of general formula I by known methods.

The hydroxyalkyl-o-group in the meaning of the symbol R2 ¹ preferably has 1 to 4, especially 2 carbon atoms. The lower acyloxy group in the meaning of the symbol R2 preferably has 1 to 4 carbon atoms and especially denotes an acetyl group. The lower alkyl groups in the meaning of the acyloxyalkyl or benzoyloxyalkyl groups in the symbol R2 preferably have 1 to 4, especially 2 carbon atoms. The number n preferably denotes the number two or three.

The compounds of the general formula I and their pharmacologically acceptable acid addition salts and quaternary salts have interesting biological and especially antimicrobial properties with low toxicity and can therefore be used as medicines. They have an inhibitory effect on bacterial growth, as can be demonstrated by in vitro studies or agar plate tests or in vivo experiments on mice using various bacterial strains. This inhibitory effect was found starting from a concentration of approximately 0.002 to 5 µg/ml, in particular an inhibitory effect was found against mycoplasmas, which appeared starting from a concentration of 0.08 to 2.5 µg/ml, therefore the compounds produced according to the invention can be used as antibacterially effective antibiotics.

The compounds of the general formula I and optionally their water-soluble, physiologically acceptable salts can be administered as pharmaceuticals in suitable pharmaceutical forms together with inorganic or organic pharmacologically acceptable excipients. For example, these substances are used as components in capsules, injection or drip preparations, which contain an amount of active substance sufficient to achieve an optimal blood level, i.e. about 10 to 500 milligrams per capsule.

The inhibitory effect against mycoplasmas was tested in vitro on the following organisms:

1. M. hominis II,

2. M. bovigenitalium,

3. M. gallisepticum,

4. M. sp. ISRí,

5. M. laidlawii,

6. M. hominis I,

7. M. hyorhinis.

The results obtained using compounds corresponding to general formula I are shown in the following Table I.

.TABLE I

Substance Minimum inhibitory concentration in ^ug/ml organisms

2 3 4 5 6 7

14-mutilyl-3-morpholinopropyl- amine-N,N-diacetate 14-de'9oxy-14-[ (3-morpholino- Propylamino Jacetoxy] - 15.6 3,125 mutilin lj4-deoxy-14-[ (2-diethylamino- 62.5 5 ethylthio j acetoxy ] mutilin 14-deoxy-14-[ (2-dimethyl- aminoethylthio)acetoxy] - 0.312 0.625 mutilin 14-deoxy-14-[(2-diethylaminoethylamino)acetoxy]- 1,561 0.31 mutilin 14-deoxy-14-[ (2-piperidino- 15,625 5 ethylthio) acetoxy ] mutilin 14-deso>xy-14-[ (2-morolino- 1.25 0.39 ethylthio) acetoxy ] mutilin — — In the following table II are summarized ex- results of tests performed in vivo during infection

0.078 12.5 250 7.81 15.6 1.25 31.25 500 12.5 25 0.039 3,125 15.6 0.195 0.78 0.019 3,125 15,625 < 0.97 — 2.5 31.25 500 3,125 12.5 0.156 6.25 15.6 1.9 — 0.97 7.81 — 0.97 7.81 of the items listed in these tables with DE95

expressed in mg/kg of weight.

Substance

TABLE II

Streptococcus infection.

DE95 in mg/kg per os subcutaneously

Streptococcus aronson infection

DE95 in mg/kg per os subcutaneously

Staph. aureus infection

DE95 in mg/kg per os subcutaneously

14-deoxy-1,4-[(2-diethyl- aminoethylthio) acetoxy ] mutilin 52.2 37.0 14-deoxy-14-[(2-t.rimethylammonioethylthio)acetoxy] mutilin iodide 8.1 14-d©so>xy-14- [ (2-diethylaminoethylthio) acetoxy ] dihydromutilin 78.5 87.1 Acute toxicity

Acute toxicity of a compound of the general formula-

113 134 92.9 23.8 101 229 1112 •42.4 these I are DL50 was investigated in mice. The results are given in Table III and are given for some compounds.

Substance

TABLE III

DLso in mg/kg per os subcutaneously

14-deoxy-14-[(2-diethylaminoethylthio)acetoxy]mutilin iodide 14-deoxy-14-[(2-trimethylammonioethylthio)acetoxy]mutilin

14-deoxy-14-[(2-diethylaminoethylthlo)acetooxy,] dihydromutilin

The pleuromutilin derivatives according to the invention are also excellent additives to animal feed mixtures. They can thus be added to feed for prophylactic purposes.

