JPH0428277B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 2-cyano-6-substituted oxypurine nucleoside compounds and methods for their production.

The 2-cyano-6-substituted oxypurine nucleoside compound of the present invention has the general formula [1] [In the formula, R ₁ represents an alkyl group or an aralkyl group, and X, Y and Z each represent hydrogen or a protective group. ] This is a new compound that has not been described in any literature. This compound is an important synthetic intermediate for homoguanosine, which is an analogue of guanosine, and is expected to have physiological activity in itself, and is also useful as a research reagent in nucleic acid chemistry.
Homoguanosine is expected to have physiological activities such as antiviral activity and antitumor activity, and is expected to be used as a pharmaceutical.

Conventionally, methods for synthesizing 2-cyanoadenosine compounds have been known (Chem.Pharm.Bull., 27 ,
183 (1979)). In this method, a methanesulfonyl group is introduced at the 2-position of adenosine, and a target compound is synthesized through a substitution reaction with a cyanide anion.

However, even when cyanide anion was allowed to act on 2-methanesulfonylinosine, no substitution reaction occurred at the 2-position.

The present invention provides 2-
Cyano-6-substituted oxypurine nucleoside compounds are provided.

Moreover, the present invention also relates to the general formula [2] [In the formula, R ₂ represents an aryl group, an alkyl group or an aralkyl group, X, Y and Z each represent a protecting group, and R ₁ has the same meaning as above. ] The present invention provides a method for producing a 2-cyano-6-substituted oxypurine nucleoside compound represented by the general formula [1] by reacting a cyanide anion with the compound represented by the formula [1] and deprotecting the compound as necessary. be.

Furthermore, the present invention provides general formula [6] [In the formula, R ₃ represents halogen, and X, Y and Z
have the same meanings as above. ] The compound represented by the general formula [7] (R ₂ S) ₂ [wherein R ₂ has the same meaning as above. ] By reacting with a disulfide compound represented by [In the formula, R ₂ and R ₃ each have the same meanings as above. ] A compound represented by the general formula [8] MOR ₁ [wherein M represents a metal and R ₁ has the same meaning as above] was obtained. ] by the action of the metal alcoholate represented by the general formula [4] [In the formula, R ₁ and R ₂ each have the same meaning as above. ] was obtained, and the hydroxyl group of the sugar moiety was protected by a conventional method to form the compound represented by the general formula [3] [In the formula, X, Y and Z each represent a protecting group, and R ₁ and R ₂ each have the same meaning as above. ] is obtained, oxidized with an oxidizing agent to obtain a compound represented by the general formula [2], and then treated with cyanide anion,
The object of the present invention is to provide a method for obtaining a 2-cyano-6-substituted oxypurine nucleoside compound represented by the general formula [1] by performing deprotection as necessary.

In the above general formula, R ₁ represents an alkyl group or an aralkyl group,
Specific examples include methyl, propyl, ethyl, butyl, benzyl, and p-methylbenzyl.

_R2 : represents an aryl group, an alkyl group, or an aralkyl group, and specific examples include phenyl, methyl, ethyl, propyl, butyl, benzyl, p-methylbenzyl, and the like.

R ₃ : Represents halogen, and specific examples include chloro, bromo, and iodo.

M: Indicates a metal, and specific examples include sodium and potassium.

X, Y, Z: Indicates a general protecting group in nucleic acid chemistry, and specifically includes acyl groups such as acetyl and benzoyl, alkylidene groups such as isopropylidene and ethylidene, and aralkyl groups such as trityl and benzyl. can.

The present invention will be explained in detail below.

Compound of general formula [6] → Compound of general formula [5] (introduction of substituted thio group to the 2-position) The reaction is carried out by reacting the disulfide compound represented by the above general formula [7] and nitrites in an aprotic solvent. It is done by certain things.

Acetonitrile as an aprotic solvent;
Examples include tetrahydrofuran, hexamethylphosphoramide, dimethylsulfoxide, dimethylformamide, dimethylacetamide, dimethoxyethane, dioxane, and the like.

R ₂ in the disulfide compound represented by general formula [7] is as described above.

As the nitrous acid, alkylated nitrous acid such as isoamyl nitrite, nitrous acid itself, or a salt thereof can be used.

The reaction conditions are preferably from room temperature to about 100°C and for about several tens of minutes to more than ten hours.

General formula [5] compound → general formula [4] compound (introduction of substituted oxy group to 6-position)
It is carried out by the action of a metal alcoholate represented by:

In the metal alcoholate of general formula [8]
R ₁ and M are as described above. The metal alcoholate can be synthesized by reacting a metal hydride such as sodium hydride (sodium hydride) or a metal such as metallic sodium with the corresponding alcohol by a conventional method.

