RU2114821C1 - Dicyclohexylamides of n-substituted alfa-aminocarboxylic acids having antiarrhytmic and antifibrillary activity - Google Patents

Abstract

FIELD: chemistry of biologically active compounds; medicine. SUBSTANCE: dicyclohexylamides of N-substituted-α-aminocarboxylic acids which are representative of novel biologically active compound group are proposed here, their formula is given in specification. Proposed compounds posses antiarrhytimic and antifibrillary activity and have characteristics of antiarrhytimic agents from both I and III classes. EFFECT: improved activity of desired compounds. 3 tbl, 2 dwg

Description

где R¹ водород или низший алкил, R² и R³ - одинаковые или различные, водород, низший алкил, оксиалкил, аминоэтил, циклогексил, либо R² и R³ вместе с несущим их атомом азота составляют насыщенный гетероцикл, имеющий один или два гетероатома и их фармацевтически приемлемые соли кислотного присоединения, а также четвертичные соли.The invention relates to a new group of biologically active chemical compounds, namely to dicyclohexylamides of N-substituted α-aminocarboxylic acids of the general formula I

where R ^{1 is} hydrogen or lower alkyl, R ² and R ³ are the same or different, hydrogen, lower alkyl, hydroxyalkyl, aminoethyl, cyclohexyl, or R ² and R ³ together with the nitrogen atom carrying them form a saturated heterocycle having one or two heteroatoms and their pharmaceutically acceptable salts of acid addition, as well as Quaternary salts.

 A number of drugs with antiarrhythmic activity are known, which by their chemical structure relate to arylamides of N-substituted α-aminocarboxylic acids, for example, lidocaine, novocainamide, pyromecaine, etc. These drugs are classified according to the modern classification of drugs for the treatment of heart rhythm disorders [1], belong to class I. Drugs of this class have a small therapeutic breadth due to fairly high toxicity, explained by the main mechanism of action of these drugs - sodium channel blockade.

 Of greatest interest to clinicians at present are drugs of class III antiarrhythmic action.

 These drugs lengthen the action potential of myocardial cells; their effect is based on the effect on potassium channels. There are currently no good enough antiarrhythmics of this class. The most famous representatives of class III amiodarone [2] and sotalol [3] have numerous side effects that preclude their long-term use [4]. The recently developed preparation sematilide (N- (2-diethylaminoethyl) -4- (methylsulfonylamino) benzamide HCl [3] is the closest to the claimed substances in antiarrhythmic action. However, it does not have a sufficiently high efficacy and therapeutic breadth. Due to the fact that the preparations class III can be widely used in the treatment of life-threatening arrhythmias and fibrillation, currently there is an intensive search for drugs of this group both in our country and in a number of foreign countries.

 Thus, despite the abundance of antiarrhythmic drugs, the clinic still needs new, more effective and universal drugs, which, with good pharmacokinetic properties, would not cause negative side effects.

 The aim of the present invention is to obtain a new series of substances with the highest antiarrhythmic and antifibrillator activity, with great therapeutic breadth and combining the properties of class I - class III antiarrhythmics.

In accordance with the invention, a new chemical group of substances is proposed - N-substituted-α-aminocarboxylic acid dicyclohexylamides of the general formula I, where R ¹ to R ³ are as previously described, their physiologically acceptable acid addition salts and their quaternary salts possessing class I antiarrhythmic properties and class III.

 Compounds of the general formula I are not described in the special and patent literature to date.

Examples of compounds of formula I of the present invention are:
1 - diethylaminoacetic acid dicyclohexylamide hydrochloride;
2 - diethylaminoacetic acid dicyclohexylamide iodomethylate;
3 - diethylaminoacetic acid dicyclohexylamide bromopropen-2-ylate;
4 - α - (diethylamino) propionic acid dicyclohexylamide hydrochloride;
5 - bis (2-hydroxyethyl) aminoacetic acid dicyclohexylamide;
6 - bis (2-hydroxyethyl) aminoacetic acid dicyclohexylamide hydrochloride;
7 - bis (2-hydroxyethyl) -α-aminopropionic acid dicyclohexylamide hydrochloride;
8 - morpholinoacetic acid dicyclohexylamide;
9 - morpholinoacetic acid dicyclohexylamide hydrochloride;
10 - hexamethyleneiminoacetic acid dicyclohexylamide hydrochloride;
11 - octahydropyrrolo (1,2-a) dicyclohexylamide pyrazinoacetic acid dihydrochloride;
12 - butylaminoacetic acid dicyclohexylamide hydrochloride;
13 - isobutylaminoacetic acid dicyclohexylamide hydrochloride;
14 - α- (N-butylamino) propionic acid dicyclohexylamide hydrochloride;
15 - cyclohexylaminoacetic acid dicyclohexylamide hydrochloride;
16 - aminoacetic acid dicyclohexylamide hydrochloride hydrate;
17 - Dicyclohexylamide (2-aminoethyl) aminoacetic acid dihydrochloride.

