FI93838C - Process for the preparation of new therapeutically useful 7,8-dihydroxy-1H-imidazo and pyrazolo [3,4-f] quinoxaline derivatives - Google Patents

Description

93838

Process for the preparation of new therapeutically useful 7,8-dihydroxy-1H-imidazo and pyrazolo [3,4-f] quinoxaline derivatives 5 Separated from application 893170 (patent 91259)

The invention relates to the preparation of new 7,8-dihydroxy-1H-imidazo and pyrazolo [3,4-f] quinoxaline derivatives of the formula

Y-NH

X. Jl m „0H

ru Y (I) 2jUs. ^

OH

Wherein R 2 is hydrogen, NO 2 or halogen and -X-Y- is -CH-N- or -N = CR 3 -, wherein R 3 is hydrogen, lower alkyl or CF 3. These compounds are useful in the treatment of indications for excitatory amino acid hyperactivity.

In Egypt. J. Chem. 24 (1983): 4, pp. 335-42 (C.A. 100 (1984) 6450) describes substituted quinoxalines. Said compounds are not 2,3-dihydroxy-substituted and no mention is made of the possible activity of the compounds.

Substituted and quinoxallinediones are known from FI patent publication 88 718. However, the publication does not describe substituted and tricyclic aromatic compounds in which 30 parts of the aromatic structure would consist of quinoxaline-ion dione. Said known compounds thus differ clearly in structure from the compounds of the formula I now described.

Compounds of formula I may be prepared as 2 93838 a) a compound of formula

Y-NH

(II) wherein -X-Y- and R 2 are as defined above are reacted with oxalic acid or a reactive derivative thereof, or b) a compound of formula nh 2

NH. N. .OH

Jr ^ y V

J Μ I (VIII) wherein R 2 is as defined above is reacted. . with a suitable carboxylic acid; .20 and, if desired, the resulting compound of formula I wherein R 2 is hydrogen is nitrated to give a compound of formula I wherein R 2 is NO 2.

L-glutamic acid, L-aspartic acid, and several other related amino acids share the ability to activate neurons in the central nervous system (CNS). Biochemical, electrophysiological and pharmacological experiments have shown this and proved that acidic amino acids act as mediators for the vast majority of irritant nerve cells in the CNS of mammals. Interaction with glutamic acid-30-mediated neurotransmission is considered a useful starting point in the treatment of neurological and psychiatric disorders. Thus, known antagonists of irritant nerve amino acids have shown potent antiepileptic and muscle relaxant properties [Jones, A. et al., Neurosci. Lett. 45, 157-161 (1984) and Turski, L. et al., Neurosci. Lett. 53, 321-326 (1985)].

3,93838

It has been suggested that the accumulation of extracellular nerve irritant and neurotoxic amino acids and the consequent hyperstimulation of neurons may explain the neurodegeneration seen in neurological diseases such as Huntington's dance disease, parkinsonism, epilepsy and dementia of old age. after cerebral ischemia, anoxia, and hypoglycemia (McGeer, EG et al., Nature, 263, 517-519 (1976) and Simon, R. et al., Science, 226, 850-852 (1984)).

Nerve-irritating amino acids act through specific receptors located after or before synapse. Such receptors are currently suitably divided into three groups based on electrophysiological and neurochemical indications: (1) NMDA (N-methyl-D-aspartate) receptors, (2) cisqualate receptors, and (3) kainate receptors.

‘* 20 L-glutamic acid and L-aspartic acid probably activate all of the above-mentioned types of irritant amino acid receptors and possibly other types as well.

As a result of the interaction of irritating amino acids with post-synaptic receptors, there is an increase in intracellular cGMP levels [Foster, G.A. et al., Life Sci. 27, 215-221 (1980)] and the opening of Na * channels in A. et al., Proc. Natl. Acad. Sci. 78, 3250-3254 (1981)]. The Na + current into the neurons depolarizes the neuronal membranes, initiates possible action, and finally results in the release of the neurotransmitter-30 from the nerve terminal. The effects of test compounds on the above-mentioned secondary responses of receptor interaction can be studied with simple in vitro systems.

