RU2643315C2 - Method of producing 3-(2-morpholinoethyl)-1,2,4-triazo[5,6-b]indole dihydrochloride - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method is described that involves the reaction of 3-mercapto-1,2,4-triazino[5,6-b]indole with 2-morpholinoethylbromide hydrobromide in the presence of an excess of alkali to produce the 3-(2-morpholinoethylthio)-1,2,4-triazino[5,6-b]indole base, wherein 58 ml of concentrated hydrochloric acid, 12 ml of water and 13 ml of propanol-2 are charged into a vessel equipped with a stirrer, thermometer and reflux refrigerator, 10.69 g of the 3-(2-morpholinoethylthio)-1,2,4-triazino[5,6-b]indole base is added with stirring; with stirring, it is boiled for 30 minutes, filtered in the hot state, with stirring, cooled to 25°C, left in the refrigerator for 20 hours; the precipitate is filtered off, washed with propanol-2 and acetone, dried in air to the constant weight; a yellow crystalline product is obtained.

EFFECT: excluding operations with gaseous hydrogen chloride, reducing the consumption of organic solvents, increasing the purity of the product.

1 ex, 8 dwg

Description

The invention relates to methods for producing 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole dihydrochloride, which is used, for example, for the treatment of sensorineural hearing loss and deafness.

From the prior art, the MEANS FOR TREATMENT OF ACUTE AND EXTRAORDINARY SENSON-NEURAL Hearing Aid and Deafness is known (RU 2119335, published: 09/27/1998). The solution describes that the dihydrochloride monohydrate of 3- (2-morpholinoethylthio) -1,2,4-triazino [5,6-b] indole (trisan) is obtained in a known manner. The interaction of 3-mercapto-1,2,4-triazino [5,6-b] indole with 2-morpholinoethyl bromide hydrobromide in the presence of an excess of alkali gives the base 3- (2-morpholinoethylthio) -1,2,4-triazino [5, 6-b] indole with a yield of about 75% of theoretical. The latter is treated with gaseous hydrogen chloride or hydrochloric acid in isopropyl alcohol to obtain trisan - dihydrochloride monohydrate 3- (2-morpholinoethylthio) -1,2,4-triazino [5,6-b] indole with a yield of about 87% of theory. The latter is purified by recrystallization from a mixture of isopropyl alcohol with dilute hydrochloric acid, dried in air and obtained in the form of lemon-yellow crystals, melting point 238-240 ° C (with decomposition). The substance is homogeneous according to thin layer chromatography.

The solution is chosen for the prototype.

The disadvantage of this method is that they manage to synthesize dihydrochloride 3- (2-morpholino-ethylthio) -1,2,4-triazino- [5,6-b] indole with insufficiently high purity.

In addition, the known method requires the production of gaseous hydrogen chloride and the preparation of a solution of HCl in dioxane, which requires significant costs for the consumption of organic solvents.

The objective of the invention is to eliminate the disadvantage of the prototype.

The technical result of the invention is the elimination of the operation of producing gaseous hydrogen chloride and preparing a solution of HCl in dioxane, as well as a significant reduction in the consumption of organic solvents. In addition, the proposed method is more environmentally friendly. It is also possible to obtain the target product with a purity of at least 99%.

The specified technical result is achieved due to the fact that the claimed method of producing dihydrochloride monohydrate 3- (2-morpholinoethylthio) -1,2,4-triazino [5,6-b] indole (trisan), characterized by the interaction of 3-mercapto-1,2 , 4-triazino [5,6-b] indole with 2-morpholinoethyl bromide hydrobromide in the presence of an excess of alkali, a 3- (2-morpholinoethylthio) -1,2,4-triazino [5,6-b] indole base is obtained, the last treated with hydrochloric acid, characterized in that at a capacity of 100 ml, equipped with a stirrer, a thermometer and a reflux condenser, load 58 ml of concentrate bath hydrochloric acid, 12 ml of water and 13 ml of propanol-2, and with stirring, 10.69 g (0.034 mol) of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] are added ] indole; the resulting reaction mixture is heated to boiling with stirring and boiled for 30 minutes, then filtered while hot, the filtrate is placed in a different container and cooled to 25 ° C with stirring, after which it is left to stand in the refrigerator for 20 hours; the precipitate formed is filtered off, washed with propanol-2 and acetone successively, and dried in air to constant weight; 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole dihydrochloride is obtained in the form of a yellow crystalline solid.

