JPH0931074A - Production of 2',3'-dideoxy-2-thiopyrimidine nucleotide and anti-herpes viral agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To newly obtain the subject compound by specific plural processes, showing excellent antiviral action on herpes virus, useful as an anti-herpes viral agent. SOLUTION: A 2',3'-dideoxy-pentofuranoside derivative of formula I (R2 is an OH-protecting group) is reacted with a bis(triorganosilyl)-2-thiopyrimidine of formula II (R1 is H or a lower alkyl; R3 to R5 are each an alkyl or an aryl; X is OH or amino; Y is ON or O; Z is an eliminable group) in the presence of a Lewis acid (e.g. tin tetrachloride, etc.) to produce 2',3'-dideoxy-2- thiopyrimidine nucleoside of formula III. The R2 group at the 5'-position of the saccharide part of the compound of formula III is deprotected to give the objective compound of formula IV. The first process is preferably carried out by using an aprotic organic solvent such as dichloromethane in a temperature range from -40 deg.C to a room temperature for 1-15 hours, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing 2 ', 3'-dideoxy-2-thiopyrimidine nucleoside and an anti-herpes containing the specific 2', 3'-dideoxy-2-thiopyrimidine nucleoside as an active ingredient. It relates to a viral agent and is useful in the field of medicine.

[0002]

2. Description of the Related Art In recent years, as researches on pathogenic viruses of viral infectious diseases have progressed, various antiviral agents have been actively developed. For example, anti-herpes virus agents such as idoxuridine and acyclovir are anti-HIV agents.
Azidothymidine, dideoxyinosine, dideoxycytidine and the like are known as agents. On the other hand, Bhalchandra
V. Joshi et al. (Nucleosides & Nucleotides, 14 , 20
9 (1995).), 2 ', 3'-dideoxy-2-thiopyrimidine nucleosides are reported to show little effect on HIV. Further, the method for producing the 2 ', 3'-dideoxy-2-thiopyrimidine nucleoside disclosed herein is 2', 3'-dideoxy-
The production of 2-thiouridine requires 5 steps from the starting material, and the production of 2 ', 3'-dideoxy-2-thiocytidine requires 7 steps from the starting material. However, there is a problem in that the yield of

[0003]

DISCLOSURE OF THE INVENTION The present inventors have proposed 2 ′,
The inventors established an efficient and novel method for producing a 3'-dideoxy-2-thiopyrimidine nucleoside, and conducted extensive studies on the effectiveness of the compound as a therapeutic agent against other viruses.

[0004]

In order to solve the above-mentioned problems, the inventors of the present invention are effective in a manufacturing method comprising two specific steps, and also a specific 2 ', 3'-dideoxy-2- It was found that thiopyrimidine nucleoside has an excellent anti-herpesvirus activity and is useful as a therapeutic drug for herpesvirus disease, and completed the present invention. That is, the first invention of the present invention is a method for producing a 2 ′, 3′-dideoxy-2-thiopyrimidine nucleoside represented by the following general formula (I), which comprises the following first step and second step. First step: 2,3-dideoxypentofuranoside derivative represented by the following general formula (II) and bis (triorganosilyl) -2-thiopyrimidine represented by the general formula (III) in the presence of Lewis acid 2 ′ represented by the general formula (IV),
A 3'-dideoxy-2-thiopyrimidine nucleoside is prepared.

[0005]

Embedded image

[In each compound of the formula (1), R ₁ represents a hydrogen atom or a lower alkyl group, R ₂ represents a hydroxyl-protecting group, and R ₃ , R ₄ and R ₅ represent an alkyl group or an aryl group. Which may be the same or different, X represents a hydroxyl group or an amino group, Y represents an NH or an oxygen atom, and Z represents a leaving group. Second step: deprotecting the R ₂ group at the 5′-position of the sugar moiety of the compound represented by the general formula (IV) to give 2 ′ represented by the general formula (I),
A 3'-dideoxy-2-thiopyrimidine nucleoside is prepared.

