JP2908844B2 - Antiviral agent - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an antiviral agent containing a specific imidazole nucleoside derivative as an active ingredient.

[Prior Art] Many nucleoside derivatives are known as antiviral chemotherapeutic agents. For example, idoxuridine (ID
U), vidarabine (ara A), acyclovir (ACV), azidothymidine (AZT), etc. are used for the treatment of certain viral diseases, but the target diseases are limited or the effects are not sufficient There is. Ribavirin, DN
It is known as a compound that has a broad and potent antiviral action against A virus and RNA virus [Ann.
w York Acad. Sci., 284 , 272-292 (1977)], however, does not have sufficient pile virus activity and has a problem in safety.

[Problems to be Solved by the Invention] As described above, although various antiviral nucleoside derivatives have already been developed and used, a compound having strong antiviral activity against a wide range of viruses is ribavirin. However, there is a need for a compound that acts more strongly on a wider range of viruses and is highly safe.

[Means for Solving the Problems] The present inventors have conducted various studies in order to obtain a useful antiviral agent under the above-described circumstances. As a result, the present inventors have found that they have an alkynyl group or a hydroxyalkynyl group as a substituent. The specific imidazole nucleoside derivative satisfies the above requirements, has a broad spectrum against various viruses, has a strong inhibitory activity, and is also excellent in safety, and has further studied to complete the present invention. .

That is, the present invention relates to the following general formula [I] [Wherein, R ¹ represents a hydrogen atom or a hydroxy lower alkyl group, R ² , R ³ and R ⁴ each represent a hydrogen atom, a hydroxyl-protecting group or a phosphoric acid residue, and R ² , R ³ and R
⁴ may be the same or different. ] The present invention provides an antiviral agent comprising an imidazole nucleoside derivative represented by the following or a salt thereof as an active ingredient.

In the general formula [I], when R ¹ is a hydroxy lower alkyl group, R ¹ is any position of a linear or branched alkyl group having any carbon number of 10 or less, preferably 4 or less. Is a hydroxy lower alkyl group having an arbitrary number of hydroxyl groups.

Specifically, hydroxymethyl, α-hydroxyethyl, β-hydroxyethyl, α, β-dihydroxyethyl, α-hydroxypropyl, β-hydroxypropyl, γ-hydroxypropyl, α, β-dihydroxypropyl, α, γ -Dihydroxypropyl, β, γ-dihydroxypropyl, α-hydroxymethylethyl, β-hydroxymethylethyl, α, β-dihydroxymethylethyl, α-hydroxybutyl, β-hydroxybutyl,
γ-hydroxybutyl, δ-hydroxybutyl, α, β
-Dihydroxybutyl, α, γ-dihydroxybutyl,
hydroxy in which a hydroxyl group is substituted at an arbitrary position of an alkyl group having 1 to 4 carbon atoms such as α, δ-dihydroxybutyl, α, β, γ-trihydroxybutyl, β, γ, δ-trihydroxybutyl; A lower alkyl group can be exemplified.

When R ² , R ³ and / or R ⁴ are protecting groups for hydroxyl groups, these are substituents commonly used as protecting groups for hydroxyl groups of nucleosides, and two or more of them are the same or different. Specifically, acetyl, chloroacetyl, dichloroacetyl, trifluoroacetyl, methoxyacetyl, propionyl, n-butyryl, (E)-
2-methyl-2-butenoyl, isobutyryl, pentanoyl, benzoyl, o- (dibromomethyl) benzoyl, o- (methoxycarbonyl) benzoyl, p-phenylbenzoyl, 2,4,6-trimethylbenzoyl, p-
Toluoyl, p-anisoyl, p-chlorobenzoyl,
acyl groups such as p-nitrobenzoyl and α-naphthoyl; alkyloxymethyl groups such as methoxymethyl, ethoxymethyl and n-propoxymethyl; substituted ethyl groups such as 1-ethoxyethyl and 1-methyl-1-methoxyethyl; benzyl , Phenethyl, 3-phenylpropyl, p
-Methoxybenzyl, p-nitrobenzyl, p-halobenzyl, p-cyanobenzyl, diphenylmethyl, triphenylmethyl, α or β-naphthylmethyl, α-
Aralkyl groups such as naphthyldiphenylmethyl: pyranyl groups such as tetrahydropyran-2-yl and 4-methoxytetrahydropyran-4-yl; trimethylsilyl, triethylsilyl, dimethylisopropylsilyl,
Silyl groups such as isopropyldimethylsilyl, methyldi-t-butylsilyl, t-butyldimethylsilyl, t-butyldiphenylsilyl, triisopropylsilyl, tetraisopropyldisiloxanyl (TIPDS); ethylidene, propylidene, isopropylidene, benzylidene;
Acetal or ketal-type protecting groups such as cyclohexylidene, cyclopentylidene, methoxymethylidene, ethoxymethylidene and dimethoxymethylidene; and alkyloxycarbonyl groups such as methoxycarbonyl, ethoxycarbonyl and t-butoxycarbonyl. it can.