The aforementioned generation of irritating amino acid receptors at NMDA, squalate and kainate receptors is primarily based on the following electrophysiological and neurochemical findings.

1) N-methyl-D-aspartate (NMDA) receptors have a high selectivity for stimulatory NMDA. Ibo-5 acetic acid, L-homocysteic acid, D-glutamic acid, and trans-2,3-piperidinedicarboxylic acid (trans-2,3-PDA) have potent moderate agonist activity at these receptors. The most potent and selective antagonists are the D-isomers of 2-amino-5-phosphonocarboxylic acids, e.g., 2-amino-5-phosphonoovaleric acid (D-APV) and 2-amino-7-phosphonoheptanoic acid (D-APH), while the long-acting D-isomers of 2-aminodicarboxylic acids (e.g., D-2-aminoadipic acid) and long-chain diaminodicarboxylic acids (e.g., diaminopimelic acid) have moderate antagonistic activity. NMDA-induced synaptic responses have been extensively studied in the mammalian CNS, particularly in the spinal cord (Davies, J. et 10al., J. Physiol. 297, 621-635 (1979)), and the responses have been shown to be strongly inhibited by Mg 2+. effect-20 ta.

It is well known that NMDA antagonists have anticonvulsant activity in seizures of various origins [Jones et al., Neurosci. Lett. 45, 157-161 (1984)], and that the abilities of the agents in disease-specific assays correspond well to the ability of the compounds to inhibit NMDA responses in electrophysiological in vivo and in vitro experiments [Watkins et al., Annu. Rev. Pharmacol. Toxicol. 21, 165-204 (1981)].

NMDA antagonists are therefore useful anticonvulsants, especially against epilepsy.

• e 2) Isqualate receptors are selectively activated by isqualic acid; other effective agonists include AMPA (2-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) and L-glutamic acid. Glutamic acid diethyl ester 35 (GDEE) is a selective but very weak antagonist 5,93838 in this case. Kisqualate receptors are relatively insensitive to Mg2 *.

It is well known that there are ärsytysamino acids transition from the front side of the cerebral cortex to nucleus accumbens 5 (a special part of the forebrain having dopamii-nineuroneja) [Christie et al., J. Neurochem. 45, 477-482 (1985)]. Furthermore, it is well known that glutamate modulates dopaminergic transition in the striatum [Rudolph et al., Neurochem. int. 5, 479-486 (1983)] and hyperactivity associated with preynaptic stimulation of the dopamine system with AMPA in the nucleus accumens [Arnt. Life Sci. 28, 1597-1603 (1981)].

Cisqualate antagonists are therefore useful as a new type of neuroleptic.

15 3) Price receptors. Irritation responses to carnic acid are relatively insensitive to antagonism of NMDA antagonists and GDEE, and it has been suggested that carnic acid activates the subunit of third acidic amino acid receptors. class. Certain lactonized derivatives of cainic acid are selective antagonists (Goldberg, O. et al.,

Neurosci. Lett. 23, 187-191 (1981) and dipeptide-3-glutamylglycine also has some selectivity for kainate receptors. Ca2 *, but not Mg2 *, is a potent inhibitor of cainic acid binding.

The affinity of a substance for one or more different types of irritating amino acid receptors can be examined by simple binding assays. Essentially, the method comprises incubating a specific radiolabeled ligand and that specific test substance with a brain homogenate containing the receptor. Receptor charge is measured by determining radioactivity bound to the homogenate and reducing non-specific binding.

The effect of glutamic acid analogs on the secondary effects of glutamate receptor-35 reactions, such as 6,93838 c-GMP formation and Na + efflux, can be studied in vitro using brain strip preparations. Such experiments provide information on the effects of test substances (agonist / antagonist). This differs from binding assays, which provide information only on the affinity of compounds for receptors.