[0007]

Embedded image

[In each compound of formula (2), R ₁ represents a hydrogen atom or a lower alkyl group, R ₂ represents a hydroxyl-protecting group, and X represents a hydroxyl group or an amino group. The second invention is 2 ′, 3 ′ represented by the following general formula (I ′).
-An anti-herpesvirus agent containing dideoxy-2-thio-5-alkyluridine as an active ingredient.

[0009]

[Chemical 6]

[In the formula (I '), R ₃ represents a lower alkyl group. Hereinafter, the present invention will be described in detail.

◎ Production Method First, a novel and efficient production method of 2 ', 3'-dideoxy-2-thiopyrimidine nucleoside comprising two steps of the first invention will be described in detail.

2 ′, 3′-dideoxy-2-thiopyrimidine nucleoside The target 2 ′, 3′-dideoxy-2-thiopyrimidine nucleoside in the production method of the first invention is represented by the above general formula (I). It is what is done. In the general formula (I), R ₁ is a hydrogen atom or a lower alkyl group. Specific examples of the lower alkyl group include alkyl groups having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, pentyl group and hexyl group. X represents a hydroxyl group or an amino group. X
Is a hydroxyl group, the structure of the compound represented by the general formula (I) is represented by the following (I ″) under normal conditions. It is represented by formula (I).

[0013]

[Chemical 7]

Typical examples of 2 ', 3'-dideoxy-2-thiopyrimidine nucleoside include, for example, 2',
3'-dideoxy-2-thiocytidine (X = amino group,
R ₁ = hydrogen atom), 2 ′, 3′-dideoxy-2-thio-5-methylcytidine (X = amino group, R ₁ = methyl group), 2 ′, 3′-dideoxy-2-thio-5- Ethylcytidine (X = amino group, R ₁ = ethyl group), 2 ′,
3′-dideoxy-2-thio-5-propylcytidine (X = amino group, R ₁ = propyl group), 2 ′, 3′-dideoxy-2-thiouridine (X = hydroxyl group, R ₁ = hydrogen atom), 3 '-Deoxy-2-thiothymidine (X = hydroxyl group, R ₁ = methyl group), 2', 3'-dideoxy-2-
Examples thereof include thio-5-ethyluridine (X = hydroxyl group, R ₁ = ethyl group) and 2 ′, 3′-dideoxy-2-thio-5-propyluridine (X = hydroxyl group, R ₁ = propyl group). Among these compounds, the present invention is a compound in which X in the general formula (I) is a hydroxyl group and R ₁ is a lower alkyl group, that is, 2 ′, 3′-dideoxy-2-thio-useful as the second invention. It is useful for the production of 5-alkyluridine.

First step In this step, the 2,3-dideoxypentofuranoside derivative represented by the general formula (II) represented by the above formula (1) and the bis (represented by the general formula (III) ( Triorganosilyl) -2-
This is a step of producing a 2 ', 3'-dideoxy-2-thiopyrimidine nucleoside represented by the general formula (IV) in which a hydroxyl group at the 5'position is protected by subjecting thiopyrimidine to a coupling reaction in the presence of a Lewis acid. . The 2,3-dideoxypentofuranoside derivative which is the starting compound in this step is
It is represented by the above general formula (II). In formula (II), R ₂ represents a hydroxyl-protecting group and Z represents a leaving group.
R ₂ is not particularly limited as long as it does not hinder the coupling reaction, and specific examples thereof include an acyl group such as an acetyl group, a propionyl group, a pivaloyl group and a benzoyl group, an arylalkyl group such as a benzyl group and a trityl group. , An alkylcarbonyloxy group such as an ethoxycarbonyloxy group, an arylcarbonyloxy group such as a phenoxycarbonyloxy group, and a trimethylsilyl group, t
Examples thereof include usual protective groups for hydroxyl groups such as triorganosilyl group such as -butyldimethylsilyl group and t-butyldiphenylsilyl group. The leaving group for Z may be any group having a leaving ability, and specific examples thereof include halogen atoms such as chlorine atom and bromine atom, alkyloxy groups such as methoxy group, ethoxy group and propoxy, and phenoxy group. Aryloxy group, acetyloxy group, propionyloxy group, acyloxy group such as pivaloyloxy group and benzoyloxy group, alkylcarbonyloxy group such as ethoxycarbonyloxy group, and arylcarbonyloxy group such as phenoxycarbonyloxy group. When these protecting groups have a phenyl group, there are also those having an alkyl group, a halogen atom, an alkoxyl group or the like as the substituent. This starting material compound can be produced according to a known method [for example, J. Org. Chem., 53 , 4780-4789 (1988).].

