RU2259368C2 - Derivatives of pyrazine and their salts, pharmaceutical composition comprising these compounds - Google Patents

Abstract

FIELD: organic chemistry, medicine, pharmacy.

SUBSTANCE: invention relates to derivatives of pyrazine of the general formula (I):

wherein R¹ means hydrogen (H) or halogen atom; R², R³ and R⁵ mean hydrogen atom (H); R⁴ and R⁶ mean hydroxy-group optionally protected with acetyl or benzoyl group; A means oxygen atom (O); n = 0; Y means oxygen atom (O), or their salts. Compounds show the excellent anti-viral activity and useful as a therapeutic agent in treatment of viral infections. Also, invention describes a pharmaceutical composition.

EFFECT: valuable medicinal properties of compounds and composition.

7 cl, 2 tbl, 15 ex

Description

The invention relates to new pyrazine derivatives or their salts, a pharmaceutical composition containing these compounds.

BACKGROUND OF THE INVENTION

The antiviral agents currently used in clinical practice include acyclovir and vidarabine directed against herpes viruses, ganciclovir and foscarnet, directed against cytomegaly viruses, and interferon, etc., directed against hepatitis viruses. In addition, vaccines are widely prevented against the influenza virus, and low molecular weight compounds such as amantadine hydrochloride and ribavirin are also used for this purpose. In addition, zanamivir has also been used recently.

On the other hand, with regard to the antiviral activity of nucleoside and nucleotide analogs based on a pyrazine ring, for example, it was previously reported that compounds of the general formula:

where R ⁷ represents a hydrogen atom, a methyl group or C ₁₀ H ₂₁ , have antiviral activity. However, this type of compound does not exhibit “activity against the Visnas virus” [Nucleosides & Nucleotides, Vol.15, Nos.11 and 12, Pages 1849-1861 (1996)]. In addition, analogues of nucleoside and nucleotide having a pyrazine ring substituted by a carbamoyl group have not yet been reported.

The problems associated with the use of amantadine are that it does not show activity against type B influenza virus, although it is effective against type A influenza virus, due to its mechanism of action, which may result in the virus becoming resistant to this compound, which leads to a nervous breakdown, etc. On the other hand, although ribavirin has an inhibitory effect on polymerase and is effective against influenza virus type A and type B, it does not show a sufficient clinical effect when used orally.

It follows that it is necessary to develop an antiviral agent that has a prophylactic effect against various viruses and, especially, against the influenza virus, and exhibits a therapeutic effect.

Description of the invention

In order to solve the above problems, comprehensive studies have been conducted. As a result, it was found that the pyrazine derivative represented by the following general formula [1]:

where R ¹ represents a hydrogen atom or a halogen atom; R ² represents hydrogen; R ³ and R ⁵ are hydrogen; R ⁴ and R ⁶ represent a substituted or unsubstituted, protected or unprotected hydroxyl or amino group; A represents an oxygen atom; n is 0; and Y represents an oxygen atom,

or its salt exhibit excellent antiviral activity. Based on the obtained data, the present invention has been completed.

The present invention is described in detail below.

The terms used in this description have the following meanings, unless otherwise indicated. The term “halogen atom” means a fluorine atom, a chlorine atom, a bromine atom or an iodine atom; “halogenated methyl group” means a mono-, di- or trisubstituted halogenated methyl group such as fluoromethyl, chloromethyl, bromomethyl, iodomethyl, dichloromethyl, trifluoromethyl, trichloromethyl and the like; "halogenated carbonyl group" means a fluorocarbonyl, chlorocarbonyl, bromocarbonyl or iodocarbonyl group; “lower alkyl group” means a C _1-5 alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl and the like; “lower alkoxy group” means a C _1-5 alkoxy group such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy and the like; “lower alkoxycarbonyl group” means a C _1-5 alkoxycarbonyl group such as methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, pentyloxycarbonyl and the like; “lower alkylamino group” means a mono- or di-C _1-5 alkylamino group such as methylamino, ethylamino, propylamino, dimethylamino, diethylamino, methylethylamino and the like; “lower alkyl group containing a halogen” means a C _2-5 alkyl group containing a halogen such as fluoromethyl, chloromethyl, bromomethyl, dichloromethyl, trifluoromethyl, trichloromethyl, chloroethyl, dichloroethyl, trichloroethyl, chloropropyl and the like; "lower alkenyl group" means a C _2-5 alkenyl group such as vinyl, allyl and the like; “cycloalkyl group” means a C _3-6 cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like; “aryl group” means a phenyl group, a naphthyl group or the like; and “heterocyclic group” means a 4-6 membered or fused heterocyclic group containing at least one heteroatom selected from an oxygen atom, a nitrogen atom and a sulfur atom, such as azetidinyl, thienyl, furyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, oxazolyl, isoxazolyl, furazanil, pyrrolidinyl, pyrrolinyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, pyrazolinyl, 1,3,4-oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,3, 4-thiadiazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, thiatriazolyl, pyridyl, pyrazinyl, pyrimide Inyl, pyridazinyl, pyranyl, morpholinyl, 1,2,4-triazinyl, benzothienyl, naphthothienyl, benzofuryl, isobenzofuryl, chromenyl, indolisinyl, isoindolyl, indolyl, indazolyl, purinyl, quinolyl, isoquinolyl, phthylazinyl vinyl, vinylphyninyl, phthalidinyl, isochromanil, chromanyl, indolinyl, isoindolinyl, benzoxazolyl, triazolopyridyl, tetrazolopyridazinyl, tetrazolopyrimidinyl, thiazolpyridazinyl, thiadiazolpyridazinyl, benzimidazolidazole, 1,2imidazole-1,2-azido-azole , 4] -triazinyl, quinuclide Neil and the like.

In those cases where the compound of the present invention and the intermediate compound contain a hydroxyl group, a mercapto group, an amino group, a carbamoyl group or a carboxy group, these substituents may be protected by known protecting groups.

The terms “monophosphoric acid group”, “diphosphoric acid group” and “triphosphoric acid group” mean groups of the following general formula:

where k is 1, 2 and 3, respectively.

The protecting groups for the monophosphoric acid, diphosphoric acid and triphosphoric acid groups include all groups commonly used to protect the phosphoric acid groups. Examples of such groups include lower alkyl groups such as methyl, cyclopropylmethyl, tert-butyl, ethane-1,2-diyl and the like; lower alkyl groups containing halogen, such as 2,2,2-trichloroethyl, 2,2,2-trichloro-1,1-dimethylethyl, 2,2,2-tribromethyl and the like; acyl lower alkyl groups such as 1-acetyl ethyl and the like; cyano lower alkyl groups such as 2-cyanoethyl and the like; lower alkylsulfonyl lower alkyl groups such as 2-methylsulfonylethyl and the like; arylsulfonyl lower alkyl groups such as 2-phenylsulfonylethyl and the like; alkenyl groups such as allyl and the like; aryl groups such as phenyl, o-hydroxyphenyl, o-chlorophenyl, p-chlorophenyl, 2,4-dichlorophenyl, p-nitrophenyl, 2-dimethylamino-4-nitrophenyl, 2-tert-butylphenyl, 2-chloromethyl-4-nitrophenyl , o-phenylene and the like; aryl lower alkyl groups such as benzyl, o-nitrobenzyl, p-nitrophenylethyl and the like; heterocyclic groups such as 8-quinolyl, 5-chloro-8-quinolyl and the like, etc. For protection, one or more kinds of the aforementioned protecting groups may be used.

Protective groups for a carboxyl group may include all groups commonly used to protect a carboxyl group. Examples of such groups include lower alkyl groups such as methyl, ethyl, n-propyl, isopropyl, 1,1-dimethylpropyl, n-butyl, tert-butyl and the like; aryl groups such as phenyl, naphthyl and the like; aryl lower alkyl groups such as benzyl, diphenylmethyl, trityl, p-nitrobenzyl, p-methoxybenzyl, bis (p-methoxyphenyl) methyl and the like; acyl lower alkyl groups such as acetylmethyl, benzoylmethyl, p-nitrobenzoylmethyl, p-bromobenzoylmethyl, p-methanesulfonylbenzoylmethyl and the like; oxygen-containing heterocyclic groups such as 2-tetrahydropyranyl, 2-tetrahydrofuranyl and the like; lower alkyl groups containing halogen, such as 2,2,2-trichloroethyl and the like; lower alkyl silyl alkyl groups such as 2- (trimethylsilyl) ethyl and the like; acyloxyalkyl groups such as acetoxymethyl, propionyloxymethyl, pivaloyloxymethyl and the like; nitrogen-containing heterocycle lower alkyl groups such as phthalimidomethyl, succinimidomethyl and the like; cycloalkyl groups such as cyclohexyl and the like; lower alkoxy lower alkyl groups such as methoxymethyl, methoxyethoxyethyl, 2- (trimethylsilyl) ethoxymethyl and the like; aryl lower alkoxy lower alkyl groups such as benzyloxymethyl and the like; lower alkylthio lower alkyl groups such as methylthiomethyl, 2-methylthioethyl and the like; arylthio lower alkyl groups such as phenylthiomethyl and the like; lower alkenyl groups such as 1,1-dimethyl-2-propenyl, 3-methyl-3-butynyl, allyl and the like, and lower alkyl substituted silyl groups such as trimethylsilyl, triethylsilyl, triisopropylsilyl, diethylisopropylsilyl, tert-butyldimethylsilyl, tert-butyl diphenylsilyl, diphenylmethylsilyl, tert-butylmethoxyphenylsilyl and the like.

Protecting groups for amino groups and lower alkylamino groups may include all groups commonly used to protect amino groups. Examples of such groups include acyl groups such as trichloroethoxycarbonyl, tribromethoxycarbonyl, benzyloxycarbonyl, p-nitrobenzyloxycarbonyl, o-bromobenzyloxycarbonyl, (mono-, di- and tri-) chloroacetyl, trifluoroacetyl, phenylacetyl, formyl, acetyl, benzoylcarbon, tert-amyl β-butoxycarbonyl, p-methoxybenzyloxycarbonyl, 3,4-dimethoxybenzyloxycarbonyl, 4- (phenylazo) benzyloxycarbonyl, 2-furfuryloxycarbonyl, diphenylmethoxycarbonyl, 1,1-dimethylpropoxycarbonyl, isopropoxycarbonyl, phthaloyl, 1-succinyl sikarbonil, 8-quinolyloxycarbonyl and the like; aryl lower alkyl groups such as benzyl, diphenylmethyl, trityl and the like; arylthio groups such as 2-nitrophenylthio, 2,4-dinitrophenylthio and the like; alkane and allensulfonyl groups such as methanesulfonyl, p-toluenesulfonyl and the like; di-lower alkylamino lower alkylidene groups such as N, N-dimethylaminomethylene and the like; aryl lower alkylidene groups such as benzylidene, 2-hydroxybenzylidene, 2-hydroxy-5-chlorobenzylidene, 2-hydroxy-1-naphthylmethylene and the like; nitrogen-containing heterocyclic alkylidene groups such as 3-hydroxy-4-pyridylmethylene and the like; cycloalkylidene groups such as cyclohexylidene, 2-ethoxycarbonylcyclohexylidene, 2-ethoxycarbonylcyclopentylidene, 2-acetylcyclohexylidene, 3,3-dimethyl-5-hydroxycyclohexylidene and the like; di-aryl or di-aryl lower alkylphosphoryl groups such as diphenylphosphoryl, dibenzylphosphoryl and the like; oxygen-containing heterocyclic alkyl groups such as 5-methyl-2-oxo-2H-1,3-dioxol-4-ylmethyl and the like; and lower alkyl substituted silyl groups such as trimethylsilyl group and the like.