It has now been found that the heterocyclic compounds of formula I have an affinity for glutamate receptors and are antagonists at this type of receptor, making them useful in the treatment of a number of indications for hyperactivity of any irritating amino acid.

The binding activity of the cisqualate receptors of the compounds of formula I can be illustrated by determining their ability to displace radiolabeled 2-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) from cisqualate-type receptors.

The squalate antagonistic properties of the compounds •. are demonstrated by their ability to antagonize squamous-stimulated Na + flux from rat striatum.

The NMDA antagonistic properties of the compounds are illustrated by determining their ability to antagonize NMDA-stimulated 3 H-GABA release from cultured cerebral cortex neurons.

The displacement activity of the compounds can be demonstrated by determining the IC50 value, which is the concentration (pg / ml) that causes 50% displacement of the specific binding of 3H-AMPA.

Thisqualate antagonism is measured by determining the EC50 value, which is the concentration that reduces the stimulated sodium flow of chisqualate acid by 50%.

The NMDA antagonistic activity of the compounds can be demonstrated by determining an IC50 value of 7,93838 (μ / g / ml) which inhibits the 50% release of NMDA-induced 3 H-GABA.

3 H-AMPA binding (Experiment 1) 500 pg of thawed rat cortical membrane homogenate in Tris-HCl (30 mM), CaCl 2 (2.5 mM) and KSCN (100 mM), pH 7.1, incubated at 0 ° C for 30 minutes using 25 μΐ 3H-AMPA (5 nM final concentration) and test compound and buffer. Non-specific binding was determined by incubating L-glutamine with 10 acids (600 μΜ: η final concentration). The binding reaction was stopped by adding 5 ml of ice-cold buffer and then filtered through Whatman GF / C glass fibers and washed with 2x5 ml of ice-cold buffer. Bound radioactivity was measured with a scintillation counter. The IC50 was determined by Hill analysis for at least four concentrations of test compound.

Antagonism of cisqualic acid-induced 22Na + release (Experiment 2) · Rat brainstem strips were preincubated with 22Na * * ’· 20 for 30 minutes. After the 22Na * loading period, the strips were passed sequentially and once per minute through a series of test tubes containing 1.5 ml of non-radioactive physiological saline impregnated with O 2 using a basket-shaped sieve. The last Fifth-25 tube contained cisqualic acid (2 pg / ml), and the test compound was present in the same five tubes and the three preceding tubes. The amount of radioactivity in each wash tube and remaining on the strips at the end of the experiment was measured with a scintillation counter. EC50 values were calculated by Hill analysis from at least three different concentrations of test compound as the concentration of test compound that reduces the efflux rate of 22Na * ions to 50% of their efflux rate without test compound.

Inhibition of NMDA-stimulated 3H-GABA release from cultured mouse cortical interneurons (Experiment 3)

Release experiments are performed using the experimental model described by Drejer et al. [Life Sci. 38 (1986) p. 2077]. Cortical interneurons cultured in petri dishes (30 mm) are supplemented with 100 pg / ml 3-vinyl-GABA one hour before the experiment to prevent GABA degradation in neurons. Thirty minutes before the experiment, 5 pCi 3 H-GABA is added to each culture, and after this preload period, the cells are washed twice with HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) buffered saline (HBS) containing 10 mM HEPES, 135 mM NaCl, 5 mM KCl, 0.6 mM MgSO 4, 1.0 mM CaCl 2, and 6 mM D-Glu-15, pH 7, and are placed in a superfusion system. This system consists of a peristaltic pump that continuously feeds a thermostated 37 ° C super-fusion medium from a tank to the top of a slightly tilted petrimal. The monomolar layer of cells at the bottom of the dish is covered with a piece of nylon mesh; this facilitates the dispersion of the medium over the cell layer. The medium is continuously collected from the lower part of the dish and transferred to a fraction collector. Initially, the cells are perfused with HBS for 15 minutes (flow rate 2 25 ml / min). The cells are then stimulated every 30 minutes for 30 seconds by changing the superfusion medium from HBS to a corresponding medium containing NMDA and antagonists according to the following scheme: Stimulation No. 1: 3 μ / g / ml NMDA Stimulation No. 2: 3 μ / g / ml ml NMDA + 0.3 pg / ml antagonist Stimulation No. 3: 3 pg / g / ml NMDA + 3 pg / ml antagonist The test substances were dissolved in water or 48% ethanol. The final ethanol content of the test must not exceed 0,1%.

