RU2091382C1 - Derivatives of 4-acetylimidazo-[4,5-b]-indole-2-thione showing antihypoxic and virus-inhibiting activity with respect to horse venezuelan encephalomyelitis and method of their synthesis - Google Patents

Abstract

FIELD: organic chemistry. SUBSTANCE: product: compound of the general formula

Description

где R атом водорода (1а), метил (1б), бензил (1в).The invention relates to the chemistry of condensed nitrogen-containing heterocyclic systems and specifically relates to three new compounds - 4-acetylimidazo (4,5-c) indol-2-thione (1a), 4-acetyl-3-methyl-imidazo / 4,5-b / indole-2-thione (1b) 4-acetyl-3-benzylimidazo (4,5-c) indole-2-thione (1c) described by the general formula (I)

where R is a hydrogen atom (1a), methyl (1b), benzyl (1c).

В литературе описана гетероциклическая азотсодержащая система - 9H-имидазо /1,2-в/индола типа B (I)

Новизна предлагаемой системы имидазо(4,5-в)индола типа A состоит в том, что в молекуле этой системы имидазольный цикл сочленен с индольным по связи C C грани (в), в то время как в известной системе типа B связь этих гетероциклических ядер проходит по связи C=N грани (а).The compounds are derivatives of a new heterocyclic system, namely imidazo / 4,5-v / indole type A

The literature describes a heterocyclic nitrogen-containing system - 9H-imidazo / 1,2-in / indole type B (I)

The novelty of the proposed system of imidazo (4,5-c) indole type A is that in the molecule of this system the imidazole ring is fused to the indole bond CC of the face (c), while in the known system of type B the bond of these heterocyclic nuclei passes by the bond C = N of the face (a).

 Condensed imidazoles, the articulation of which passes along the edge (c), are not described in the literature.

 Representatives of the new type A heterocyclic system are compounds of the general formula (I).

 When studying their biological activity, it was found that they have the property of protecting the brain during anoxia and exhibit virus-inhibiting activity against the Venezuelan encephalomyelitis virus in horses (VEL).

 It should be noted that in the literature there is no information about the biological activity of the known system B and its derivatives.

 Currently, in medical practice and in the literature there is no information about compounds possessing complexes of the above properties. Compounds having virus-inhibiting activity against the VEL virus are also not known.

Это соединение принято в качестве аналога предлагаемых соединений по одному свойству, а именно противогипоксическому. Соединение формулы (C) проявляет относительно невысокую защитную активность при аноксии мозга и не обладает вирусингибирующей активностью (2).In a series of imidazoindoles, compounds exhibiting protective properties in brain anoxia are not described. Compounds with antihypoxic properties in the series of triazinoindoles are described. For example, 3- (3-dimethylaminopropylthio) -1,2,4-triazino / 5,6-b / indole hydrochloride of the formula (C) has this property

This compound is taken as an analogue of the proposed compounds for one property, namely antihypoxic. The compound of formula (C) exhibits a relatively low protective activity in brain anoxia and does not have virus-inhibiting activity (2).

 The purpose of the invention are compounds with antihypoxic activity and virus-inhibiting activity against Venezuelan horse encephalomyelitis and a method for their preparation.

 The goal is achieved by the chemical structure of the new compounds of formula 1a-b - derivatives of a new heterocyclic system of imidazo (4,5-b) indole having the above properties.

 The proposed compounds are crystalline substances of light gray color, hardly soluble in most organic solvents.

 The structure of the compounds is confirmed by elemental analysis and spectral characteristics given in table. one.

The proposed method for producing derivatives of 4-imidazo (4,5-c) indoles of the general formula (1) is that 1-acetyl-2-alkylamino-3-indolinone in the form of a hydrochloride of the general formula (II), where R has the above meanings are reacted with potassium thiocyanate in boiling acetic acid to form 1-acetyl-2-alkylthioureido-3-indodinone of the general formula (III), where R has the above meanings, is isolated and cyclized with a mixture of phosphoric anhydride and 87% phosphoric acid taken in the weight ratio (33 ^o C40): (67 ^o C60), respectively, in the medium of diethylene glycol dimethyl ether (diglyme) at 100-160 ^o C.

a) R H; б) R CH₃; в) R CH₂C₆H₅
Исходные соединения IIа-в-гидрохлориды 1-ацетил-2-алкиламино-3-индолиноны новые (в литературе не описаны); физикохимические свойства их приведены в табл. 1.The scheme of the proposed method

a) RH; b) R CH ₃ ; c) R CH ₂ C ₆ H ₅
The starting compounds IIa-b-hydrochlorides 1-acetyl-2-alkylamino-3-indolinones are new (not described in the literature); their physicochemical properties are given in table. one.

Example 1. Obtaining compounds 1A-4-acetylimidazo (4,5-b) indol-2-thione:
a). Obtaining the starting compound of 1-acetyl-2-amino-3-indolinone hydrochloride (IIa).