 Thus, the claimed group of substances of the general formula I prototypes on the chemical structure is not described.

 As a comparison drug for antiarrhythmic activity, the drug lidocaine, which belongs to class I antiarrhythmics, and the sematilide drug, which refers to class III antiarrhythmics, were selected. The choice of these drugs is due to the fact that the compounds of the claimed group combine the properties of class I and III antiarrhythmics.

где
Hal = Cl или Br
IV.1 R¹=H, R²=R³=C₂H₅, R⁴=H, x = Cl
IV.2 R¹=H, R²=R³=C₂H₅, R⁴=CH₃, x = J
IV.3 R¹=H, R²=R³=C₂H₅, R⁴=CH₂CH=CH₂, x = Br
IV.4 R¹=CH₃, R²=R³=C₂H₅, R⁴=H, x = Cl
IV.5 R¹=H, R²=R³=CH₂CH₂OH, R⁴=H, x = Cl
IV.6 R¹=CH₃, R²=R³=CH₂CH₂OH, R⁴=H, x = Cl
IV.7 R¹=H,

, R⁴=H, x = Cl
IV.8 R¹=H,

, R⁴=H, x = Cl
IV.9 R¹=H,

, R⁴=H, x = Cl
IV.10 R¹=R²=H, R³=H-C₄H₉, R⁴=H, x = Cl
IV.11 R¹=R²=H, R³=CH₂CH(CH₃)₂, R⁴=H, x = Cl
IV.12 R¹=CH₃, R²=H, R³=H-C₄H₉, R⁴=H, x = Cl
IV.13 R¹=R²=H, R³=C₆H₁₁, R⁴=H, x = Cl
IV.14 R¹=R²=H, R³=CH₂CH₂NH₂, R⁴=H, x = Cl
IV.15 R¹=R²=R³=R⁴=H, x = Cl
Дициклогексиламиды N-замещенных α- аминокарбоновых кислот I получены при кипячении амидов I с избытком соответствующего амина III без растворителя или в среде органического растворителя с выходом 50-60% от теории. В качестве растворителей могут быть использованы спирт, бензол, толуол и др. Условия проведения реакций зависят от строения исходных аминов и температуры кипения растворителя. Амиды I представляют собой кристаллические или маслообразные вещества основного характера. Чистота их контролировалась методом тонкослойной хроматографии на ДС Alufolien Kieselgel 60 F 254 в системе бензол: спирт: водный аммиак (8:2:0,1). Значение Rf 0,24-0,58.The synthesis of the claimed compounds I and IV is carried out by the interaction of dicyclohexylamide α-halogenocarboxylic acids II with primary, secondary, heterocyclic amines III with the subsequent conversion of the obtained bases I to the corresponding salts of acid addition or quaternary salts (IV) according to the following scheme:

Where
Hal = Cl or Br
IV.1 R ¹ = H, R ² = R ³ = C ₂ H ₅ , R ⁴ = H, x = Cl
IV.2 R ¹ = H, R ² = R ³ = C ₂ H ₅ , R ⁴ = CH ₃ , x = J
IV.3 R ¹ = H, R ² = R ³ = C ₂ H ₅ , R ⁴ = CH ₂ CH = CH ₂ , x = Br
IV.4 R ¹ = CH ₃ , R ² = R ³ = C ₂ H ₅ , R ⁴ = H, x = Cl
IV.5 R ¹ = H, R ² = R ³ = CH ₂ CH ₂ OH, R ⁴ = H, x = Cl
IV.6 R ¹ = CH ₃ , R ² = R ³ = CH ₂ CH ₂ OH, R ⁴ = H, x = Cl
IV.7 R ¹ = H,