The other raw material compound in this step, bis (triorganosilyl) -2-thiopyrimidine, is represented by the above general formula (III). General formula (I
In II), R ₁ represents a hydrogen atom or a lower alkyl group, and Y represents NH or an oxygen atom. Examples of the lower alkyl group for R ₁ include those similar to the above formula (I).
R ₃ , R ₄ and R ₅ in the general formula (III) are an alkyl group or an aryl group, and they may be the same or different. Specific examples of the alkyl group include a methyl group and a t-butyl group, and specific examples of the aryl group include a phenyl group. In the general formula (III), the triorganosilyl group represented by “R ₃ R ₄ R ₅ Si—” may be any group that is usually used as a protective group for a hydroxyl group, an amino group or a thiol group. Include a trimethylsilyl group, a t-butyldimethylsilyl group, a phenyldimethylsilyl group and the like, and the trimethylsilyl group is preferable because it can be easily hydrolyzed by treatment with a weak base aqueous solution after the coupling reaction. The compound can be produced by a known method, for example, R ₃ ,
A compound in which R ₄ and R ₅ are methyl groups is prepared by applying a known method [eg, Chem. Pharm. Bull., 12 , 352-356 (1964).] To 2-thiopyrimidine and 1,1,1. , 3, 3, 3-
It can be prepared by reaction with hexamethylsilazane.

The reaction between the 2,3-dideoxypentofuranoside derivative represented by the general formula (II) and the bis (triorganosilyl) -2-thiopyrimidine represented by the general formula (III) is usually carried out respectively. Are reacted in equimolar amounts in the presence of a Lewis acid. Examples of the Lewis acid include tin tetrachloride, titanium tetrachloride, ethyl aluminum chloride, diethyl aluminum chloride, trimethylsilyl trifluoromethanesulfonate and the like. As the amount of Lewis acid,
The amount is preferably 0.5 equivalent or more, more preferably 1 equivalent or more with respect to the 2,3-dideoxypentofuranoside derivative. The reaction is preferably carried out in an aprotic organic solvent. Examples of the aprotic organic solvent include dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, ether, dioxane, toluene. , Acetonitrile and nitromethane. The reaction temperature is from -78 ° C to 50.
It can be carried out in the range of ℃, preferably -40 ℃ to room temperature. The reaction time of this coupling reaction varies depending on the reaction temperature and the type and amount of the Lewis acid used, but it is usually completed in 1 to 15 hours. After completion of the reaction, the reaction product is treated with water to give “R ₃
R ₄ R ₅ Si- "group is hydrolyzed, a compound of the formula of the object (IV) is obtained. In this case, treating the reaction solution with an aqueous solution containing a basic compound such as an aqueous pyridine solution or an aqueous sodium hydrogencarbonate solution facilitates hydrolysis of the “R ₃ R ₄ R ₅ Si—” group, and It is preferable because the Lewis acid can be removed at the same time. After treating the basic compound with an aqueous solution, the product represented by the general formula (IV) can be isolated from the reaction mixture by a conventional method. For example,
After the post-treatment such as extraction with an organic solvent, a method of purifying by chromatography as needed may be mentioned.

