EP0812316A1

EP0812316A1 - Novel derivatives of ethyl-1 dihydro-1,2 oxo-2 methylamino-3 quinoxaline, utilization as drugs, and pharmaceutical compositions containing them

Info

Publication number: EP0812316A1
Application number: EP96905885A
Authority: EP
Inventors: Jean-François Patoiseau; Jean-Pierre Tarayre; Jean-Marie Autin
Original assignee: Pierre Fabre Medicament SA
Current assignee: Pierre Fabre Medicament SA
Priority date: 1995-03-01
Filing date: 1996-02-29
Publication date: 1997-12-17
Also published as: CA2214572A1; FR2731221A1; AU4946796A; FR2731221B1; AU707032B2; NZ303226A; JPH11502519A; WO1996026928A1

Abstract

The present invention relates to novel derivatives of ethyl-1 dihydro-1,2 oxo-2 methylamino-3 quinoxaline having general formula (I), wherein R1 is hydrogen or methyl group, and the salt thereof with pharmaceutically acceptable acids. It also relates to their utilization as drugs useful particularly in the treatment of diseases such as chronic obstructive bronchopneumopathies, particularly asthma, respiratory insufficency, emphysema. Finally, it relates to pharmaceutically compositions containing them.

Description

NEW ETHYL-1 DIHYDRO-1,2 DERIVATIVES

OXO-2 METHYIΛMINO-3 QUINOXALINE,

IJEUR USE AS A MEDICINAL PRODUCT

AND I £ S PHARMACEUTICAL COMPOSITIONS COMPRISING THE SAME

The present invention, carried out at the Pierre Fabre Research Center, relates to new chemical compounds and their application as drugs.

The Applicant has previously described a series of compounds with bronchodilator activity (PIERRE FABRE MEDICAMENT patent FR-2 696 456 of 7/10/92).

This previous invention covers compounds of general formula I

in which

- RI, R2 represent, independently of one another, hydrogen or a linear or branched CC ₄ alkyl radical,

- R3 represents an alkyl, alkenyl or hydroxyalkyl group, C ₃ -C ₆ linear or branched.

The present invention relates specifically to the compounds of general formula I for which:

- RI represents hydrogen or the methyl group,

- R2 represents the methyl group, and - R3 represents the ethyl group.

In addition, the invention covers the salts of the compounds of general formula I defined above with the pharmaceutically acceptable acids.

The compounds of the present invention differ from the prior art and in particular compounds of the same chemical family described previously by the applicant, by their high solubility in an aqueous medium. Indeed, the compounds of the invention have a solubility in water at 25 ° C greater than or equal to 5% against a solubility less than or equal to OJ% for the compounds described previously and the products for which R3 = methyl. This unexpected property also gives these products an increase in their bioavailability and their duration of action. The compounds of the present invention are also characterized by the demonstration, in vivo, of anti-inflammatory properties on a model of allergic bronchial inflammation caused in the Brown Norway rat. The compounds notably reduce bronchial eosinophilia. The examples below illustrate the invention without, however, limiting its scope.

The centesimal analyzes as well as the infrared and NMR spectra confirm the structure of the products obtained. EXAMPLE 1 Ethyl hydrochloride-1 dihydro-1, 2 oxo-2 methylamino-3 quinoxaline

1) Ethyl-1 dihydro-1,2-oxo-2 quinoxaline carboxylate ethyl-3.

To a suspension of 18.25 g (0.084 mole) of 2-hydroxyethyl quinoxaline carboxylate-3 in 300 ml of acetone, 11.55 g (0.084 mole) of potassium carbonate are added, 12.6 ml (0.096 mole) of ethyl sulfate, and the whole is heated for 1 hour at reflux. After evaporation of the solvent under vacuum, the residual mass is extracted with ethyl ether. The mineral salts are then filtered, and the filtrate evaporated in vacuo. The brown oil thus obtained is purified on a silica column. Elution with an ethyl acetate-hexane mixture 30-70 provides, after evaporation, 12.41 g (yield 60%) of compound in the form of off-white crystals. M = 80-81 ° C TLC: Rf = 0.30 (ethyl acetate - hexane 30-70).