The protecting groups for the hydroxyl group and mercapto group may include all groups commonly used to protect the hydroxyl group. Examples of such groups include acyl groups such as benzyloxycarbonyl, 4-nitrobenzyloxycarbonyl, 4-bromobenzyloxycarbonyl, 4-methoxybenzyloxycarbonyl, 3,4-dimethoxybenzyloxycarbonyl, methoxycarbonyl, ethoxycarbonyl, tert-butoxycarbonyl, 1,1-dimethylpropyloxycarbonyl, 1,2-dimethylphenoxycarbonyl, 2-methoxycarbonyl, 2-methoxycarbonyl, 2-methoxycarbonyl, 2-methoxycarbonyl, 2-methoxycarbonyl, 2-methoxycarbonyl, 2-methoxycarbonyl, 2-methoxycarbonyl, 2-methoxycarbonyl, 2-methoxycarbonyl, 2-methoxycarbonyl and 2-methoxycarbonyl. , 2,2-trichloroethoxycarbonyl, 2,2,2-tribromethoxycarbonyl, 2- (trimethylsilyl) ethoxycarbonyl, 2- (phenylsulfonyl) ethoxycarbonyl, 2- (triphenylphosphonio) ethoxycarbonyl, 2-furfuryloxycarbonyl, 1-adamantyloxy rbonyl, vinyloxycarbonyl, allyloxycarbonyl, S-benzylthiocarbonyl, 4-ethoxy-1-naphthyloxycarbonyl, 8-quinolyloxycarbonyl, acetyl, formyl, chloroacetyl, dichloroacetyl, trichloroacetyl, trifluoroacetyl, methoxyacetyl, phenoxyacetyl; lower alkyl groups such as methyl, tert-butyl, 2,2,2-trichloroethyl, 2-trimethylsilylethyl and the like; lower alkenyl groups such as allyl and the like; aryl lower alkyl groups such as benzyl, p-methoxybenzyl, 3,4-dimethoxybenzyl, diphenylmethyl, trityl and the like; oxygen-containing and sulfur-containing heterocyclic groups such as tetrahydrofuryl, tetrahydropyranyl, tetrahydrothiopyranyl and the like; lower alkoxy and lower alkylthio lower alkyl groups such as methoxymethyl, methylthiomethyl, benzyloxymethyl, 2-methoxyethoxymethyl, 2,2,2-trichloroethoxymethyl, 2- (trimethylsilyl) ethoxymethyl, 1-ethoxyethyl and the like; alkane and allensulfonyl groups such as methanesulfonyl, p-toluenesulfonyl and the like; substituted silyl groups such as trimethylsilyl, triethylsilyl, triisopropylsilyl, diethylisopropylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, diphenylmethylsilyl, tert-butylmethoxyphenylsilyl and the like; substituted aryl groups such as hydroquinone, p-methoxyphenol and the like; enol- (ether) ether groups such as (2-methyl-3-oxo-1-cyclopenten-1-yl) and the like.

The protecting groups for a carbamoyl group may include all groups commonly used to protect a carbamoyl group. Examples of such groups include aryl lower alkyl groups such as benzyl, 4-methoxybenzyl, 2,4-dimethoxybenzyl and the like; lower alkoxyalkyl groups such as methoxymethyl and the like; aryl lower alkoxy groups such as benzyloxymethyl and the like; substituted silyl lower alkoxy lower alkyl groups such as tert-butyldimethylsiloxymethyl and the like; lower alkoxy groups such as methoxy and the like; aryl lower alkoxy groups such as benzyloxy and the like; lower alkylthio groups such as methylthio, triphenylmethylthio and the like; aryl lower alkylthio groups such as benzylthio and the like; substituted silyl groups such as tert-butyldimethylsilyl and the like; aryl groups such as 4-methoxyphenyl, 4-methoxymethylphenyl, 2-methoxy-1-naphthyl and the like; acyl groups such as trichloroethoxycarbonyl, trifluoroacetyl, tert-butoxycarbonyl and the like, etc.

Substituents of the hydroxyl group represented by R ³ , R ⁴ , R ⁵ , R ⁶ , Z ² , Z ³ , Z ⁴ and Z ⁵ which may be substituted may include a protected or unprotected carboxyl group, a lower alkyl group, a lower alkoxycarbonyl group, an aryl group, a cycloalkyl group, a lower alkenyl group, a lower alkyl group containing a halogen, and a heterocyclic group. For substitution, one or more types of substituents selected from the above substituents may be used.

Substituents of the amino group represented by R ³ , R ⁴ , R ⁵ , R ⁶ , Z ² , Z ³ , Z ⁴ and Z ⁵ which may be substituted may include substituted, protected or unprotected carboxyl, hydroxyl, amino and lower alkylamino groups, a lower alkyl group, a lower alkoxy group, a lower alkoxycarbonyl group, an aryl group, a cycloalkyl group, a lower alkenyl group, a lower alkyl group containing a halogen, and a heterocyclic group. For substitution, one or more substituents selected from the above groups may be used.

Substituents of the phenylsulfanyl group, phenylsulfinyl group and phenylsulfonyl group represented by R ²² may include lower alkyl groups such as methyl, ethyl and the like.

Salts of the compounds of general formulas [1] can usually include known salts formed by a basic group, such as an amino group, etc., and salts formed by an acid group, such as a hydroxyl group, a phosphoryl group, a carboxyl group, etc. Salts formed by the main group include, for example, salts of an inorganic acid such as hydrochloric acid, hydrobromic acid, sulfuric acid and the like; organic acid salts such as tartaric acid, formic acid, citric acid, trichloroacetic acid, trifluoroacetic acid and the like, and sulfonic acid salts such as methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, mesitylene sulfonic acid, naphthalene sulfonic acid and the like. Salts formed by the acid group include salts with an alkali metal such as sodium, potassium and the like; salts with an alkaline earth metal such as calcium, magnesium and the like; ammonium salts; and salts with nitrogen-containing organic bases such as trimethylamine, triethylamine, tributylamine, pyridine, N, N-dimethylaniline, N-methylpiperidine, N-methylmorpholine, dmethylamine, dicyclohexylamine, procaine, dibenzylamine, N-benzyl-β-phenethylamine, , N, N'-dibenzylethylenediamine and the like.

Of the salts mentioned above, pharmacologically acceptable salts are preferred.

In some cases, compounds of the general formulas [1] and their salts have isomers, such as optical isomers, geometric isomers and tautomers. In such cases, the present invention includes these isomers and, in addition, includes solvated products, hydrates, as well as various crystalline forms.

Of the pharmaceutical compositions of the present invention, the preferred pharmaceutical compositions are antiviral agents, and furthermore, the preferred antiviral compositions are agents against influenza virus, RS virus (Raus sarcoma), AIDS virus, papilloma virus, adenovirus, hepatitis A virus, hepatitis B virus, hepatitis C virus, polio virus, ECHO virus, Coxsackie virus, enterovirus, rhinovirus, rotavirus, Nowycastle disease virus, mumps virus, vesicular stomatitis virus and Japanese encephalitis virus.

Even more preferred antiviral agents are those directed against rotavirus, RS virus and influenza virus. The most preferred antiviral agent is an anti-influenza agent.

Of the compounds of the present invention, preferred compounds are those in which R ⁴ and R ⁶ represent a protected or unprotected hydroxyl group, and salts thereof.

Even more preferred compounds include compounds in which R ¹ means a hydrogen atom, a chlorine atom or a fluorine atom, as well as salts of these compounds; and preferred compounds also include those compounds in which R ¹ is a hydrogen atom or a fluorine atom, as well as salts of said compounds.

Among the compounds of the present invention, typical compounds are, for example, those shown in Table I-1, where “Bn” represents a benzyl group and “-” represents a single bond.

Table I-1 R ¹ R ² R ³ R ⁴ R ⁵ R ⁶ A n Y H H H OH H OH O 0 O n H H OH H OH O 0 NH H H H OH H OH O 0 S 6-f H H OH H OH O 0 O 6-f H H OH H OH O 0 NH 6-cl H H OH H OH O 0 O 6-f H H OH H H O 0 O H H H OH H H O 0 O H H H OH H F O 0 O 6-f H H OH H NH ₂ O 0 O 6-f H H NH ₂ H OH O 0 O 6-f H H OH OH H O 0 O H H H OH H NH ₂ O 0 O H H H NH ₂ H OH O 0 O H H H OH OH H O 0 O H H H OH F H O 0 O H H H OH N ₃ H O 0 O 6-f H H N ₃ H H O 0 O 6-f H H H H H O 0 O 6-f (HO) ₂ PO H OH H OH O 0 O H H H N ₃ H H O 0 O H H H H H H O 0 O H (HO) ₂ PO H OH H OH O 0 O H (BnO) ₂ PO H. OH H OH O 0 O 6-f H H OH H OH CH ₂ 0 O H H H OH H OH CH ₂ 0 O H H H OH OH H CH ₂ 0 O H H H H H H CH ₂ 0 O H H H - H - CH ₂ 0 O H H H OH H H O 1 O H H H OH H OH O 1 O 6-f H [OP (O) OH] ₃ H OH H OH O 0 O H H [OR (O) OH] ₃ H OH H OH O 0 O 6-f [CH ₂ = CHCH ₂ O] P (O) H OH H OH O 0 O H [CH ₂ = CHCH ₂ O] P (O) H OH H OH O 0 O

The following describes a method for producing compounds according to the present invention.

Compounds according to the present invention can be obtained according to the schemes of the synthesis method from I-1 to I-4, below.

where R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ , A, Y and n are as defined above; R ⁸ represents a lower alkyl group; Z ¹ represents a hydrogen atom or a protective group for a hydroxyl group; Z ² , Z ³ , Z ⁴ and Z ⁵ , which may be the same or different, represent a hydrogen atom, a halogen atom, an azido group, a protected hydroxy group or an amino group; or Z ³ and Z ⁵ taken together form a single bond.

(a) A compound of general formula [1a] or a salt thereof can be prepared by deprotecting a compound of general formula [2a] or a salt thereof.

The solvent used in this reaction is not limited, unless the solvent has a detrimental effect on the reaction. Examples of solvents include aromatic hydrocarbons such as benzene, toluene, xylene and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylacetamide and the like; alcohols such as methanol, ethanol, propanol and the like; sulfoxides such as dimethyl sulfoxide and the like; water, etc. The listed solvents may be used as such or as a mixture of two or more solvents.