9 93838 The release of 3H-GABA in the presence of NMDA (stimulated release in cpm) is corrected for the mean basal release (cpm) before and after stimulation.

5 Stimulated release in the presence of antagonists is expressed relative to stimulated release of NMDA alone and the IC50 of the antagonist (concentration of test substance (pg / ml) that inhibits NMDA-induced 3H-GABA release by 50%) is calculated from either the dose / response curve. 10 or from the formula: IDS0 = test substance concentration used x ---------- pg / kg [CQ _ 1] C * 15 where CG is the stimulated release in the comparative experiments and C is the stimulated release in the actual experiment (calculation requires a normal mass effect reaction) . Before calculating the IC50 value, 25 to 75% • must be obtained. inhibition of NMDA stimulation.

* · 20 The results obtained with the compounds of formula I are shown in Table 1 below.

Table 1 Compound Experiment 1 Experiment 3 from Example IC50 pg / ml IC50 pg / ml

Example 2 0.41 0.14

Example 3 9.6 30 Example 5 8.9 ': The following examples illustrate the invention.

10 93838

Example 1 7,8-Dihydroxy-1H-pyrazolo [3,4-f] quinoxaline

A solution of 6,7-diaminoindazole hydrochloride (1.0 g, 5.4 mmol) and oxalic acid dihydrate (0.9 g, 57 mmol) in 10 mL of 4 M hydrochloric acid was refluxed on an oil bath for 1.5 h. The cooled mixture was filtered and the isolated product was washed with water and ethanol and dried in vacuo over phosphorus pentoxide to give 1.0 g (91%) of pure title compound; mp: > 300 ° C; IR 10 (KBr): 3300-2000, 1700 cm -1; 1 H-NMR (DMSO-d 6): 6.3 (very broad s, 2H, NH and OH), 6.93 (d, J = 9 Hz, 1H, ArH), 7.43 (d, J = 9 Hz , 1H, ArH), 8.00 (s, 1H, H-3), 12.1 (broad s, 1H, OH).

Example 2 7,8-Dihydroxy-4-nitro-1H-pyrazolo [3,4-f] quinoxaline

Finely ground potassium nitrate (0.11 g, 1 mmol) was added with stirring to a solution of 7,8-dihydroxy-1H-pyrazolo [3,4-f] quinoxaline (0.2 g, 1 mmol) ** 2 mL: concentrated sulfuric acid, at room temperature. The solution was stirred for 1 h at this temperature and then poured into 50 ml of ice / water. After 30 minutes, the precipitated solid was isolated by filtration and washed with water. Recrystallization from a mixture of N, N-dimethylformamide and water gave 0.13 g (53%) of the nitro compound; mp. > 300 ° C; IR (KBr): 3300 - 2500, 1705 cm-1; 1 H-NMR (DMSO-d 6): 7.83 (s, 1H, ArH), 8.37 (s, 1H,

ArH), 12.2 (broad s, 2H, 20H).

Example 3 30 a. 6-Chloro-7-ethoxycarbonylamino-2,3-dihydroxyquinoxaline

A solution of 10 g (47.3 mmol) of 6-amino-7-chloro-2,3-dihydroxyquinoxaline in 200 ml of 0.5 N sodium hydroxide was cooled with ice and then 35 ml of 0.36 ml of sodium hydroxide were added. mmol) ethyl chloroformate. Stirring was continued at 0 ° C for 1 h and at 25 ° C for 1 h. To the reaction mixture 11 93838 was added 1 N hydrochloric acid so that the pH became