, R ⁴ = H, x = Cl
IV.8 R ¹ = H,

, R ⁴ = H, x = Cl
IV.9 R ¹ = H,

, R ⁴ = H, x = Cl
IV.10 R ¹ = R ² = H, R ³ = HC ₄ H ₉ , R ⁴ = H, x = Cl
IV.11 R ¹ = R ² = H, R ³ = CH ₂ CH (CH ₃ ) ₂ , R ⁴ = H, x = Cl
IV.12 R ¹ = CH ₃ , R ² = H, R ³ = HC ₄ H ₉ , R ⁴ = H, x = Cl
IV.13 R ¹ = R ² = H, R ³ = C ₆ H ₁₁ , R ⁴ = H, x = Cl
IV.14 R ¹ = R ² = H, R ³ = CH ₂ CH ₂ NH ₂ , R ⁴ = H, x = Cl
IV.15 R ¹ = R ² = R ³ = R ⁴ = H, x = Cl
The dicyclohexylamides of N-substituted α-aminocarboxylic acids I were obtained by boiling amides I with an excess of the corresponding amine III without solvent or in an organic solvent with a yield of 50-60% of theory. Alcohol, benzene, toluene, etc. can be used as solvents. The reaction conditions depend on the structure of the starting amines and the boiling point of the solvent. Amides I are crystalline or oily substances of a basic nature. Their purity was monitored by thin layer chromatography on Alufolien Kieselgel 60 F 254 DS in the benzene: alcohol: aqueous ammonia system (8: 2: 0.1). The value of Rf is 0.24-0.58.

Under the action of inorganic acids, for example, hydrochloric acid, amides I give acid addition salts (IV.1, IV.4-IV.15), and with the action of methyl iodide or allyl bromide they give quaternary salts (IV.2, IV.3). The structure of salts IV is proved by elemental analysis and spectral data. In the IR spectra recorded in KBr plates, there are intense absorption bands in the region of 1640–1660 cm ^–1 , corresponding to stretching vibrations of the carbonyl group, bands in the region of 3300 cm ^–1 ; characteristic of the hydroxy group (IV.5, IV.6), as well as the absorption band of 3496 cm ^-1 , characteristic of the amino group of primary amines (IV.10).

 Salts IV are white crystalline substances, sparingly soluble in water, highly soluble in alcohol, insoluble in ether, benzene.

 The following are production examples illustrating the claimed group of compounds. Example 1. Diethylaminoacetic acid dicyclohexylamide hydrochloride (IV.1).

A mixture of 10.32 g (0.04 mol) of dichloroacetic acid dicyclohexylamide and 29.24 g (0.4 mol) of diethylamine was boiled for 6 hours. The excess diethylamine was distilled off, the residue was washed with water and extracted with benzene. The benzene solution is washed twice with water and evaporated to dryness. The residue (oil) is dissolved in 70 ml of acetone, concentrated hydrochloric acid is added to pH 1-2 and left to stand overnight. The precipitate is filtered off, washed with acetone. Yield 6.6 g (50%). T. pl. 221-222 ^o C (decomp.) (From a mixture of absolute alcohol with acetone).

Found,%: C 65.32; H 10.66; N 8.49; Cl 10.72. C ₁₈ H ₃₅ ClN ₂ O.

 Calculated,%: C 65.33, H 10.66, N 8.46; Cl 10.71.

 Example 2. Diethylaminoacetic acid dicyclohexylamide iodomethylate, (IV.2).

To a solution of 2 g of diethylaminoacetic acid dicyclohexylamide (for preparation see Example 1) in 10 ml of ether is added a solution of 1.5 ml of methyl iodide in ether. Leave to stand at night. The precipitate is filtered off. Yield 3.1 g (90%). T. pl. 195-196 ^o C (from acetone).

Found,%: I 29.09, C ₁₉ H ₃₇ IN ₂ O.

 Calculated,%: I 29.08.

 Example 3. Brompropen-2-ylate diethylaminoacetic acid dicyclohexylamide (IV.3).

To a solution of 2.94 g (0.01 mol) of diethylaminoacetic acid dicyclohexylamide (see Example 1) in 25 ml of benzene, 9 ml of allyl bromide was added and the reaction mixture was boiled for 5 hours. The precipitate was filtered off. Yield 2.1 (50.6%). Mp 162-163 ^o C (from a mixture of alcohol with ether).

Found,%: C 60.46; H 9.43; N, 6.48; Br 19.13. C ₂₁ H ₃₉ BrN ₂ O.

 Calculated,%; C 60.71; H 9.46; N, 6.74; Br 19.24.

 Example 4. Diethylaminopropionic acid dicyclohexylamide hydrochloride (IV.4).

3.2 g (0.01 mol) of α-bromopropionic acid dicyclohexylamide are boiled in 10 ml of diethylamine for 7 hours. The reaction mass is cooled, poured into 100 ml of water. The aqueous solution was extracted with benzene, the benzene solution was evaporated to dryness. Oil (2.4 g) was dissolved in 25 ml of acetone, ether saturated with hydrogen chloride was added to pH 1, and left to stand overnight. The precipitate is filtered off. Yield 1.92 g (51.31%). T. pl. 222-223 ^o C (decomp.) (From isopropyl alcohol).

