RU2394034C2 - DERIVATIVES OF 4,6-DIMETHYL-2,3-DIHYDRO-1H-PYRAZOLO[4,3-c] PYRIDINE-3-ONES AND ETHERS 2,6-DIMETHYL-4-PHENYL-HYDRAZINE NICOTINIC ACIDS AS INTERMEDIATE PRODUCTS FOR THEIR SYNTHESIS, POSSESSING ANTIDEPRESSANT AND ANXIOLYTIC POTENCY - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to compounds having anxiolytic and antidepressant activity, which are derivatives of the formula 1 (a-b), or formula 2 (a-b) at that compounds of formula 2 (a-b) are intermediate products in synthesis of compounds of the formula

, where R-Cl is a compound 1a or R'=COOC₂H₅ - compound 1b,

, where R=COOC₂H₅ and R'=C1 - compound 2a; R=R-COOC₂H₅ - compound 2b.

EFFECT: obtaining new biologically active compounds that differ from analogues as intended in low toxicity and lack of side effects.

5 cl, 3 ex, 5 tbl

Description

The invention relates to the chemistry of biologically active compounds, specifically to derivatives of 4,6-dimethyl-2- (nR-phenyl) -2 / 3-dihydro-1H-pyrazolo [4,3-c] pyridin-3-ones (compounds 1a b):

as well as esters of 2,6-dimethyl-4 (n-R-phenylhydrazino) nicotinic acid (compound II), which serve as intermediates in the synthesis of compounds I

When studying the pharmacological activity of both groups of compounds, it was found that they have antidepressant and anxiolytic effects.

It is known that some pyrazolo [C] pyridine derivatives, as well as pyrazolo [b] pyridine derivatives, exhibit a variety of biological activity, in particular anxiolytic, anticonvulsant, antidepressant [J. Kitaura et al., J. Med. Chem., 1982, Vol.25, No. 4, pp. 337-339; S. Takada et al., J. Med. Chem., 1988, Vol. 31, No. 9, pp. 1738-45; M.S. Allen et al., J. Med. Chem., 1992, Vol. 35, pp. 368-374; J.T. Forbes et al., J. Amer. Chem., 1990, Vol. 33, No. 9, pp. 2640-45; M.Williams, J. Med. Chem., 1983, Vol. 26, No. 5, pp. 619-628].

Among the pyrazolo [b] pyridine derivatives, substances with antidepressant and anxiolytic activity (tracozolate, cartazolate) are known, but in medical practice they have found limited use as anxiolytics [Lecci, A., Borsini, F., Gragnani, L., Volterra, G. and Meli, A., Effect of psychotomimetics and some putative anxiolytics on stress-induced hyperthermia. Journal of Neural Transmission General Section, 83 (1991) 67-76; VonVoigtlander, P.F. and Lewis, R.A., A rapid screening method for the assessment of benzodiazepine receptor-related physical dependence in mice. Evaluation of benzodiazepine-related agonists and partial agonists. Journal of Pharmacologlcal Methods, 26 (1991) 1-5].

Among pyrazolo [c] pyridines, substances that have shown significant antidepressant activity have not yet been described.

Anxiety-depressive disorders are one of the most common forms of mental pathology. According to the World Health Organization, the incidence of depression is currently approaching 3%, that is, annually about 180 million people on our planet detect signs of depression and need adequate medical care. With a combination of anxiety and depressive disorders, there is a decrease in the effectiveness of treatment, a worsening prognosis of the disease.