As a reagent for deprotection, reagents that are commonly used to deprotect a hydroxyl group, an amino group and a phosphoric acid group can be used. However, bases such as sodium methoxide, hydrogen gas, ammonia gas, aqueous ammonia, butylamine and the like are preferred; acids such as formic acid, an aqueous solution of acetic acid, an aqueous solution of trifluoroacetic acid, hydrochloric acid and the like; palladium catalysts such as tetrakis-triphenylphosphine palladium (0) and the like; and phosphines, such as triphenylphosphine and the like. These deprotecting reagents may be used in combination or may be prepared in a reaction system. The deprotecting reagent is used in an amount of at least 0.01 mol per mol of the compound of general formula [2a] or its salt. If desired, a deprotecting reagent may be used as a solvent.

The deprotection reaction is usually carried out at a temperature of from -50 ° C to 170 ° C and preferably from -20 ° C to 100 ° C, for a period of time from 1 minute to 100 hours, and preferably for a time of 5 minutes to 50 hours.

(b) A compound of general formula [1a] in which Y is an oxygen atom or a salt thereof can be obtained by ammonolysis of a carboxylic acid ester of a compound of general formula [2b] or a salt thereof in the presence or absence of a catalyst.

The solvent used in this reaction is not limited, unless it has a detrimental effect on the reaction. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like; alcohols such as methanol, ethanol, propanol and the like; sulfoxides such as dimethyl sulfoxide and the like; water, etc. The listed solvents may be used as such or as a mixture of two or more solvents. The reaction can be carried out in the presence of reagents and under conditions that are usually used in the ammonolysis reaction of aromatic carboxylic acid esters. However, it is preferable to use gaseous ammonia, liquid ammonia or aqueous ammonia. These reagents are used in an amount of at least 0.5 mol per mol of the compound of formula [2b] or its salt. You can also use these solvents as a solvent, if desired. Catalysts that can be used if necessary in the reaction include acidic ammonium salts such as ammonium chloride; bases such as sodium methoxide, butyl lithium and the like; and alkali metal amides such as sodium amide and the like. The catalyst is used in an amount of from 0.01 mol to 100 mol and preferably from 0.01 to 20 mol per mol of the compound of formula [2b] or its salt.

The reaction is usually carried out at a temperature of from -100 ° C to 250 ° C and preferably from -78 ° C to 100 ° C for a period of time from 1 minute to 72 hours and preferably from 30 minutes to 50 hours.

where R ¹ , R ³ , R ⁴ R ⁵ , R ⁶ , R ⁸ , Z ² , Z ³ , Z ⁴ , Z ⁵ , A, n and Y are as defined above; R ⁹ represents a protected or unprotected monophosphoric acid group or monophosphoric acid chloride; and R ¹² represents a protected or unprotected group of diphosphoric acid or triphosphoric acid.

(a) A compound of general formula [2c] or its salt can be prepared by protecting a compound of general formula [2b] or its salt with a reagent in the presence or absence of an acid catalyst or base.

The solvent used in this reaction is not strictly limited, unless it has a detrimental effect on the reaction. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylacetamide and the like; alcohols such as methanol, ethanol, propanol and the like; sulfoxides such as dimethyl sulfoxide and the like; ketones such as acetone and the like; water, etc. The listed solvents may be used as such or as a mixture of two or more solvents.

The reagent used is those which are usually used to protect the hydroxyl group and amino group, and preferably 2,2-dimethoxypropane, acetyl chloride and benzoyl chloride. If desired, these reagents can be obtained in the reaction system. The amount of reagent is at least an equimolar amount and preferably 1.0-10 mol per mol of the compound of formula [2b] or its salt.

The acid catalyst or base used in this reaction includes, for example, p-toluenesulfonic acid, triethylamine and the like. The amount of these compounds may be for both 0.01-10 mol and preferably 0.05-10 mol per mol of the compound of formula [2b] or its salt.

The specified reaction is usually carried out at a temperature of from -50 ° C to 170 ° C and preferably from 0 ° C to 150 ° C for a period of from one minute to 24 hours and preferably from 5 minutes to 10 hours.

(b) A compound of general formula [2d] or its salt can be obtained (1) by reacting a compound of general formula [2c] or its salt with a phosphorylating reagent in the presence or absence of an additive according to the method described in Jikken Kadaku Koza, 4 ^th Edition, Vol, 22, Pages 313-438 (edited by the Chemical Society of Japan (corporate juridical person), 1992) or by (2) reacting said compound with a phosphitizing agent and then with an oxidizing agent.

In the method (1), the solvent used in this reaction is not strictly limited, unless the solvent has a detrimental effect on the reaction. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like; sulfoxides such as dimethyl sulfoxide and the like; pyridine etc. The listed solvents may be used as such or as a mixture of two or more solvents.

As the phosphorylating reagent, reagents that are commonly used to phosphorylate a hydroxyl group can be used. Examples of such a phosphorylating agent include phosphoric acid diesters such as dibenzyl phosphate and the like; phosphoric acid dithioesters such as S, S'-diphenylphosphorodithioate monocyclohexylammonium and the like; phosphoric acid chlorides such as phosphoryl chloride, diallyl chlorophosphonate and the like, etc. The phosphorylating reagent is used at least in an equimolar amount and preferably in an amount of 1.0-5.0 mol per mol of the compound of formula [2c] or its salt. Additives include, for example, azo compounds such as diethyl ether azodicarboxylic acid, diisopropyl ether azodicarboxylic acid and the like; phosphines such as triphenylphosphine and the like; allensulfonic acid chlorides such as 2,4,6-triisopropylbenzenesulfonic acid chlorides and the like, etc .; bases such as pyridine, magnesium tert-butylate chloride and the like; etc. If desired, these additives may be used in combination. The additive is used at least in an equimolar amount and preferably in an amount of 1.0-5.0 mol per mol of the compound of formula [2c] or its salt.

The specified reaction is usually carried out at a temperature of from -50 ° C to 170 ° C and preferably from 0 ° C to 100 ° C for a time from 1 minute to 72 hours and preferably from 5 minutes to 24 hours.

In the method (2), the solvent used in this reaction is not strictly limited, unless the solvent has a detrimental effect on the reaction. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like; sulfoxides such as dimethyl sulfoxide and the like; pyridine etc. The listed solvents may be used as such or as a mixture of two or more solvents.

As the phosphitizing reagents, those reagents that are commonly used in the phosphitization reaction of the hydroxyl group can be used. Examples include phosphoramidites, such as diallyldiisopropylphosphoramidite and the like, and phosphoric acid chlorides, such as diallyl phosphorochloridite and the like. The phosphitizing reagent is used at least in an equimolar amount and preferably in an amount of 1.0-3.0 mol per mol of the compound of formula [2c] or its salt. As the additive, for example, tetrazole compounds, such as 1H-tetrazole and the like, and bases, such as pyridine, collidine and the like, and these additives can be used in combination, if desired. The additive is used at least in an equimolar amount and preferably in an amount of 1.0-5.0 mol per mol of the compound of formula [2c] or its salt.

The oxidizing agents used in this reaction include, for example, peroxides such as m-chloroperbenzoic acid, tert-butyl hydroperoxide and the like, and halogen compounds such as iodine and the like. The oxidizing agent is used at least in an equimolar amount and preferably in an amount of 1.0-5.0 mol per mol of the compound of formula [2c] or its salt.

The specified reaction is usually carried out at a temperature of from -78 ° C to 100 ° C and preferably at a temperature of from -50 ° C to 50 ° C for a period of time from 1 minute to 24 hours and preferably from 5 minutes to 6 hours.

(c) A compound of general formula [1b] or a salt thereof can be prepared by the reaction according to method I-1 (b) using a compound of general formula [2d] or a salt thereof.

(d) A compound of general formula [1c] or a salt thereof can be prepared by the reaction according to method I-1 (a) using a compound of general formula [1b] or a salt thereof.

(e) A compound of general formula [1b] or a salt thereof can be prepared by a reaction according to method I-2 (b) using a compound of general formula [1d] or a salt thereof.

(f) A compound of general formula [1e] or a salt thereof can be prepared by reacting a compound of general formula [1c] or its salt with a phosphorylating agent in the presence or absence of a condensing reagent according to the method described, for example, in Chem. Rev., Vol. 100, Pages 2047-2059 (2000).

The solvent used in this reaction is not strictly limited, unless the solvent has a deleterious effect on the reaction. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like; sulfoxides such as dimethyl sulfoxide and the like; pyridine etc. The listed solvents may be used as a single solvent or as a mixture of two or more solvents.

As the phosphorylating reagent, those reagents that are commonly used to phosphorylate the monophosphoric acid group can be used. Examples of such a phosphorylating agent include phosphoric acid salts such as tri-n-butylammonium phosphate, n-butylammonium pyrophosphate and the like, and said phosphorylating reagents can be synthesized in the reaction system, if desired. The phosphorylating reagent is used at least in an equimolar amount and preferably in an amount of 1.0-10 mol per mol of the compound of formula [1c] or its salt. As a condensing reagent, for example, imidazoles such as N, N-carbonyldiimidazole, N-methylimidazole and the like, and amines such as morpholine, diisopropylamine and the like, and such amines can be used in combination, if desired. The condensing reagent is used at least in an equimolar amount and preferably in an amount of 1.0-5.0 mol per mol of the compound of formula [1c] or its salt.

The specified reaction is carried out at a temperature of from -50 ° C to 100 ° C and preferably at a temperature of from 0 ° C to 50 ° C for a period of time from 1 minute to 72 hours and preferably from 5 minutes to 24 hours.

[Production Method 3]

where R ¹ , R ⁸ , A, n, Z ¹ , Z ² , Z ³ , Z ⁴ and Z ⁵ are as defined above; Y ¹ represents an oxygen atom or an NH group, and R ¹⁰ represents a halogen atom, a carbonyloxy group or a sulfonyloxy group.

(a) A compound of general formula [2a] or its salt can be obtained by (1) converting a compound of general formula [3a] or its salt into a compound of general formula [3b] or its salt according to a conventional silylation method in the presence or absence of an additive, and followed by (2) reacting the obtained compound with a compound of the general formula [4a] or a salt thereof in the presence or absence of a Lewis acid.

The solvent used in this reaction is not strictly limited, unless the solvent has a deleterious effect on the reaction. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like; sulfoxides such as dimethyl sulfoxide and the like; and halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane and the like. The listed solvents may be used as a single solvent or as a mixture of two or more solvents.

The silylating reagent used in reaction (1) can be any silylating reagent that is commonly used to convert a carbonyl group to a silyl enol ether. Examples of such reagents include 1,1,1,3,3,3-hexamethyldisilazane, N, O-bis (trimethylsilyl) acetamide, trimethylsilyl chloride and the like. The silylating reagent is used at least in an equimolar amount and preferably in an amount of 1.0-10.0 mol per mol of the compound of formula [3a] or its salt.

An additive which, if necessary, can be used in said reaction includes, for example, ammonium sulfate and the like. The specified additive is used in an amount of 0.01-10.0 mol and preferably 0.05-5.0 mol per mol of the compound of formula [3a] or its salt.

This reaction is usually carried out at a temperature of 0-200 ° C and preferably at a temperature of 0-150 ° C for a time from 5 minutes to 24 hours and preferably from 5 minutes to 12 hours.

In the reaction (2), the compound of the formula [4a] or its salt is used in an amount of 0.5-10 mol and preferably 0.5-5 mol per mol of the compound of the formula [3a] or its salt.