The invention is illustrated by the results of analyzes (in the drawings).

In FIG. 1 - FIG. 7 shows examples of gas chromatography-mass spectrometric analyzes of products.

In FIG. Figure 8 shows the results of analysis of a sample of 3- (2-morpholinoethylthio) -1,2,4-triazino- [5,6-b] indole dihydrochloride using HPLC).

The implementation of the invention

Optimization of the production of 3-mercapto-1,2,4-triazino [5,6-b] indole 2 by combining the steps for the preparation of 3-thiosemicarbazone isatin and its cyclization.

The process we developed for producing 3-mercapto-1,2,4-triazino [5,6-b] indole 2 consists of 2 stages. Initially, 3-thiosemicarbazone isatin is prepared in aqueous hydrochloric acid,

which is then subjected to cyclization in an alkaline environment.

We decided to optimize this process by conducting both stages sequentially, i.e. without isolation of thiosemicarbazone.

47 ml of water, 5.1 ml (0.06 mol) of concentrated hydrochloric acid were loaded into a 100 ml beaker, and 4.56 g (0.05 mol) of thiosemicarbazide were added with stirring. It was stirred for 30 minutes until completely dissolved and the resulting solution was transferred to a dropping funnel.

In a 0.5-liter 3-necked flask equipped with a stirrer, dropping funnel and reflux condenser, 300 ml of water, 1 drop of 2-ethylhexanol (to prevent strong foaming during boiling) were charged, and 7.02 g (0.047) was added with stirring mole) of isatin. The mass was heated to a gentle boil, and a thiosemicarbazide hydrochloride solution was added over 30 minutes with stirring, while maintaining a gentle boil. Upon completion of the addition, the mixture was boiled for 20 minutes, cooled to 30 ° C, 5.6 g (0.14 mol) of NaOH were added, heated to boiling, and boiled for 3 hours. In this case, complete dissolution did not occur. The mixture was cooled, filtered from the precipitate, the filtrate was acidified with hydrochloric acid. The precipitate was filtered off, washed with water and dried in an oven. 7.9 g (72% of theory) of a non-uniformly colored product were obtained (product spectrum O-001). A modification of this method, when instead of hydrochloric acid we used an equimolecular amount of acetic acid, led to a more contaminated product (product spectrum O-002).

Conducting the condensation of isatin with thiosemicarbazide in the absence of acids, followed by boiling with alkali, gave an even more contaminated product (product spectrum O-003).

We hypothesized that the alkali concentration is insufficient for the complete cyclization reaction to proceed. However, an increase in the amount of alkali by a factor of two (spectrum of the product O-004) and then four times (spectrum of the product O-005) resulted in a product with a slightly lower content of impurities. A twofold increase in the boiling time with alkali did not lead to complete dissolution; the product turned out to be contaminated (product spectrum O-006). Replacing NaOH with an equimolecular amount of KOH also did not lead to an improvement in product quality (product spectrum O-007).

Thus, our attempts to combine the stages of the formation of thiosemicarbazone and its cyclization were unsuccessful. Then we decided to return to the variant of the synthesis of 3-mercapto-1,2,4-triazino [5,6-b] indole 2 in one stage.

In our study, a one-step process described in the literature led to contaminated thiol.

since, as we found out, under these conditions an adverse reaction occurs [Tomchin, A.B .; Joffe, I.S .; Rusakov, E.A. // JOK. 1971.Vol. 41. Issue. 8. S. 1791-1796].

Our attempts to direct this reaction in the direction we need by regulating the alkalinity of the medium were unsuccessful.