The reaction is carried out in an inert solvent such as dimethylformamide at around room temperature for several hours.

Compound of general formula [4] → Compound of general formula [3] (protection of hydroxyl group in sugar moiety) The types of protecting groups used are as described above. In the case of an alkylidene group, X and Y represent one protecting group.

The reaction is carried out using conventional methods in nucleic acid chemistry.

General formula [3] compound → General formula [2] compound (oxidation of substituted thio group to substituted sulfonyl group) The reaction is performed using potassium permanganate, hydrogen peroxide,
It is carried out using common oxidizing agents such as potassium dichromate.

The solvent may be any solvent as long as it does not react with the oxidizing agent, and examples include acetic acid and water.

The reaction conditions are not limited, but the reaction may be carried out under ice cooling for several hours.

General formula [2] compound → General formula [1] compound (introduction of cyano group to the 2-position) The cyanide anion used in the reaction is usually
It is provided in the form of salts such as sodium and potassium.

As the reaction solvent, an aprotic polar solvent is used, and examples thereof include dimethylformamide, dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, tetrahydrofuran, dioxane, and acetonitrile.

Reaction conditions are not particularly restricted, but are usually room temperature to
The reaction is carried out under heating conditions at a solvent reflux temperature, and the reaction is completed in several tens of minutes to more than ten hours.

Isolation and purification of the target product from the synthesis reaction solution may be carried out by conventional methods, for example, by appropriately combining adsorption chromatography, ion exchange chromatography, extraction with a solvent, recrystallization, and the like.

The compound represented by the general formula [1] of the present invention can be converted to homoguanosine by the method of the reference example. That is, after catalytic reduction of the compound of general formula [1], the amino group at the 2-position is protected with a protecting group such as an acetyl group or a trifluoroacetyl group, and the substituent at the 6-position is protected with trimethylsilyl chloride and sodium iodide. Homoguanosines can be obtained by removal and deprotection.

Hereinafter, the present invention will be explained more specifically using Examples and Reference Examples.

Example 1 2-cyano-6-methoxy-9-(1-β-D
Synthesis of -2,3,5-tri-O-acetylribofuranosyl)purine 6-methoxy-2-phenylsulfonyl-9-
822 mg of (1-β-2,3,5-tri-O-acetylribofuranosyl)purine was dissolved in 8 ml of dimethylformamide (DMF), and 108 mg of sodium cyanide was added thereto and reacted at room temperature for 2 hours. .

Next, the solvent was removed under reduced pressure, the resulting residue was dissolved in 120 ml of ethyl acetate, and this was dissolved in 10 ml of water.
and dried over anhydrous sodium sulfate. The anhydrous sodium sulfate was removed by filtration, the solvent was removed under reduced pressure, and the obtained white crystals were recrystallized from methanol to give 2-cyano-6-methoxy-9-(1-
464mg of β-D-2,3,5-tri-O-acetylribofuranosyl)-purine as colorless prism crystals
(71.4%) obtained.

Melting point 188-189℃ Elemental analysis C HN Calculated value 49.87 4.42 16.17 Measured value 50.26 4.41 16.25 NMR (CDCl ₃ ) δ: 4.17 (3H, S, -OCH ₃ ) 8.85 (1H, S, C(8)-H) Implementation Example 2 6-methoxy-2-phenylthio-9-(1-
Synthesis of β-D-2,3,5-tri-O-acetylribofuranosyl)purine 0.239 g of sodium was added to 60 ml of methanol.
Add 6-chloro-2-phenylthio-9- to this solution.
3.4 g of (1-β-D-2,3,5-tri-O-acetylribofuranosyl)purine was added and reacted with stirring at room temperature. After 6 hours, the mixture was neutralized with 2N HCl, the solvent was removed under reduced pressure, and benzene was added for azeotropic dehydration.

The obtained residue was dissolved in 70 ml of acetonitrile, 5 ml of acetic anhydride and 0.115 g of dimethylaminopyridine were added, and the mixture was reacted at room temperature for 4 hours. After 4 hours, methanol was added to the reaction solution to decompose excess acetic anhydride, and then the solvent was removed under reduced pressure. The obtained residue was dissolved in 150 ml of ethyl acetate, water, saturated sodium bicarbonate solution,
After washing with water and drying with anhydrous sodium sulfate, removing ethyl acetate, 6-methoxy-2
-phenylthio-9-(1-β-D-2,3,5
3.24 g (95.9%) of -tri-O-acetylribofuranosyl) purine was obtained as a powder.