Found,%: C 66.18; H 10.76; N 8.19; Cl 10.27. C ₁₉ H ₃₇ ClN ₂ O.

 Calculated,%: C 66.15; H 10.82; N, 8.12; Cl 10.28.

 Example 5. Bis (2-hydroxyethyl) aminoacetic acid dicyclohexylamide hydrochloride (IV.5).

A mixture of 10.3 g (0.04 mol) of dicyclohexylamide of chloroacetic acid and 10.5 g (0.1 mol) of diethanolamine in 30 ml of absolute alcohol is boiled for 8 hours. The reaction mass is cooled, poured into 350 ml of ice water and left to stand overnight . The precipitate is filtered off, washed with water, and dried. Yield 13.7 g (94.5%) T. pl. 101-102 ^o C.

Found,%: C 66.34; H 10.52; N, 8.65. C ₁₈ H ₃₄ N ₂ O ₃
Calculated,%: C 66.22; H 10.5; N, 8.58. 3 g of the base are dissolved in 30 ml of acetone, concentrated hydrochloric acid is added to pH 1, and left to stand overnight. The precipitate was filtered off, washed with acetone, and dried in air. The yield of IV.5 hydrochloride is 2.6 g (77.8%). T. pl. 219-220 ^o C (decomp.) (From isopropyl alcohol).

Found,%: C 59.46; H 9.68; N, 7.74; Cl 9.86. C ₁₈ H ₃₅ ClN ₂ O ₃ .

 Calculated,%: C 59.57; H 9.72; N 7.72; Cl 9.77.

 Example 6. Bis (2-hydroxyethyl) -α-aminopropionic acid dicyclohexylamide hydrochloride (IV.6).

A mixture of 6.08 g (0.02 mol) of α-bromopropionic acid dicyclohexylamide and 5.25 g (0.05 mol) of diethanolamine in 30 ml of absolute alcohol is boiled for 8 hours. After cooling, the reaction mixture is poured into water and extracted with benzene. The benzene is evaporated to dryness. In the residue of 5.75 g of an oil, which is dissolved in 50 ml of acetone, concentrated hydrochloric acid is added to a pH of 1-2 and left to stand overnight. The precipitate is filtered off. Yield 5 g (66.3%). T. pl. 168-169 ^o C (from a mixture of absolute alcohol with ether).

Found,%: C 60.44; H 9.84; N, 7.60; Cl 9.29. C ₁₉ H ₃₇ ClN ₂ O ₃ .

 Calculated,%: C 60.54; H 9.89; N, 7.43. Cl 9.40.

 Example 7. Morpholinoacetic acid dicyclohexylamide hydrochloride (IV. 7).

A mixture of 2.58 g (0.01 mol) of dicyclohexylamide of chloroacetic acid and 4.36 g (0.05 mol) of morpholine in 25 ml of toluene is boiled for 5 hours. The reaction mixture is washed with water; evaporated to dryness. Yield 2.85 g (92.5%) mp. 117-118 ^o C (from 60% alcohol)
Found,%: C 70.4; 10.48; N, 9.11. C ₁₈ H ₃₂ N ₂ O ₂ .

 Calculated,%: C 70.09; H 10.46; N, 9.08.

Ether, saturated with hydrogen chloride, is added to a solution of 1.5 g of base in ether. The precipitate is filtered off. The yield of IV.7 hydrochloride is 1.3 g (71.4%). T. pl. 260-261 ^o C (decomp.) (From a mixture of acetone with absolute alcohol) (3: 1).

Found,%: Cl 10.30, C ₁₈ H ₃₂ ClN ₂ O ₂ .

 Calculated: Cl 10.28.

 Example 8. Hexamethyleneiminoacetic acid dicyclohexylamide hydrochloride (IV.8).

A mixture of 2.6 g (0.01 mol) of dicyclohexylamide of chloroacetic acid and 4 g (0.04 mol) of hexamethyleneimine in 25 ml of toluene is boiled for 3.5 hours. The reaction mass is cooled, washed with water and evaporated to dryness. In the residue, oil (3.2 g) is dissolved in 32 ml of acetone and ether saturated with hydrogen chloride is added to pH 1. The precipitate is filtered off, washed with acetone. Yield 2 g (55.8%). T. pl. 246-247 ^o C (decomp.) (From isopropyl alcohol).

