JPH075465B2 - Antiviral agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an antiviral agent containing a specific pyrimidine nucleoside derivative as an active ingredient.

[Problems to be Solved by Prior Art and Invention] In recent years, human acquired immunodeficiency virus (HIV) infection, which is a type of retrovirus, has become a major social problem. Currently, 3'-deoxy-3'-azidothymidine is known as a nucleoside compound that is clinically used for the treatment of HIV infection. However, since it is highly toxic to host cells, its side effects are a problem.

Also, 2 ', 3'-dideoxyribonucleoside is known as a nucleoside compound having antiretroviral activity, but it is desired to develop a substance having higher activity and low toxicity to host cells ( Hiroaki Mitsuya, Biological Defense, Volume 4, pages 213-223, 1987).

On the other hand, since acyclovir (acycloguanosine) was developed as an antiviral agent against herpes virus, various acyclonucleoside compounds have been synthesized, but [CK, Chu and SJCulter, J. Hetero cy
clic Chem., 23 , 289 (1986)], and a compound showing an effective activity against a retrovirus in particular has not been found yet.

Accordingly, the present inventors have focused on 6-substituted acyclopyrimidine nucleoside compounds, and have proposed a novel 6-substituted acyclic pyrimidine nucleoside compound in order to provide an antiviral agent that exhibits effective activity against a retrovirus. We synthesized various acyclopyrimidine nucleoside compounds and searched for compounds with antiretroviral activity. As a result, they have found that the intended purpose can be achieved by the specific 6-substituted acyclopyrimidine nucleoside derivative (WO89 / 09213).

Conventionally, as a 6-substituted Acyclonucleotides pyrimidine nucleoside, 6-fluorine substituents or 6-alkylamino substituted derivatives such as (East German Patent Publication No. 232,492), or 6-methyl substituents (CA 107, 129717 w (1987 )) However, there is no description of antiviral activity.

[Means for Solving Problems] As a result of further intensive investigations by the present inventors to obtain a compound having antiviral activity, particularly antiretroviral activity,
Among the specific 6-substituted acyclopyrimidine nucleoside compounds described in WO89 / 09213, a compound having an ethyl group or an isopropyl group at the 5-position of the pyrimidine ring and a phenylthio group at the 6-position has exceptional activity. The present invention has been completed and the present invention has been completed.

That is, the gist of the present invention is 5-ethyl-1-[(2-hydroxyethoxy) methyl] -6-phenylthiouracil or 1-[(2-hydroxyethoxy) methyl] -6.
-An antiviral agent containing phenylthio-5-isopropyluracil as an active ingredient.

Hereinafter, the present invention will be described in detail.

The pyrimidine nucleoside derivative which is an active ingredient in the antiviral agent of the present invention is represented by the following structural formula.

5-ethyl-1-[(2-hydroxyethoxy) methyl] -6-phenylthiouracil 1-[(2-hydroxyethoxy) methyl] -6-phenylthio-5-isopropyluracil The compound can be synthesized, for example, according to the following reaction formula (1) or (2).

(In the formula, R ¹ represents an ethyl group or an isopropyl group, and R ²
Represents a hydroxyl-protecting group, and M represents an alkali metal. ) In the formula, as the protective group represented by R ² , any of those commonly used as a protective group for alcohol can be used as long as it is not eliminated under alkaline conditions.

Specifically, for example, aralkyl groups such as benzyl group, trityl group, monomethoxytrityl group, dimethoxytrityl group and trimethoxytrityl group, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, t-butylphenylsilyl. Group, a silyl group such as a dimethylphenylsilyl group, a tetrahydropyranyl group, a substituted alkyl group such as a methoxymethyl group, and the like, and a silyl group is particularly preferable.

First, a compound represented by the general formula [III] or [IV] and an organic alkali metal are mixed in a solvent, for example, an ether solvent such as diethyl ether or tetrahydrofuran,
The reaction is carried out at a temperature of 80 ° C to -10 ° C for 0.2 to 10 hours. Examples of the organic alkali metal include potassium bistrimethylsilylamide, sodium bistrimethylsilylamide and lithium alkylamide,
Especially lithium diisopropylamide (LDA), lithium
2,2,6,6-Tetramethylpiperidide (LTMP) is preferred. It is preferable to use the lithium alkylamide prepared immediately before the reaction. For example, a secondary amine such as diisopropylamine and an alkyllithium such as n-butyllithium in a solvent such as diethyl ether, dioxane, tetrahydrofuran, dimethoxyethane,
In the presence of an inert gas, for example, argon gas, -80 ° C ~
It is preferable to carry out stirring reaction at -10 ° C for 0.2 to 5 hours.

This organic alkali metal has the general formula [III] or [IV]
It is usually used in the range of 2 to 5 mol with respect to 1 mol of the compound represented by.