However, our literature search on the reactions of 6- (2-aminophenyl) -3-thio-1,2,4-triazine-3,5 (2H, 4H) -dione 24 showed that in an acidic environment [Doleschall, G. ; Lempert, K. // Acta Chim. Acad. Sci. Hung 1970. Vol. 64. N. 4. P. 369-391], as well as when heated above 120 ° C [Doleschall, G .; Simon-Ormai, K. // Acta Chim. Acad. Sci. Hung 1980. Vol. 104. N. 2. P. 107-11] this substance is able to cyclize to the desired synthesis of 3-mercapto-1,2,4-triazino [5,6-b] indole 2 .

To verify this, we conducted experiments on the conversion of the previously obtained substance 24 into thiol 2 .

1) Reaction in acetic acid. A mixture of 1 g (0.045 mol) of a substance of 24 and 30 ml of acetic acid was boiled in a flask under reflux with stirring on a magnetic stirrer for 30 minutes, while the mixture remained heterogeneous. After cooling to room temperature, the precipitate was filtered off, washed with water and dried in air. Yield 0.87 g (95.1% of theoretical); PMR spectrum corresponds to structure 2 (product spectrum O-012). Product analysis by TLC in a system of benzene-acetone-hexane-acetic acid (2: 2: 1: 0.2), where R _{f of} substance 2 is 0.90, and R _{f of} substance 24 is 0.12, also showed completeness the course of the reaction.

2) Reaction in aqueous hydrochloric acid. A mixture of 1 g (0.045 mol) of a substance 24 , 12 ml of concentrated hydrochloric acid and 25 ml of water was boiled with stirring on a magnetic stirrer for 30 minutes, while the mixture remained heterogeneous. After cooling to room temperature the precipitate was filtered off and washed with 3 ml of 5% NaHCO ₃ solution and 5 ml of water. The weight after drying is 0.85 g (93% of theoretical), the spectrum and TLC of the product correspond to structure 2 (product spectrum O-013).

3) Reaction in boiling dimethylformamide. A mixture of 1 g (0.045 mol) of a substance of 24 and 6 ml of DMF was boiled for one hour with stirring on a magnetic stirrer. During boiling, a precipitate gradually precipitates from the initially formed brown solution. After cooling, it was filtered, washed with 2 × 5 ml of water and dried. The weight after drying is 0.60 g (63% of theory), the spectrum and TLC of the product correspond to structure 2 (product spectrum O-014).

Based on the obtained data, we assumed that the impurity of substance 24 formed during the one-stage synthesis of thiol 2 can be converted into the desired product by interaction with hydrochloric acid. And since hydrochloric acid is used in this reaction to acidify the reaction mixture, an excess of hydrochloric acid will suffice to obtain pure thiol 2 .

A mixture of 0.1 mol of isatin 11 , 0.11 mol of thiosemicarbazide, 0.15 mol of potassium carbonate was boiled in 500 ml of water for 10 hours. The resulting solution was cooled to 50 ° C and 500 ml of 10% hydrochloric acid was gradually added (strong foaming!). The reaction mass was stirred for 1 hour at 50 ° C, cooled to room temperature, the precipitate was filtered off, washed with 2 × 50 ml of water and dried in air. Yield 18.0 g (89.1% of theory). Judging by TLC and spectrum (spectrum of the product O-015), the substance is a pure thiol 2 .

Repeating this experiment gave similar results: yield 18.2 g (90.3% of theoretical) (product spectrum O-016).

Comparison of this method with the previously developed 2-stage method shows that, with almost equal yields (about 89% for the 2-stage and about 90% for the one-stage method), the one-stage method is much simpler, since this eliminates the lengthy operation of filtering, washing and drying 3-thiosemicarbazone isatin, safer potassium carbonate is used instead of caustic soda.

Optimization of the process of obtaining the base of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole by eliminating the crystallization stage of N- (2-bromoethyl) morpholine hydrobromide.

As the results previously obtained by us have shown, the base of 3- (2-morpholino ethylthio) -1,2,4-triazino [5,6-b] indole 1 is equally well obtained when used as an alkylating reagent as N- (2-chloroethyl hydrochloride) ) morpholine 3 and hydrobromide N- (2-bromoethyl) morpholine 4 .