When R ² , R ³ and / or R ⁴ are phosphate residues,
These have the formula [II] or [III] Is represented by M in the formulas [II] and [III] represents one or more cations having a positive charge corresponding to the negative charge of the phosphate residue, and specifically includes hydrogen ion, sodium ion, potassium ion, calcium ion , Magnesium ion, ammonium ion and the like. The phosphate residue of the formula [II] forms a phosphate with one hydroxyl group of the ribose skeleton in the imidazole nucleoside derivative of the formula [I], and the phosphate residue of the formula [III] forms two phosphate groups of the ribose skeleton. Forms hydroxyl groups and cyclic phosphate esters.

The imidazole nucleoside derivative of the formula [I] may be in the form of a salt, for example, an inorganic acid such as hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid or citric acid, acetic acid, succinic acid, maleic acid, methanesulfonic acid And an acid addition salt with an organic acid such as p-toluenesulfonic acid.

The imidazole nucleoside derivative represented by the general formula [I] is a known compound and can be prepared by a known method [Japanese Pharmaceutical Society 108th Annual Meeting, Abstracts of Lecture, No. 41]
P. 5E062-1 (1988); Chem. Pharm. Bull., 36 (7), 2
730, (1988); Japanese Patent Laid-Open No. 1-221388].

Specific examples of the imidazole nucleoside derivative represented by the general formula [I] are as follows.

5-ethynyl-1- [beta] -D-ribofuranosylimidazole-4-carboxamide; 5- (3-hydroxy-1-propyn-1-yl)-
1-β-D-ribofuranosylimidazole-4-carboxamide; 5- (3-hydroxy-1-butyn-1-yl) -1
-Β-D-ribofuranosylimidazole-4-carboxamide; 5- (4-hydroxy-1-butyn-1-yl) -1
-Β-D-ribofuranosylimidazole-4-carboxamide; 5- (3,4-dihydroxy-1-butyn-1-yl)
-1-β-D-ribofuranosylimidazole-4-carboxamide; 5- (3-hydroxy-1-pentyn-1-yl)-
1-β-D-ribofuranosylimidazole-4-carboxamide; 5- (4-hydroxy-1-pentyn-1-yl)-
1-β-D-ribofuranosylimidazole-4-carboxamide; 5- (5-hydroxy-1-pentyn-1-yl)-
1-β-D-ribofuranosylimidazole-4-carboxamide; 5- (3,4-dihydroxy-1-pentyn-1-yl) -1-β-D-ribofuranosylimidazole-4-
Carboxamide; 5- (4,5-dihydroxy-1-pentyn-1-yl) -1-β-D-ribofuranosylimidazole-4-
Carboxamide; 5- (4-hydroxy-3-methyl-1-butyne-1
-Yl) -1-β-D-ribofuranosylimidazole-
4-carboxamide; 5- (6-hydroxy-1-hexyn-1-yl)-
1-β-D-ribofuranosylimidazole-4-carboxamide; 5- (4-hydroxy-1-hexyn-1-yl)-
1-β-D-ribofuranosylimidazole-4-carboxamide; 5- (3-methyl-5-hydroxy-1-pentyne-
1-yl) -1-β-D-ribofuranosylimidazole-4-carboxamide.