A variety of medications are currently used to treat depression. These are tricyclic antidepressants, primarily amitriptyline and imizin, MAO inhibitors, pyrazidol and moclobemide, non-selective noradrenaline reuptake inhibitors, desipramine, nortriptyline, maprotiline. These substances have a powerful antidepressant effect and are most effective in treating severe depression. However, they have pronounced side effects, cardiotoxic and anticholinergic, high mortality in case of overdose, which limits their use. Therefore, they are referred to as the so-called “old antidepressants” and try to use “new antidepressants”. These are selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, paroxetine, sertraline, fluvoxamine, citalopram, selective norepinephrine reuptake inhibitors (reboxitin), double or mixed-acting mediator reuptake inhibitors (venlafaxine, milnincipran, milnacipran). These drugs are less powerful than the “old” or typical antidepressants, but have little cardiotoxic and anticholinergic effects, have low or moderate mortality in case of overdose. Therefore, “new antidepressants” have a favorable “benefit / risk” ratio and are considered as drugs of choice in most patients with mild depression, especially in somatic practice [A.V. Ushkalova. Modern antidepressants: problems of rational choice. Farmateka, 2006, special issue “Psychiatry / Neurology”, pp. 9-19]. This determines the choice of fluoxetine (Fluoxetine (±) -N-methyl-gamma- [4- (trifluoromethyl) phenoxy] benzene propanamine (and in the form of hydrochloride) as a reference preparation; a racemic (50/50) mixture of R and S enantiomers) . Fluoxetine Lannacher, company Lannacher Heilmittel (Austria). See: Russian Medicines Register of the Radar. Encyclopedia of medicines. - 14th issue / Ch. ed. G.L. Vyshkovsky. - M .: RLS-2006, 2005. - S.862-864. Farmgroup 9.2), the most studied representative of the SSRI group [Prescrire. Int .; 10 (51): 25-31, (2001)], widely used in clinical practice.

However, these antidepressants are also flawed. Their use can cause sleep disturbances, appetite, nausea, vomiting, diarrhea, decreased sexual function. One of the most common side effects of SSRIs is increased anxiety in the first days of admission, which complicates the use of drugs in the treatment of combined anxiety-depressive disorders.

Therefore, the search for new antidepressants, less toxic, devoid of side effects and have an anti-anxiety effect, remains relevant.

The inventive substances (compounds I and II) have a pronounced antidepressant effect, which, when compared with the effect of the most studied and widely used fluoxetine, is more pronounced when studied in a forced swimming model, is not accompanied by signs of excitement with the introduction of high doses. Compound I has lower toxicity (LD _{50 of} fluoxetine in rats is 452 mg / kg, for compound Ia - 825.3 mg / kg).

The technical result of the claimed invention consists in the synthesis of 2 new groups of compounds, one of which (compounds IIa-b) serve as intermediates for the preparation of heterocyclic (compounds Ia-b) pyrazolo [4,3-c] pyridines, in which during their pharmacological study high antidepressant activity was found to be superior to fluoxetine activity. Moreover, their antidepressant properties are combined with anxiolytic action, which allows the use of the above compounds for the treatment of anxiety-depressive disorders.

The inventive compounds I and II were synthesized according to the scheme:

where a) R = Cl, b) R = COOC ₂ H ₅

Upon alkylation of ethyl 4-chloro-2,6-dimethyl-nicotinic acid III with 1 mole of the corresponding phenylhydrazine (IVa-b), esters IIa-b are formed in boiling alcohol, and when compound III is heated with 2 moles of hydrazine (IVa-b) at 140-150 ° C without solvent, or in DMF or in xylene, pyrazolo [c] pyridines Ia-b are obtained. To improve product yield and purity, compound Ia is prepared by alkaline hydrolysis of compound IIa.

Experimental chemical part

IR spectra were obtained on a Perkin-Elmer 580 spectrometer in KBr. 1 H NMR and ¹³ C NMR spectra were taken on a Bruker-AC 250 instrument, and the internal standard was TMS.

Data on physico-chemical properties are shown in tables 1 and 2.

Example 1

2,6-Dimethyl-4- (4-chlorophenylhydrazino) nicotinic acid ethyl ester, hydrochloride (compound II a).

A mixture of 1 g (5 mmol) of ethyl 2,6-dimethyl-4-chloronicotinic acid (III) and 0.73 g (5.1 mmol) of 4-chlorophenylhydrazine (IVa) in 15 ml of ethanol is boiled for 4 hours, the reaction mixture is evaporated dry, the residue is taken up in ether to give 1.45 g of compound IIa.