Subsequently, various aryl thiolizing agents or alkylating agents are added in an amount of about 1 to 5 mol per mol of the compound represented by the general formula [III] or [IV], and the same reaction as the above-mentioned organic alkali metal is carried out. React under conditions. Examples of the aryl thiolizing agent include diphenyl disulfide,
Examples thereof include halogenated benzenesulfenyl.

Examples of the alkylating agent include alkyl halides such as ethyl chloride, isopropyl chloride, ethyl bromide, isopropyl bromide, ethyl iodine and isopropyl iodine, and alkyl sulfonates such as ethyl mesylate, isopropyl mesylate, ethyl tosylate and isopropyl tosylate. Is mentioned.

The compound represented by the general formula [III] can be prepared according to a known method. For example, trimethylsilylated uracil derivative and (2-acetoxyethoxy)
A raw material compound represented by the general formula [III] can be obtained by a method in which methyl bromide is condensed, hydrolyzed, and then the above protecting group is introduced (for details, see Can. J. Chem., 60 , 547).
(1982) and others).

The protecting group can be introduced according to a conventional method.

For example, the introduction of a silyl protecting group can be accomplished by introducing pyridine, picoline,
In the presence of a base such as diethylaniline, dimethylaniline, triethylamine, imidazole, etc., a silylating agent such as trimethylsilyl chloride or t-butyldimethylsilyl chloride in a 1 to 10-fold molar ratio in a single solvent or a mixed solvent of dimethylformamide, acetonitrile, tetrahydrofuran or the like. The reaction can be carried out at a reaction temperature of 0 to 50 ° C.

The compound represented by the general formula [IV] is synthesized in the same manner as in the above-mentioned reaction formula (1).

Then, the compound represented by the general formula [V] thus obtained is, if necessary, separated and purified by a usual nucleoside separation and purification means such as recrystallization, adsorption and ion exchange chromatography, and then the protection of the hydroxyl group. Remove the group.

As a method for removing the protective group, a known method such as an acid hydrolysis method, ammonium fluoride treatment, or a catalytic reduction method can be appropriately selected and carried out depending on the protective group used.

The pyrimidine nucleoside derivative thus obtained can be separated and purified by appropriately selecting a usual nucleoside separation and purification method, for example, recrystallization, adsorption or ion exchange chromatography.

Such a compound may be converted into its pharmaceutically acceptable salt according to a conventional method. Examples of such salts include alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as magnesium salt, ammonium salt, methylammonium salt, dimethylammonium salt, trimethylammonium salt and alkyl such as tetramethylammonium salt. Examples thereof include ammonium salts.

The pyrimidine nucleoside derivative thus obtained can be administered to humans by any route such as oral, enteral, parenteral or topical administration, for the purpose of preventing or treating retrovirus infection. The dose is appropriately determined according to the age, health condition, body weight, etc. of the patient, but generally an appropriate dose is 1 to 100 mg / kg body weight, preferably 5 to 50 mg / kg body weight per day. It is selected from the range and is administered once or more.

In formulating the compound, it is usually used as a composition containing a commonly used carrier for formulation, an excipient, and other additives. The carrier may be solid or liquid. Examples of the solid carrier include lactose, white clay (kaolin),
Examples thereof include sucrose, crystalline cellulose, corn starch, talc, agar, pectin, stearic acid, magnesium stearate, lecithin and sodium chloride.

Examples of the liquid carrier include glycerin, peanut oil,
Examples thereof include polyvinylpyrrolidone, olive oil, ethanol, benzyl alcohol, propylene glycol, water and the like.

The dosage form can take various forms. When using a solid carrier, tablets, powders, granules, capsules, suppositories,
Examples include troches and the like. When a liquid carrier is used, examples include syrup, emulsion, soft gelatin capsule, cream, gel, paste, spray, and injection solution.

[Effects of the Invention] The antiviral agent of the present invention has effective activity against retroviruses and the like, and has relatively low toxicity to host cells. Therefore, it can be effectively used as an antiviral agent against AIDS virus. obtain.

[Examples] Hereinafter, the present invention will be specifically described with reference to Synthesis Examples, Formulation Examples, and Examples.

