JP3015096B2 - Novel purine nucleosides, production method thereof and antiviral agent using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] An object of the present invention is a novel antiviral agent represented by the general formula [I] and a method for producing the same.

(In the formula, X is a hydrogen atom or an amino group, and R is a hydrogen atom or any of an acetyl group, a propionyl group, a benzoyl group, or another acyl group of C1 to C20.) ] formula shown in [I], the purine base portion having a hydrazino group _{(-NHNH 2), 2 ',} 3'- dideoxy purine nucleosides and reports on their synthesis is not known.

Also, no report on the antiviral effect is known.

[Problems to be solved by the invention]

Today, when bacterial infections are no longer a threat with the advent of antibiotics, it is almost always viral infections that cause serious illness.

For example, adult T-cell leukemia, hepatitis B, viral pneumonia, various herpes infections, etc. are HTLV-1,
It is a disease caused by viruses such as HBV, CMV, and HSV.

In addition, influenza, which repeats a pandemic every year, is also a disease caused by the virus, and has become a modern social problem.

Among the numerous viral diseases, the most important and urgent issue at present is HIV (Human Immunodef
AIDS (acquired immunodeficiency syndrome), which is caused by iciency virus.

Many AIDS patients have been reported to be superinfected with viruses other than HIV, such as HBV, CMV, and HHV-6 (a type of herpes virus), and have an excellent effect on suppressing these viruses. Drugs are highly desired.

AZT (azidothymidine) (Proc.
Natl.Acad.Sci.USA 82, 7096 (1985)) are the best known, is currently the only approved drugs. AZT is said to be not only a therapeutic drug, but also effective in preventing the onset of disease in people who are carriers of HIV.

However, AZT is extremely expensive as an antiviral agent, has side effects, and has various problems.

That is, if administered in a large amount or too long, bone marrow toxicity (N. Eng. J. Med. 317 , 192 (1987)) is observed, or a resistant strain of the virus (Science 243 , 1731 (1989)) is formed.
It is known that the effects of AZT may be weakened.

From the above, there is a need for new antiviral agents that reduce the drawbacks (such as side effects) of antiviral agents such as AZT and have the same effect on other viruses when superinfected.

An object of the present invention is to provide a novel antiviral agent having a remarkable effect on various viral infections, and a method for synthesizing the same.

[Means for solving the problem]

The present invention provides a compound represented by the general formula [I]: (Wherein X is a hydrogen atom or an amino group, and R is a hydrogen atom or any one of an acetyl group, a propionyl group, a benzoyl group, and other acyl groups from C1 to C20). Based on the finding that various nucleic acid derivatives have antiviral activity.

The present invention relates to 2 ′, 3 ′ represented by the above general formula [I].
The present invention relates to a novel antiviral agent comprising at least one of dideoxypurine nucleosides as an active ingredient, and a method for producing the same.

In the present invention, the purine derivative represented by the general formula [II] used as a starting material can be easily obtained by using a base exchange reaction with a microorganism [Japanese Patent Application No. 01-46].
No. 183 (JP-A-2-308797)].

If the immobilized microorganism is used, it can be obtained industrially at low cost [Japanese Patent Application No. 01-181885 (Japanese Unexamined Patent Application Publication No.
086)].

Wherein X is a hydrogen atom or an amino group, Y is a halogen atom, and R is a hydrogen atom or any of an acetyl, propionyl, benzoyl or other acyl group of C1 to C20. The treatment of the purine compound represented by the general formula [II] with anhydrous hydrazine in an organic solvent produces 2 ′, 3′-dideoxypurine ribonucleosides represented by the general formula [I]. Can be.

(Operation)

Hereinafter, the novel antiviral agent of the present invention, namely, 6-
The antiviral action of hydrazinopurine-2 ', 3'-dideoxyribofuranosides will be described.

The antiviral effect of the novel antiviral agent of the present invention is:
It is expressed by a synergistic effect of the antagonistic effect and the DNA chain termination effect.

These effects indicate that the novel antiviral agent of the present invention
It is derived from having a special structure called 2 ', 3'-dideoxypurine ribofuranoside skeleton.

That is, the novel antiviral agent of the present invention has a structure
It is very similar to nucleosides (particularly, 2'-deoxyadenosine, 2'-deoxyguanosine, etc.) which are components of DNA.

Therefore, the novel antiviral agent of the present invention has a good affinity for a virus-derived enzyme, and is different from a DNA-constituting nucleic acid (2′-deoxyadenosine, 2′-deoxyguanosine, etc.) which is an original substrate. Incorporation, and consequently, interferes with the synthesis of viral DNA (competitive inhibition) to produce the first antiviral effect.

Further, the novel antiviral agent of the present invention has a structure in which no hydroxyl group is present at the 3'-position. For this reason, once incorporated into the viral DNA, the next nucleic acid cannot be linked and the viral DNA strand terminates here (chain termination). Therefore, the virus cannot grow any further and is killed.

In this manner, the novel antiviral agent of the present invention
Acts as a chain terminator and exerts a second antiviral effect.

Therefore, the novel antiviral agent of the present invention is useful as a medicine and a reagent for a dideoxy method experiment (lab manual genetic engineering) used in genetic engineering.