However, if the process of producing N- (2-chloroethyl) morpholine 3 hydrochloride occurs in anhydrous solvents (chloroform, benzene), then in the process of producing N- (2-bromoethyl) morpholine 4 hydrobromide, an aqueous solution of hydrobromic acid is used, the excess of which during isolation the product is removed by distillation. At the same time, our optimized procedure for the preparation of free base 1 involves the occurrence of an alkylation reaction in water.

This allowed us to assume that, to simplify the process, we can exclude the stage of isolation and crystallization of hydrobromide 4 . Thus, the reaction mass after distillation of the excess hydrobromic acid is diluted and introduced in this form into the alkylation reaction.

In a 3-necked flask with a capacity of 100 ml, equipped with a stirrer, a thermometer and a dropping funnel, load 20 ml of 46% hydrobromic acid and cool it in a bath of ice water to 10-15 ° C. With stirring, 5 ml (5.35 g; 0.04 mol) of N- (2-hydroxy-ethyl) morpholine is added dropwise, adjusting the cooling and the rate of addition so that the temperature does not exceed 35 ° C, which takes 25-35 minutes . Then, the dropping funnel is replaced by a descending cooler connected to the reaction flask using a 30 cm long evacuated reflux condenser.

The flask is placed in an oil bath, heated to a boil (bath temperature 112 ° C, running temperature 100 ° C) and water is distilled off, raising the bath temperature for 2 hours to 116 ° C. Then, for 6 hours, the bath is heated to 126 ° C, distilling off dilute hydrobromic acid (overhead temperature 110-123 ° C). Then, an azeotropic mixture of hydrobromic acid and water is distilled off (48%; the bath temperature is not more than 135 ° C, the running temperature is 124-126 ° C) until the distillation is completely stopped. The reaction mixture is cooled to a temperature below 100 ° C and 35 ml of water are added to it, the resulting solution is cooled to room temperature and filtered through a paper filter.

In a 500 ml beaker equipped with a stirrer, a thermometer and a dropping funnel, 4.41 g (0.11 mol) of NaOH and 90 ml of water are placed and mixed until a solution forms. After cooling the solution to 20-25 ° C, 7.50 g (0.037 mol) of 3-mercapto-1,2,4-triazino [5,6-b] indole are added and stirred for 10-15 minutes until dissolved, after which add a solution of 11.34 g (0.041 mol) of N- (2-bromoethyl) -morpholine hydrobromide in 35 ml of water dropwise from a dropping funnel, adjusting the rate of addition so that the temperature of the mixture does not exceed 30 ° C.

The reaction mixture is stirred at 18-20 ° C for one day, after which the mass is diluted with 250 ml of water and stirred for 15 minutes. The precipitate formed is filtered off and washed with water (2 × 10 ml). The product is dried at room temperature in a vacuum desiccator to a constant weight. 7.92 g (67.7% of theory, based on 3-mercapto-1,2,4-triazino [5,6-b] indole) of base 3- (2-morpholino-ethylthio) -1.2 are obtained, 4-triazino [5,6-b] indole as a yellow crystalline powder (product spectrum O-017).

Repeating this procedure twice led to similar results: 7.88 g (67.0% of theory) (product spectrum O-018) and 7.92 g (67.7%) (product spectrum O-019).

Comparison of this method with the previously described a) a method using N- (2-chloroethyl) morpholine hydrochloride and b) a method using crystalline N- (2-bromoethyl) morpholine hydrobromide allows us to draw the following conclusions:

1) This method eliminates the use of caustic and toxic reagents - thionyl chloride and avoids the release of toxic and aggressive gases - sulfur dioxide and hydrogen chloride into the environment.

2) This method eliminates the operation of recrystallization of N- (2-chloroethyl) morpholine hydrochloride or N- (2-bromoethyl) -morpholine hydrobromide.

Optimization of the production of N- (2-bromoethyl) -morpholine hydrobromide by combining the steps for the preparation of N- (2-hydroxyethyl) -morpholine and its reaction with hydrobromic acid.

The implementation of the optimization option described by us in the previous section allowed us to further propose the idea of a more substantial simplification of the process.

