BG60435B2 - Riphamicyn compounds - Google Patents

Abstract

The compounds have increased antibacterial activity on grampositive and gramnegative bacteria, especially on Mycobacterium tuberculosis having the general formula (formula) with specific substitutes. The invention is also related to methods for their preparation and to pharmaceutical compositions and preparations containing them.

Description

The invention relates to novel rifamycin compounds, methods for their preparation, pharmaceutical compositions and preparations containing them, and is an improvement or modification of patent GB No. 1 542 063 of the same applicant. with respect to Gram-positive and Gram-negative bacteria, in particular with respect to Mycobacterium tuberculosis. According to the present invention, rifamycin compounds prepared by reacting 3-amino-4-deoxy-4-iminorifamycin S with certain 4-piperidones of structural formula

It has good therapeutic activity, as illustrated by in vitro experiments on mice infected intravenously with Mycobacterium tuberculosis.

The present invention provides novel rifamycin compounds of formula I,

wherein R is selected from hydrogen, C ₄ -C, straight chain alkyl, C ₃ -C, branched chain alkyl, C ₃ -C 1 alkenyl, C ₃ -C _a cycloalkyl, C ₇ -C, cycloalkylalkyl, C _3- C, alkoxyalkyl, C ₃ C, alkyltetrahydrofuryl, C ₃ -C, alkanoyl and C ₂ -C ₃ monohaloalkanoyl, and Y is -H or -COCH ₃ .

When R is a branched chain alkyl radical, it may be, for example, alkyl with

4,5 or 6 carbon atoms. In other compounds according to this embodiment of the invention it may be a 2-alkyl furyl radical or

2-alkyltetrahydrofuryl radical.

The compounds of the invention show good activity illustrated in in vivo experiments on white Cl 1 mice.

Among the piperidinylidene derivatives described in patent No. 1 542 063, the rifamycin compounds of formula 1 prepared by reaction of a rifamycin compound of formula II

with L1-ethyl-4-piperidone, called the "ethyl derivative", have the highest therapeutic activity.

The rifamycin compounds of the invention have higher therapeutic activity than the rifamycin compounds prepared using the 4-piperidone according to the known patent, which activity is illustrated by the following experiments.

White CD1 mice are infected with

H _3? An RV culture was intravenous, with 0.2 ml of said culture containing twice the amount of the LD ₃₀ dose being injected into each mouse.

Three days after the infection of the mice, they were treated with the rifamycin compounds of the invention using doses ranging from 20 to 1.25 mg / kg. Groups of 15 mice were treated with each rifamycin compound, administered once daily for five consecutive days with a total treatment duration of 6 weeks.

At the end of treatment, the dead mice were counted and the _PD10 value was determined.

Animals have been observed for about two months.

The PD ^ dose of the "ethyl derivative" is 20 mg / kg.

In Table 1, the test compounds are designated by their R radical, and the radical Y in each compound is hydrogen. The table shows the results of the in vivo and in vitro experiments and the visible UV absorption spectrum.

Table 1

Activity

In vitro MIC micrograms / ml

In vivo Ultraviolet visible absorptionPD _j0 mg / kg ion spectrum in methanol peaks observed or pt.

n-butyl 0,0005 5 496, 317, 276, 240 n-hexyl 0,0005 10 497, 314, 278, 239 allyl 0,0012 5 491, 314, 276, 235 butyl 0,0012 2.6 493, 315, 274, 238 methyl allyl 0,005 5 498, 313, 275, 238 secondary butyl 0,005 3.7 500, 315, 275, 240 2-methylfuryl 0,0012 - - 1,2-dimethyl propyl 0,005 2.5 - n-pentyl 0,0012 5 500, 316, 278, 240 1,3-dimethylbutyl 0,0012 2.5 500, 315, 277, 240 3-pentyl 0,0012 2.5 500, 315, 276, 240 ethyl 0.01 20

The results obtained from carrying out these experiments with the "ethyl derivative" and with some of the new compounds of the invention show that the _PD10 of the new compounds is lower than that of the "ethyl derivative" and is therefore more effective than the latter.