A solution of 6.4 g (0.04 mol) of bromine in 100 ml of dioxane is added to a solution of 7 g (0.04 mol) of 1-acetyl-3-indolinone in 100 ml of dioxane at 20 ^° C. To the mixture containing the resulting 1-acetyl-2-bromo-3-indolinone was added 120 ml of a 1 N solution of ammonia in dioxane. The mixture is stirred for 30 minutes, the precipitate of ammonium bromide is filtered off, washed with ether. The filtrate containing 1-acetyl-2-amino-3-indolinone is combined with the wash liquid and 50 ml of a 1.5 N solution of hydrogen chloride in ether are added. The precipitate formed is filtered off, washed with ether and dried over phosphoric anhydride in vacuo.

 6.8 g (75% based on 1-acetyl-3-indolinone) of 1-acetyl-2-amino-3-indolinone hydrochloride are obtained in the form of pink crystals.

 Similarly receive 1-acetyl-2-methylamino-3-indolinone (IIb) (73% counting on 1-acetyl-3-indolinone) and 1-acetyl-2-benzylamino-3-indolinone (IIc) (93% counting 1 -acetyl-3-indolinone).

 The products are used for further synthesis without crystallization.

Elemental analysis and physicochemical constants of compounds IIa (RH), IIb (R CH ₃ and IIc (R CH ₂ C ₆ H ₅ are shown in Table 1).

 b) Obtaining an intermediate product of 1-acetyl-2-thioureido-3-indolinone (IIIa).

 A mixture of 4.5 g (0.02 mol) of 1-acetyl-2-amino-3-indolinone hydrochloride, 2.0 (0.021 mol) of potassium thiocyanate and 10 ml of glacial acetic acid is heated to boiling with vigorous stirring. The mixture is boiled for 1 min, then cooled and 10 ml of water are added, the resulting thick paste is thoroughly mixed. The precipitate formed is filtered off, washed with water, isopropanol and dried in vacuo over phosphoric anhydride.

 This gives 3.9 g (79% based on 1-acetyl-2-amino-3-indolinone) 1-acetyl-2-thioureido-3-indolinone (IIIa) in the form of lilac crystals.

 Similarly receive 1-acetyl-2-methylthioureido-3-indolinone (IIIb, 89% counting 1-acetyl-2-methylamino-3-indolinone) and 1-acetyl-2-benzylthioureido-3-indolinone (IIIc, 59% counting on 1-acetyl-2-benzylamino-3-indolinone).

 The products are used for further synthesis without crystallization.

Elemental analysis and physicochemical constants of compounds IIIa (RH), IIIb (R CH ₃ ) and IIIc (R CH ₂ C ₆ H ₅ ) are given in table. one.

 in). Obtaining the target product 1A.

 A mixture of 1 g (0.004 mol) of 1-acetyl-2-thioureido-3-indolinone, 4 ml of a cyclizing mixture (prepared from 0.32 g of phosphoric anhydride, 0.48 g of 87% phosphoric acid) and 3 ml of diglyme, is boiled 5 min After cooling, the precipitate formed is filtered off, washed with isopropanol and dried in vacuo over phosphoric anhydride.

 Obtain 0.46 g (50% based on 1-acetyl-2-thioureido-3-indolinone) 4-acetylimidazo (4,5-c) indol-2-thione in the form of light gray crystals.

 4-acetyl-3-methylimidazo (4,5-c) indol-2-thion (1b, 89% based on 1-acetyl-2-methylthioureido-3-indolinone) and 4-acetyl-3-benzylimidazo ( 4,5-c) indol-2-thion (1c, 68% based on 1-acetyl-2-benzylthioureido-3-indolinone.

Elemental analysis and physicochemical constants of compounds 1a (RH), 1b (R CH ₃ ) and 1c (R CH ₂ C ₆ H ₅ ) are given in table. one.

 The resulting products do not contain impurities according to TCX and can be used without further purification.

 The study of the biological activity of the claimed compounds.

To study the antiviral activity of 4-acetylimidazo (4,5-b) indole-2-thione derivatives, a primary trypsinized chicken embryo fibroblast culture (FEC) was used, which was obtained by trypsinization of 9 day old chicken embryos. The cell monolayer was infected with 10-100 TPCD ₅₀ of the Venezuelan encephalomyelitis virus virus (VEL) strain N 230 and placed in a thermostat at 37 ^° C for 1 h for adsorption. Then, the studied substances were introduced into the infected culture.

 The compounds were used in concentrations of 1/4, 1/8, 1/16 of the maximum tolerated concentration (BMD), which was previously determined by detecting the cytotoxic effect of the substance on the cells.

The antiviral activity of the compounds was judged by lowering the infectious titer of the virus in test tubes treated with the studied compounds with a monolayer of cell culture as compared with the control (monolayer of cell culture without the studied compound). The results were expressed in lg TCD ₅₀ . The breadth of the antiviral effect was judged by the value of the chemotherapeutic index (CTI), which was determined as the value of the maximum tolerated concentration of the compound to the minimum active.

 The results are presented in table. 1a.

 The antiviral activity of the compounds was studied in 4 experiments on 450 tubes with a pronounced monolayer of cell culture. The cytotoxicity of the compounds was studied in preliminary experiments on 80 tubes.