Lewis acid, which, if necessary, can be used in this reaction, includes, for example, trimethylsilyl trifluoromethanesulfonic acid, tin (IV) chloride, titanium (IV) chloride, zinc chloride and the like. Lewis acid is used at least in an amount of 0.5 mol and preferably in an amount of 0.5-10 mol per mol of the compound of formula [3a] or its salt.

This reaction is usually carried out at a temperature of 0-100 ° C. And preferably at a temperature of 0-50 ° C for a time from 1 minute to 72 hours and preferably from 5 minutes to 24 hours.

(b) A compound of the general formula [2a] or its salt can be prepared by reacting a compound of the general formula [3a] or its salt with a compound of the general formula [4b] or its salt in the presence or absence of an additive using a base as an acid-removing reagent .

The solvent used in this reaction is not strictly limited, unless the solvent has a deleterious effect on the reaction. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene and the like; halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like; sulfoxides such as dimethyl sulfoxide and the like, etc. The listed solvents may be used as a single solvent or as a mixture of two or more solvents.

The bases used in this reaction include, for example, inorganic and organic bases such as triethylamine, potassium tert-butoxide, potassium carbonate, sodium carbonate, cesium carbonate, sodium hydride and the like. In carrying out this reaction, the compound of the formula [4b] or its salt is used in an amount of 0.1-5 mol and preferably 0.2-2 mol per mol of the compound of the general formula [3a] or its salt. In carrying out this reaction, the base is used in an amount of 0.1-10 mol and preferably 0.2-10 mol per mol of the compound of general formula [3a] or its salt.

An additive which, if necessary, can be used in said reaction includes, for example, palladium catalysts such as tetrakis-triphenylphosphine palladium and the like; phosphines such as triphenylphosphine and the like; and polyethers such as 18-crown-6- (ether) ether and the like. The specified additive is used in an amount of 0.01-10.0 mol and preferably 0.03-5.0 mol per mol of the compound of formula [3a] or its salt.

This reaction is usually carried out at a temperature of from -50 ° C to 170 ° C and preferably at a temperature of from 0 ° C to 120 ° C for a period of time from 1 minute to 72 hours and preferably from 5 minutes to 24 hours.

where R ¹ , A, n, Z ¹ , Z ² , Z ³ , Z ⁴ and Z ⁵ are as defined above.

A compound of general formula [2g] or its salt can be prepared by reacting a compound of general formula [2f] or its salt with a thionation reagent in the presence or absence of a base as described, for example. Shin Jikken Kagaku Koza, Vol, 14, Pages 1819-1831 (edited by the Chemical Society of Japan (corporate juridical person), 1978).

The solvent used in this reaction is not strictly limited, unless the solvent has a deleterious effect on the reaction. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene and the like; halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like; sulfoxides such as dimethyl sulfoxide and the like, etc. The listed solvents may be used as such or as a mixture of two or more solvents.

As a thionation reagent, such reagents as are commonly used for thionation of acid amides can be used. Examples of such reagents include hydrogen sulfide gas, diphosphorus pentasulfide, Lauson reagent, etc. The thionation reagent is used in this reaction in an amount of 0.1-10 mol and preferably 0.2-5.0 mol per mol of the compound of general formula [2f] or its salt.

The base used in this reaction, for example, includes bases such as ammonia, triethylamine, morpholine, pyridine, 4-dimethylaminopyridine and the like. In carrying out this reaction, the base is used at least in an amount of 0.01 mol per mol of the compound of formula [2f] or its salt. If desired, the base can be used as a solvent.

The specified reaction is usually carried out at a temperature of from -50 ° C to 170 ° C and preferably from 0 ° C to 120 ° C for a time from 1 minute to 24 hours and preferably from 5 minutes to 6 hours.

Next, a method for producing compounds of the general formulas [2a], [2b], [3a '] and [3j] and their salts, which are the starting materials for the preparation of the compound according to the present invention, will be described.

Compounds of the general formulas [2a], [2b], [3a '] and [3j] can be prepared by well-known methods or an appropriate combination of methods. For example, these compounds can be obtained according to the following method I-A.

where R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁸ , A, n, Z ¹ , Z ² , Z ³ , Z ⁴ , Z ⁵ and R ¹⁰ are as defined above.

(a) A compound of the general formula [2e] or a salt thereof can be prepared by reacting a compound of the general formula [3c] or its salt with a compound of the general formula [4a] or its salt according to the synthesis method I-3 (a).

(b) A compound of general formula [2e] or its salt can be prepared by reacting a compound of general formula [3c] or its salt with a compound of general formula [4b] or its salt according to the synthesis method I-3 (b).

(c) A compound of the general formula [2b] or a salt thereof can be prepared by reacting a compound of the general formula [2e] or a salt thereof according to the synthesis method I-1 (a).

Among the starting materials for carrying out the aforementioned reactions, a compound of the general formula [3c] or its salt can be obtained by the method, for example, described in J. Heterocyclic Chem., Vol. 34, No.1, Pages 27-32 (1997) or J. Med . Chem., Vol. 12, No.2, Pages 285-287 (1969); the compound of General formula [4A] or its salt can be obtained by the method, for example, described in J. Med. Chem., Vol. 28, No.7, Pages 904-910 (1985); and a compound of general formula [4b] or a salt thereof can be prepared by the method described in J. Chem. Soc. PERKIN TRANS. 1, Pages 2419-2425 (1992), J. Med. Chem., Vol. 36, No.14, Pages 2033-2040 (1993) or Bio. Med. Chem. Lett., Vol.6, No.13, Pages 1457-1460 (1996).

where R ⁸ is as defined above; R ^1a represents a halogen atom; R ¹¹ represents a protective group for a hydroxyl group and X represents a halogen atom other than a fluorine atom.

(a) A compound of general formula [3f] or a salt thereof can be prepared by reacting a compound of general formula [3e] or a salt thereof using a diazotizing reagent and an alcohol.

The solvents used in this reaction may be any solvents, provided that they do not adversely affect the reaction. Examples of the solvent include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; halogenated hydrocarbons such as dichloromethane, chloroform, dichloroethane and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylformamide, N-methyl-2-pyrrolidone and the like; sulfoxides such as dimethyl sulfoxide and the like; amines and amino oxides such as triethylamine, N, N-dimethylaniline, pyridine-N-oxide and the like; ketones such as acetone and the like; alcohols such as methanol, ethanol and the like; water etc. If desired, these solvents may be used as a mixture. The diazotizing reagents used in this invention are practically unlimited, if they are usually used for diazotization of aromatic amino compounds. However, it is preferred that alkali metal nitrites such as sodium nitrite and the like are used. The diazotizing reagent is used at least in an equimolar amount and preferably in an amount of 1.0-5.0 mol per mol of the compound of formula [3e] or its salt.

The alcohol used in this reaction includes, for example, methanol and the like. Alcohol is used at least in an equimolar amount with respect to the compound of formula [3e] or its salt. Alcohol can also be used as a solvent, if desired.

The specified reaction is usually carried out at a temperature of from -70 ° C to 200 ° C and preferably at a temperature of from -50 ° C to 100 ° C for a time from 1 minute to 24 hours and preferably from 30 minutes to 10 hours.

(b) A compound of the general formula [3g] or its salt can be obtained (1) by reacting a compound of the general formula [3f] or its salt with an imine in the presence of a catalyst and a base as a reagent for eliminating acidity, according to the method described in the literature [ Tetrahedron Letters, Vol. 38, No.36, Pages 6367-6370 (1997)], and (2) by its hydrolysis in the presence of an additive.

When carrying out the reaction (1), the solvents used are not strictly limited, unless they have a harmful effect on the reaction. Examples of solvents include aromatic hydrocarbons such as benzene, toluene, xylene and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like, etc. The listed solvents may be used as such or as a mixture of two or more solvents.

To carry out this reaction, the catalyst may be selected from combinations of a palladium catalyst such as palladium (II) acetate, tris (dibenzylidene-acetone) dipalladium and the like, a nickel catalyst such as bis (1,5-cyclooctadiene) nickel (0) and the like and a phosphine ligand such as 1,1'-bis (diphenylphosphino) ferrocene, (s) - (-) - 2,2'-bis (diphenylphosphino) -1,1'-binaphthyl and the like. The catalyst is used in an amount of 0.001-1.0 mol and preferably 0.002-0.5 mol per mol of the compound of formula [3f] or its salt.

The base used in this reaction includes alkali metal salts such as sodium tert-butoxide, cesium carbonate and the like. The base is used at least in an equimolar amount and preferably in an amount of 1.0-3.0 mol per mol of the compound of formula [3f] or its salt.

The imine used in this reaction includes, for example, benzophenonyminine and the like. The imine is used at least in an equimolar amount and preferably in an amount of 1.0-3.0 mol per mol of the compound of formula [3f] or its salt.

The specified reaction is usually carried out at a temperature of 0-120 ° C and preferably at a temperature of 5-100 ° C for a time from 1 minute to 48 hours and preferably from 5 minutes to 24 hours.

(2) When carrying out the reaction (2), the solvents used are not strictly limited, unless they have a detrimental effect on the reaction. Solvents used are, for example, ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; alcohols such as methanol, ethanol and the like; water, etc. The listed solvents may be used as such or as a mixture of two or more solvents.

The additive used in this reaction includes, for example, salts of organic and inorganic acids, such as sodium acetate, hydroxylamine hydrochloride, ammonium formate and the like; inorganic acids such as hydrochloric acid and the like; and palladium catalysts such as palladium on carbon and the like.

These additives can be used in combination, if desired. The additive is used in an amount of 0.01-50 mol and preferably 0.1-20 mol per mol of the compound of general formula [3f] or its salt.

The specified reaction is usually carried out at a temperature of 0-120 ° C and preferably at a temperature of 5-100 ° C for a time from 1 minute to 48 hours and preferably from 3 minutes to 24 hours.

(c) A compound of general formula [3h] or a salt thereof can be prepared by reacting a compound of general formula [3g] or a salt thereof according to synthesis method I-1 (b).

(a) A compound of general formula [3i] or its salt can be obtained by deamination of the amino group of a compound of general formula [3h] or its salt using a diazotizing reagent in the presence of acid, in the presence or absence of an additive according to the method described, for example, in Fusso Kagaku Nyumon, Pages 219-230 (edited by Nippon Gakujutsu Shinkokai, 155 Fluorine Chemistry Committee, 1997), followed by a fluorination reaction.

The solvent used in this reaction is not strictly limited, unless the solvent has a deleterious effect on the reaction. Examples of solvents include ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; halogenated hydrocarbons such as dichloromethane, chloroform, dichloroethane and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylformamide, N-methyl-2-pyrrolidone and the like; sulfoxides such as dimethyl sulfoxide and the like; amines and amino oxides such as triethylamine, N, N-dimethylaniline, pyridine, pyridine-N-oxide and the like; ketones such as acetone and the like; water etc. The listed solvents may be used as a mixture, if desired.

The diazotizing reagents used in this reaction can be any reagents, if they are usually used for diazotization of aromatic amino compounds. Preferred diazotizing agents are, for example, alkali metal salts of nitrous acid such as sodium nitrite and the like. The diazotizing reagent is used at least in an equimolar amount, preferably in an amount of 1.0-5.0 mol, and in addition, preferably 1.0-1.5 mol per mol of the compound of formula [3h] or its salt.