Found,%: C 67.33, H 10.44; N, 7.83; Cl 9.84. C ₂₀ H ₃₇ ClN ₂ O
Calculated,%: C 67.30; H 10.45; N, 7.85; Cl 9.93.

 Example 9. Octahydropyrrolo (1,2-a) pyrazinoacetic acid dicyclohexylamide dihydrochloride (IV.9).

A mixture of 2.6 g (0.01 mol) of dicyclohexylamide of chloroacetic acid and 2.52 g (0.02 mol) of octahydro-pyrrolo (1,2-a) pyrazine in 25 ml of toluene is boiled for 3 hours. The reaction mass is cooled, washed with water and evaporated to dryness. In the residue, oil (2.8 g) was dissolved in 20 g of acetone and ether saturated with hydrogen chloride was added to pH 1. The precipitate was filtered off, yield 2.3 g (54.7%). T. pl. 239-240 ^o C (decomp.) (From isopropyl alcohol).

Found,%: C 59.91; H 9.45; N, 10.11; Cl 16.80. C ₂₁ H ₃₉ Cl ₂ N ₃ O.

 Calculated,%: C 59.99; H 9.35; N, 9.99; Cl 16.86.

 Example 10. The dicyclohexylamide hydrochloride of n-butylaminoacetic acid (IV.10).

A mixture of 5.16 (0.02 mol) of dichloroacetic acid dicyclohexylamide and 14.6 g (0.2 mol) of n-butylamine was boiled for 6 hours. The excess butylamine was distilled off, the residue was washed twice with water and extracted with benzene. The benzene solution is washed with water and evaporated to dryness. The residue (oil) is dissolved in 30 ml of acetone and concentrated hydrochloric acid is added to pH 1. The precipitate is filtered off, washed with ether. Yield 4.3 g (65%). T. pl. 210-211 ^o C (from isopropyl alcohol).

Found,%: C 65.24; H 10.54; N, 8.51; Cl 10.66. C ₁₈ H ₃₅ ClN ₂ O.

 Calculated,%: C 65.33; H 10.66; N, 8.46; Cl 10.77.

 Example 11. Isobutylaminoacetic acid dicyclohexylamide hydrochloride (IV.11).

A mixture of 5.16 g (0.02 mol) of dicyclohexylamide of chloroacetic acid and 14.6 g (0.2 mol) of isobutylamine is boiled for 6 hours. The reaction mixture is evaporated to dryness. The toluene solution was evaporated to half the volume and ethyl acetate saturated with hydrogen chloride was added to the residue. The precipitated crystalline precipitate was left in the refrigerator for a day, then it was filtered off, washed with ether and dried in vacuo at 70 ^° C. Yield 5.6 g (84.7%). T. pl. 240-241 ^o C (from isopropyl alcohol).

Found,%: C 65.36; H 10.72; N, 8.33; Cl, 10.91. C ₁₈ H ₃₅ ClN ₂ O.

 Calculated,%: C 65.33; H 10.66; N, 8.46; Cl 10.71.

 Example 12. Dicyclohexylamide hydrochloride of α- (n-butyl) aminopropionic acid (IV.12).

A mixture of 2.63 g (0.0087 mol) of α-bromopropionic acid dicyclohexylamide and 6.36 g (0.1 mol) of n-butylamine is boiled for 10 hours. The reaction mixture is evaporated to dryness, the residue is washed with water and extracted with benzene. The benzene solution is washed with water and evaporated to dryness. The residue was dissolved in benzene and ether saturated with hydrogen chloride was added. The precipitate was filtered off, washed with ether, and dried. Yield 0.6 g (20%). T. pl. 265-266 ^o C from isopropyl alcohol).

Found,%: C 66.33; H 11.07; Cl 10.61. C ₁₉ H ₃₇ ClN ₂ O.

 Calculated,%: C 66.15; H 10.81; Cl 10.28.

 Example 13. Dicyclohexylamide cyclohexylaminoacetic acid hydrochloride (IV.13).

A mixture of 2.57 g (0.01 mol) of dicyclohexylamide of chloroacetic acid and 10 ml of cyclohexylamine is boiled for 5 hours. The excess cyclohexylamine is evaporated. The residue was dissolved in 25 ml of acetone, concentrated hydrochloric acid was added to pH 1, and left to stand overnight. The precipitate is filtered off. Yield 2.2 g (61.6%). T. pl. 242-243 ^o C (decomp.) (From isopropyl alcohol).

Found,%: C 67.19; H 10.50; N, 7.90; Cl 9.90. C ₂₀ H ₃₇ ClN ₂ O.