2,6-Dimethyl-4- (4-ethoxycarbonylphenylhydrazino) nicotinic acid ethyl ester, hydrochloride (compound IIb) are prepared analogously to compound IIa from compounds III and IVb.

Example 2

4,6-dimethyl-2- (4-chlorophenyl) -2,3-dihydro-1H-pyrazolo [4,3-c] pyridin-3-one, hydrochloride (compound Ia).

A) A mixture of 1 g (5 mmol) of ethyl 4-chloro-2,6-dimethylnicotinic acid (III) and 1.42 g (10 mmol) of 4-chlorophenylhydrazine (IIa) is heated for 4 hours at 150 ° C, to the reaction mass 70 ml of acetone are added, heated to boiling and allowed to stand for 1 h. The precipitate is filtered off, washed with ether and 0.8 g of the base of compound Ia is obtained, which is dissolved in 150 ml of alcohol, ethereal hydrogen chloride is added and 0.8 g of hydrochloride Ia is obtained.

B) A mixture of 16 g (50 mmol) of the base of compound IIa and 5.6 g (100 mmol) of potassium hydroxide in 160 ml of water is boiled for 5 hours, the precipitate formed is filtered off, washed with water, acetic acid, water and 2.5 g of the base of the compound are obtained 1. 9.07 g of the base of compound Ia is isolated from an alkaline solution by acidification with acetic acid. Total yield Ia 11.57 g (84.4%), melting point 300 ° C (decomp. From acetone). The base is converted by the action of ethereal HCl to compound Ia, yield 11.5 g.

Example 3

4,6-dimethyl-4 (p-ethoxycarbonylphenyl) -2,3-dihydro-1H-pyrazolo [4,3-c] pyridin-3-one, hydrochloride (compound IB).

A mixture of 3.18 g (15 mmol) of ethyl 4-chloro-2,6-dimethylnicotinic acid (III) and 3.24 g (18 mmol) of 4-ethoxycarbonylphenylhydrazine (IVb) in 15 ml of dry dimethylformamide is heated for 10 hours at 120- 130 ° C, filtered, and 1.95 g of the base of compound 1b are obtained. An additional 1 g of base is precipitated from the filtrate by adding ether. The total yield of the base of compound IB is 2.95 g (63.5%), which is converted into hydrochloride by the action of ethereal HCl to give 2.90 g of compound IB.

Pharmacological study of the claimed compounds.

The study of the antidepressant activity of the compounds.

The antidepressant activity of the compounds was studied using the model of forced swimming in rats - the despair test (Andreeva NI Methodological guidelines for the study of the antidepressant activity of pharmacological substances. A guide to the experimental (before clinical) study of new pharmacological substances. - Second edition, revised and supplemented. / Edited by R.U. Khabriev. - M., 2005. - P.244-252) according to the methods of Porsolt et al. (Eur. J. Pharmacol., Vol. 47, P.379-391, 1978) and S. Nomura et al. (Eur. J. Pharmacol. - Vol. 83, No. 3-4. - P.171-175, 1982). Studies were performed on white outbred male rats, 2-2.5 months old and weighing 220-250 g.

To evaluate the antidepressant effect of the compounds according to the method of Nomura et al. (1984) in the test of forced swimming in rats in a vessel with water and freely rotating wheels, a four-channel setup developed at the State Research Institute of Pharmacology named after V.V.Zakusova RAMS (Molodavkin G.M., Voronina T.A., Mdzinarishvili A.L. Features of the influence of pharmacological substances of different classes on forced swimming in rats. Exper. And wedge. Pharmacol., 1994, v. 57, No. 1, p. 3-5). The installation is a vessel measuring 64 × 30 × 42 cm, divided into 4 equal compartments. In the compartments there are wheels 11 cm wide with 12 blades 2 cm wide, the outer diameter of the wheels is 10 cm. Magnets are mounted on the edges of each wheel, and reed switches are mounted above the wheels, which operate each time the magnet passes under them. This is how automatic registration of wheel speed occurs, which is an objective measure of animal activity. The vessel was filled with water at a temperature of 25 ° C to the middle of the wheels. Rats were placed in each compartment with the muzzle from the wheel and the number of wheel revolutions was recorded for 10 min using electromechanical counters.