The acid used in this reaction is not strictly limited, unless it has a detrimental effect on the reaction. Examples of acids include acids such as hydrochloric acid, hydrofluoric acid, hydrogen fluoride and the like; solutions of hydrogen fluoride in bases, such as a solution of hydrogen fluoride in pyridine, etc. These acids may be used as a mixture, if desired.

To carry out this reaction, the acid is used in at least 1 ml and preferably 1-50 ml per g of the compound of general formula [3h] or its salt, which is determined based on the volume / weight ratio.

The additive used in this reaction includes hydrofluoric acid, sodium tetrafluoride, ammonium fluoroborate and the like. The acid is used at least in an equimolar amount and preferably 1.0 to 20.0 mol per mol of the compound of formula [3h] or its salt.

The specified reaction is usually carried out at a temperature of from -70 ° C to 100 ° C and preferably at a temperature of from -60 ° C to 30 ° C for a period of time from 50 minutes to 24 hours and preferably from 1 hour to 10 hours.

(e) A compound of general formula [3i] or a salt thereof can be prepared by reacting a compound of general formula [3f] or a salt thereof according to synthesis method I-1 (b).

(f) A compound of general formula [3a '] or a salt thereof can be prepared by reacting a compound of general formula [3i] or a salt thereof with a reagent to remove a protective group.

The solvent used in this reaction is not strictly limited, unless the solvent has a deleterious effect on the reaction. Examples of solvents include alcohols such as methanol, ethanol, propanol and the like; thioalcohols such as ethanethiol, thiophenol and the like; aromatic hydrocarbons such as benzene, toluene, xylene and the like; halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; thioethers such as dimethyl sulfide and the like; ketones such as acetone, methyl ethyl ketone and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like; sulfoxides such as dimethyl sulfoxide and the like; inorganic acids such as sulfuric acid, hydrochloric acid and the like; carboxylic acids such as acetic acid, trifluoroacetic acid and the like; sulfonic acids such as trifluoromethanesulfonic acid and the like; organic bases such as pyridine, triethylamine and the like; water etc. The listed solvents may be used as such or as a mixture of two or more solvents.

As a reagent that promotes the removal of the protective group, reagents that are usually used to remove the protection of the aromatic alcohol can be used. Preferably, trimethylsilyl iodide and the like can be used. It is also acceptable to obtain a reagent that promotes the removal of the protective group in the reaction system. The deprotecting reagent is used in an amount of 0.01-50 mol and preferably 0.1-30 mol per mol of the compound of formula [3i] or its salt.

The specified reaction is usually carried out at a temperature of from -80 ° C to 200 ° C and preferably at a temperature of from 0 ° C to 160 ° C for a period of from one minute to 48 hours and preferably from 5 minutes to 20 hours.

A compound of the general formula [3e] or a salt thereof, which are the starting material for carrying out the above reaction, can be prepared, for example, by the method described in J. Am. Chem. Soc., Vol. 71, Pages 2798-2800 (1949).

[Production Method I-C]

where R ¹ is as defined above, and R ¹³ represents a lower alkoxy group or an aryloxy group.

(a) A compound of the general formula [3k] or its salt can be prepared by reacting a compound of the general formula [3l] or its salt with an alcohol in the presence or absence of an acid catalyst or base according to the procedure described, for example, in Shin Jikken Kagaku Koza, Vol .14, Pages 1599-1602 (edited by the Chemical Society Japan (corporate juridical person), 1978).

The solvent used in this reaction is not strictly limited, unless the solvent has a deleterious effect on the reaction. Examples of solvents include aromatic hydrocarbons such as benzene, toluene, xylene and the like; halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like; sulfoxides such as dimethyl sulfoxide and the like, etc. The listed solvents may be used as such or as a mixture of two or more solvents.

The alcohol used in this reaction includes, for example, methanol, ethanol, phenol and the like. Alcohol is used at least in an equimolar amount with respect to the compound of formula [3l] or its salt. The use of alcohol as a solvent is permissible, if desired.

As the acid catalyst used in this reaction, reagents are used that are commonly used to imitate nitriles. For these purposes, for example, hydrogen chloride and the like can be used. The acid catalyst is used in an amount of at least 0.1 mol per mol of the compound of formula [3I] or its salt.

The base used in this reaction may include, for example, metal alkoxides such as sodium methoxide, sodium ethoxide, sodium phenoxide and the like. It is permissible to obtain these bases in the reaction system, if desired. To carry out this reaction, the base is used in an amount of at least 0.01 mol and preferably 1.0-5.0 mol per mol of the compound of the formula [3I] or its salt.

The specified reaction is usually carried out at a temperature of from -78 ° C to 170 ° C and preferably at a temperature of from -40 ° C to 120 ° C for a period of from one minute to 72 hours and preferably from 5 minutes to 24 hours.

(b) A compound of the general formula [3j] or its salt can be prepared by reacting a compound of the general formula [3k] or its salt with a reagent according to the procedure described, for example, in Shin Jikken Kagaku Koza, Vol.14, Pages 1614-1617 (edited by the Chemical Society Japan (corporate juridical person), 1978).

The solvent used in this reaction is not strictly limited, unless the solvent has a deleterious effect on the reaction. Examples of solvents include aromatic hydrocarbons such as benzene, toluene, xylene and the like; halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like; sulfoxides such as dimethyl sulfoxide and the like, etc. The listed solvents may be used as such or as a mixture of two or more solvents.

As the aforementioned reagent used in this reaction, such reagents are used that are commonly used for amidination of imidates. Examples of the above reagent include gaseous ammonia, alcoholic ammonia solution, aqueous ammonia solution and ammonium acid salts such as ammonium chloride and the like. The reagent is used at least in an equimolar amount with respect to the compound of formula [3k] or its salt. The use of a reagent as a solvent is permissible, if desired.

The specified reaction is usually carried out at a temperature of from -78 ° C to 170 ° C and preferably at a temperature of from 0 ° C to 120 ° C for a period of from one minute to 72 hours and preferably from 5 minutes to 24 hours.

[Production Method I-D]

where R ^1a is as defined above.

(a) A compound of the general formula [3m] or its salt can be prepared by reacting a compound of the general formula [3n] or its salt with a diazotizing agent and a hydroxylating agent in the presence or absence of an additive according to the procedure described for example in Shin Jikken Kagaku Koza, Vol.14, Pages 537-538 (edited by the Chemical Society Japan (corporate juridical person), 1977).

The solvent used in this reaction is not strictly limited, unless the solvent has a deleterious effect on the reaction. Examples of solvents include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid and the like; ethers such as dioxane, tetrahydrofuran, anisole, diethylene glycol diethyl ether, dimethyl cellosolve and the like; halogenated hydrocarbons such as dichloromethane, chloroform, dichloroethane and the like; nitriles such as acetonitrile and the like; amides such as N, N-dimethylformamide, N-methyl-2-pyrrolidone and the like; sulfoxides such as dimethyl sulfoxide and the like; amines and amino acids such as triethylamine, N, N-dimethylaniline, pyridine-N-oxide and the like; ketones such as acetone and the like; water etc. The listed solvents may be used as such or as a mixture.

The diazotizing reagent used in this reaction is not strictly limited, if it is usually used for deaminohydroxylation of aromatic amino compounds. Preferably, alkali metal nitrites such as sodium nitrite and the like are used. The diazotizing reagent is used at least in an equimolar amount, preferably in an amount of 1.0-5.0 mol, and, in addition, preferably 1.0-2.0 mol per mol of the compound of the formula [3n].

The hydroxylating reagent used in this reaction may include, for example, water and the like. The hydroxylating reagent is used at least in an equimolar amount with respect to the compound of formula [3n], although the hydroxylating reagent can also be used as a solvent, if desired.

The additive used in this reaction may include, for example, copper salts such as copper sulfate and the like; and inorganic bases such as sodium hydroxide, sodium carbonate and the like. The additive is used in an amount of 0.01-100 mol and preferably 0.1-50 mol per mol of the compound of the formula [3n].

The specified reaction is usually carried out at a temperature of from -70 ° C to 200 ° C and preferably at a temperature of from -50 ° C to 100 ° C for a period of from one minute to 24 hours and preferably from 30 minutes to 10 hours.

(b) A compound of the general formula [3n] or its salt can be obtained (1) by reacting a compound of the general formula [3o] or its salt with an electrophilic fluorinating agent in the presence or absence of an additive and, in more detail, according to the procedure described in Fusso no Kagaku, Pages 28-37 (edited by Kodansha Scientific, 1993) or (2) by reacting a compound of the formula [3o] or its salt with a halogenating reagent in the presence or absence of an additive according to the procedure described, for example, in Shin Jikken Kagaku Koza, Vol .14, Pages 354-360 (edited by the Chemical Society Japan (corporate juridical person), 1977).

In the method (1), the solvents used are not strictly limited, unless they have a deleterious effect on the reaction. Examples of the solvent include halogenated hydrocarbons such as methylene chloride, chloroform, fluorotrichloromethane, 1,1,2-trichlorotrifluoroethane and the like; ethers such as diethyl ether, tetrahydrofuran, diethylene glycol diethyl ether, dimethyl cellosolve and the like; alcohols such as methanol and the like; nitriles such as acetonitrile and the like; organic acids such as acetic acid, formic acid, trifluoroacetic acid and the like; inorganic acids such as hydrofluoric acid, sulfuric acid and the like; water etc. These solvents may be used as such or in the form of two or more solvents.

The electrophilic fluorinating reagents that are used in this reaction are not strictly limited if they are usually used for the reaction of attachment of fluorine atoms to carbon-carbon multiple bonds. Preferred examples of such reagents include fluorine gas, trifluoromethylhypofluorite, acetyl hypofluorite, difluorxenone, perchloric acid fluoride, cesium sulfate fluorite, N-fluoropyridinium triflate, N-fluoro-N-alkyl-allenesulfonamide,

N-fluorosaccharinesultam, N-fluorobis (trifluoromethanesulfone) imide, N-fluorobis (benzenesulfone) imide and N-fluoro-O-benzenesulfonimide. Of these electrophilic fluorinating reagents, gaseous fluorine is preferred. The electrophilic fluorinating reagent is used in an amount of 0.05-50 mol and preferably 0.1-20 mol per mol of the compound of formula [3o] or its salt.

The additive, which if necessary can be used in this reaction, is not strictly limited, if it is usually used in electrophilic fluorination reactions. Preferred examples of such additives include acid catalysts such as boron trifluoride, hydrofluoric acid and the like; organic and inorganic bases such as triethylamine, sodium fluoride and the like; and halogens such as chlorine, bromine, iodine and the like. These additives can be used as such or as a mixture of two or more additives. In this reaction, the additive is used in an amount of 0.01-10 mol and preferably 0.1-10 mol per mol of the compound of formula [3o] or its salt.

The specified reaction is usually carried out at a temperature of from -80 ° C to 170 ° C and preferably at a temperature of from -80 ° C to 100 ° C for a period of from one minute 72 hours and preferably from 5 minutes to 48 hours.