Compounds in which the hydroxyl group of the ribose skeleton, particularly the hydroxyl group at the 5-position, of the above-exemplified compounds are protected with a phosphoric acid residue, and hydrochlorides, sulfates, succinic acids, and the like of the above-mentioned exemplified compounds can also be exemplified as preferred compounds. .

The imidazole nucleoside derivatives of the formula [I] show excellent antiviral activity. That is, for example, vesicular stomatitis virus, reovirus, parainfluenza virus (Parain)
fluenza virus, Coxsackie v
irus), poliovirus (Polio virus), herpes simplex virus (Herpes simplex virus), vaccinia virus (Vaccinia virus), influenza virus, Sindbis virus (Sindbis virus), Semliki forest virus (Semliki forest virus) The cytopathic effect can be suppressed at a very low concentration. On the other hand, the imidazole nucleoside derivative of the formula [I] has low toxicity to cells and is highly safe. Compounds in which R ² , R ³ and / or R ⁴ in the formula [I] are protecting groups or phosphate residues are of course also used as active ingredients of the antiviral agent of the present invention.

The dose of the compound of the formula [I] or a salt thereof, which is an active ingredient of the antiviral agent of the present invention, varies depending on the severity of the patient, tolerability to the drug, etc., and is ultimately determined by the judgment of a physician. Should be, but usually 0.
02 to 2 g, which can be administered once or in divided doses. The administration method can be any method suitable for the administration route.

The antiviral agent of the present invention can be prepared for administration by any conventional formulation method.

For example, in the case of a preparation for oral administration, it is provided in a form suitable for absorption from the gastrointestinal tract, and tablets, capsules,
Solid preparations such as powders, dragees, and granules; liquid preparations such as syrups, suspensions, and elixirs may be prepared. In the case of solid preparations, binders such as syrup, gum arabic, gelatin, sorbite, tragacanth, polyvinylpyrrolidone; excipients such as lactose, sugar, corn starch, calcium phosphate, sorbite, glycine; magnesium stearate, talc, polyethylene It can be formulated by selecting and using a lubricant such as glycol or silica; a disintegrating agent such as potato starch; or an auxiliary such as a wetting agent, a stabilizing agent, a flavoring agent or the like in consideration of pharmaceutically. In the case of a liquid preparation, if necessary, a suspending or emulsifying agent such as sorbitol syrup, methylcellulose, glucose / sugar syrup, gelatin, hydroxyethylcellulose, carboxymethylcellulose, aluminum stearate gel, hydrogenated edible fat, etc. Preservatives such as methyl hydroxybenzoate, propyl p-hydroxybenzoate, and sorbic acid can be used.

When preparing a formulation for injection administration, a pH adjuster, a buffer, a stabilizing agent, a preservative, a solubilizing agent, if necessary, for the compound of the formula [I] of the present invention or a salt thereof, which is an active ingredient of the present invention. And the like, and subcutaneously, intramuscularly, or intravenously injectable in a conventional manner.

[Examples] Hereinafter, the present invention will be described in more detail with reference to Test Examples and Formulation Examples.

Test Examples Suppression of cytopathic effect and measurement of cytotoxicity (i) Test compounds The following three compounds specifically described in JP-A-1-221388 were used as test compounds.

Compound A: 5-ethynyl-1-β-D-ribofuranosylimidazole-4-carboxamide Compound B: 5- (3-hydroxy-1-propyn-1-yl) -1-β-D-ribofuranosylimidazole -4-
Carbomixamide Compound C: 5- (4-Hydroxy-1-butyn-1-yl) -1-β-D-ribofuranosylimidazole-4-
Carboxamide (ii) Study-1 Antimicrobial Agents and Chemotherapy, Vol.28, No.
1, p.84-89 (1985), the suppression of the cytopathic effect of the virus by the test compound and the cytotoxicity of the test compound were examined.

