RU2126391C1 - 5-hydroxy-6-methyluracil synthesis method - Google Patents

Abstract

FIELD: industrial organic synthesis. SUBSTANCE: 5-hydroxy-6-methyluracil manifests immunotrope activity and is allowed to be applied in medicine and produced on a commercial scale. It can be, in particular, used in treatment of various-genesis immuno-deficiency conditions. Synthesis: reaction mixture obtained on alkali hydrolysis of β-uraminocroton ester is oxidized with ammonium persulfate in alkali medium at 85-95 C. Intermediate product - 6-methyluracil-5-ammonium sulfate (isolated by crystallization or not isolated) is hydrolyzed with sulfuric acid. EFFECT: increased yield and purity of product. 5 ex

Description

проявляющему выраженную иммунотропную активность, и может быть использовано в медицине и ветеринарии. Созданный новый оригинальный иммуномодулятор 5-гидрокси-6-метилурацил ("оксиметацил") усиливает реакцию иммунитета и эффективный при терапии инфекций, препарат не токсичен, не вызывает побочных явлений, проявляет универсальные антисептические свойства, способствует заживлению ран, трофических язв и ожогов и ослабляет вредное влияние радиации, защищает от отравления алкоголем, нитратами, фосфорорганическими веществами (дихлофос, хлорофос, карбофос), нормализует количество лейкоцитов, усиливая гуморальный и клеточный иммунитет, обладает антистрессовым, кардиостимулирующим и антитоксическим действием.The present invention relates to organic chemistry, in particular, to a method for producing 5-hydroxy-6-methyluracil of the formula

exhibiting pronounced immunotropic activity, and can be used in medicine and veterinary medicine. The created new original 5-hydroxy-6-methyluracil (“oxymethacil”) immunomodulator enhances the immune response and is effective in treating infections, the drug is non-toxic, does not cause side effects, exhibits universal antiseptic properties, promotes healing of wounds, trophic ulcers and burns and reduces harmful the effect of radiation, protects against poisoning by alcohol, nitrates, organophosphorus substances (dichlorvos, chlorophos, karbofos), normalizes the number of leukocytes, enhancing humoral and cellular immunity, possesses antistress, kardiostimuliruyuschy and antitoxic effect.

 5-Hydroxy-6-methyluracil is focused on the production of a product with new consumer qualities: treatment of immunodeficiency states of various origins (infection process, tumor diseases, radiation injuries, poisoning with various poisons, including dioxins). This property increases the value of the drug, especially in regions with a developed petrochemical industry.

 5-Hydroxy-6-methyluoacid by order of the Ministry of Health and Medical Industry of the Russian Federation 302 dated 07.29.96 was registered in the Russian Federation and is approved for medical use and industrial production (registration certificate 96/2).

 A known method of producing 5-hydroxy-6-methyluracil (Henze HR, Kahlenberg EN, J. Am. Chem. Soc., 1958, v. 80, 7, p. 1664-1666) in 7 stages with a total yield of 9% by reaction monochloroacetic acid (I) with secondary sodium butylate, the resulting secondary butoxy acid (II) is treated with thionyl chloride and the resulting acid chloride (III) is converted to secondary butyloxyacetate (IV) with an excess of secondary butyl alcohol, the self-condensation of which with sodium methylate gives secondary γ-butyl - dialkoxyacetate (V), treatment of the latter with thiourea gives 5-secondary butox Secondary -6-butoxymethyl-2-thiouracil (VI), is converted, by the action of monochloroacetic acid in 5 secondary-butoxy-6-secondary-butoksiuratsil (VII), which processing hydriodic acid gave the desired product (VIII).

Общий выход 9% (0,8 х 0,6 х 0,56 х 0,79 х 0,84 х 0,51).

The total yield of 9% (0.8 x 0.6 x 0.56 x 0.79 x 0.84 x 0.51).

 The disadvantage of this method is the multi-stage, low yield of the target product.

A known method of producing 5-hydroxy-6-methyluracil by oxidation of 6-methyluracil with potassium permanganate in acetic acid at a temperature of 20-40 ^o With a yield of 15-25% at a molar ratio of 6-MU: KMnO ₄ : CH ₃ COOH = 1.5 : 1: 1 (Behrung R., Grunewald R., Justus Liebigs Annalen der chemie, 1902, v. 323, s.186-204).