NMR (CDCl ₃ ) δ: 3.94 (3H, S, -OCH ₃ );
8.38(1H,S,C(8)-H) Example 3 6-methoxy-2-phenylsulfonyl-9
Synthesis of -(1-β-D-2,3,5-tri-O-acetylribofuranosyl)-purine 6-methoxy-2-phenylthio-9-(1-
2.0 g of β-D-2,3,5-tri-O-acetylribofuranosylpurine was dissolved in 50 ml of acetic acid and cooled on ice.

After adding 1.5 g of potassium permanganate and stirring for 1 hour, 30% hydrogen peroxide solution was added until the reaction solution became colorless and transparent.

Next, the reaction solution was extracted 4 times with 20 ml of chloroform.
Combine the chloroform layers, add 15 ml of saturated sodium bicarbonate solution four times, and add water.
After washing once with 20 ml, it was dried with anhydrous sodium sulfate. After filtering off the anhydrous sodium sulfate and removing the solvent, 6-methoxy-2-phenylsulfonyl-9
-(1-β-D-2,3,5-tri-O-acetylribofuranosyl)purine 1.95g as powder
(91.5%) obtained.

NMR (CDCl ₃ ) δ: 4.10 (3H, S, -OCH ₃ ):
8.70(1H,SC(8)-H) Example 4 6-chloro-2-phenylthio-9-(1-β
Synthesis of -D-2,3,5-tri-O-acetylribofuranosyl)purine 2-amino-6-chloro-9-(1-β-D-
2,3,5-tri-O-acetylribofuranosyl)purine 3.5g, phenyl disulfide 5g,
8ml of isoamyl nitrite in 40ml of acetonitrile
℃ for 30 minutes.

After 30 minutes, the solvent was removed and purified with a silica gel column to give 6-chloro-2-phenylthio-9-(1-β
2.33 g (54.7%) of -D-2,3,5-tri-O-acetylribofuranosyl)-purine was obtained as a powder.

Example 5 6-benzyloxy-2-phenylthio-9-
Synthesis of (1-β-D-2,3,5-tri-O-acetylribofuranosyl)purine 0.45g of sodium hydride in 10ml of DMF
(50% oil suspension) was added and cooled.
1.3 ml of benzyl alcohol was added dropwise to this solution.
Then, 6-chloro-2-phenylthio-9-(1-β-D-2,3,5-tri-O
-acetylribofuranosyl)purine (1.32 g) was added dropwise. After the dropwise addition, the reaction was continued for another 2 hours at room temperature. 2
After an hour, the solvent was removed under reduced pressure. Dissolve the obtained residue in 200 ml of ethyl acetate, and add this to 20 ml of water.
After washing four times with
Phenylthio-9-(1-β-D-2,3,5-
tri-O-acetylribofuranosyl) purine 0.62
g (41.2%) was obtained as a powder.

Elemental analysis C HN Calculated value 58.77 4.77 9.46 Actual value 59.01 4.82 9.30 Example 6 6-benzyloxy-2-phenylsulfonyl-9-(1-β-D-2,3,5-tri-O
Synthesis of -acetylribofuranosyl)purine 6-benzyloxy-2-phenylthio-9-
(1-β-D-2,3,5-tri-O-acetylribofuranosyl)purine 0.6 g, acetic acid 6 ml, water 4
ml of mixed solvent and cooled on ice. 0.5 g of potassium permanganate was added to this and reacted for 4 hours.

30% hydrogen peroxide was added to this reaction solution until the reaction solution became colorless and transparent. Next, this reaction solution was extracted 4 times with 20 ml of chloroform, and the chloroform layer was extracted with 10 ml of water.
ml, washed twice with 10 ml of saturated sodium bicarbonate solution, and then with 10 ml of water,
After drying over anhydrous sodium sulfate and removing chloroform, the desired product 6-benzyloxy-2-phenylsulfonyl-9-(1-β-D-2,3,5-tri-
O-acetylribofuranosyl) purine 0.583g
(92.5%) was obtained as a powder.

Reference example 2-trifluoroacetylaminomethyl-6-
Synthesis of methoxy-9-(1-β-D-2,3,5-tri-O-acetylribofuranosyl)purine 2-cyano-6-methoxy-9-(1-β-D
460 mg of (2,3,5-tri-O-acetylribofuranosyl) purine was dissolved in a mixed solvent of 40 ml of acetic acid and 40 ml of ethanol.