That is, Vero cells are cultured to confluence in a microtiter plate, and various virus stock solutions are added to the cultured cells with 100 TCID ₅₀ (Tissue Culture Infectiv).
e Dose-50) (1 CCID ₅₀ is 50% of the cultured cells)
Equating to the amount of virus inoculated necessary to infect the virus). One hour after the virus adsorbed on the cells, the remaining virus was removed and replaced with Eagle's minimum essential medium containing 3% fetal bovine serum and various concentrations of the test compound. 10% by virus in virus-infected cultured cells not treated with test compound
Immediately after the 0% cytopathic effect (CPE) began to be observed, the CPE in the virus-infected cultured cells treated with the test compound was measured. The concentration of the test compound required to suppress virus-induced CPE by 50% was determined. The results are shown in Table 1.

Cytotoxicity was measured as follows. That is, Vero cells not infected with the virus and Vero cells infected with the virus were treated with various concentrations of the test compound and incubated. When virus cytopathic effect (CPE) was observed on virus-infected Vero cells, morphological observations were performed on the virus-uninfected Vero cells treated with the test compound using a microscope. Using cell detachment and morphological degeneration as indicators of cytotoxicity, the minimum concentration of the test compound that exerted cytotoxicity was determined. The results are shown in Table 1.

The viruses used here were parainfluenza virus type 3 (ATCC VR-93) and reovirus type 1 (ATCC
CC VR-230), Sindbis virus and Coxsacki-virus B4 [Life Sci., 17 , p. 187-194 (1975)], and Semliki Forest fever virus (ATCC VR-67).

(Iii) Test-2 The same test as Test-1 was carried out by changing the test compound.
The results are as shown in Table 2.

(Iv) Test-3 Using dog-derived kidney cells MDCK as cultured cells, A / Kumamoto / Y5 / 57 and B / Yamagata as influenza viruses
The inhibition of the cytopathic effect of the test compound was measured by partially modifying the method of Test-1 using / 1/73 as follows.

That is, the micro in titer plate, and cultured MDCK cells on confluent, were inoculated various of virus stock solution to the cell culture in an amount of 10 TCID _50. 30 minutes after the virus adsorbs on the cells, remove the residual virus,
The medium was replaced with Eagle's minimum essential medium enriched with glucose and vitamins containing 0.2% bovine serum albumin and various concentrations of the test compound. In the system using A / Kumamoto / Y5 / 57, 10 μg / ml of trypsin was further added. Hereinafter, Test-1
The concentration of the test compound required to suppress the virus-induced CPE by 50% was determined in the same manner as described above.

 The results are as shown in Table 3.

As is clear from Tables 1 to 4, the compounds of the present invention can suppress the cytopathic effect of various viruses, while having low cytotoxicity and high safety.

Formulation Example 1 Production of tablets 5-ethynyl-1-β-D-ribofuranosylimidazole-4-carboxamide 10 g corn starch 65 g carboxymethylcellulose 20 g polyvinylpyrrolidone 3 g calcium stearate 2 g total amount 100 g A tablet of 100 mg is prepared by a conventional method. Each tablet contains 10 mg of 5-ethynyl-1-β-D-ribofuranosylimidazole-4-carboxamide.

Formulation Example 2 Production of powder and capsule 5- (3-hydroxy-1-propyn-1-yl) -1
-Β-D-Ribofuranosylimidazole-4-carboxamide 20 g Microcrystalline cellulose 80 g Total amount 100 g Both powders are mixed to make a powder. Also, 100 mg of the powder is filled into a No. 5 hard capsule to prepare a capsule.

[Effect of the Invention] The imidazole nucleoside derivative used in the present invention is:
Strongly suppress the cytopathic effect of various viruses,
It has low cytotoxicity and high safety. Therefore, the antiviral agent of the present invention containing the imidazole nucleoside attractant as an active ingredient is extremely excellent as a pharmaceutical, and its significance is great.

──────────────────────────────────────────────────の Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) A61K 31/70 C07H 19/052 CAPLUS (STN) REGISTRY (STN) WPI (DIALOG)

Claims (1)

(57) [Claims] 1. A compound represented by the following general formula [I] [Wherein, R ¹ represents a hydrogen atom or a hydroxy lower alkyl group, R ² , R ³ and R ⁴ each represent a hydrogen atom, a hydroxyl-protecting group or a phosphoric acid residue, and R ² , R ³ and R ⁴
May be the same or different. ] The antiviral agent which contains the imidazole nucleoside derivative represented by these or its salt as an active ingredient.