Недостатком данного способа является низкий выход целевого продукта.

The disadvantage of this method is the low yield of the target product.

A method is described for the oxidation of 6-methyluracil with ammonium persulfate in an alkaline medium (Elbs reaction) followed by hydrolysis with hydrochloric acid at 100 ^° C (Hurst DT, Austr. J. Chem, 1983, 36, p. 1285-1289).

 The disadvantage of this method is that it leads to the production of 5-hydroxy-6-methyluracil with a yield of 50% and a pure 80-90%.

 A known method of producing 5-hydroxy-6-methyluracil by oxidation of 9-methyluracil with potassium persulfate (Gashev SB, Goltsova L.V., Smirnov L.D., Lezina V.P., CGS, 1989, 5, p. 636-640).

The authors identified an intermediate product, 6-methyl-5-hydroxyuracil sulfate, with a yield of 24%, hydrolysis of which 10% H ₂ SO ₄ gives 5-hydroxy-6-methyluracil (VIII) with a yield of 78% (technical product).

Недостатком данного способа является низкий выход целевого продукта.

The disadvantage of this method is the low yield of the target product.

 As you can see, all methods for producing 5-hydroxy-6-methyluracil come from methyluracil. Currently methyluracil in industry (Russia) is obtained by condensation of diketene with urea in the presence of acetic anhydride and pyridine with a yield of 75% (Khromov N.V., Borisov, Karlinskaya R.S., Zhokh, 1956, v. 26, 4-6 , p. 1728).

Недостаток метода в том, что метилурацил выпускается в недостаточном количестве и не может обеспечить все потребности страны.

The disadvantage of this method is that methyluracil is produced in insufficient quantities and cannot provide all the needs of the country.

 The synthesis of methyluracil by condensation of acetoacetic ester and urea is known (Synthesis of Organic Preparations, 1949, Sat 2, p.335).

При этом конденсация мочевины с ацетоуксусным эфиром (XVII) в присутствии концентрированной соляной кислоты в этаноле дает β - ураминокротоновый эфир (XVIII), щелочной гидролиз которого при 100^oС в течение 1 ч приводит к натриевой соли β - ураминокротоновой кислоты (XIX), обработка последней соляной кислотой дает 6-метилурацил (VIII) с выходом 75%.

In this case, the condensation of urea with acetoacetic ester (XVII) in the presence of concentrated hydrochloric acid in ethanol gives β - uraminocrotonic ether (XVIII), alkaline hydrolysis of which at 100 ^o C for 1 h leads to the sodium salt of β - uraminocrotonic acid (XIX), processing the latter hydrochloric acid gives 6-methyluracil (VIII) with a yield of 75%.

 The disadvantage of this method is the duration of the process, multi-stage, low yield and purity.

Closest to the proposed is a method for producing 5-hydroxy-6-methyluracil by oxidation of 6-methyluracil with ammonium persulfate in an alkaline medium at 40-70 ^o With the allocation of the intermediate product of 6-methyluracil-5-ammonium sulfate and hydrolysis of the latter with sulfuric acid at 85-95 ^o C (RF Patent 2000278 by Krivonogov V.P. et al.).

Недостаток метода в том, что метилурацил выпускается в промышленности в недостаточном количестве и не может обеспечить все потребности страны.

The disadvantage of this method is that methyluracil is produced in industry in insufficient quantities and cannot provide all the needs of the country.

 The aim of the invention is to find a method that allows to obtain 5-hydroxy-6-methyluracil in high yield, high purity, as well as reducing the multi-stage and duration of the process.

This goal is achieved by the fact that urea is condensed with acetoacetic ether to produce β - uraminocrotone ether (UKE). The latter is subjected to saponification with a solution of sodium hydroxide to obtain an alkaline solution of the reaction mixture, which is cooled to 40-50 ^o C, solid sodium hydroxide is added in a molar ratio of 1: 1-2 and then ammonium persulfate for oxidation. The oxidation is carried out in an alkaline medium at 40-70 ^o C, mainly for 30 minutes, while getting 6-methyluracil-5-ammonium sulfate, which is subjected to hydrolysis after isolation or directly in the reaction mixture with sulfuric acid at 85-95 ^o C.