The rifamycin compounds of the invention are prepared by a method (representing a second object of the present invention) wherein a compound of formula II in which Y is -H or -COCH ₃ is reacted with 4piperidone of formula III in which R is hydrogen, an alkyl radical 4 to 8 straight chain carbon atoms, 3 to 8 branched chain alkyl atoms, alkenyl 3 or 4 carbon atoms, 3 to 6 carbon cycloalkyl, 7 or 8 alkyloxy radicals, cycloalkylalkyl radicals a 3 to 7 carbon radical days atoms, an alkyl furyl radical of 5 or 6 carbon atoms, an alkyltetrahydrofuryl radical of 5 or 6 carbon atoms, an alkanoyl radical of 5 or 6 carbon atoms, or a monohaloalkanoyl radical of 2 to 6 carbon atoms.

The process is easily carried out in the presence of zinc and acetic acid or zinc and ammonium acetate.

A third object of the invention includes pharmaceutical compositions containing the rifamycin compound of the invention and the pharmaceutically acceptable carriers or diluents therefor.

A fourth object of the invention are pharmaceutical preparations which comprise the rifamycin compound or pharmaceutical composition of the invention in a unit dosage form.

The invention is illustrated by the following examples.

Example 1. 8 g of 3-amino-4-dioxy-4-iminorifamycin S was dissolved in 40 ml of dichloromethane and reacted with 2.6 g of 1-n-hexyl-4-piperidone at + 5 ° C for 48 hours. The solution was diluted with 600 ml of ethyl ether, filtered and washed with water. The organic phase was dried over sodium sulfate and evaporated to dryness. The residue was extracted with petroleum ether and the violet solution was evaporated to dryness. Yield: 2.5 g of the product of formula I, in which Y is -COCH ₃ and R represents a nhexyl radical. The electronic absorption spectrum in methanol shows peaks at 497, 314, 278 and 239 pt.

Example 2 8 g of 3-amino-4-deoxy-4-iminorifamycin S was dissolved in 40 ml. 4 g of 1- (1 ', 3'-dimethylbutyl) -4-piperidone, 0.5 g of zinc and 0 were added. 5 g of ammonium acetate and the mixture was stirred at room temperature for 30 minutes. The reaction mixture was treated as in Example 1 to give 3.5 g of the product of formula I, wherein Y is -COCH ₃ and R is a 1,3-dimethylbutyl radical. The electronic absorption spectrum in methanol shows peaks at 500, 315, 277 and 240 nm.

Example 3. 8 g of 3-amino-4-dioxo-4-iminorifamycin S were dissolved in 40 ml of tetrahydrofuran. 1.8 g of 1-Methyl-4-piperidone, 0.2 g of zinc and 0.2 g of ammonium acetate were added and the mixture was allowed to stand at + 5 ° C overnight.

The reaction mixture was treated as in Example 1 to give 5.5 g of the product of formula I, in which Y is -COCH ₃ and R is a metal radical.

The electronic absorption spectrum in methanol shows peaks at 498, 313, 275 and 238 pt.

Example 4 8 g of 3-amino-4-deoxy-4-iminorifamycin S were dissolved in 40 ml of tetrahydrofuran. 3 g of 1-cyclohexyl-4-piperidone, 0.2 g of zinc and 0.2 g of ammonium acetate were added and the mixture was stirred for 2.5 hours at room temperature. The unreacted zinc was filtered off and the solution was diluted with 1000 ml of ethyl ether. The ether solution was washed with sodium phosphate buffer solution at pH 7.8 and then extracted with dilute acetic acid. The violet aqueous solution was extracted with chloroform, the organic phase was washed with water and dried over sodium sulfate. The chloroform was evaporated to dryness. Yield: 3.8 g of the product of formula I, wherein Y is -COCH ₃ and R is a cyclohexyl radical. The electronic absorption spectrum in methanol shows peaks at 498, 312, 273 and 235 nm.

Example 5. 8 g of 3-amino-4-deoxy-4-iminorifamycin S were dissolved in 40 ml of tetrahydrofuran. 0.5 g of zinc, 0.5 g of ammonium acetate and 5.5 g of 1-2'-methylfuryl-4-piperidone are added. The mixture was stirred at room temperature for 24 hours and filtered, diluted with 500 ml diethyl ether and washed with water. The diluted organic phase was concentrated to 250 ml and extracted with aqueous acetic acid. The violet aqueous solution was extracted with dichloromethane and the organic phase, washed with water and dried over sodium sulfate, evaporated to dryness. Yield: 3.3 g of the product of formula I, wherein Y is -COCH ₃ and R is a 2'-methylfuryl radical. The electronic absorption spectrum in methanol shows peaks at 497, 316, 276 and 240 nm.