2) Ethyl-1 acid dihydro-1, 2 oxo-2 quinoxaline carboxylic-3. A solution of 13.79 g of the preceding ester (0.056 mole) in 50 ml of 95 ° ethanol and 56 ml of 2N sodium hydroxide (0J 12 mole) is stirred for 30 minutes at 60 ° C. After cooling, acidification by addition of a solution of hydrochloric acid N, the suspension obtained is ice-cold for one hour. The crystals are then filtered, washed with water, with ethanol and then dried under vacuum at 50 ° C. 10.38 g of acid are thus recovered, in the form of yellow flakes. Yield 85 96, mp 182 ° C. TLC: Rf = 0.65 (methanol - chloroform 50-50). 3) Ethyl-1 dihydro- 1, 2 oxo-2 terbutoxycarbonylamino-3 quinoxaline.

A solution of 11.40 g (0.05227 mole) of the acid obtained above, 15J ml of triethylamine (0J 1 mole), 23J ml (0J05 mole) of diphenylphosphorylazide in 350 ml of tertiobutanol is heated for 6 hours at reflux. After evaporation of the solvent, the residual oil is taken up in a sodium bicarbonate solution and extracted with ethyl acetate. The organic phase is washed with water, with salt water, then dried over sodium sulfate and concentrated in vacuo. The solid obtained is triturated in ethyl ether, filtered, washed and dried to give 9.07 g of white crystals (yield 60 96), melting at 98 ° C.

TLC: Rf = 0.43 (ethyl acetate - hexane 30-70).

4) 1-Dihydro-1,2-hydrochloride, 2-oxo-2-methylamino-quinoxaline L A solution of 8.68 g (0.03 mole) of carbamate previous in

100 ml of tetrahydrofuran is stirred for 24 hours at room temperature in the presence of 3.4 ml of methyl sulphate, 21 ml of 6N sodium hydroxide and 684 mg of benzyltriethylammonium chloride.

After evaporation of the solvent, the residue is taken up in water and extracted with ethyl acetate.

After washing with water, drying over sodium sulphate and evaporation under vacuum, the recovered oil (intermediate N-methylcarbamate) is treated with a solution of 50 ml of 6N hydrochloric acid for 2 hours at 60 ° C. This solution is then poured onto ice and neutralized by adding 6N sodium hydroxide. The solid formed is extracted with ethyl acetate, the solution is dried and then an ethanolic solution of hydrochloric gas is added thereto; the precipitate formed is filtered, washed with ether and then dried.

6.40 g are thus recovered (yield = 89%) of compound (1) in the form of white crystals. M = 171 ° C.

TLC: Rf = 0.35 (ethyl acetate - hexane 30-70). EXAMPLE 2:

1,2-Dihydro-1,2 hydrochloride 2-dimethylamino- hydrochloride

3 quinoxaline, 2_. Stir for one hour at room temperature 2J 5 g

(0.009 mole) of compound (1) in 15 ml of N, N dimethylacetamide in the presence of 0.4 g of 60% sodium hydride. 1.54 ml (0.025 mole) is then added methyl iodide and heated 1 hour at 60 ° C. After evaporation of the solvent under vacuum, the hydrochloride is obtained as in the previous example. 1.96 g of white crystals are isolated (yield = 86%), mp 130-131 ° C. TLC: Rf = 0.39 (toluene - ethyl acetate 95-05).

SOLUBILITIES

The solubilities in water at 25 ° C. of the compounds of the invention 1 and 2 are compared in Table I with those of the corresponding compounds 3 _. to 6 described and claimed previously (FR-A-2 696 456) and 7 described by JW CLARK-LEWIS (J. Chem. Soc. 1957, 42).