 Calculated,%: C 67.29; H 10.45; N, 7.85; Cl 9.93.

 Example 14. β-aminoethyl) aminoacetic acid dicyclohexylamide dihydrochloride hydrate (IV.15).

A mixture of 2.58 g (0.01 mol) of dicyclohexylamide of chloroacetic acid and 3 g (0.5 mol) of 88% ethylenediamine in 25 ml of alcohol is boiled for 11 hours. The reaction mass is evaporated to dryness. The residue was made basic with concentrated aqueous ammonia and recovered with benzene. The benzene solution is washed with water and evaporated to dryness. The residue was dissolved in ether and ether saturated with hydrogen chloride was added to pH 1. The precipitate was filtered off and washed with ether. Yield 1.8 g (48.4%). T. pl. 243-244 ^o C (from a mixture of alcohol with ether).

Found,%: C 51.61; H 9.39; N, 11.42; Cl 18.86. C ₁₆ H ₃₅ Cl ₂ N ₃ O ₂ .

 Calculated,%: C 51.60; H 9.47; N, 11.28; Cl 19.04.

 Example 15. Aminoacetic acid dicyclohexylamide hydrochloride hydrate (IV.4).

To a solution of 2.58 g (0.01 mol) of dicyclohexylamide of chloroacetic acid in 25 ml of alcohol was added a saturated aqueous solution of ammonia to pH 10-12 (10 ml) and left to stand at 20 ^o C for 2-3 weeks. Water was added to the reaction mass, a small amount of a 25% aqueous ammonia solution, and the mixture was extracted with ether. The ether solution is washed with water and evaporated to dryness. The residue was dissolved in ether and ether saturated with hydrogen chloride was added to pH 1. The precipitate was filtered off and washed with ether. Yield 1.7 g (58%). Mp 229-230 ^o C (from a mixture of alcohol with ether).

Found,%: C 57.24; H 9.83; N, 9.48; Cl 11.95; C ₁₄ H ₂₉ ClN ₂ O ₂ .

 Calculated,%: C 57.42; H 9.98; N, 9.57; Cl 12.11.

 Pharmacological results obtained in the study of dicyclohexylamides of N-substituted α-amino acids.

 Pharmacological studies of compounds of general formula IV have been carried out, which are soluble in water, physiological saline and therefore convenient for intravenous and intraperitoneal administration. For research, aqueous solutions of compounds of formula I can also be used at pH 3-5. In this case, equimolar amounts of compounds of the general formula I and IV showed the same pharmacological effect, therefore, the tables give the results of studies of the compounds of the general formula IV, which are more convenient for experimental work.

 A pharmacological study of the claimed compounds of general formula IV was initially carried out using a set of methods used for the initial assessment of the antiarrhythmic effect, taking into account the correlation between the chemical structure of the new compounds and their antiarrhythmic activity. For this purpose, the aconitine and calcium chloride models of arrhythmias were used.

The effective dose (ED ₅₀ ) and lethal dose (LD ₅₀ ) and their confidence limits were calculated by the method of Miller and Taint (10) with a probability level of p = 0.05. The experiments were carried out on outbred white rats weighing 180-200 g with intravenous administration of the claimed compounds. The ratio of the lethal dose (LD ₅₀ ) to the average effective dose (ED ₅₀ ) -LD ₅₀ ED ₅₀ , which was designated as the antiarrhythmic index, was used as a criterion for the therapeutic breadth of the claimed compounds [5]. The spectrum of antiarrhythmic activity of the most promising compounds was further studied on a heart rhythm model with a threshold for electrical ventricular fibrillation in cats [6 and 7] to detect antifibrillator agents, on a barium chloride model to identify class III properties [8], as well as a two-stage coronary artery ligation model in dogs according to the Harris method [9] to identify properties characteristic of class I antiarrhythmics.

 Thus, for the study used a set of methods of experimental reproduction in awake and anesthetized animals, allowing to identify antiarrhythmic properties of the claimed compounds.

 Table 1 presents the results of a study of the antiarrhythmic properties of the claimed compounds in the calcium chloride model of arrhythmia. The experiments were performed on awake outbred rats weighing 180-200 g. Calcium chloride was introduced in the form of a 10% solution at a dose of 200-250 mg / kg. At the beginning, a dose of calcium chloride was selected for each weight of the animal, causing a lethal outcome from ventricular fibrillation occurring within 1-1.5 minutes, then the test compounds were administered 1-3 minutes before the administration of calcium chloride. The ECG was recorded in standard lead II on an ELKAR-2 device. Antiarrhythmic effect was evaluated by reducing the number of cases of lethal ventricular fibrillation. The data obtained were processed according to the Litchfield method [10].