 Analyzing the obtained results, we can conclude that the proposed compounds exhibit significant reliable antiviral activity, inhibiting the replication of the VEL virus, which is the causative agent of especially viral infections in humans and animals. The most active of the studied compounds is compound 1b.

The cytotoxicity of the proposed compounds for cell culture FEC is small and is 20 μg / ml for all studied compounds /
The proposed compounds are not toxic to animals. With the introduction of peros. Once a day for 5 days, white non-inbred mice weighing 14-16 g (80 pcs.) Did not cause the death of animals in doses exceeding 1000 mg / kg.

 Thus, the proposed compounds have an antiviral effect against the causative agent of especially dangerous infections of humans and animals of the Venezuelan encephalomyelitis virus in horses. The relationship between the chemical structure and severity of the antiviral effect, as well as the low toxicity of the compounds for animals, indicate the promise of a further search for antiviral agents in this chemical series.

 The study of antihypoxic activity was carried out on white male rats weighing 200 220 g of 25 animals in the group. The indicated form of hypoxia was reproduced by disabling artificial respiration in rats whose own respiratory activity was inhibited by the administration of muscle relaxants (tubocurarine, 0.5 mg / kg ip). ECoG was recorded in animals. 30 seconds after the disappearance of the electrical activity of the brain, renewal was resumed. Survival was judged by the restoration of brain electrogenesis. The drug was administered intraperitoneally at doses of 25, 50 and 100 mg / kg 1 hour before the experiment, 100 animals were used in each experiment. The claimed compounds are 4-acetylimidazo (4,5-c) indol-2-thion (1a), 4-acetyl-3-methylimidazo (4,5-c) indol-2-thion 1 (b) and 4-acetyl 3-benzylimidazo (4,5-c) -indole-2-thion (1c) was compared with a well-known analogue of the same as compounds 1a-c, for use with 3- (3-dimethylaminopropylthio) -1,2,4-triazino hydrochloride (5,6-c) indole (C).

 Control group of animals of the same batch as above, but receiving saline instead of the studied compounds. The test compounds were administered to animals as a suspension in water with the addition of Tween-80.

The number of animals that restored electrogenesis in relation to the control was expressed in
The results of the study are presented in table. 2.

 As can be seen from the table. 2, the proposed compounds in the most effective dose (50 mg / kg) are superior to the known analogue C in antihypoxic effect in severe anoxia. The restoration of brain electrical activity using compounds 1a-c is achieved in 160,225 animals versus 140% for the analogue (control was taken as 100%).

 Assessed the toxic effects of the proposed compounds 1A-C. The toxicity of the compounds is judged by the values of their average flying doses calculated according to the known method [3] The study was conducted on white non-linear male mice weighing 16 to 22 g. Compounds 1a-c were administered intraperitoneally once in the form of a suspension in water with Tween-80 in doses 1600 2000 mg / kg. For each dose of the compound, 10 animals are used. Observation of the state of experimental animals is carried out for 3 days. The death of animals is observed within 2 days. The survival of animals in the group is presented in table. 3.

 The results obtained indicate that compounds (1a-c) can be classified as low-toxic substances. For them, the LD50 values for intraperitoneal administration are in the range 1800 1800 mg / kg. They are less toxic than the known analogue C of the same purpose, for which the LD50 value for intraperitoneal administration is 560 mg / kg. The proposed compounds 1A-b have sufficient pharmacological breadth.

 Thus, the proposed compounds have antihypoxic effect and exhibit high protective activity in brain anoxia. The relationship between the chemical structure and the severity of the antihypoxic effect, as well as the low toxicity of these compounds for animals, indicates the promise of a further search for antihypoxic agents in this chemical series.

In the table. 4 shows the dependence of the degree of reaction on the type of cyclizing agent and solvent according to qualitative estimates of TLC at 100 - 160 ^o C.

 As the experiment showed, an attempt to cyclize intermediate product III without cyclizing agents, in one diglyme, during boiling or under the action of the above cyclizing mixture in accordance with the diglyme did not lead to the desired result: the target product does not form.

Claims (2)

1. Derivatives of 4-acetylamidazo (4,5-b) indol-2-thione of the general formula I

where R is hydrogen, methyl, benzyl,
possessing antihypoxic and virus-inhibiting activity against the Venezuelan encephalomyelitis virus in horses. 2. The method of obtaining derivatives of 4-acetylimidazo (4,5-b) indol-2-thione according to claim 1, characterized in that 1-acetyl-2-alkylamino-3-indolinone in the form of a hydrochloride of the general formula II

where R has the indicated meanings,
subjected to interaction with potassium thiocyanate in a medium of acetic acid during boiling, the resulting 1-acetyl-2-alkylthioureido-3 indolinone of General formula III

where R has the indicated meanings,
isolated and subjected to cyclization with a mixture of phosphoric anhydride and 87% phosphoric acid, taken in a mass ratio of 33 40 67 60, respectively, in a medium of diethylene glycol dimethyl ether at 100 - 160 ^o C.

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