It is based on the fact that our previously proposed method for producing N- (2-hydroxyethyl) morpholine from morpholine and 2-chloethanol is carried out in a medium

benzene, in which the resulting morpholine hydrochloride is insoluble and is separated by filtration during the synthesis. Presumably, the filtrate may contain the following components: N- (2-hydroxyethyl) morpholine and residual amounts of the starting morpholine and 2-chloroethanol. Chromatomass spectrometric analysis of crude N- (2-hydroxyethyl) -morpholine samples confirmed the absence of any other components (see Fig. 1 - Fig. 7, which show examples of Chromatomass spectrometric analyzes of products).

The sample was investigated on a GCMS-QP2010 Plus chromatomass spectrometer (SHIMADZU) with GCMSsolution software for data processing and a NIST08 mass spectral information database.

Chromatographic separation was carried out on an Ultra-2 capillary column 25 m long and 0.2 mm inner diameter.

The chromatogram of the sample was recorded by the total ion current in the mass range from 30 to 450.

Chromatography conditions:

• Injector temperature - 280 ° С

• The initial temperature of the column is 40 ° C

• Time at initial temperature - 3 minutes

• Heating rate - 10 ° С / minute

• Column temperature - 120 ° С

• Time at this temperature - 0 minutes

• Heating rate - 30 ° C / minute

• The final temperature of the column is 290 ° C

• Time at the final temperature - 10.34 minutes

• Carrier gas Not - 1 ml / min

• Flow division 1:30

• Sample injection volume - 1 μl.

The impurities in the samples were identified by comparing the mass spectra of the separated components of the mixture with the mass spectra contained in the NIST08 computer library, as well as based on the analysis of spectral information.

The essence of our optimization is to introduce a solution of benzene in a benzene solution instead of vacuum distilling pure N- (2-hydroxyethyl) morpholine in a further reaction to obtain N- (2-bromoethyl) -morpholine hydrobromide. In this case, benzene and unreacted 2-chloroethanol will be completely distilled off with water and hydrobromic acid, and the residual amounts of morpholine will not participate further in the alkylation reaction of 3-mercapto-1,2,4-triazino [5,6-b] indole. This eliminates the stage of evaporation and vacuum distillation.

19.1 g (0.22 mol) of morpholine and 40 ml of benzene were charged into a 100 ml flask equipped with a stirrer, a thermometer and a dropping funnel, heated to 60 ° C and 8.1 g (0) was added over 20 minutes with stirring , 1 mol) of 2-chloroethanol, and then the reaction mixture was stirred at this temperature for 1 hour, with a gradual precipitation of morpholine hydrochloride. Then the dropping funnel was replaced by a reflux condenser, and the mass was boiled with stirring for 8 hours. After cooling to room temperature, the reaction mixture was filtered from a precipitate of morpholine hydrochloride, and the precipitate was washed on the filter with benzene (2 × 10 ml).

In a 3-necked flask with a capacity of 250 ml, equipped with a stirrer, a thermometer and a dropping funnel, 60 ml of 46% hydrobromic acid were charged and cooled in a bath of ice water to 10-15 ° C. With stirring, a benzene solution of N- (2-hydroxy-ethyl) morpholine was added dropwise, controlling the cooling and the rate of addition so that the temperature did not exceed 35 ° C, which took 25-35 minutes. Then, the dropping funnel is replaced by a descending cooler connected to the reaction flask using a 30 cm long evacuated reflux condenser.

The flask is placed in an oil bath, heated to boiling (bath temperature 112 ° C, running temperature 100 ° C) and water and benzene are distilled off, raising the bath temperature to 116 ° C for 2 hours. Then, for 6 hours, the bath is heated to 126 ° C, distilling off dilute hydrobromic acid (overhead temperature 110-123 ° C). Then, an azeotropic mixture of hydrobromic acid and water is distilled off (48%; the bath temperature is not more than 135 ° C, the running temperature is 124-126 ° C) until the distillation is completely stopped. The reaction mixture is cooled to a temperature below 100 ° C and 85 ml of water are added to it, the resulting solution is cooled to room temperature and filtered through a paper filter.