Example 6 8 g of 3-amino-4-dioxo-4-iminorifamycin S were dissolved in 40 ml of tetrahydrofuran and the resulting solution was added dropwise at 50 ° C in a mixture of 15 ml of tetrahydrofuran, 5 ml of acetic acid, 1 g of zinc and 5 g 1- (2'-methyltetrahydrofuryl) -4-piperidone. The heating was continued for 30 minutes, after which the reaction mixture was treated as in Example 5. Yield: 2.1 g of the product of formula I, in which Y is -COCH ₃ and R is a 2'-methyl-tetrahydrofuryl radical. The electronic absorption spectrum in methanol shows peaks at 495, 314, 275 and 239 pt.

Example 7 32 g of 3-amino-4-dioxo-4-iminorifamycin S were dissolved in 200 ml of tetrahydrofuran. 9 g of 4-piperidone monohydrate hydrochloride, µg ammonium acetate and 0.4 zinc were added, then the mixture was stirred at room temperature for 12 hours. The reaction mixture was filtered off and added dropwise to 1500 ml of diluted acetic acid. After filtration, the aqueous solution was neutralized with sodium bicarbonate to pH 6, then extracted twice with dichloromethane. Yield: 13.4 g of the product of Formula I, wherein Y is -COCH ₃ and R is hydrogen. The electronic absorption spectrum in methanol shows peaks at 500, 315, 275 and 240 nm.

Example 8 8 g of 3-amino-4-deoxy-4-imino-rifamycin S were dissolved in 50 ml of tetrahydrofuran. 0.3 g of zinc, 0.3 g of ammonium acetate and 2.5 g of 1-chloroacetyl-4-piperidone are added, then the mixture is allowed to react at + 5 ° C for 48 hours. The reaction mixture was filtered and diluted with 150 ml of dichloromethane and 800 ml of cyclohexane. The solution was filtered again, washed with sodium phosphate buffer solution at pH 7.5 and then with water. The solvent was evaporated in vacuo and the residue was crystallized from cyclohexane. Yield: 3.2 g of the product of Formula I, wherein Y is - COCH ₃ and R is a chloroacetyl radical. The electronic absorption spectrum in methanol shows peaks at 497, 310, 273, and 235 sh.

Example 9 8 g of 3-amino-4-deoxy-4-iminorifamycin S were dissolved in 40 ml of tetrahydrofuran. 0.5 g of zinc, 5 ml of acetic acid and 4.5 g of 1-n-octyl-4-piperidone are added. The mixture was stirred for 10 minutes at room temperature. The unreacted zinc is filtered off, the solution is diluted with 700 ml of diisopropyl ether and filtered again and concentrated to 300 ml in vacuo. 300 ml of petroleum ether are added and the solution is filtered one more time. After evaporation of the solvent, the oily residue was dissolved in 40 ml of methanol and the solution added dropwise to 400 ml of water. The resulting precipitate was filtered off, washed with water and dried at 40 ° C in vacuo. Yield: 3.8 g of the product of formula I, wherein Y is -COCH ₃ and R is an n-octyl radical. The electronic absorption spectrum in methanol shows peaks at 497, 310, 274 and 236 nm.

Example 10. 16 g of 3-amino-4-deoxy-4-iminorifamycin S were dissolved in 100 ml of tetrahydrofuran. 1 g of zinc, 0.5 g of ammonium acetate and 8 g of 1- (3'-methoxy-propyl) are added.

4-piperidone, after which the mixture was stirred at room temperature for 60 minutes. The reaction mixture was filtered, diluted with 1500 ml of xylene and washed with water. The organic phase was extracted with dilute acetic acid and then separated. The aqueous solution dissolved at pH 7 with sodium phosphate buffer solution was extracted with dichloromethane. After dilution with petroleum ether, the resulting violet solution is filtered off and evaporated to dryness. Yield: 3.0 g of the product of Formula I, wherein Y is -COCH ₃ and R is

3-methoxypropyl radical. Thin layer chromatography on silica gel using chloroform: methanol 9: 1 for the mobile phase showed a violet spot with Rf = 0.43.