727.6 10.62

620.6 256.0 tics at concentrations between 0.05 and 5 ppm. The compounds of the invention can also be used as additives to drinking water. Compounds of general formula Ia,

where

Ri and Rz ¹ have the meanings given above, can be obtained by reacting the compound of general formula IV,

Ri has the meaning given above and

R s is an alkyl or aryl group, which, when reacted with a compound of general formula V,

HS-(CH ₂ ) ₂ -θ-R*

-ÍCW^-zQ,(laf 'hol, such as ethanol, dissolves the acid addition salt of the general formula V, for example the hydrohalide or the free base. To this solution is added a solution of the compound of the general formula IV in an inert solvent, for example an aliphatic ketone, such as dimethyl ketone or ethyl methyl ketone. The reaction is preferably carried out at room temperature up to the temperature of the reaction mixture, in particular at 25 to 50 ° C, and lasts between 2 to 12 hours.

In the following examples, which further explain the invention, the temperatures are given in degrees Celsius.

Example 1

14-Desoxy-14{[2-(4-acetoxyethyl]piperazinoethylmercaptoacetoxyjmutilin and}(4-HydrOxyethylpiperazino)ethanethlol

4-Hydroxyethylpiperazine is heated with a solution of ethylene sulfide in benzene in a molar ratio of 3:1 in an autoclave for 17 hours at 100°. After cooling the reaction mixture, the polymer material is filtered off, washed with benzene, the solvent is evaporated and the product is distilled through a Vigreux column. The boiling point of the title compound is 97.5°/13.33 Pa.

h) 14-Desoxy-14-{[2-( 4-acetoxyethyl )plperazinoethylmercaptoacetoxyjmutilin

1.81 g of (4- ^, hydroxyethylpiperazino)ethanethiol is added under nitrogen to a solution of 0.35 g of sodium in 25 ml of anhydrous ethanol and po(V) where

Rz ¹ has the above meaning.

The method can be carried out, for example, by adding dropwise to a solution of sodium in anhydrous low alcohol a solution of 5.85 g of 14-deoxy-14-tosyloxyacetoxymutilin in 15 ml of ethyl methyl ketone. After stirring for four hours at room temperature, the solvent is removed in vacuo, the residue is taken up in 50 ml of ethyl acetate, whereby partial transesterification occurs. The separation of the acetylated product from the unacetylated is carried out by column chromatography on silica gel, eluting with a 7:1 chloroform-methanol mixture. The faster-moving fraction is converted with ethereal hydrochloric acid into the hydrochloride, which softens at 137-140°. Melting point of the acid salt of maleic acid (bis-maleate) 142-144°.

Example 2

14-Desoxy-14-j [ 2-(4-acetoxyethyl jpiperazinoethylmercaptoacetoxyjmutilin

a) 14-Desoxy-14-{[ 2-(4-hydroxyethyl)piperazinoethylmercaptoacetoxyjmutilin

The procedure is as in Example 1b, but the residue after vacuum evaporation from the solvent is taken up in 50 ml of methylene chloride, washed 5 times with water and dried over magnesium sulfate. The solution is mixed with 5 ml of a 5.8 N solution of hydrochloric acid in ether. After further addition of ether, the hydrochloride precipitates as a crystalline mass. Melting point 192-197°.

b) 14-Desoxy-14-{ [ 2-(4-acetoxyethyl)piperazinoethylmercaptoacetoxyjmutilin

To 4.0 g of 14-desoxy-14-{[ 2-(4-hydroxyethyl Jpiperazino] ethylmercaptoacetoxy}mutilin, 10 ml of acetic anhydride is added under ice cooling and then stirred at room temperature for 5 hours. Then the mixture is poured into 150 ml of cold water, stirred for 1 hour and extracted 3 times with ether. The ether phase is removed and the aqueous phase is made alkaline with 10 N aqueous sodium hydroxide solution under cooling. The precipitated free base is taken up in ethyl acetate. After drying the solution with magnesium sulfate and evaporation of the solvent, the pure base remains. Melting point of bi3(hydrogenmaleate): 142 — 144°.

Example 3

14-Desoxy-14-{[2-(4-propionyloxyethyljpiperazinoethylmercaptoacetoxyjmutilin

0.50 g of 14-desoxy-14-{[2-(4-hydroxyethyl)piperazmethylmercaptoacetoxy]mutilin is refluxed for 2 hours in 5 ml of dichloromethane with 0.20 g of propionyl chloride. After cooling, the crystalline dihydrochloride is precipitated by adding ethereal hydrochloric acid and diluting with anhydrous ether. The salt is filtered off with suction and washed with ether. Melting point 182-187°.