The studied compounds on antiarrhythmic activity on the model of calcium chloride arrhythmia can be arranged in the following sequence:
IV.11>IV.10>IV.12>IV.14>IV.6> 6 = IV.9>IV.7>IV.4> IV.8
Aconitine arrhythmia was caused in awake rats weighing 180-200 g, introducing aconitine solution at a dose of 30-40 μg / kg into the tail vein. At the same time, rhythm disturbances of a mixed atrioventricular nature occurred, which are usually polytopic extrasystoles. The inventive compounds were administered intravenously 1-3 minutes before the introduction of aconitine.

As can be seen from table 2, most of the claimed compounds were very effective in preventing arrhythmias in this model, significantly superior to drugs of class I antiarrhythmic action lidocaine, chanidine and novocainamide, taken for comparison as reference drugs. In accordance with the average effective dose, the compounds can be arranged in the following order of decreasing antiarrhythmic activity:
IV.10>IV.11>IV.5>IV.6> IV.2 = IV.1> IV.14
To detect antifibrillator activity of compounds IV.1; IV.10 studied their effect on the threshold of ventricular electrical fibrillation caused by electrical stimulation.

 This method makes it possible to compare the antifibrillatory properties of the compounds, which are important in connection with the need to prevent the occurrence of ventricular fibrillation due to electrical myocardial instability and thus solve the problem of sudden death that has been increasing in recent years.

 The experiments were carried out on cats weighing 2-3 kg, anesthetized with Nembutal (35 mg / kg) with artificial respiration. After opening the chest and pericardium, platinum electrodes were applied to the left ventricular myocardium. Electrical irritation from a 3-channel electronic stimulator SEN-7201 (Nihon Kohden, Japan) created an "ectopic focus of excitation." Heart rhythm disturbances (ventricular fibrillation) were caused by a series of rectangular pulses of increasing intensity (20 pulses per burst), each 4 ms in duration and a repetition rate of 50 Hz. The minimum amount of mA of irritating current, which caused fibrillation, was taken as the ventricular fibrillation threshold. The moment of occurrence was recorded according to ECG and a drop in blood pressure. Blood pressure in the femoral artery was recorded using an Elema electrometer (Sweden). The ECG was recorded in the II standard lead on an ELKAR-2 electrocardiograph and the Atask-350 analyzer coordinate recorder (Nihon Kohden, Japan), simultaneously with the recording of pulse pressure.

 The studied drugs were injected into the femoral vein in 10 ml of saline for 3 minutes. Doses of 4.5 and 8 mg / kg for lidocaine and 2 and 5 mg / kg for quinidine were used.

 Defibrillation was performed using a capacitor discharge of a given intensity supplied directly to the myocardium from the DI-03 defibrillator.

 As can be seen from the results presented in table 3, the studied compounds IV. one; IV.10 have pronounced antifibrillatory properties. They increase the threshold more intensively and for longer than the comparison drug lidocaine, which is practically the only drug widely used in the clinic to treat life-threatening arrhythmias in post-infarction patients and to prevent sudden death.

 Ventricular arrhythmias caused by occlusion of the descending branch of the left coronary artery are obtained in awake dogs operated on using the Harris method (1950). The experience of many pharmacological laboratories in the world shows that compounds that demonstrate activity on this model are highly effective in the clinic and reveal antiarrhythmic properties of class I that suppress the fraction of a constant level of sodium currents in myocardial cells depolarized by ischemia.

 The experiments were performed on dogs weighing 8-15 kg. Animals were anesthetized with Nembutalum (35 mg / kg intravenously), after intubation they were transferred to artificial respiration, fixed on the operating table in the position on the right side. Under aseptic conditions, the chest was opened in the fourth intercostal space on the left. The pericardium was incised, a descending branch of the left coronary artery was isolated 2-3 cm below the left edge of the abalone. A N20 injection needle was placed parallel to the artery axis. The first ligature was tied to a needle, which created a drop in blood circulation in the underlying myocardium after removal of the needle. The second ligature was tied tight 30 minutes after the first. The wound was sutured in layers, antibiotics were administered. During the operation, ECG was recorded in the II standard lead, constant monitoring was performed. Polyethylene catheters filled with heparin were implanted into the jugular vein, and catheters were subcutaneously inserted into the neck in the back of the head. After 24 hours, only animals that were in satisfactory condition and had stable ventricular rhythm disturbances were taken into the experiment. The test substances were injected slowly into the jugular vein in 10 ml of physiological saline.