2-3, and the precipitated product was filtered and washed with water to give 12 g of crude product. Recrystallization (dimethyl sulfoxide - 0.5 N hydrochloric acid) gave 10 g (75%) of 6-chloro-7-ethoxycarbonylamino-2,3-dihydroxyquinoxaline, m.p. > 300 ° C. NMR

(DMSO-d 6): 11.9 (2H, broad s), 8.9 (1H, broad s), 7.37 (1H, s), 7.17 (1H, s), 4.1 (2H, q), 1.28 (3 H, t).

b. 7-Chloro-6-ethoxycarbonylamino-5-nitro-2,3-dihydroxyquinoxaline To an ice-cold mixture of 50 ml of 100% nitric acid and 100 ml of glacial acetic acid was gradually added 10 g of 6-chloro-7- ethoxycarbonylamino-2,3-dihydro-roksikinoksaliinia. Stirring was continued at 0 ° C for 90 min. The reaction mixture was poured into 500 ml of ice water to give 10 g (86%) of 7-chloro-6-ethoxycarbonylamino-5-nitro-2,3-dihydroxyquinoxaline as yellow crystals, m.p. > 300 ° C. NMR (DMSO-d 6): 12.2 (1H, broad s), 11.7 (1H, broad, m), 9.3 (1H, broad s), 7.33 (1H, s), 4.0 (2H, q), 1.2 • 20 (3H, t).

c. 6-amino-7-chloro-5-nitro-2,3-dihydroxyquinoxaline

A mixture of 5 g (15.4 mmol) of 7-chloro-6-ethoxycarbonylamino-5-nitro-2,3-dihydroxyquinoxaline and 10 g of potassium hydroxide in 60 ml of 2-methoxyethanol was refluxed for 15 min. After the reaction mixture was cooled to 25 ° C, 20 ml of 2-methoxyethanol and 40 ml of ether were added thereto. The precipitated black product was filtered and washed with ether. The crude product was dissolved in 100 ml of water. 4N Hydrochloric acid was added to bring the pH to 5-6 to give 3.4 g (87%) of 6-amino-7-chloro-5-n-nitro-2,3-dihydroxyquinoxaline as red crystals, m.p. .

> 300 eC. NMR (DMSO-d 6): 12.3 (2H, broad m), 7.40 (1H, s), 6.8 (2H, broad s).

12 93838 d. 5,6-Diamino-7-chloro-2,3-dihydroxyquinoxaline

A solution of 3 g (11.9 mmol) of 6-amino-7-chloro-5-nitro-2,3-dihydroxylquinoxallin adimethylformamide (80 ml) and trethylamine (7.5 ml) was hydrogenated at atmospheric pressure. using 5% Pd-C (0.5 g) as a catalyst. The reaction mixture was filtered and evaporated in vacuo. The residue was mixed with 100 ml of water, 4N hydrochloric acid was added so that the pH became 5-6, and the precipitate was filtered to give 2.1 g of crude product. Recrystallization (dimethylformamidimethanol) gave 1.95 g (74%) of 5,6-diamino-7-chloro-2,3-dihydroxyquinoxaline, m.p. > 300 ° C. NMR (DMSO-d 6): 11.6 (1H, broad s), 11.0 (1H, broad m), 6.47 (1H, s), 5.1 (2H, broad s), 4.6 ( 2H, broad s).

15 e. 4-Chloro-7,8-dihydroxy-1H-imidazo (4,5-f) -quinoxaline

A mixture of 0.3 g (1.35 mmol) of 5,6-diamino-7-chloro-2,3-dihydroxyquinoxaline and 8 ml of formic acid. poa, refluxed for 2 h. After cooling to 25 ° C, the reaction mixture was poured into 30 ml of water to give 0.21 g (67%) of 4-chloro-7,8-dihydroxy-1H-imidazo. (4,5-f) -quinoxaline, m.p. > 300 eC. NMR (DMSO-d 6): 7.37 (1H, s), 6.70 (1H, S).