Add 100 mg of 10% palladium activated carbon to this solution,
The mixture was reacted with hydrogen gas under a pressurized condition of 5 atm for 16 hours. Next, hydrogen gas was removed, insoluble materials were removed by filtration, and the filtrate was concentrated. The resulting residue was dissolved in 8 ml of methylene chloride, 60 mg of pyridine and 1 ml of trifluoroacetic anhydride were added, and the mixture was reacted at room temperature for 1 hour, and then overnight. The reaction was carried out in the refrigerator.

The solvent was then removed under reduced pressure and the residue was dissolved in chloroform.
ml, washed in this order with water, saturated aqueous sodium bicarbonate, and water, and dried over anhydrous sodium sulfate.

The anhydrous sodium sulfate was filtered off and the solvent was removed, and the resulting residue was purified using a silica gel column.
-trifluoroacetylaminomethyl-6-methoxy-9-(1-β-D-2,3,5-tri-O
-acetylribofuranosyl) purine 530 mg (93.6
%) was obtained as a powder.

NMR ( _CDCl3 ) δ: 3.32 (2H,S,N- CH2- ); 4.08 (3H,S, _{-OCH3 )} ; 8.56 (1H,S,C(8)-H) 2-trifluoroacetyl aminomethyl-2′,
Synthesis of 3',5'-tri-O-acetylinosine 500 mg of sodium iodide in 10 ml of acetonitrile
was dissolved, and 0.24 ml of trimethylsilyl chloride was added to this solution under a nitrogen stream.

6 dissolved in 5 ml of acetonitrile was added to this solution.
-methoxy-2-trifluoroacetylaminomethyl-9-(1-β-D-2,3,5-tri-O
430 mg of -acetylribofuranosyl)-purine was added and allowed to react at room temperature.

After 1 hour, 7 ml of saturated sodium bicarbonate solution was added to adjust the pH to 8, and the mixture was concentrated under reduced pressure. Benzene was further added to remove water azeotropically, and the residue was purified with a silica gel column to give 2-trifluoroacetylaminomethyl-2',3. 360 mg (85%) of ',5'-tri-O-acetylinosine was obtained.

Synthesis of 2-aminomethylinosine (homoguanosine) 2-trifluoroacetylaminomethyl-2',
170 mg of 3',5'-tri-O-acetylinosine was dissolved in 20 ml of ammonia-saturated methanol and reacted at room temperature. After 18 hours, the solvent was removed and the residue was reconstituted from water-methanol to give 80 mg of 2-aminomethylinosine.
(84%) was obtained as white crystals.

Melting point 150-153℃ (decomposition) NMR (DMSO- _d6 ) δ: 3.66 (2H, S, _NC H2- ); 8.25 (1H, S, C(8)-H)

Claims (1)

[Claims] 1 General formula [1] [In the formula, R ₁ represents an alkyl group or an aralkyl group, and X, Y and Z each represent hydrogen or a protective group. ] A 2-cyano-6-substituted oxypurine nucleoside compound. 2 General formula [2] [In the formula, R ₁ represents an alkyl group or an aralkyl group, R ₂ represents an aryl group, an alkyl group, or an aralkyl group, and X, Y and Z each represent hydrogen or a protective group. ] By reacting cyanide anion with the compound represented by the general formula [1] [In the formula, R ₁ represents an alkyl group or an aralkyl group, and X, Y and Z each represent hydrogen or a protective group. ] A method for producing a 2-cyano-6-substituted oxypurine nucleoside compound, characterized by obtaining a compound represented by the following. 2 General formula [6] [In the formula, R ₃ represents halogen, and X, Y and Z
each represents hydrogen or a protecting group. ] The compound represented by the general formula [7] (R ₂ S) ₂ [wherein R ₂ represents an aryl group, an alkyl group or an aralkyl group]. ] By reacting a disulfide compound represented by [In the formula, R ₂ , R ₃ , X, Y and Z each have the same meanings as above. ] was obtained, and the compound represented by the general formula [8] MOR ₁ [wherein M represents a metal,
R ₁ represents an alkyl group or an aralkyl group. ]
The general formula [4] is obtained by the action of a metal alcoholate represented by [In the formula, R ₁ and R ₂ have the same meanings as above. ] was obtained, the hydroxyl group of the sugar moiety was protected by a conventional method, and then oxidized with an oxidizing agent to obtain the general formula [2] [In the formula, R ₁ , R ₂ , X, Y and Z each have the same meanings as above. ] is obtained, and then treated with cyanide anion to form the compound represented by the general formula [1] [In the formula, R ₁ , X, Y and Z each have the same meanings as above. A method for producing a 2-cyano-6-substituted oxypurine nucleoside compound, which comprises obtaining a 2-cyano-6-substituted oxypurine nucleoside compound represented by the following.