Second step In this step, the R ₂ group at the 5′-position of the sugar moiety of the compound represented by the general formula (IV) represented by the above formula (2) is deprotected to give the general formula (I). Is a step of producing a 2 ′, 3′-dideoxy-2-thiopyrimidine nucleoside represented by This step can be carried out by appropriately selecting a usual deprotection treatment such as acidic hydrolysis, alkaline hydrolysis or ammonium fluoride treatment, depending on the type of R ₂ group. For example, when the protective group is an arylalkyl group such as a trityl group, a methoxytrityl group and a dimethoxytrityl group, an inorganic acidic substance such as hydrochloric acid or sulfuric acid, or acetic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid. Organic acids such as methanesulfonic acid and toluenesulfonic acid can be used for deprotection by acidic hydrolysis. When the protecting group is an acyl group such as an acetyl group or a benzoyl group, deprotection can be carried out by usual alkaline hydrolysis using ammonia, amine, alkoxide or the like. When the protecting group is an organosilyl group such as t-butyldimethylsilyl group, deprotection can be performed with ammonium fluoride salt such as tetrabutylammonium fluoride. The above-mentioned proportions of the inorganic acidic substance, organic acid, ammonia, amine, alkoxide, ammonium fluoride salt and the like may be used in the usual amounts used for deprotection in consideration of the reaction conditions. The reaction temperature is usually room temperature so that the reaction proceeds sufficiently and heating can be performed for the purpose of shortening the reaction time. The reaction time depends on the reaction temperature, R ₂
Depending on the type of group and the deprotection method selected,
Usually, it is completed in 1 to 20 hours. After completion of the reaction, the desired compound represented by the general formula (I) can be isolated from the reaction mixture by a conventional method. For example, the solvent in the reaction solution is removed under reduced pressure, and the residue is purified by column chromatography and high performance liquid chromatography.

◎ Anti-herpes virus agent As described above, the literature of Bhalchandra V. Joshi et al. (Nuc
leosides & Nucleotides, 14 , 209 (1995).)
It has been reported that 2 ', 3'-dideoxy-2-thiopyrimidine nucleosides show little effect on HIV. However, the present inventors have found that 2 ', 3'-dideoxy-2-thio- belonging to the nucleosides.
It was found that 5-alkyluridine has a strong anti-herpesvirus activity against herpes simplex virus type 1 (HSV-1).

The 2 ', 3'-dideoxy-2-thio-5-alkyluridine, which is the active ingredient of the anti-herpesvirus agent of the present invention, is represented by the above general formula (I'). In the general formula (I ′), R ₃ is a lower alkyl group, and specific examples of the lower alkyl group include the above formula (I).
The same as those listed for R ₁ in R. As a typical example of this compound, for example, 3'-deoxy-2-
Thiothymidine (R ₂ = methyl), 2 ', 3'-dideoxy-2-thio-5-ethyl uridine (R ₂ = ethyl) and 2', 3'-dideoxy-2-thio-5-propyl uridine ( R ₂ = propyl group) and the like. Among these, 3′-deoxy-2-thiothymidine is particularly preferable because it has a strong antiviral activity against herpes simplex type-1 (HSV-1) belonging to the herpesvirus family.

The anti-herpesvirus agent of the present invention is administered by any suitable route for the treatment of animals including humans. The route includes oral, rectal, nasal, topical (oral, sublingual and transdermal), vaginal, and parenteral (subcutaneous, muscular, intravenous and intradermal) and the like. The anti-herpesvirus agent of the present invention can be used by various methods such as oral administration, parenteral administration and topical application depending on the intended route, and is used in the following forms depending on each method. Oral administration The anti-herpesvirus agent of the present invention is an aqueous solution, an aqueous suspension,
It is administered in the form of tablets, large pills, granules, pellets or paste. Parenteral administration The anti-herpesvirus agent of the present invention is subcutaneously, intramuscularly or intravenously injected as a sterile solution or suspension. O Topical application The anti-herpesvirus agent of the present invention is applied to the skin as a cream, salve or spray. Vaginal administration The anti-herpesvirus agent of the present invention is administered as a pessary, cream or foam. The route, form and amount of use of the anti-herpesvirus agent of the present invention may be appropriately selected depending on the symptoms, weight, age and sex of the patient, the nature of infection and the selected active ingredient.