The effect of each compound was studied in 10 animals, the substances were suspended using Tween-80 and administered intraperitoneally at a dose of 20 mg / kg 40 minutes before the experiment. Comparison was made with the antidepressant fluoxetine.

It was found that compound Ia, compounds IIa-b significantly increase the number of wheel revolutions compared to the control group (Table 3). The maximum effect exceeding the effect of fluoxetine was observed for compound Ia.

The studied compounds also showed high efficiency in the forced swimming test in rats according to the Porsolt method. The effect of the compounds was evaluated in comparison with fluoxetine.

40 minutes after drug administration, animals were placed in a vessel with water with a diameter of 40 cm and a depth of 60 cm, so that the rat could neither get out of the vessel nor find support in it. In such a situation, the animal is forced to make active swimming movements to get out, or freeze in the water and make minor rowing movements to maintain the muzzle above the surface of the water. The water temperature was maintained at 25 ° C. The state of immobilization was evaluated visually with the determination of its duration for 10 min of observation.

It was found that compounds Ia, b and IIa-b significantly reduce the immobility time of rats compared with the control group (table 4). It was also found that the effect of compound Ia is comparable to the effect of fluoxetine in a forced swimming test in rats according to Porsolt.

The study of anxiolytic activity of compounds.

The anxiolytic activity of compounds Ia-b and IIa-b was studied in a conflict test based on the collision of drinking and defensive motivation (Voronina T.A., Seredenin S.B. Methodological guidelines for the study of the tranquilizing (anxiolytic) action of pharmacological substances. Manual for experimental (preclinical) study of new pharmacological substances. - Second edition, revised and supplemented. / Ch. ed. R.U. Khabriev. - M., 2005. - P.253-262). Studies were performed on white outbred male rats, 2-2.5 months old and weighing 220-250 g.

Previously, the animals were deprived of water and succulent food for 24 hours, and then they developed the skill of taking water from the drinker by placing the rat in the chamber where she found a drinker with water and started drinking. The chamber has a size of 275 × 275 × 450 mm, an electrode floor and a drinking bowl with water (a vessel with a nipple on the wall) located at a height of 5 cm from the floor. To conduct a conflict situation, a four-chamber installation developed at the State Research Institute of Pharmacology named after V.V.Zakusova RAMS (Molodavkin G.M., Voronina T.A. Multichannel installation for searching for tranquilizers and studying the mechanisms of their action by the method of a conflict situation. Exper. And Wedge Pharmacol., 1995 vol. 58, No. 2, p. 54-56).

The training was carried out for 5 minutes, which allowed developing the skill of taking water from rats and preventing the animals from getting drunk before the experiment, i.e. keep drinking motivation. The next day, the rat was placed in the chamber for 10 minutes and 10 seconds after the start of drinking, each water intake was punished with electric pain irritation. In the experiment, a current of 0.5 mA is used, which makes it possible to detect anxiolytics of medium strength. As a result, in order to satisfy drinking motivation, the rat must overcome the fear of punishment. The number of punishable water taken for 10 minutes in the cell is a measure of anxiogenic state. Tranquilizers eliminate feelings of anxiety and fear and increase the number of punishable water take.

The anxiolytic effect of compound Ia was studied at doses of 5, 10 and 20 mg / kg, and the remaining compounds at a dose of 20 mg / kg. The effect of the compounds at each dose was studied in 10 animals. The substances were suspended using Tween-80 and administered intraperitoneally 40 minutes before the experiment. Diazepam at a dose of 5 mg / kg and fluoxetine at a dose of 20 mg / kg were used as a comparison drug.

The anxiolytic effects of compound Ia at doses of 10 and 20 mg / kg, compound 11b were found to significantly exceed the effect of the control group in the conflict test. Compound Ia exhibits a maximum anxiolytic effect at a dose of 20 mg / kg, exceeding the effect of diazepam and fluoxetine (Table 5).