(2) In the method (2), the solvents used are not strictly limited, unless they have a detrimental effect on the reaction. Examples of the solvent include halogenated hydrocarbons such as methylene chloride, chloroform, fluorotrichloromethane, 1,1,2-trichlorotrifluoroethane and the like; ethers such as diethyl ether, tetrahydrofuran, diethylene glycol diethyl ether, dimethyl cellosolve and the like; alcohols such as methanol and the like; nitriles such as acetonitrile and the like; organic acids such as acetic acid, formic acid, trifluoroacetic acid and the like; inorganic acids such as sulfuric acid and the like; water etc. These solvents may be used as such or as a mixture of two or more solvents.

The halogenating reagents that are used in this reaction are not strictly limited if they are usually used to halogenate aromatic compounds. Preferred examples of such reagents include bromine, chlorine, sulfuryl chloride, N-bromosuccinimide, N-chlorosuccinimide and the like. The halogenating reagent is used in an amount of 0.05-50 mol and preferably 0.1-20 mol per mol of the compound of formula [3o] or its salt.

Additives that are used if necessary in this reaction are not strictly limited, if they are usually used for halogenation of aromatic compounds. Preferred examples of additives include sodium bromide, lead tetraacetate, titanium (IV) chloride, aluminum chloride, silver sulfate and the like. These additives can be used as such or as a mixture of two or more additives. In this reaction, the additive is used in an amount of 0.01-10 mol and preferably 0.1-10 mol per mol of the compound of formula [3o] or its salt.

The specified reaction is usually carried out at a temperature of from -80 ° C to 170 ° C and preferably at a temperature of from -80 ° C to 100 ° C for a period of from one minute 72 hours and preferably from 5 minutes to 48 hours.

In the above methods for producing compounds, all compounds can be used in the form of their salts. As the indicated salt, the same salts may be used as described in the paragraph on the salt of the compound of the general formula [1]. If desired, these reactions can be carried out in an atmosphere of inert gas, such as nitrogen. The compound of the general formula [1] or its salt, which were obtained by the aforementioned method, can be converted into other compounds of the general formula [1] or their salts by carrying out known reactions such as oxidation, reduction, rearrangement, substitution, halogenation, dehydration, hydrolysis and similar or by the implementation of an appropriate combination of these reactions.

Some compounds referenced in the above preparation methods may have isomers, such as optical isomers, geometric isomers, tautomers, etc. In such cases, these isomers are also used in the present invention, and solvated products, hydrates and various crystalline forms are also used. After completion of the reaction, the target compound can be used in the next reaction step without isolation, if desired.

Some compounds referred to in the above methods for their preparation may have an amino group, a hydroxyl group or a carboxyl group. If desired, it is possible to pre-protect said groups with a conventional protecting group and, after the reaction has ended, remove the protecting group in a manner well known per se.

A compound of the general formula [1] or a salt thereof can be isolated, purified or recrystallized by conventional methods such as extraction, crystallization and / or column chromatography, etc.

The compound of the present invention is formulated with various pharmaceutical additives, such as an inert filler, a binding agent, a disintegrant, an anti-disintegrating agent, a release agent and a non-sticking agent, a lubricating agent, an absorption adsorption carrier, a solvent, a filler, an isotonic agent, an dissolution promoting agent , emulsifier, suspending agent, thickener, coating agent, absorption promoter, gelation-coagulation promoter, light stabilizer , preservative, moisture insulating agent, emulsion-suspension-dispersion stabilizer, color protector, deoxygenation-oxidation inhibiting agent, sweetening-flavoring agent, colorant, blowing agent, anti-foaming agent, painkiller, antistatic, buffering agent, pH adjusting agent, etc. ., and form in a pharmaceutical composition, such as an oral composition (tablet, capsule, powder, granule, fine granule, pill, suspension, emulsion, solution, syrup, etc.), injection, suppository, external composition (ointment , adhesive, etc.), aerosol, etc.

Based on the above compositions, pharmaceutical formulations are prepared according to conventional methods.

Solid preparations for oral administration, such as a tablet, powder, granule and the like, are prepared according to the usual method together with pharmaceutical additives intended for solid preparations, including excipients such as lactose, sucrose, sodium chloride, glucose, starch, calcium carbonate, kaolin crystalline cellulose, anhydrous secondary acidic calcium phosphate, partially pregelatinized starch, corn starch, alginic acid and the like; binding agents such as syrup, glucose solution, starch solution, gelatin solution, polyvinyl alcohol, polyvinyl ether, polyvinylpyrrolidone, carboxymethyl cellulose, shellac, methyl cellulose, ethyl cellulose, sodium alginate, gum arabic, hydroxypropyl methyl cellulose, hydroxypropyl methyl cellulose, ethanol, cellulose, hydroxypropylmethyl cellulose, hydroxypropylmethyl cellulose, ethanol, cellulose, hydroxypropylmethyl cellulose, hydroxypropylmethyl cellulose, ethanol; disintegrants such as dry starch, alginic acid, agar powder, starch, cross-linked polyvinyl pyrrolidone, cross-linked sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, starch glycolic acid sodium salt and the like; disintegration inhibitors such as stearyl alcohol, stearic acid, cocoa butter, hydrogenated oil and the like; anti-adhesive and anti-sticking agents such as aluminum silicate, calcium hydrogen phosphate secondary, magnesium oxide, talc, silicic anhydride and the like; lubricating agents such as carnauba wax, volatile silicic anhydride, aluminum silicate, magnesium silicate, hydrogenated oil, derivatives of hydrogenated vegetable oil, sesame oil, white wax, titanium oxide, dry aluminum hydroxide gel, stearic acid, calcium stearate, magnesium stearate, talc , secondary acidic calcium phosphate, sodium lauryl sulfate, polyethylene glycol and the like; absorption promoters such as quaternary ammonium salts, sodium lauryl sulfate, urea, enzymes and the like; absorption-adsorption carriers such as starch, lactose, kaolin, bentonite, silicic anhydride, hydrated silicon dioxide, magnesium metasilicate-aluminate, colloidal silicic acid and the like, etc.

In addition, if desired, the tablet can be made in the form of conventional coated tablets, such as a sugar-coated tablet, a gelatin-coated tablet, a stomach-soluble tablet, an enteric-coated tablet, or a water-soluble film-coated tablet.

A capsule is prepared by mixing together the aforementioned pharmaceutical ingredients and filling the resulting mixture with a hard gelatin capsule, soft capsule, etc.

In addition, an aqueous or oily suspension, solution, syrup and elixir can be prepared by forming a pharmaceutical composition together with the aforementioned additives for the preparation of a liquid preparation, such as a solvent, excipient, isotonic agent, emulsifier, suspension stabilizer, thickener, etc. ., in the form of a liquid preparation according to the usual method.

A suppository can be prepared by adding an appropriate absorption promoter to polyethylene glycol, cocoa butter, lanolin, higher alcohol, higher hydroxy acid ester, gelatin, semi-synthetic glyceride, Witepsol or the like, and mixing these ingredients together with the pharmaceutical composition to form a suppository.

An injection form is prepared by mixing the pharmaceutical composition with pharmaceutical additives for the manufacture of a liquid preparation, including diluents, such as water, ethyl alcohol. Macrogol, polyethylene glycol, citric acid, acetic acid, phosphoric acid, lactic acid, sodium lactate, sulfuric acid, sodium hydroxide and the like; pH adjusting agents and buffering agents such as sodium citrate, sodium acetate, sodium phosphate and the like; stabilizers such as sodium pyrosulfite, ethylenediaminetetraacetic acid, thioglycolic acid, thiolactic acid and the like; isotonic agents such as sodium chloride, glucose, mannitol, glycerin and the like; dissolution promoting agents such as sodium carboxymethyl cellulose, propylene glycol, sodium benzoate, benzyl benzoate, urethane, ethanolamine, glycerin and the like; a painkiller such as calcium gluconate, chlorobutanol, glucose, benzyl alcohol and the like; local anesthetics; etc., and the formation of the mixture in the form of an injection solution according to the usual method.

An ointment in the form of a paste, cream or gel can be prepared by forming a pharmaceutical composition with a base, such as white petrolatum, polyethylene, paraffin, glycerin, cellulose derivatives, polyethylene glycol, silicon, bentonite and the like; preservatives such as paraoxybenzoic acid methyl ester, paraoxybenzoic acid ethyl ester, paraoxybenzoic acid propyl ester and the like; stabilizers; wetting agents, etc., and the formation of a mixture in the form of an ointment according to the usual method.

The patch can be made using the aforementioned ointment, cream, gel, or paste applied to a conventional substrate according to a conventional method. As the substrate, you can use textile and non-textile fabrics and films or foam plates made of soft vinyl chloride, polyethylene, polyurethane and the like.

The route of administration of the aforementioned pharmaceutical composition is not limited to any particular one, and can, in fact, be determined in accordance with the form of the preparation, age, gender and other conditions of the patient, as well as according to the severity of the symptoms of the patient.

The dose of the active ingredient of the pharmaceutical composition according to the present invention is essentially determined based on the method of application of the composition, age and gender of the patient, type of disease and other conditions. Typically, a dose based on the active ingredient of 0.1-100 mg / kg / day for an adult individual can be administered in the composition, either as a single dose or as several parts of a dose.

The following describes the antiviral and cytotoxic activity of pyrazine derivatives represented by the general formula [1] according to the present invention, or their salts.

Sample: a pyrazine derivative represented by the general formula [1] or a salt thereof was dissolved in dimethyl sulfoxide to give a solution with a concentration of 10 mg / ml. At the time of use, the solution was diluted to the desired concentration with the culture medium and used.

Culture medium: minimum maintenance culture medium (E'-MEM) with 10% fetal bovine serum added was used for the growth of MDCK cells (obtained from a dog’s kidney), MA-104 (obtained from a monkey’s kidney) and HEP-2 (obtained from a tumor with human pharyngeal cancer) and to test cytotoxicity.

MDCK cells were used as influenza virus host cells and to check for cytotoxicity. MA-104 cells were used as rotavirus host cells, and HEP-2 cells were used as Rous sarcoma virus host cells.

Test Example 1 [Activity against influenza virus]

MDCK cells were placed in a 6-well plate (manufactured by CORNING) with a density of 5 × 10 ⁵ cells / well and cultured overnight at 35 ° C. under 5% carbon dioxide. The influenza virus (strain A / PR / 8/34) was diluted to 200 PFU / ml with a serum-free culture medium and the cells were infected, the virus was adsorbed at a rate of 0.5 ml / well for one hour. At the end of infection and adsorption, an E'-MEM culture medium was added to the wells containing the test compound at a predetermined concentration together with 0.6% purified agar, 1% bovine serum albumin and 3 μg / ml acetylated trypsin. Upon achieving sufficient coagulation, the plate was turned upside down and cultured for 3 days. At the end of the cultivation, living cells were stained with 1% neutral red, the cells were fixed with 10% formalin, the agar medium was removed with running water, and the number of spots was counted.

The stain inhibition rate was expressed as a percentage with respect to a control sample containing no test compound.

The results are shown in table I-2, where the presented series of test compounds is the same as in the examples.