[0022]

The present invention will be described more specifically with reference to the following examples. ◎ Example 1 Synthesis of 3′-deoxy-2-thiothymidine ○ Synthesis of 2- (trimethylsilylthio) -4- (trimethylsilyloxy) -5-methylpyrimidine 5-methyl-2-thiouracil 1.04 g and 1,1, 1,
15 ml of 3,3,3-hexamethyldisilazane was heated under reflux in the presence of 10 mg of ammonium sulfate for 1 hour. The reaction solution was returned to room temperature, and excess 1,1,1,3,3,3- was formed under reduced pressure.
Hexamethyldisilazane was distilled off. Anhydrous toluene was added to the residue, the insoluble material was filtered off, and the filtrate was concentrated under reduced pressure. First step: The concentrated residue containing 2- (trimethylsilylthio) -4- (trimethylsilyloxy) -5-methylpyrimidine was dissolved in 40 ml of 1,1,2,2-tetrachloroethane under a nitrogen atmosphere, Cooled to -40 ° C. While maintaining the reaction temperature, 1.28 ml of tin tetrachloride and 1.00 g of 1-O-acetyl-5-Ot-butyldimethylsilyl-2,3-dideoxypentofuranose were added to this solution, while keeping the reaction temperature. A 5 ml solution of chloroethane was sequentially added dropwise to the above solution. The reaction temperature was gradually raised to 0 ° C. over 2 hours, and further 2
Stir at this temperature for hours. After a part of the reaction solution was collected and disappearance of the starting dideoxy sugar was confirmed by thin layer chromatography, 5 ml of pyridine and 10 ml of water were added to the reaction solution and stirred. The solution was filtered through Celite, washed with methylene chloride, the filtrates were combined, washed with water, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure to obtain 1.4 g of product. Second step: 5'-Ot-butyldimethylsilyl-3'-deoxy-2-thiothymidine obtained in the first step is dissolved in 20 ml of tetrahydrofuran (hereinafter abbreviated as THF) and cooled to 0 ° C under 1M. 3.6 ml of a solution of tetrabutylammonium fluoride in THF was added, and the mixture was stirred at room temperature for 15 hours. The solvent was removed under reduced pressure, and the residue was subjected to column chromatography using 30 g of silica gel as a carrier (chloroform / methanol = 9/1).
Elute with, combine the fractions containing the desired product and concentrate,
The residue was further purified by high performance liquid chromatography 7
Obtained 75 mg (36%) of 3'-deoxy-2-thiothymidine. The obtained compound was analyzed by ¹ H-NMR and ¹³ C-N
The structure was confirmed by MR. The spectrum data is shown below.

¹ H NMR (CDCl ₃ ) δ 8.13 (s, 1H, 6-H) 6.64 (dd, J = 2.4, 6.8Hz, 1'-H) 4.25
(m, 1H, 4'-H) 4.10 (dd, J = 2.4, 12Hz, 1H, 5'-H _a ) 3.82 (dd, J = 3, 12Hz,
1H, 5'-H _b ) 2.53 (m, 1H, 2'-H) 2.15 (m, 1H, 2'-H) 1.93-2.01 (m, 2H, 3'-
H) 1.94 (s, 3H, 5-Me) · 13 C NMR (CDCl 3) δ 173.62, 161.13, 137.37, 115.40, 90.75, 82.63, 6
2.42, 33.09, 24.24, 12.85

Example 2 Synthesis of 2 ', 3'-deoxy-2-thiouridine The reaction was performed in the same manner as in Example 1 except that 2-thiouracil was used instead of 5-methyl-2-thiouracil, and the title compound was obtained. Was obtained in a yield of 25%. The structure of the obtained compound was confirmed by ¹ H-NMR and ¹³ C-NMR. The spectrum data is shown below.