12.0 g (0.3 mol) of NaOH and 220 ml of water are placed in a 1 L beaker equipped with a stirrer, a thermometer and a dropping funnel and mixed until a solution forms. After cooling the solution to 20-25 ° C, 18.8 g (0.092 mol) of 3-mercapto-1,2,4-triazino [5,6-b] indole are added and stirred for 10-15 minutes until dissolved, after which a solution of N- (2-bromoethyl) -morpholine hydrobromide is added dropwise from the dropping funnel, adjusting the rate of addition so that the temperature of the mixture does not exceed 30 ° C.

The reaction mixture is stirred at 18-20 ° C for one day, after which the mass is diluted with 550 ml of water and stirred for 15 minutes. The precipitate formed is filtered off and washed with water (2 × 25 ml). The product is dried at room temperature in a vacuum desiccator to a constant weight. 19.92 g (68.1% of theory, based on 3-mercapto-1,2,4-triazino [5,6-b] indole) of base 3- (2-morpholino-ethylthio) -1.2 are obtained, 4-triazino [5,6-b] indole as a yellow crystalline powder (product spectrum O-020).

A repetition of this technique led to similar results: yield — 19.88 g (68.0% of theoretical).

Thus, our optimization of the process allows us to significantly simplify the synthesis of the free base of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole without reducing the yield and quality of the product, namely:

1) To exclude the operation of evaporation of a benzene solution of N- (2-hydroxyethyl) -morpholine in vacuum.

2) To exclude the operation of vacuum distillation of N- (2-hydroxyethyl) -morpholine.

3) To exclude the operation of vacuum distillation of the combined predagon of N- (2-hydroxyethyl) -morpholine.

In addition, this version of the methodology is more environmentally friendly, since in it benzene, which is a toxic substance, does not pollute the environment, but is stored in pursuit and can be reused.

Optimization of the preparation of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole dihydrochloride by eliminating the operation of preparing a solution of HCl in dioxane.

In developing the method for producing dihydrochloride 1, we encountered difficulties, since its solubility in organic solvents increased sharply in the presence of even small amounts of water, which prevented crystallization and reduced the yield of the target product.

To increase the yield, we developed a technique according to which a solution of the free base of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole in ethyl acetate was treated with a previously prepared 20% solution of HCl in dioxane. The oily precipitate formed during further processing with propanol-2 gave a fine crystalline precipitate of dihydrochloride 1 .

However, the operation of preparing a 20% solution of HCl in dioxane is time-consuming and dangerous, since it requires work with hydrogen chloride, a caustic and aggressive gas, and dioxane vapors when inhaled cause severe headaches. In addition, this procedure requires the use of significant amounts of organic solvents that cannot be reused.

In search of ways to optimize this procedure, we drew attention to the fact that dihydrochloride 1 is practically insoluble in concentrated hydrochloric acid.

We have investigated the possibility of obtaining crystalline dihydrochloride 1 in hydrochloric acid of various concentrations. It turned out that the optimal concentration of HCl is 31.5%.

10.7 g of free base 1 was added to 60 ml of 31.5% hydrochloric acid, with slight heating of the mixture. To completely form a solution, the mixture was heated to boiling, boiled for 10 minutes, filtered through an Ilsan filter, the filtrate was cooled to 25 ° C with stirring, and the product partially crystallized. To complete the precipitation, the filtrate was kept for 20 hours in a refrigerator, the precipitate was filtered off, washed with a filter of 5 ml of propanol-2 and 5 ml of acetone in succession, and dried in air to a constant weight. Yield 9.43 g (66.4% of theory) (product spectrum O-021).

At higher concentrations of HCl, base 1 is poorly soluble in hydrochloric acid; at lower concentrations, dihydrochloride 1 is too soluble.

The main disadvantage of this method is the release of gaseous hydrogen chloride by boiling the solution and filtering it in hot form. We were able to eliminate this inconvenience by adding a small amount of propanol-2. The optimal amount of propanol-2 added was determined, in which the solubility of base 1 remains high enough and the solubility of dihydrochloride 1 in the cold is quite low.

The method we developed is carried out using the following example.

A 100 ml flask equipped with a stirrer, a thermometer and a reflux condenser was charged with 58 ml of concentrated hydrochloric acid, 12 ml of water and 13 ml of propanol-2. With stirring, 10.69 g (0.034 mol) of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole base are added. The reaction mixture is heated to boiling with stirring and boiled for 30 minutes, after which it is filtered while hot through a Buchner funnel.