Table I-2 Compound (Example) FROM (%) 4 - [(2R, 3R, 4S, 5R) -3,4-dihydroxy-5- (hydroxymethyl) tetrahydro-2-furanyl] -oxo-3,4-dihydro-2-pyrazinecarboxamide (I-2) 10 95 4 - [(2R, 3R, 43.5R) -3,4-dihydroxy-5- (hydroxymethyl) tetrahydro-2-furanyl] -6-fluoro-oxo-3,4-dihydro-2-pyrazinecarboxamide (1-4 ) 10 47 6-fluoro-3-hydroxy-2-pyrazinecarboxamide (1-5) 100 42 C — Concentration of the added test compound, μg / ml; (%) - Inhibition rate in%.

In addition, the activity against the influenza virus exhibited by nitrogen-containing heterocyclic carbamoyl derivatives represented by the general formula [23], which are derivatives of the compounds of the present invention, or salts of these derivatives, was determined in the same manner as in Test Example 1. As the test compound, 6-fluoro-3-hydroxy-2-pyrazinecarboxamide dissolved in dimethyl sulfoxide to form a solution with a concentration of 10 mg / ml, which was diluted with a culture solution to a certain concentration before use. The results showed that the activity against influenza virus was 100% in the form of the degree of inhibition at a concentration of the test compound of 1 μg / ml, which indicates that this test compound is an excellent antiviral drug.

Test Example 2 [Activity against rotavirus]

MA-104 cells were placed in a 6-well plate (manufactured by CORNING) with a density of 5 × 10 ⁵ cells / well and cultured overnight at 37 ° C. under 5% carbon dioxide. Rotavirus (Ku strain), activated with acetylated trypsin at a concentration of 10 μg / ml for 30 minutes, was diluted to 140 PFU / ml with a serum-free culture medium and the cells were infected, the virus was adsorbed at a rate of 0.5 ml / well for one hour. After completion of the infection and adsorption, the infectious medium was removed and an E'-MEM culture medium containing 30 μg / ml of test compound, 5 μg / ml trypsin and 1.4% agarose was added. Rotavirus infected MA-104 cells were cultured for 3 days at 37 ° C under 5% carbon dioxide, after which a 0.7% agarose solution containing 0.005% neutral red was layered and continued to be cultured for one day in the same conditions as described above. At the end of the cultivation, the plate was fixed with a 3% formaldehyde solution, the culture medium hardened with agar was removed, and then the number of spots was counted. The rate of inhibition against rotavirus was calculated based on the number of spots in the group of cells treated with the compound and in the untreated group of cells.

As a result, the compound of Example I-1 was shown to be active against rotavirus.

Test Example 3 [Activity against RS virus (Routh sarcoma) (respiratory syncytial virus)]

HEP-2 cells were scattered on a 6-well plate (manufactured by CORNING) with a density of 5 × 10 ⁵ cells / well and cultured overnight at 37 ° C. under 5% carbon dioxide. The RS virus (strain A-2) was diluted to 140 PFU / ml with a serum-free culture medium and the cells were infected; the virus was adsorbed at a rate of 0.5 ml / well for one hour. At the end of infection and adsorption, the infectious medium was removed and an E'-MEM culture medium containing 30 μg / ml of the test compound, 0.12% glutamine, 2% fetal bovine serum and 1% methylcellulose was added to the wells. Hep-2 cells infected with the RS virus were cultured for 3 days at 35 ° C. under 5% carbon dioxide. At the end of the cultivation, the plate was fixed with a 3% formaldehyde solution, and the culture medium containing methyl cellulose was removed. After this, the plate was stained with 5% Giemza solution, and the number of spots was counted. The inhibition rate against RS virus was calculated based on the number of spots in the group of cells treated with the compound and in the untreated group of cells.

Test Example 4 (Cytotoxic Activity)

A culture medium containing the test compound at a predetermined concentration was added to a 96-well plate (manufactured by CORNING CO.) At a volume of 100 μl / well. Then, a dispersion of MDCK cells having a concentration of 2 × 10 ⁴ cells / ml in a culture medium was prepared, dispersed at a rate of 100 μl / well and cultured for 3 days at 37 ° C under 5% carbon dioxide. At the end of the cultivation, the number of living cells was calculated by the XTT method [for example, CANCER RESEARCH, Vol. 48, Pages 4827-4833 (1988), etc.].

The results showed that the concentration of all compounds listed in table I-2, in which there is an inhibition of the growth of 50% of the cells (IC ₅₀ ), is 100 μg / ml or higher.

PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION

The compounds of the present invention and the intermediates of the present invention are described below using reference examples and examples according to the invention. The present invention is in no way limited to these examples.

In the examples below, mixed relationships that relate to eluents, all options in “volumetric relationships”. Silica gel BW-127ZH (manufactured by Fuji Silysia Chemical Co.) was used as a carrier for column chromatography; YMC · GEL ODS-AM 120-S50 (YMC CO., LTD.) was used as a carrier for reverse phase chromatography and DEAE cellulose (manufactured by Wako Pure Chemical Industries) was the carrier for ion exchange column chromatography.

The abbreviation used in the reference examples and examples according to the invention has the following meaning:

DMSO-d ₆ : deuterated dimethyl sulfoxide.

Reference Example I-1

17.0 g of methyl 3-amino-6-bromo-2-pyrazinecarboxylate were dissolved in 100 ml of concentrated sulfuric acid. Then, 10.1 g of sodium nitrite was added to the ice-cooled solution and stirred for 30 minutes. The reaction mixture was poured into 920 ml of methanol and heated at the boil under reflux for 5 hours. After cooling, the reaction mixture was concentrated under reduced pressure, the obtained residue was added to the mixture with 500 ml of ice water and 600 ml of chloroform, and the resulting mixture was separated into layers. The organic layer was washed successively with saturated aqueous sodium bicarbonate, water and saturated aqueous sodium chloride, and dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. Thus, 6.30 g of methyl 6-bromo-3-methoxy-2-pyrazinecarboxylate was obtained as a pale yellow oily product.

IR (KBr) cm ^-1 : 1735

¹ H-NMR (CDCl ₃ ) δ: 3.97 (3H, s), 4.06 (3H, s), 8.37 (1H, s).

Reference Example I-2

In 227 ml of toluene, 11.4 g of methyl 6-bromo-3-methoxy-2-pyrazinecarboxylate was dissolved in a stream of nitrogen gas, and 10.3 g of benzophenonimine, 0.42 g of tris (dibenzylideneacetone) dipalladium, 0.86 g were successively added.

(s) - (-) - 2,2'-bis (diphenylphosphino) -1,1'-binaphthyl and 6.20 g of sodium tert-butoxide. The mixture was stirred at 80 ° C for one hour. After cooling the reaction mixture, it was filtered. The filtrate was purified by column chromatography [eluent: toluene: ethyl acetate = 20: 1]. The resulting oily product was dissolved in 140 ml of tetrahydrofuran, 7 ml of a 2 mol / L hydrochloric acid solution was added, and the mixture was stirred at room temperature for 15 minutes. Then, a mixture of 200 ml of chloroform and 50 ml of water was added to the reaction mixture, and then 1 mol / L sodium hydroxide solution was added to alkalize the mixture, and the organic layer was separated. The resulting organic layer was washed with a saturated aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The residue was purified by column chromatography [eluent: toluene: ethyl acetate = 1: 1] to obtain 3.64 g of methyl 6-amino-3-methoxy-2-pyrazinecarboxylate as a yellow oily product.

IR (KBr) cm ^-1 : 1716, 1670

¹ H-NMR (DMSO-d ₆ ) δ: 3.80 (3H, s), 3.82 (3H, s), 7.20 (2H, br s), 7.77 (1H, s).

Reference Example I-3

3.5 g of methyl 6-amino-3-methoxy-2-pyrazinecarboxylate was dissolved in 70 ml of methanol. After feeding ammonia gas into the solution to prepare a saturated solution, the solution was stirred at room temperature for 14 hours. Removal of the solvent from the reaction mixture under reduced pressure afforded 3.1 g of 6-amino-3-methoxy-2-pyrazinecarboxamide as a solid.

IR (KBr) cm ^-1 : 1684

¹ H-NMR (DMSO-d ₆ ) δ: 3.79 (3H, s), 5.87 (2H, br s), 7.30-7.75 (3H, m).

Reference Example I-4

1.50 g of 6-amino-3-methoxy-2-pyrazinecarboxamide was dissolved in 12 ml of a 70% solution of hydrogen fluoride-pyridine in a nitrogen gas atmosphere, while cooling the solution with ice. Then, 0.71 g of sodium nitrite was added at -50 ° C, and the resulting mixture was stirred at 10 ° C for one hour. After stirring the reaction mixture for another hour, a mixture of 50 ml of ice water and 100 ml of chloroform was added, and the resulting mixture was separated into layers. The organic layer was washed with a saturated aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. Thus, 1.29 g of 6-fluoro-3-methoxy-2-pyrazinecarboxamide was obtained as a solid.

IR (KBr) cm ^-1 : 1707

¹ H-NMR (DMSO-d ₆ ) δ: 3.95 (3H, s), 7.55-8.15 (2H, m), 8.39 (1H, d, J = 8.3 Hz).

Reference Example I-5

1.51 g of sodium iodide was dissolved in 22 ml of acetonitrile in a nitrogen gas atmosphere. After adding 1.10 g of trimethylsilyl chloride, the resulting mixture was stirred at room temperature for 20 minutes. Then, 0.43 g of 6-fluoro-3-methoxy-2-pyrazinecarboxamide was added and the resulting mixture was stirred at the same temperature as described above for 18 hours. The reaction mixture was added to the mixture of 10 ml of water and 200 ml of chloroform, and the resulting mixture was separated into layers. The organic layer was washed successively with a 5% aqueous sodium thiosulfate solution and a saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The residue was purified by column chromatography [eluent: hexane: ethyl acetate = 2: 1] to obtain 0.06 g of 6-fluoro-3-hydroxy-2-pyrazinecarboxamide as a white solid.

IR (KBr) cm ^-1 : 1685, 1658

¹ H-NMR (CDCl ₃ ) δ: 5.40-7.80 (2H, m), 8.31 (1H, d, J = 7.8 Hz), 12.33 (1H, s).

Reference Example I-6

1.0 g of methyl 6-chloro-3-oxo-3,4-dihydro-2-pyrazinecarboxylate was dissolved in 40 ml of dichloroethane. Then, 1.0 ml of 1,1,1,3,3,3-hexamethyldisilazane and 0.54 ml of chlorotrimethylsilane in a nitrogen gas atmosphere were successively added to the solution and heated at 90 ° C for 2 hours. The mixture was cooled and the solvent was removed under reduced pressure. The residue was dissolved in 30 ml of dichloroethane, then 2.68 g of β-D-ribofuranose-1-acetate-2,3,5-tribenzoate and 1.24 ml of tin (IV) chloride were successively added, and the resulting mixture was stirred at room temperature in within 16 hours. The reaction mixture was added to 30 ml of ice water and adjusted to pH 8 with saturated aqueous sodium bicarbonate and separated into layers. The organic layer was washed successively with water and a saturated aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate, then the solvent was removed under reduced pressure. The resulting residue was purified by column chromatography [eluent: hexane: ethyl acetate = 4: 1] to obtain 1.76 g of methyl 4 - {(2R, 3R, 4R, 5R) -3,4-bis (benzoyloxy) -5 - [(benzoyloxy ) methyl] tetrahydro-2-furanyl) -6-chloro-3-oxo-3,4-dihydro-2-pyrazinecarboxylate as a yellow oily product.