¹ H NMR (DMSO-d6) δ 12.42 (br, 1 H, NH D ₂ O exchangeable) 8.35 (d, J = 8 Hz, 1
H, 6-H) 6.59 (dd, J = 2.8, 6.4Hz, 1H, 1'-H) 5.87 (d, J = 8Hz, 5-H) 5.07 (br s, 1H, 5'-OH D ₂ O exchangeable) 4.17 (m, 1H, 4'-
H) 3.90 (d, J = 12Hz, 5'-H _a ) 3.65 (d, J = 12Hz, 5'-H _b ) 2.47
(m, 1H, 2'-H) 2.11 (m, 1H, 2'-H) 1.92 (m, 2H, 3'-H) ¹³ C NMR (DMSO-d6) δ 175.22, 160.15, 140.89, 105.83, 90.34, 82.95, 6
1.47, 33.14, 24.01

Example 3 Synthesis of 2 ', 3'-deoxy-2-thiocytidine The reaction was performed in the same manner as in Example 1 except that 2-thiocytidine was used instead of 5-methyl-2-thiouracil, and the title compound was obtained. Was obtained in a yield of 22%. The structure of the obtained compound was confirmed by ¹ H-NMR. The spectrum data is shown below.

¹ H NMR (DMSO-d6) δ 8.31 (d, J = 7.4Hz, 1H, 6-H) 7.43 (br s, 1H, NH D ₂ O exch
angeable) 7.37 (br s, 1H, NH D ₂ O exchangeable) 6.70 (dd, J = 2.8,
6.8Hz, 1H, 1'-H) 6.07 (d, J = 7.4Hz, 1H, 5-H) 5.08 (t, J = 5Hz, 1H, 5'-OH D ₂ 0 e
xchangeable) 4.14 (m, 1H, 4'-H) 3.82 (m, 1H, 5'-H _a ) 3.63 (m, 1H, 5'-
H _b ) 2.45 (m, 1H, 2'-H) 2.02 (m, 1H, 2'-H) 1.83 (m, 2H, 3'-H)

Example 4 The effect of 3'-deoxy-2-thiothymidine was examined on HSV-1 using RPM8226 cells as host cells. Table 1 shows the results. In Table 1, EC
The 50 value and CC50 value are the concentrations that inhibit virus growth and host cell growth by 50%, respectively, and the SI value represents their ratio (CC50 value / EC50 value), that is, selectivity.
As shown in Table 1, it is clear that this drug has a strong anti-herpesvirus activity, has no cell-killing activity, and has excellent selectivity.

[0029]

[Table 1]

[0030]

EFFECT OF THE INVENTION 2 ', 3'-dideoxy-2-of the present invention
The method for producing a thiopyrimidine nucleoside is capable of efficiently obtaining the target product in two steps in comparison with the conventional production method, and 2 ′ among 3 ′, 3′-dideoxy-2-thiopyrimidine nucleosides. , 3'-dideoxy-
2-Thio-5-alkyluridine exhibits an excellent antiviral action against herpes virus.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location (C07D 405/04 239: 56 307: 12)

Claims (2)

[Claims] 1. A 2 ', 3'-dideoxy-2- represented by the following general formula (I) comprising the following first step and second step.
Process for producing thiopyrimidine nucleoside. First step: 2,3-dideoxypentofuranoside derivative represented by the following general formula (II) and bis (triorganosilyl) -2-thiopyrimidine represented by the general formula (III) in the presence of Lewis acid 2 ′ represented by the general formula (IV),
A 3'-dideoxy-2-thiopyrimidine nucleoside is prepared. Embedded image [In each compound of the formula (1), R ₁ represents a hydrogen atom or a lower alkyl group, R ₂ represents a hydroxyl-protecting group, R _2
3 , R ₄ and R ₅ represent an alkyl group or an aryl group,
Each may be the same or different, X represents a hydroxyl group or an amino group, Y represents NH or an oxygen atom, and Z represents a leaving group. Second step: deprotecting the R ₂ group at the 5′-position of the sugar moiety of the compound represented by the general formula (IV) to give 2 ′ represented by the general formula (I),
A 3'-dideoxy-2-thiopyrimidine nucleoside is prepared. Embedded image [In each compound of formula (2), R ₁ represents a hydrogen atom or a lower alkyl group, R ₂ represents a hydroxyl-protecting group, and X represents
Represents a hydroxyl group or an amino group. ] 2. A 2 ', 3'represented by the following general formula (I'):
-An anti-herpesvirus agent containing dideoxy-2-thio-5-alkyluridine as an active ingredient. Embedded image [In the formula (I ′), R ₃ represents a lower alkyl group. ]