The filtrate is placed in a glass with a capacity of 100 ml and, with stirring, cooled to 25 ° C, after which it is left to stand in the refrigerator for 20 hours. The precipitate formed is filtered off, washed successively with 10 ml of propanol-2 and 10 ml of acetone, and dried in air to constant weight. 10.4 g (73.2% of theory) of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole dihydrochloride are obtained as a yellow crystalline solid.

Repetition of this technique yielded 73.4% of the theoretical yield (product spectra — O-022 and O-023, respectively).

Analysis of the 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole dihydrochloride thus obtained by HPLC showed a basic substance content of 99.9% (see FIG. 8, which shows analysis results of a sample of 3- (2-morpholino-ethylthio) -1,2,4-triazino- [5,6-b] indole dihydrochloride by HPLC).

Thus, the application of the optimized procedure for the preparation of dihydrochloride 1 allowed us to exclude the operations of obtaining gaseous hydrogen chloride and preparing a solution of HCl in dioxane, as well as significantly reduce the consumption of organic solvents.

Thus, based on the foregoing, it follows that the method for producing 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole dihydrochloride consists of the steps of:

- a step for the synthesis of 3-thiosemicarbazone isatin from isatin and thiosemicarbazide in aqueous hydrochloric acid with a yield of about 97%;

- the stage of synthesis of 3-mercapto-1,2,4-triazino [5,6-b] indole by cyclization of 3-thiosemicarbazone isatin in an aqueous alkaline medium with a yield of about 92%;

- the stage of synthesis of N- (2-hydroxyethyl) morpholine from morpholine and 2-chloroethanol in benzene with a yield of about 87%;

- a step for the synthesis of N- (2-chloroethyl) morpholine hydrochloride from N- (2-hydroxyethyl) morpholine and thionyl chloride in chloroform medium with a yield of about 70%;

- a step for the synthesis of N- (2-bromoethyl) morpholine hydrobromide from N- (2-hydroxyethyl) morpholine and hydrobromic acid with a yield of about 75%;

a step for synthesizing the base of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole from 3-mercapto-1,2,4-triazino [5,6-b] indole and N- (2-chloroethyl) morpholine in an aqueous alkaline medium with a yield of about 68%;

a step for synthesizing the base of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole from 3-mercapto-1,2,4-triazino [5,6-b] indole and N- (2-bromoethyl) morpholine in an aqueous alkaline medium with a yield of about 68%;

- the stage of synthesis of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole dihydrochloride from the base of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5 , 6-b] indole and a 20% solution of HCl in dioxane with a yield of about 74%;

All stages of the process for producing 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole dihydrochloride are reliably reproduced and ensure high purity of products. The target product is obtained with a purity of at least 99%.

Claims (1)

The method of obtaining dihydrochloride monohydrate 3- (2-morpholinoethylthio) -1,2,4-triazino [5,6-b] indole (trisan), characterized by the interaction of 3-mercapto-1,2,4-triazino [5,6-b ] indole with 2-morpholinoethyl bromide hydrobromide in the presence of an excess of alkali to obtain a base of 3- (2-morpholinoethylthio) -1,2,4-triazino [5,6-b] indole, the latter being treated with hydrochloric acid, characterized in that 100 ml capacity, equipped with a stirrer, thermometer and reflux condenser, load 58 ml of concentrated hydrochloric acid, 12 ml of water and 13 ml of propanol-2, and with stirring Denmark add 10.69 g (0.034 mol) of the base of 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole; the resulting reaction mixture is heated to boiling with stirring and boiled for 30 minutes, then filtered while hot, the filtrate is placed in a different container and cooled to 25 ° C with stirring, after which it is left to stand in the refrigerator for 20 hours; the precipitate formed is filtered off, washed successively with propanol-2 and acetone, and dried in air to constant weight; 3- (2-morpholino-ethylthio) -1,2,4-triazino [5,6-b] indole dihydrochloride is obtained in the form of a yellow crystalline solid.

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