 The separation of 6-methyluracil-5-ammonium sulfate from the reaction mixture is carried out by adding sulfuric acid to a pH of 6-7 and, if necessary, recrystallized from water with coal.

The proposed method differs from the known one in that urea and acetoacetic ether are condensed to produce β-uraminocrotone ether, which is saponified with sodium hydroxide solution to obtain an alkaline solution of the reaction mixture, cooled to 40-50 ^° C, followed by the addition of solid sodium hydroxide at molar ratio: UKE: tv. NaOH = 1: 1-2, then ammonium persulfate for oxidation, to give 6-methyluracil-5-ammonium sulfate, which is hydrolyzed.

The target product is obtained with a yield of 50-58%. Preferably the molar ratio of the components of UKE: NaOH: TV. NaOH: PSA: H ₂ SO ₄ = 1: 2: 1-2: 1-1.19: 1-1.5, respectively. The reaction proceeds as follows.

Изобретение поясняется следующими примерами.

The invention is illustrated by the following examples.

 Example 1. In a three-necked flask with a capacity of 1000 ml, equipped with a mechanical stirrer, reflux condenser, load 86.1 g (0.5 mol) of β-uraminocrotone ether obtained by the method of J. Donlivi and M. Kais (Synthesis of Organic Preparations, 1949 - Sat.2, p.335) NaOH solution is added (40 g / 1 mol in 600 ml of water), the reaction mixture is heated in a boiling water bath until the crystals are dissolved, stirred for an additional 30 minutes, and then the resulting solution is divided into 2 parts (325 each ml of solution).

1a. To an alkaline solution (235 ml) cooled to 40-50 ^{° C.} , 20 g (0.5 mol) of NaOH are sprinkled and solid ammonium persulfate (0.33 mol or 75.2 g) is sprinkled in portions. After the complete addition of ammonium persulfate, the reaction mixture was stirred for an additional 30 minutes and then acidified with sulfuric acid until neutral (12 ml) at 60 ^{° C.} and left overnight. The next day, the precipitated crystals are filtered through a Schott funnel, washed with acetone (2 x 20 ml), dried in air and 35.7 g (60%) of 6-methyluracil-5-ammonium sulfate are obtained.

1b. The second part of op. 1 (325 ml) of the solution is poured into a 1000 ml three-necked flask equipped with a mechanical stirrer, reflux condenser, sprinkled with 20 g (0.5 mol) of NaOH, heated to 40-50 ^o С and solid parted at this temperature ammonium persulfate (0.33 mol or 75.2 g) for 30 minutes After complete addition of ammonium persulfate, the reaction mixture was stirred for an additional 1 h 20 min, and then acidified with sulfuric acid to a neutral reaction, pH 6-7 (14 ml) for 30 min and left overnight. The next day, the precipitated crystals are filtered through a Schott funnel, washed with acetone (2 x 20 ml), dried in air and 43.27 g (73%) of light yellow crystals of 6-methyluracil-5-ammonium sulfate are obtained. Purity proved by TLC (thin layer chromatography).

Example 2. Obtaining 5-hydroxy-6-methyluracil. In a three-necked flask, 28.4 g (0.0118 mol) of 6-methyluracil-5-ammonium sulfate (op. 1a) are charged, dissolved in 135 ml of water, heated to 85-95 ^{° C.} and 14 ml are added dropwise at this temperature conc. H ₂ SO ₄ . At the end of the addition of acid, precipitation of crystals is noticeable. The reaction mixture is left overnight. The next day, the precipitated crystals are filtered off, washed with water until neutral (3 x 20 ml), acetone (2 x 15 ml) and 11.5 g (68.2% of the taken 6-methyluracil-5-ammonium sulfate or 41% per taken β - uraminocrotonic ester) 5-hydroxy-6-methyluracil in the form of light yellow crystals with so pl. 340-345 ^o With (crystals in the form of a rhombus).