Table I

Compounds R I R 2 R 3 S e l Solub ility

I CH ₃ HC ₂ H ₅ HC1 5%

2 CH ₃ CH ₃ C2H5 HC1 10%

3 CH ₃ H nC ₃ H ₇ HC1 <0.1 6

4 CH ₃ CH ₃ nC ₃ H- HC1 <0.1 96

5 CH ₃ H nC ₄ Hg HC1 <0.1 6

6 CH ₃ CH ₃ nC ₄ H ₉ HC1 <0.1 96

7 CH ₃ H CH ₃ HC1 <0.1 96

BIOLOGICAL EXPERIMENTATIONS

1 - Pharmacological study

a) Spasmolvtic activity on isolated trachea of cobave. in vitro The compounds of the invention have been subjected to pharmacological tests which have shown their interest as bronchial spasmolytic agents.

To this end, the compounds have been studied for their antagonistic effect of the contractions caused by histamine according to the following protocol. A piece of tricolor guinea pig male of 400 g on average is cut in a spiral and mounted (about 2.5 cm) in an insulated organ tank thermostatically controlled at 37 ° C and filled with oxygenated tyrode. Isometric contractions caused by histamine are recorded using a UC2 Gould Statham (Gould Inc. Oxnard, California, USA) or UF1 Palmer Bioscience sensor connected to a potentiometric recorder (Linseiss, Selb, RFA).

At the start of the experiment, the trachea flap is subjected to a tension of 1 g and left to stand for 1 h.

Histamine hydrochloride is used at a concentration of 10 μg / ml (concentration generally causing maximum contraction).

The concentration of agent used causes contractions which become maximum after 5 to 15 minutes and then continue to level off. A concentration of the studied product is administered for each contraction, and the product is left in contact with the trachea for 5 min. The possible inhibition obtained after this time is measured (percentage change in the amplitude of the contraction). The trachea is then washed for 15 seconds and left to stand for approximately 10 minutes (time necessary to return to the basic ronus) before causing a new contraction. Compound 5 _. , insoluble in water is diluted in 0J 78% (v / v)

(final concentration in the bath) of dimethyl sulfoxide (DMSO). This concentration of DMSO has no effect on the contractions of the mediator studied.

The 50% inhibitory concentrations (IC ₅₀ ) are calculated using a SAS program (Statistical Anah sis System) inspired by Bliss and Cattel (BLISS CI. And CATTEL McK. Biological Assay Ann. Rev. Physiol. 5, 479, 1943).

The results obtained on compounds 1 and 2 of the present invention are reported compared to the representative compound 5 of the series described previously in Table II. Table II

Histamine

Compound N ° IC ₅₀ (μg / ml)

I 3.8

2 8.8

5 2.3

b) Bronchodilator activity, in vivo: exposure test to a histamine aerosol in the vigilant guinea pig

Male Dunkin Hartley guinea pigs of 300 - 350 g are placed in a circular glass enclosure of 8 1 volume. Guinea pigs are exposed to an aerosol of histamine dihydrochloride at 1% (W / V) generated by a Jouan aerolizer (Paris) causing the formation of dry particles of 1 - 3 μm and supplied with compressed air at a rate 28 ml schedule at a pressure of 1 bar.

We measure the time when the animal falls on its side (pre-convulsion time). At this time, the animal is removed from the enclosure and the possible mortality within 10 min is noted. The maximum duration of aerosol exposure is 3 min.

The animals are treated with the products to be studied intraperitoneally 15 min before the test or orally 1 h before the test. For oral administration, the products are dissolved in distilled water (soluble products, I and II) or suspended in a mixture of tween 80 and distilled water (product III). For intraperitoneal administration, the products are dissolved in 9% NaCl o (W / V) or suspended in a tween 80 and 9% NaCl mixture. The control animals receive the only appropriate solvent in the administration conditions identical to those of the treated animals. The volume administered is always 10 ml / kg. The possible protective activity of the products is quantified by the evaluation of the protected animals in comparison with the respective control animals. When possible, an ED ₅₀ (effective dose in 50% of animals) was determined (Table III). Table III

DE ₅₀ ip DE ₅₀ po

Compound No. (mg / kg) (mg / kg) po / ip

I 9.7 8.4 0.9

5 8.6 21 2.4

Reports of ₀ OF ₅ inch / ip show an increase in the bioavailability of the product 1 object of the present invention, administered orally.