Example 4 4-Chloro-7,8-dihydroxy-2-trifluoromethyl-1H-imidazo (4,5-f) quinoxaline

A mixture of 0.3 g (1.35 mmol) of 5,6-diamino-7-chloro-2,3-dihydroxyquinoxaline and 8 ml of trifluoroacetic acid was refluxed for 3 h. Cooled to 0 ° C, min-30 The precipitated product was filtered off and washed with ice-cold trifluoroacetic acid and ether to give 0.28 g (68%) of 4-chloro-7,8-dihydroxy-2-trifluoromethyl-1H-imidazo (4,5-f ) quinoxaline, m.p. > 300 eC. NMR (DMSO-d 6): 7.10 (1H, s).

13 93838

Example 5 4-Chloro-7,8-dihydroxy-2-methyl-1H-imidazo- (2,3-E) quinoxaline

A mixture of 0.5 g (2.24 mmol) of 5,6-diamino-7-5 chloro-2,3-dihydroxyquinoxaline and 0.33 g (3.3 mmol) of 2,4-pentadione in 20 ml glacial acetic acid, stirred at 100 ° C for 30 min. After cooling to 25 ° C, the precipitate was filtered and washed with glacial acetic acid and ether to give 0.53 g (100%) of 4-chloro-7,8-dihydroxy-10 2-methyl-1H-imidazo (2,3- f) quinoxaline, m.p. > 300 ° C.

NMR (DMSO-d 6): 7.0 (1H, s), 2.53 (3H, s).

Example 6 7,8-Dihydroxy-2-methyl-1H-imidazo (2,3-f) quinoxaline A mixture of 0.5 g (2.56 mmol) of 5,6-diamino-2,3-dihydroxyquinoxaline and 0.52 g (5.2 mmol) of 2,4-pentanedione in 20 ml of glacial acetic acid were stirred at 100 ° C for 1.5 h. After cooling to 25 ° C, the precipitate was filtered off. . was washed and washed with water and ethanol to give 0.56 g (100%) of 7,8-dihydroxy-2-methyl-1H-imidazo (2,3-f) quinoxaline, m.p. > 300 eC. NMR (DMSO-d 6): 7.17 (1H, d), 6.93 (1H, d), 2.53 (3H, s).

Claims (2)

93838 Claim A process for the preparation of new therapeutically useful 7,8-dihydroxy-1H-imidazo and pyrazolo [3,4-f] quinoxaline-5 derivatives of the formula Y-NH X. m OH ΊγιΓ Y (i) Wherein R 2 is hydrogen, NO 2 or halogen and -XY- is -CH = N- or -N = CR 3 -, wherein R 3 is hydrogen, lower alkyl or CF 3, characterized in that compound 15 a) , wherein Y-NH Vy "" 1 wherein -XY- and R2 are as defined above, is reacted with oxalic acid or a reactive derivative thereof, or b) a compound of formula NHj 30 OJL JL -JC (VIII ) * •. . . wherein R 2 is as defined above, is reacted with a suitable carboxylic acid; And, if desired, the resulting compound of formula I wherein R 2 is hydrogen is nitrated to give a compound of formula I wherein R 2 is NO 2. 93838 For the preparation of therapeutically active compounds 7,8-dihydroxy-1H-imidazo and pyrazolo-5- [3,4-f] quinoxal derivatives with the formula Y-NH Xv X.N. .OH IU Ύ (I) 10 RH OH or R2 is a derivative, NO2 or halogen and -XY- is -CH = N- or -N-CR3-, colors R3 is a derivative, lgre alkyl or CF3, k-n -15 In the case of a mixture, a) is used in the form of Y-NH - • 20 (II) in the form of -XY- and R2 in the same manner as in the case of the oxalic acid or react of the form of nh2 NH ' J ^ N ^ 0H (VIII) 30. jr τ »d2 R2 is selected from the group consisting of carboxy; 35 och, om sd önskas, nltreras en erh & llen förenlng med formuleln I, där R2 är väte, varvid erhdlls en förenlng med formuleln I, där R2 är N02.