A study of acute toxicity and possible side effects of compound Ia.

The acute toxicity of compound Ia when administered intraperitoneally at increasing doses of 300, 400, 500, 600, 800 and 900 mg / kg was evaluated in experiments on outbred white male rats weighing 220-250 g at a constant ambient temperature (20-21 ° C ) (Arzamastsev E.V., Guskova T.A., Berezovskaya I.V. et al. Methodological guidelines for the study of the general toxic effects of pharmacological substances. A guide to the experimental (preclinical) study of new pharmacological substances. - Second edition, revised and supplemented. / Ch. Ed. R.U. Khabriev. - M.: 2005. - S. 41-53). The death of animals was recorded 24 hours after the administration of compound Ia. It was found that LD ₅₀ when administered intraperitoneally to rats is 825.3 mg / kg.

When evaluating the muscle relaxant effect of compound Ia, it was found that animals that were previously injected with compound Ia at a dose of 150 mg / kg are easily kept on a rotating rod, while exhibiting a pronounced research activity. All rats of this group easily restore the pull-up reflex on the horizontal bar and are not inferior to the animals of the control group. Thus, compound Ia upon intraperitoneal administration of doses 7.5 times higher than therapeutic (180 mg / kg) does not cause muscle relaxation, unlike diazepam. It was found that the ED _{50 of the} muscle relaxant effect of substance 1a upon intraperitoneal administration to rats is 243.6 mg / kg.

When evaluating the sedative effect of compound Ia by examining its effect on the horizontal activity of rats, it was found that compound Ia at a dose of 20 mg / kg does not have the sedative effect characteristic of diazepam.

Conclusion

Studies have shown a pronounced antidepressant effect of compounds Ia-b, IIa-b. The effect of the most active compound Ia exceeds the effect of fluoxetine.

Unlike fluoxetine, which increases anxiety, an anxiolytic effect was found in the compounds of the proposed series. It was found that compound Ia exhibits an anxiolytic effect exceeding the effect of diazepam.

Along with the above, compound 1a has low toxicity and does not cause muscle relaxant and sedative effects characteristic of diazepam.

The toxicity of fluoxetine in the literature is 452 mg / kg in rats (for compound Ia, this indicator is 825.3 mg / kg).

The claimed compounds do not cause side effects characteristic of fluoxetine: increased anxiety, sleep disturbances, appetite, nausea, vomiting, diarrhea.

Table 1 Characterization of synthesized compounds Compound % Yield T _melt in ° C Solvent Gross formula IR spectrum ν _max cm ^-1 PMR spectrum (DMSO-d ₆ ), δ etc. one 2 3 four 5 6 Ia A) 55.0 > 320 ethanol C ₁₄ H ₁₂ ClN ₃ O · HCl - 2.40 s (3H, 6-CH ₃ ), 2.74 s (3H, 2-CH ₃ ), 6.84 s (1H, 5-H Ry), 7.49 and 8.08 m (4H AA 'xx', ArH), 12.95 broad s (1H, N ⁺ H) B) 74.2 Ib 55.9 237-238 ethanol C ₁₇ H ₁₇ N ₃ O ₃ · HCl 1.30 (3H, t, CH ₃ -et), 2.33 (3H, C, 6-CH ₃ ), 2.68 (3H, C, 2-CH ₃ ), 4.28 (2H, q, CH ₂ -ethyl), 6.75 (1H, C5-H Py), 7.98 and 8.24 (4H, m, Ar), 12,43 (br s, NH ⁺ Py) IIa 86.9 198-199 C ₁₆ H ₁₈ ClN ₃ O ₂ · HCl 3170 and 3073 (C, broad. Ν _NH ) 1647 (ν _co ) 1615 1.33 (3H, T, CH ₃ -et), 2.63 (2.38 2nd isomer), (6H, C, 2-CH ₃ ), 4.38 (2H, q, CH ₂ et ), 6.76 and 7.27 (4H, m, ArH), 7.04 (6.89 2nd isomer) (1H, s, PyN), 8.73 (8.61 - 2nd isomer) and 10.02 (10.69 2nd isomer (2H, two s, NH-NH), 14.27 (1H, m.c., NH rings) IIb 87.3 197-198 (decomp.) Absolute ethanol C ₁₉ H ₂₃ N ₃ O ₄ · HCl 3560 and 3290 (C, broad. Ν _NH ) 1690 (ν _co ) 1610 and 1598 (doublet) 1.29 ^b and 1.34 ^m (6H, two t from 2 isomers, CH ₃ -et), 2.50 ^b and 2.63 ^m (6H by 2C, 2CH ₃ ), 4.25 ^b and 4 40 ^m (4H, two square CH ₂ -et), 6.82 and 7.85 (4H, two d AR-H), 6.95 ^m and 7.01 ^b (1H, two s, NH), 10.12 ^b and 10.87 ^m (1H, two s, NH), 14.4 (1H, very m.sup. N ⁺ H rings)