Example 11 8 g of 3-amino-4-deoxy-4-iminorifamycin S were dissolved in 40 ml of tetrahydrofuran. 0.5 g of zinc, 0.5 g of ammonium acetate and 4.5 g of 1- (1 ', 4'-dimethyl-pentyl) -4-piperidone are added, then the mixture is stirred at room temperature for 30 minutes. . The reaction mixture was treated as in Example 10. Yield: 5.0 g of the product of formula I in which Y is -COCH ₃ and R is

1,4-dimethylpentyl radical. Thin layer chromatography on silica gel using chloroform: methanol 9: 1 for the mobile phase showed a violet spot with Rf-0.52.

Example 12 8 g of 3-amino-4-deoxy-4-imino-rifamycin S were dissolved in 50 ml of tetrahydrofuran. 0.2 g of zinc, 0.2 g of ammonium acetate and 3 g of 1-pivaloyl-4-piperidone are added, then the mixture is kept at 0 ° C for three days. The reaction mixture was filtered, diluted with 300 ml of diethyl ether and washed with pH 7.5 buffered sodium phosphate. The organic phase was washed with water, dried over sodium sulfate and evaporated to dryness. The residue was crystallized from cyclohexane. Yield: 7 g of a product of formula I, wherein Y is -COCH ₃ and R is a pivaloyl radical. The electronic absorption spectrum in methanol shows peaks at 497, 316, 276 and 238 nm.

Claims (14)

Claims Compounds of rifamycin of the formula wherein R is selected from hydrogen, C ₁ -C ₈ straight chain alkyl, C ₃ -C ₄ branched chain alkyl, C ₃ -C ₄ alkenyl, C ₃ -C ₃ cycloalkyl, C ₇ -C, cycloalkylalkyl, C ₃ -C ₇ alkoxyalkyl, C ₃ -C, alkylfuryl, C ₃ -C, alkyltetrahydrofuryl, C _s -C _t alkanoyl and C ₃ -C ₄ monohaloalkanoyl and Y is -H or -COCH ₃ . A compound according to claim 1, wherein R is an alkyl radical having 4, 5 or 6 branched chain carbon atoms. The compound of claim 1, wherein R is a 2-alkyl-furyl radical or a 2-alkyl-tetrahydrofuryl radical. The compound of claim 3, wherein R is a 2-alkyl-tetrahydrofuryl radical. A compound according to claim 2, 3 or 4, wherein Y is -COCH ₃ . 6. A compound of rifamycin prepared according to any one of the examples. A method for preparing a rifamycin compound according to claims 1 to 6, characterized in that the compound of formula II / wherein Y is -H or -COCH ₃ , is reacted with 4-piperidone of the formula ⁺ ύ t (iii) wherein R is hydrogen, an alkyl radical of C 1-4 4 to 8 straight-chain carbon atoms, 3 to 8 branched-chain alkyl radicals, alkenyl radicals with 3 or 4 carbon atoms, 3 to 6 carbon atoms cycloalkyl radicals with 7 or 8 carbonalkyl radicals with 3 to 7 carbon atoms, an alkyl furyl radical with 5 or 6 carbon atoms, an alkyltetrahydrofuryl radical with 5 or 6 carbon atoms, an alkanoyl radical with 5 or 6 carbon atoms or a monohaloalkanoyl radical of 2 to 6 carbon atoms. A method according to claim 7, characterized in that the reaction with piperidone is carried out in the presence of zinc and acetic acid. A method according to claim 7, characterized in that the reaction with piperidone is carried out in the presence of zinc and ammonium acetate. The method of claim 7, essentially as described in the description. A method for preparing a compound of rifamycin of formula I, wherein R-Y has the meanings set forth in claim 1, substantially as described in any example of the description. A rifamycin compound prepared by the method of claims 7 to 11. A pharmaceutical composition comprising the compound of rifamycin according to claims 1 to 6 and claim 12 together with a pharmaceutically acceptable carrier or diluent. A pharmaceutical composition comprising a rifamycin compound according to claims 1 to 6 and claim 12 or a pharmaceutical composition according to claim 13 in a unit dosage form. Expert: R Jovovich Publication of the Patent Office of the Republic of Bulgaria Sofia - 1113, Γ Blvd. M. Dimitrov 52-B Editor: N. Bozhinova Cf. 37398 Circulation: 40 SK