Synthesis Example 1 Preparation of 5-ethyl-1-[(2-hydroxy) methyl] -6-phenylthiouracil (Compound No. 1) 5-Ethyluracil 5.6 g (40 mmol) was added to dichloromethane 10
Suspended in 0 ml, added bis- (trimethylsilyl) -acetamide 22 ml (88 mmol) at room temperature under nitrogen atmosphere, and added 3
Stir for hours. In addition, 3.4 ml of 1,3-dioxolane (48 mmo
l) and tin tetrachloride 5.6 ml (48 mmol) slowly,
Refluxed for 17 hours. The reaction mixture was added to 22 g of baking soda in methanol:
The mixture was poured into 100 ml of a mixed solution of water (1: 1), stirred for 2 hours, and then filtered through Celite. The filtrate was concentrated to dryness, and under a nitrogen atmosphere, 120 ml of acetonitrile, 12 g (80 mmol) of t-butyldimethylsilyl chloride and 5.4 g (80 mmol) of imidazole were added at room temperature, and the mixture was stirred for 14 hours. The reaction mixture was concentrated, partitioned with ethyl acetate-water, and the organic layer was concentrated to dryness. The residue was adsorbed on a silica gel column, eluted with chloroform, and crystallized from chloroform-hexane to give 1-[(2
-T-butyldimethylsilyloxyethoxy) methyl]
6.9 g (52%) of -5-ethyluracil was obtained.

Then, 30 ml of tetrahydrofuran was cooled to −70 ° C., and then 11 ml (22 mmol) of a 2.0 M solution of lithium diisopropylamide in tetrahydrofuran was added thereto under a nitrogen stream. To this was added 1-[(2-t-butyldimethylsilyloxyethoxy) methyl] -5-ethyluracil 3.3 g (10 mmol) of 14
A ml tetrahydrofuran solution was added dropwise while keeping the reaction solution at -70 ° C or lower, and the mixture was stirred at -70 ° C for 1 hour. Next, 10 ml of a tetrahydrofuran solution containing 2.8 g (13 mmol) of diphenyl disulfide was added dropwise and reacted for 1 hour. Acetic acid in the reaction mixture
1.3 ml was added, the temperature was returned to room temperature, the mixture was partitioned with ethyl acetate-water, and the organic layer was concentrated to dryness. The residue was adsorbed on a silica gel column and eluted with chloroform to give 1-[(2-t-
Butyldimethylsilyloxyethoxy) methyl] -5-
3.4 g (76%) of ethyl-6-phenylthiouracil was obtained.

0.41 g (0.94 mmol) of the above compound obtained was added to 5 ml of methanol.
Dissolve in, add 1N hydrochloric acid to adjust the pH to 1, then concentrate to dryness,
Crystallized from ethyl acetate-hexane to give the target compound 0.18
g (60%) was obtained.

Melting point: 117 to 120 ° C. Synthesis example 2 1-[(2-hydroxyethoxy) methyl]
Production of -6-phenylthio-5-isopropyluracil (Compound No. 2) The target compound was obtained by the same method except that 5-isopropyluracil was used in place of 5-ethyluracil of Synthesis Example 1.

Melting point: 85 to 87 ° C Formulation example 1 (production of tablets) 5-ethyl-1-[(2-hydroxyethoxy) methyl] -6-
Phenylthiouracil 10g Corn starch 65g Carboxycellulose 20g Polyvinylpyrrolidone 3g Calcium stearate 2g Total amount 100g Mixing the above ingredients well, 1 tablet 100mg by direct compression method
Tablets were prepared. One tablet is 5-ethyl-1-
It contains 1.0 mg of [(2-hydroxyethoxy) methyl] -6-phenylthiouracil.

Formulation Example 2 (Production of powders and capsules) 5-Ethyl-1-[(2-hydroxyethoxy) methyl] -6-
Phenylthiouracil 20 g Crystalline cellulose 80 g Total amount 100 g Both powders were well mixed to obtain a powder. Also this powder 100mg
Was filled in a No. 5 hard capsule to obtain a capsule.

Example (Effect of preventing HIV infection) MT-4 cells (HI) in RPMI 1640DM medium containing 20 mM Hepes buffer, 10% fetal bovine serum and 20 μg / ml gentamicin.
V) Human T-cell coulombs that die when infected) 3 × 10 ⁴
50% of the cells were infected with 100 times the amount of HIV, and immediately, a predetermined amount of a sample prepared at 50 mg / ml with dimethyl sulfoxide was added and cultured at 37 ° C.

After 5 days of culture, the number of surviving cells was measured to determine the compound concentration required to prevent 50% cell death of MT-4 cells. Also, HIV
The cells were cultured in the same manner as above except that the cells were not infected, and the compound concentration required for 50% of MT-4 cells to die was determined. Both results are shown in Table-1 (Compound No. corresponds to the compound No. described in the above Synthesis Example).

Front page continuation (72) Inventor Richard Thomas Walker Birmingham Seri Oak Middle Park Road, England 50 (72) Inventor Ken Uvazawa 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryo Kasei Co., Ltd.

Claims (1)

[Claims] 1. 5-Ethyl-1-[(2-hydroxyethoxy) methyl] -6-phenylthiouracil or 1-
An antiviral agent containing [(2-hydroxyethoxy) methyl] -6-phenylthio-5-isopropyluracil as an active ingredient.