table 2 Elemental Analysis Data Compound Found,% Calculated,% FROM N Cl N FROM N Cl N Ia 54.21 4.15 22.79 13.45 54,20 4.22 22.86 13.55 Ib 58.28 5.14 10.08 12.34 58.70 5.21 10.19 12.08 IIa 53.88 5.35 19.92 11.77 53.94 5.38 19.90 11.80 IIb 57.86 6.13 8.99 10.46 57.93 6.14 9.00 10.66

Table 3 Antidepressant effect of compounds in the forced swimming test in rats according to S. Nomura Group Dose, mg / kg / kg Wheel speed The control - 94.3 ± 15.6 Compound Ia twenty 189.5 ± 34.9 * Compound ib twenty 89.1 ± 17.5 Compound IIa twenty 162.8 ± 35.2 * Compound IIb twenty 128.7 ± 17.9 * Fluoxetine twenty 130.6 ± 7.4 * Note: * - the difference with the control group is significant at P <0.05.

Table 4 Antidepressant effect of compounds in the forced swimming test according to the Porsolt method Group Dose, mg / kg / kg Immobility time (s) The control - 462.4 ± 29.4 Compound Ia twenty 378.2 ± 21.1 * Compound ib twenty 459.7 ± 24.6 Compound IIa twenty 405.3 ± 19.9 * Compound IIb twenty 389.7 ± 22.3 * Fluoxetine twenty 396.4 ± 20.9 * Note: * - the difference with the control group is significant at P <0.05.

Table 5 Anxiolytic effect of compounds in the conflict test Group Dose, mg / kg / kg Number of punishable water draws The control - 13.29 ± 4.2 Compound Ia 5 13.5 ± 7.3 Compound Ia 10 41.7 ± 19.8 * Compound Ia twenty 83.5 ± 25.1 * Compound ib twenty 29.2 ± 5.9 Compound IIa twenty 8.7 ± 3.6 Compound IIb twenty 42.6 ± 9.6 * Diazepam 5 26.3 ± 5.8 * Fluoxetine twenty 6.4 ± 2.2 * Note: * - the difference with the control group is significant at P <0.05.

Claims (5)

1. Derivatives of 4,6-dimethyl-2,3-dihydro-1H-pyrazolo [4,3-c] pyridin-3-ones of the general formula:

where the derivative with R '= Cl is compound 1a,
derivative with R '= СООС ₂ Н ₅ - compound 1b. 2. Compound 1a according to claim 1, which is 4,6-dimethyl-2- (para-chlorophenyl) -2,3-dihydro-1H-pyrazolo [4,3-c] pyridin-3-one. 3. The compound according to claims 1 and 2, having antidepressant and anxiolytic activity. 4. Esters of 2,6-dimethyl-4- (para-R'-phenylhydrazino) -nicotinic acid of the general formula:

where at R = СООС ₂ Н ₅ ; R '= Cl - compound 2A,
when R = R '= СООС ₂ Н ₅ - compound 2b,
as intermediates in the synthesis of compounds 1a, b according to claim 1. 5. Compounds according to claim 4, having antidepressant and anxiolytic activity.