); 1680 (-NH-CO-NH-); 3260 ( -ОН). ЯМР¹ Н (δ м.д., D²⁰): 1,99 (с., 3Н, С₆-СН₃); 4,75 (с, 2Н, СН=СН). УФ-спектр (нм): λ $\genfrac{}{}{0ex}{}{\text{7}}{\text{min}}$ 243,60; λ $\genfrac{}{}{0ex}{}{\text{7}}{\text{min}}$ = 277,6.Found,%: C 42; H 4.1; N, 19.9. The content of 5-hydroxy-6-methyluracil is 98.9% (by titration). Purity was also proved by TLC (absence of methyluracil). Calculated for C ₅ H ₆ N ₂ O ₃ ,%: C 42; H 4.2; N, 19.7. IR spectrum (ν cm ^-1 : 1130 (= С-ОН); 1260 (СО-NH); 1380 (δ ^s СН ₃ ); 1660, 3100 (

); 1680 (-NH-CO-NH-); 3260 (-OH). NMR ¹ H (δ ppm, D ²⁰ ): 1.99 (s, 3H, C ₆ -CH ₃ ); 4.75 (s, 2H, CH = CH). UV spectrum (nm): λ $\genfrac{}{}{0ex}{}{\text{7}}{\text{min}}$ 243.60; λ $\genfrac{}{}{0ex}{}{\text{7}}{\text{min}}$ = 277.6.

Example 3. In a three-necked flask with a capacity of 500 ml, equipped with a mechanical stirrer, reflux condenser, load 21.5 g (0.125 mol) of β-uraminocrotone ether obtained by the method of J. Donlivy and M. Kayz, NaOH solution is added (20 g (0 5 mol of NaOH) in 150 ml of water), the reaction mixture is heated in a boiling water bath until the crystals dissolve, stirred for an additional 30 minutes, cooled to 63-68 ^° C, and then 8 g (0.2 mol) of NaOH are added and sprinkled in parts solid ammonium persulfate (0.158 mol, or 36 g). After complete addition of ammonium persulfate, the reaction mixture was stirred for an additional 120 minutes and then heated to 85-95 ^{° C.} and 34 ml of conc. Were added dropwise at this temperature. H ₂ SO ₄ . At the end of the addition of acid, precipitation of crystals is noticeable. The reaction mixture is left overnight. The next day, the precipitated crystals are filtered off, washed with water until neutral (3 x 20 ml), acetone (2 x 15 ml) and 10.3 g (58% of the taken β - uraminocrotone ether) of 5-hydroxy-6-methyluracil in in the form of yellow crystals with so pl. 340 ^o .

 Example 4. Synthesis of 5-hydroxy-6-methyluracil without isolation of the intermediate product - 6-methyluracil-5-ammonium sulfate.

In a three-necked flask with a capacity of 500 ml equipped with a mechanical stirrer, reflux condenser, 21.5 g (0.125 mol) of β-uraminocrotone ether obtained by the method of J. Donlivy and M. Kais are charged, NaOH solution (20 g (0.5 mol) is added NaOH) in 150 ml of water), the reaction mixture is heated in a boiling water bath until crystals are dissolved, stirred for an additional 30 minutes, cooled, and then sprinkled with 5 g (0.125 mol) of NaOH and sprinkled with solid ammonium persulfate (0.158 mol, or 36 g) in parts. . After complete addition of ammonium persulfate, the reaction mixture is stirred for an additional 90 minutes, then a little activated carbon is added, boiled for 15 minutes, the activated carbon is filtered off on a Schott funnel, and the mother liquor is heated to 85-95 ^° C and at this temperature 20 ml of conc. Are added dropwise. H ₂ SO ₄ . At the end of the addition of acid, precipitation of crystals is noticeable. The reaction mixture is left overnight. The next day, the precipitated crystals are filtered off, washed with water until neutral (3 x 20 ml), acetone (2 x 15 ml) and 7.1 g (40% of taken β - uraminocrotone ether) of 5-hydroxy-6-methyluracil in in the form of light yellow crystals with so pl. 342-345 ^o C.