IR (neat) cm ^-1 : 1728

¹ H-NMR (CDCl ₃ ) δ: 3.94 (3H, s), 4.5-4.9 (3H, m), 5.6-6.0 (2H, m), 6.3-6 5 (1H, m), 7.1-8.2 (16H, m).

Reference Example I-7

0.80 g of methyl 4 - {(2R, 3R, 4R, 5R) -3,4-bis (benzoyloxy) -5 - [(benzoyloxy) methyl] tetrahydro-2-furanyl} -6-chloro was suspended in 16 ml of methanol -3-oxo-3,4-dihydro-2-pyrazinecarboxylate. The suspension was ice-cooled, and 0.73 g of a 28% methanol solution of sodium methoxide was added at the same time, and the resulting mixture was stirred at the same temperature as described above for one hour. After the mixture was stirred at room temperature for an additional 3 hours, the mixture was adjusted to pH 7 with a solution of 6 mol / L hydrochloric acid, and the solvent was removed under reduced pressure. The residue was purified by column chromatography [eluent: chloroform: methanol = 10: 1] to obtain 0.29 g of methyl 6-chloro-4 - [(2R, 3R, 4S, 5R) -3,4-dihydroxy-5- (hydroxymethyl) tetrahydro-2-furanyl] -3-oxo-3,4-dihydro-2-pyrazinecarboxylate as a yellow oily product.

IR (neat) cm ^-1 : 1728

¹ H-NMR (CDCl ₃ + DMSO-d ₆ ) δ: 3.6-5.6 (11H, m), 5.99 (1H, s), 8.67 (1H, s).

Example I-1

In 5.0 ml of 1, 1,1,3,3,3-hexamethyldisilazane, 1.0 g of 3-hydroxy-2-pyrazinecarboxamide was suspended. The suspension was heated under reflux for 30 minutes and allowed to cool, and the solvent was removed under reduced pressure. The residue was dissolved in 5.0 ml of dichloroethane in a nitrogen gas atmosphere, then 3.11 g (3-0-ribofuranoso-1-acetate-2,3,5-tribenzoate and 0.50 ml of tin (IV) chloride were successively added and the resulting the mixture was stirred at room temperature for 22 hours.The reaction mixture was diluted with 30 ml of ethyl acetate and 20 ml of water, adjusted to pH 8 with saturated aqueous sodium bicarbonate, the precipitate was filtered off and the organic layer was separated.The organic layer was washed successively with water and saturated aqueous sodium chloride and dried over anhydrous sou magnesium sulfate and the solvent was removed under reduced pressure. The residue was purified by column chromatography [developing solution: ethyl acetate: methanol = 10: 1], then isopropyl ether was added and the solid material was collected by filtration, so 0.41 g [(2R, 3R, 4R) was obtained , 5R) -5- [3- (aminocarbonyl) -2-oxo-1 (2H) -pyrazinyl] -3,4-is (benzoyloxy) tetrahydro-2-furanyl] methylbenzoate as a white solid.

IR (KBr) cm ^-1 : 1734, 1685

¹ H-NMR (CDCl ₃ ) δ: 4.6-5.1 (3H, m), 5.8-6.2 (3H, m), 6.39 (1H, d, J = 2.5 Hz ), 7.2-8.2 (17H, m), 8.95 (1H, br s).

Example I-2

0.37 g of [(2R, 3R, 4R, 5R) -5- [3- (aminocarbonyl) -2-oxo-1 (2H) pyrazinyl] -3,4-bis (benzoyloxy) tetrahydro was dissolved in 4 ml of methanol -2-furanyl] methylbenzoate. While cooling the solution with ice, gaseous ammonia was supplied to saturation. The reaction mixture was stirred at room temperature for 15 hours and the solvent was removed under reduced pressure. Methanol was added to the residue and the precipitate was collected by filtration to obtain 0.12 g of 4 - [(2R, 3R, 4S, 5R) -3,4-dihydroxy-5- (hydroxymethyl) tetrahydro-2-furanyl] -3-oxo-3 , 4-dihydro-2-pyrazinecarboxamide as a light brown solid.

IR (KBr) cm ^-1 : 1654

¹ H-NMR (DMSO-d ₆ ) δ: 3.73 (2H, dd, J = 5.4, 5.4 Hz), 3.8-4.2 (3H, m), 5.08 (1H broad s), 5.24 (1H, t, J = 5.4 Hz), 5.61 (1H, broad s), 5.92 (1H, s), 7.54 (1H, d, J = 4.2 Hz), 7.71 (1H, br s), 8.27 (1H, d, J = 4.2 Hz), 8.30 (1 H, br s).

Example I-3

6-Fluoro-3-hydroxy-2-pyrazinecarboxamide was treated in the same manner as in Example I-1 to obtain [(2R, 3R, 4R, 5R) -5- [3- (aminocarbonyl) -5-fluoro-2 -oxo-1 (2H) -pyrazinyl] -3,4-bis (benzoyloxy) tetrahydro-2-furanyl] methylbenzoate.

IR (KBr) cm ^-1 : 1726, 1690

¹ H-NMR (DMSO-d ₆ ) δ: 4.6-5.0 (3H, m), 5.9-6.1 (2H, m), 6.33 (1H, s), 7.3 -8.2 (17H, m), 8.53 (1H, br s).

Example I-4

0.15 g of [(2R, 3R, 4R, 5R) -5- [3- (aminocarbonyl) -5-fluoro-2-oxo-1 (2H) -pyrazinyl] -3.4 was dissolved in 2.0 ml of methanol bis (benzoyloxy) tetrahydro-2-furanyl] methylbenzoate. Then, 0.14 g of a 28% methanol solution of sodium methoxide was added to the ice-cooled solution, and stirred at this temperature for 20 minutes and then at room temperature for 30 minutes. The reaction mixture was acidified with 0.75 ml of a 1 mol / L hydrochloric acid solution, and the solvent was removed under reduced pressure. After purification of the residue by column chromatography [developing solution: chloroform: methanol = 5: 1], isopropanol and diethyl ether were added, and the solid product was collected by filtration to obtain 40 mg

4 - [(2R, 3R, 43.5R) -3,4-dihydroxy-5- (hydroxymethyl) tetrahydro-2-furanyl] -6-fluoro-3-oxo-3,4-dihydro-2-pyrazinecarboxamide.

IR (KBr) cm ^-1 : 1686

Example I-5

0.26 g of methyl 6-chloro-4 - [(2R, 3R, 4S, 5S) -3,4-dihydroxy-5- (hydroxymethyl) tetrahydro-2-furanyl] -3-oxo-3 was dissolved in 4 ml of methanol , 4-dihydro-2-pyrazinecarboxylate. Ammonia gas was supplied to the solution cooled by ice until saturation. The reaction mixture was stirred under ice cooling for one hour, and then the solvent was removed under reduced pressure. Purification by column chromatography [eluent: chloroform: methanol = 7: 1] of the residue gave 0.06 g of 6-chloro-4 - [(2R, 3R, 43.5R) -3,4-dihydroxy-5- (hydroxymethyl) tetrahydro -2-furanyl] -3-oxo-3,4-dihydro-2-pyrazinecarboxamide as a pale yellow solid.

IR (KBr) cm ^-1 : 1693

Example I-6

5.3 g of 6-fluoro-3-hydroxy-2-pyrazinecarboxamide were suspended in 53 ml of acetonitrile in a stream of nitrogen gas. Then, 8.4 ml of N, O-bis (trimethylsilyl) acetamide was added to the suspension, cooling the mixture with ice, and the mixture was stirred at room temperature for 1.5 hours. A solution of 9.4 g of (2R, 3R, 4R) -4,5-bis (acetyloxy) -2- (hydroxymethyl) -tetrahydro-3-furanyl acetate, previously synthesized previously by the method mentioned in Carbohydr, was successively added to an ice-cooled reaction mixture. . Res., Vol.203, No.9, Pages 324-329 (1990), in 53 ml of acetonitrile and 7.2 ml of tin (IV) chloride, the resulting mixture was stirred at room temperature for 20 minutes. The reaction mixture was poured into a mixture, 100 ml of ethyl acetate and 300 ml of a saturated aqueous solution of sodium bicarbonate, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate. All organic layers were combined and dried over anhydrous magnesium sulfate, then the solvent was removed under reduced pressure. The residue was dissolved in 200 ml of methanol, 100 ml of an 80% aqueous solution of acetic acid was added, and the resulting mixture was stirred at room temperature for 2 hours. The solvent was removed under reduced pressure, the residue was purified by silica gel column chromatography [developing solution: chloroform: methanol = 40: 1], chloroform and isopropyl ether were added, and the solid product was collected by filtration to obtain 9.3 g (2R, 3R, 4R, 5R) - 4- (acetyloxy) -2- [3- (aminocarbonyl) -5-fluoro-2-oxo-1 (2H) -pyrazinyl] -5- (hydroxymethyl) tetrahydro-3-furanyl acetate as a pale yellow solid.

IR (KBr) cm ^-1 : 3411, 1752, 1686

¹ H-NMR (DMSO-d ₆ ) δ: 2.04 (3H, s), 2.10 (3H, s), 3.64 (1H, ddd, J = 2.5, 5.0, 13 Hz ), 3.86 (1H, ddd, J = 2.5, 5.0, 13 Hz), 4.29 (1H, d, J = 6.0 Hz), 5.35 (1H, t, J = 6.0 Hz), 5.49 (1H, dd, J = 3.0, 5.0 Hz), 5.65 (1H, t, J = 5.0 Hz), 6.11 (1H, d, J = 3.0 Hz), 7.96 (1H, br s), 8.42 (1H, D, J = 5.0 Hz), 8.49 (1H, br s).

Industrial application

Derivatives of pyrazine or their salts according to the present invention, namely the compounds according to the present invention, have excellent antiviral activity and are used as a pharmaceutical drug.

Claims (7)

1. The pyrazine derivative represented by the following general formula:

where R ¹ represents a hydrogen atom or a halogen atom; R ² represents hydrogen; R ³ and R ⁵ represent hydrogen; R ⁴ and R ⁶ represent a hydroxyl group optionally protected by an acetyl or benzoyl group; A represents an oxygen atom; n is 0; and Y represents an oxygen atom, or its salt. 2. The pyrazine derivative or its salt according to claim 1, where R ⁴ and R ⁶ represent a hydroxyl group. 3. The pyrazine derivative or its salt according to claims 1 and 2, where R ¹ represents a hydrogen atom or a fluorine atom. 4. The pharmaceutical composition, which is an antiviral agent, containing the compound or its salt according to any one of claims 1 to 3. 5. The pharmaceutical composition according to claim 4, where the virus is an influenza virus, RS virus (Raus sarcoma), AIDS virus, papilloma virus, adenovirus, hepatitis A virus, hepatitis B virus, hepatitis C virus, poliovirus, ECHO virus, virus Coxsackie, enterovirus, rhinovirus, rotavirus, Newcastle disease virus, mumps virus, vesicular stomatitis virus and Japanese encephalitis virus. 6. The pharmaceutical composition according to claim 5, where the specified virus is an influenza virus. 7. The pharmaceutical composition according to claim 5, where the specified virus is a hepatitis C.