Example 4

14-Desoxy-14-{ [ 2-(4-plvaloy ioxyethyl) piperazmoethylmercaptoacetoxyjmutilin

0.50 g of 14-desoxy-14-{[2-(4-hydroxyethyl)piperazino]ethylmercaptoacetoxy]mutilin is refluxed for 4 hours in 5 ml of dichloromethane with 0.15 g of pivaloyl chloride. After cooling by adding ethereal hydrochloric acid and diluting with anhydrous ether, the crystalline dihydrochloride precipitates. After suction filtration, this is briefly washed with anhydrous ether and dried in vacuo. The substance hydrolyzes very easily to the parent substance in the presence of water.

Example 5

14-Desoxy-14-{ [ 2-(4-benzoyloxyethyl 1)piperazinoethylmercaptoacetoxyjmutilin

0.50 g of 14-deoxy-14-{[2-(4-hydroxyethyl)piperazin]ethylmercaptoacetoxy]mutilin is reacted with 0.16 g of benzoyl chloride for 2 hours as described in Examples 3 and 4. The dihydrochloride is then precipitated as described. It softens at 132-135°.

Example 6

14-De'oxy-14-{ [ 2-(4-acetoxyethyl j piperazino] ethyl mercaptoacetoxy j dihydromutilin

a) 14-Desoxy-14-tosyloxyacetoxydihydromutilin

Method «:

To a solution of 8.86 g of dihydropleuromutilin in 30 ml of dry pyridine at -15°, 6.10 g of p-toluenesulfochloride are added all at once with vigorous stirring. The mixture is stirred for 2 hours at -15° and then for another hour at 0°. It is then poured into ice water and the product is extracted with methylene chloride. The organic phase is washed with ice water and then saturated sodium bicarbonate solution while cooling. Drying with sodium sulfate and evaporation give a product that is uniform by thin-layer chromatography and softens at 78 - 80°.

Method /3}:

0.53 g of 14-deoxy-14-tosyloxyacetoxymutililine is hydrogenated in 10 ml of ethyl acetate over 0.10 g of 10% palladium on carbon at atmospheric pressure and room temperature. The calculated amount of hydrogen is absorbed after about 1 hour. The catalyst is removed from the solution by filtration and evaporated in vacuo. The substance has a softening point of 78-80°.

b) 14-Desoxy-14-{ [2-(4-hydroxyethyl j piperazine-ethyl mercaptoacetoxy j dihydromutilitn

14-Deoxy-14-tosyloxyacetoxydihydromutilin is reacted with-(4-hydroxyethylpiperazino)ethanethiol analogously to Example 2 to give 14-deoxy-14-{[2-(4-hydroxyethyl)piperazino]ethylmercaptoacetoxy]dihydromutilin. Melting point of the dihydrochloride 135-140°.

c) 14-Desoxy-14-{[ 2-(4-acetoxyethyl)piperazino]ethylmercaptoacetoxy(dihydromuitilin

0.50 g of 14-desoxy-14-{[2-(4-hydroxyethyl]piperazino]ethylmercaptoacetoxy}dihydromutilin is left at room temperature for 2 hours with 1.5 ml of acetic anhydride and then diluted with 10 ml of water and stirred at room temperature for 1 hour to decompose the excess acetic anhydride. The solution is extracted 3 times with ether. The dihydrochloride is precipitated from the concentrated solution with ethereal acetic acid as in Example 4. Melting point 133-135°.

Claims (2)

SUBJECT INVENTION U Ri ethyl or vinyl group, and R2 is ^{1-acyloxyalkyl} o * 2-5 carbon atoms in the acyloxy portion and 1 to 4 carbon atoms in the alkyl group or benzoyloxyalkyl their addition salts with acids, and one quaternary salts thereof, wherein the compound of formula Ia . where R1 is as defined above and R &lt; ^{21 &} gt ^; is C1-C4 hydroxyalkyl, reacted with an acylating agent of formula III, R <—C — B II o (III), where B is C 1 -C 4 alkoxy, bromine, chlorine, or -O-C-R 4; and II o R4 is alkyl of 1 to 4 carbon atoms or phenyl, and the resulting pleuromutilins of formula I are optionally converted into their acid addition salts or quaternary salts. 2. A process for the preparation of the novel pleuromutilins of the formula I, wherein R1 is as defined in 1 and R2 is acyloxyalkyl of 2 to 5 carbon atoms in the acyloxy group and 1 to 4 carbon atoms in the alkyl group, and their acid addition salts and quaternary acids. a salt, characterized in that the compound of formula (Ia) wherein R 1 is as defined above and R ²¹ is C 1 -C 4 hydroxyalkyl is reacted with a compound of formula (III) wherein B is C 1 -C 4 alkoxy and R 4 is C 1 -C 4 alkyl and the pleuromutilins of formula I obtained are optionally converted to their acid addition salts or quaternary salts.