A duration of action of approximately 4 hours is also observed for compound 5_ and greater than 8 hours for compound _ c) Test for allergic bronchial inflammation

The compounds of the invention were tested on the model of allergic bronchial inflammation caused in Brown Norway rats (JP TARAYRE, M. ALIAGA, M. BARBARA, N. TISSEYRE, S. VIEU, J. TISNE-VERSAILLES: Model of bronchial allergie inflammation in Brown Norway rat. Pharmacological modulation. Int. J. Immunopharπi 1992, 14, 5, 847-855). This model reproduces in Brown Norway rats bronchial eosinophilia obtained in the atopic asthmatic patient 24 h after the inhalation of allergen (DE MONCHY JGR, KAUFFMAN HF, VENGE P., KOETER GH, JANSEN HM, SLUITER HJ, DE VRIES L Arn. . Resp. Say. 13 1, 373-376, 1985). The products are administered intraperitoneally 5 min and

5 h after exposure to the aerosol of antigen (ovalbumin). The number of bronchial eosinophils is determined after collection by bronchoalveolar lavage 24 h after exposure to the antigen. The possible reduction of bronchial eosinophils by the compounds tested is quantified in comparison with controls receiving only the solvent under the same conditions of administration (Table IV). Table IV

Inhibition Dose (%) of

Compound No. mg / kg (x 2) Bronchial peosinophilia

I 5 52

2 5 69

2 - Therapeutic applications.

The compounds of the invention are bronchodilators which can be used for the treatment of diseases such as chronic obstructive pulmonary disease, respiratory failure, emphysema.

The compounds of the invention may be used in particular in the treatment of asthma. In recent years, the role of inflammation in the deterioration of the bronchial mucosa has been well demonstrated in this pathology. The blood eosinophils that accumulate in the mucosa and bronchial lumen appear to be the main sources of the mediators that cause this inflammation in asthma (GLEICH GJ. The eosinophil and bronchial asthma: current understanding. J. Allergy Clin. Immunol. 85, 422-436, 1990).

The addition of anti-inflammatory properties to the bronchodilator properties of the claimed compounds could allow their use in chronic treatment in asthma.

The pharmaceutical compositions contain as active principle at least one compound defined according to the invention associated with an inert pharmaceutical carrier or other pharmaceutically acceptable vehicle or any other suitable excipient. The pharmaceutical compositions can be in a form suitable for oral, rectal, parenteral or local administration, for example in the form of capsules, tablets, granules, capsules or liquid solutions, syrups or oral suspensions, aerosols or sprayable solutions, and contain the appropriate excipients.

The pharmaceutical compositions can contain as active principle at least one compound defined according to one of claims 1 or 2 associated with another active principle.

The daily dosage can range from 50 to 1000 mg.

Claims

1 / The derivatives of ethyl-1-dihydro l, 2-oxo-2 methylamino-3 quinoxaline of general formula I

in which RI represents hydrogen or the methyl group, and their salts with pharmaceutically acceptable acids.

2 / Derivatives of general formula I according to claim 1, characterized in that they are chosen from:

• ethyl-1-dihydro-1,2-oxo-2-methylamino-3-quinoxaline hydrochloride; and

• ethyl-1-dihydro-1,2-oxo-2-dimethylamino-3-quinoxaline hydrochloride.

3 / As new medicines, the compounds defined according to one of claims 1 or 2.

4 / Medicines according to claim 3, useful in particular in the treatment of diseases such as chronic obstructive pulmonary disease including asthma, respiratory failure, emphysema.

5 / Pharmaceutical compositions characterized in that they contain as active principle at least one compound defined according to one of claims 1 or 2, associated with an inert pharmaceutical carrier or other pharmaceutically acceptable vehicle or any other suitable excipient.

6 / Pharmaceutical compositions characterized in that they contain as active principle at least one compound defined according to one of claims 1 or 2, associated with another active principle.