Example 5. In a three-necked flask with a capacity of 500 ml, equipped with a mechanical stirrer, reflux condenser, load 51.6 g (0.3 mol) of β-uraminocrotonic ether, pour a solution of NaOH (24 g (0.6 mol NaOH) in 300 ml of water ), the reaction mixture is heated in a boiling water bath until the crystals dissolve, stirred for an additional 30 minutes, cooled to 40-50 ^o C, and then the resulting solution (300 ml) is divided into three parts:
5a. Solid ammonium persulfate (0.1 mol or 22.8 g) was sprinkled in portions of 100 ml of the solution obtained above at a temperature of 30-40 ^° C. After the complete addition of ammonium persulfate (30 min), the reaction mixture was stirred for an additional 2 hours, and then neutralized with sulfuric acid (4 ml), heated to 85-95 ^o C and at this temperature added 26 ml of concentrated sulfuric acid, stirred for 1 h, but the crystals did not precipitate, then 5-hydroxy-6-methyluracil did not work.

5 B. To 100 ml of the solution obtained above, 4 g (0.1 mol) of NaOH are sprinkled and solid ammonium persulfate (0.1 mol or 22.8 g) is sprinkled in portions at a temperature of 40 ^° C. After complete addition of ammonium persulfate (30 min) the reaction mixture is stirred for an additional 2 hours and then neutralized with sulfuric acid (4 ml), heated to 85-95 ^o C and at this temperature 26 ml of concentrated sulfuric acid are added. At the end of the addition of sulfuric acid, crystals of 5-hydroxy-6-methyluracil precipitate. The reaction mixture was stirred for 1 h, cooled and 5.9 g (41.6%) of 5-hydroxy-6-methyluracil was isolated.

5c. 8 g (0.2 mol) of NaOH are sprinkled with 100 ml of the solution obtained above and solid ammonium persulfate (0.1 mol or 22.8 g) is sprinkled in portions at a temperature of 40 ^° C. At the end of the complete addition of ammonium persulfate (30 min) ) precipitate. The reaction mixture is heated to 55 ^° C (the precipitate dissolves), stirred for an additional 2 hours, and then heated to 85-95 ^° C and 30 ml of concentrated sulfuric acid are added at this temperature. At the end of the addition of sulfuric acid, crystals of 5-hydroxy-6-methyluracil precipitate. The reaction mixture was stirred for 1 h, cooled and 7.1 g (50%) of 5-hydroxy-6-methyluracil were isolated.

 According to the invention, laboratory tests were carried out. It was shown for the first time that the reaction mixture obtained after saponification of β - uraminocrotonic ester in an alkaline medium can be oxidized with ammonium persulfate to give 5-hydroxy-6-methyluracil. It was found that this method is easily reproducible and can be used to develop laboratory regulations and establish the production technology of 5-hydroxy-6-methyluracil in an enlarged installation with the subsequent development of technological regulations.

The technical and environmental advantages of this method is the reduction of two stages, namely:
- reducing the stage of hydrolysis of the sodium salt of β - uraminocrotonic acid (hydrochloric acid is not consumed);
- methyluracil is not released, and the reaction mixture obtained after saponification of β - uraminocrotonic ether is oxidized with ammonium persulfate in an alkaline medium. The yield of the target product is 50-58%. As a result of this, an additional amount of alkali is not consumed for the formation of methyluracil disodium salt (4 moles of sodium hydroxide were consumed per 1 mol of methyluracil when oxidized with ammonium persulfate);
- thanks to this, the cost of 5-hydroxy-6-methyluracil will be almost 2 times cheaper than that obtained from methyluracil.

Claims (3)

1. The method of obtaining 5-hydroxy-6-methyluracil of the formula

using oxidation with ammonium persulfate in an alkaline medium at 40 - 70 ^o C, to obtain 6-methyluracil-5-ammonium sulfate, which is hydrolyzed with sulfuric acid at a temperature of 85 - 95 ^o C, characterized in that the urea and acetoacetic ether are condensed to obtain β - uraminocrotonic ether (UKE), which is saponified with a sodium hydroxide solution, to obtain an alkaline solution of the reaction mixture, cooling it to 40-50 ^° C, followed by the addition of solid sodium hydroxide, in a molar ratio of UKE: tv. NaOH = 1: 1 - 2, and then ammonium persulfate for oxidation, to give 6-methyluracil-5-ammonium sulfate, which is hydrolyzed.  2. The method according to claim 1, characterized in that 6-methyluracil-5-ammonium sulfate is isolated from the reaction mixture by adding sulfuric acid to a pH of 6-7 and recrystallized.  3. The method according to p. 1, characterized in that the oxidation is carried out for 30 minutes