 The effectiveness of substances was evaluated by their ability to restore normal sinus rhythm, as well as by the degree of decrease in the frequency of ectopic excitations of the ventricles. For statistical processing of the results, Student t-test was used.

 The effect of the most active of the previously identified compounds IV was investigated. 1 in doses of 3.3 and 8 mg / kg and IV.10 in doses of 3.3; 5.0 and 6.6 mg / kg when administered intravenously in 10 ml of physiological saline. The efficacy of the compounds in this model was compared with the efficacy of lidocaine acting at doses of 5 and 8 mg / kg. A reduction in ectopic contractions of 50% or more was taken as a positive antiarrhythmic effect.

 A total of 27 experiments were conducted in this series. With intravenous administration of compound IV. 10 at a dose of 5 mg / kg already at the 1st minute of action, ectopic contractions are completely eliminated, and the total number of heart contractions is reduced by 30%. As seen in FIG. 1, persistent antiarrhythmic effect is maintained for more than 30 minutes (lower graphs). At 45 minutes, the percentage of ectopic contractions returns to the original. Lidocaine in an equimolar dose is significantly inferior in activity to compound IV.10. At this dose, this compound reduces the total number of heart contractions by an average of 6% and the duration of suppression of ectopic contractions is more than 30 minutes. The duration of the lidocaine effect was no more than 15 minutes.

 Compound IV.1 at a dose of 3.3 mg / kg 5 minutes after intravenous administration reduced the total number of heart contractions by 13% and the number of ectopic contractions by 30-8%. At a higher dose of 8 mg / kg, this compound also reduces the total number of heart contractions by 13%, and ectopic excitations of the ventricles by 42-100%, while lidocaine at this dose reduces the total number of heart contractions by 8%, and ectopic by 70%. The duration of the antiarrhythmic effect is 30 minutes. As seen in FIG. 2, compound IV.1 (lower plots - solid lines) significantly exceeds lidocaine in antiarrhythmic activity (upper plots - dotted line).

 Thus, the most active compounds IV.1 and IV.10 have pronounced antiarrhythmic properties of class I "B".

 As is known, the arrhythmogenic effect of BaCl is associated with a decrease in potassium conductivity; therefore, the barium chloride model of arrhythmia is considered adequate for the appearance of properties of class III antiarrhythmic action.

 The experiments were carried out on awake rabbits of both sexes weighing 2-4 kg according to the method described by L. Szektres and Gy.J. Papp (1971). Rabbits were injected with 4 mg / kg BaCl in the marginal ear vein in the form of a 2% solution for 1 min. In response to the intravenous administration of a BaCl solution after a latent period of several seconds, heart rhythm disturbances occur in the form of a polyteopeic ventricular extrasystole, which lasts up to 30 minutes.

 An ECG was recorded in standard II lead every minute for 15 minutes. ECG was recorded every minute for 12 s. In subsequent experiments, we took those rabbits who had at least one extrasystole for 15 minutes at every minute.

 Since BaCl is a very toxic substance and is slowly excreted from the body, the rabbits selected in the control experiments were kept for 3-4 days before the experiment. Then they were injected with 4 mg / kg BaCl for 1 min. Arrhythmia was recorded on an ECG after administration of a BaCl solution for 1 and 2 minutes, and then the test substance was administered as a 1% solution for 30 s. An ECG was recorded at every minute for 15 minutes.

 The effect of the compound was evaluated by the ability to restore normal sinus rhythm within 1 or more minutes. For each rabbit selected in the control, 3-5 doses of the compound were watched at intervals of 3-4 days.

 Class III antiarrhythmic sematilide, taken as a standard, at a dose of 2.5-5.0 mg / kg eliminated arrhythmia caused by intravenous administration of barium chloride. The most active of the claimed compounds IV.10 was effective in the dose range of 0.125-0.25 mg / kg, which indicates its significantly higher efficiency in this model.

Claims (1)

N-substituted α-aminocarboxylic acid dicyclohexylamides of the general formula

where R ¹ is hydrogen or lower alkyl;
R ² and R ³ are the same or different and mean hydrogen, lower alkyl, hydroxy (lower alkyl), aminoethyl, cyclohexyl, or R ² and R ³ together with the nitrogen atom carrying them form a saturated 6- or 7-membered heterocycle, which can additionally contain a nitrogen or oxygen atom, or mean piperazine, in which the nitrogen atom in the 4th position and the adjacent carbon atom are connected by a propylene group,
or their pharmaceutically acceptable salts of acid addition, or their Quaternary salts.

Images