Currently, AZT has already been approved as an AIDS treatment,
The antiviral effect of the clinical drug ddI and the like is also attributed to the synergistic effect of antagonistic inhibition and DNA chain termination, but the novel antiviral agent of the present invention (ie, 6-hydrazinopurine-2 ', 3). As described below, '-dideoxyribofuranosides) have properties and advantages not possessed by conventionally known drugs (such as AZT and ddI).

That this advantage, the compounds of the present invention, having a hydrazino group (-NHNH ₂₎ in the molecule, and, due to the fact that the hydrazino group is located at the 6-position of the purine base.

The hydrazino group (—NHNH ₂ ) has a structure in which a hydrogen bond is more likely to occur than a functional group (for example, a hydroxyl group or an amino group) generally present in a nucleic acid.

For this reason, the affinity for the enzyme increases, and once incorporated into the viral DNA (in addition to the chain termination effect due to the dideoxy structure), the hydrazine group is strongly bound to the viral RNA by hydrogen bonding. It has the function of preventing viral RNA from degrading.

For this reason, reverse transcriptase is double-blocked, and the effect can be further enhanced.

In addition, due to the effect of the strong hydrogen bond of the hydrazino group, an effect can be expected even for a virus having no reverse transcriptase.

In the present invention, the hydrazino group is located at the 6-position of the purine base, which is also an important factor for effectively exhibiting the antiviral effect.

That is, substitution of a large functional group at another position of the purine base (eg, position 2 and position 8) is not suitable because it increases the toxicity of the compound or decreases the recognition of the enzyme as a substrate.

Therefore, in the present invention, the hydrazine group is substituted at the 6-position to achieve both high antiviral effect and low toxicity.

Furthermore, since the compound of the present invention is a 6-hydrazino compound, it has several tautomers.

For simplicity, the general formula [I] (In the formula, X is a hydrogen atom or an amino group, and R is a hydrogen atom or any one of an acetyl group, a propionyl group, a benzoyl group and other acyl groups from C1 to C20.) Among them, 6-hydrazinopurine-
The case of 2 ', 3'-dideoxyribofuranoside (1) will be described as an example.

(Wherein, R is the same as described above.) In compound (1), two types of conformational isomers are considered due to free rotation on the carbon-nitrogen bond at position 6 of the purine base (2,3) In addition, when these exchange protons with the purine ring, two more tautomers (4, 5) are considered.

These tautomeric (and conformational) isomers do not have the property of being separable, for example, by crystallization. However, the ability to quickly change to another tautomeric structure in a solution is an advantageous effect for the present compound exhibiting antiviral properties.

A) Increased affinity for various enzymes and increased recognition as a substrate.

B) It is difficult to produce antiviral drug-resistant virus strain.

Are the main effects.

As described above, the novel antiviral agent of the present invention has a special structure of 6-hydrazinopurine in the molecule, so that it can rapidly tautomerize, and has a low enzyme affinity for viruses and resistance to virus-resistant strains. It is an excellent antiviral agent with new properties.

The novel antiviral agent of the present invention has a partial structure
Because it has a 2 ', 3'-deoxyribofuranoside skeleton,
Especially HIV (AIDS virus) and RSV (Avian sarcoma virus)
It is effective against retroviruses such as the virus, but also effective against other viruses such as hepatitis B virus and herpes virus.

The 2 ', 3'-dideoxypurine nucleoside having a halogen at the 6-position used as a raw material in the present invention can be easily obtained by a base exchange reaction with a microorganism as described above (Japanese Patent Application No. 01-46183). issue). For example, when 6-chloroguanine and dideoxyuridine are used as raw materials, when a base exchange reaction is performed using a microorganism (for example, Escherichia coli), the reaction products 2 ′,
3'-Dideoxy-6-chloroguanosine is obtained in good yield. Further, by using an immobilized microorganism, it can be obtained more easily (Japanese Patent Application No. 01-181885).

Using the 2 ', 3'-dideoxypurine nucleoside having a halogen at the 6-position synthesized as described above, a suitable organic solvent (eg, ethanol) and anhydrous hydrazine, the novel antiviral agent of the present invention can be easily prepared. Can be synthesized.

For example, when 2-amino-6-chloro-2 ', 3'-dideoxypurine ribofuranoside is added to ethanol in which anhydrous hydrazine is dissolved, and the mixture is stirred under reflux conditions, chlorine at position 6 and hydrazine can easily be obtained. As a result, 2-amino-6-hydrazinopurine-2 ', 3'-dideoxyribofurinoside, which is the target substance, is produced. After completion of the reaction, when the reaction solution is returned to room temperature, a white precipitate of the target substance is formed from the reaction solution.

As described above, according to the synthesis method of the present invention,
The antiviral agent of the present invention can be synthesized from easily available raw materials by a simple method.

[Examples] The present invention will be described in more detail with reference to the following examples. However, the following examples are for illustrative purposes only, and are not intended to limit the scope of the present invention in any case.

(1) Production Example Production Example 1 Synthesis of 6-hydrazinopurine-9-β-D-2 ′, 3′-dideoxyribofuranoside 6-chloropurine-2 ′,
0.700 g (2.75 mmol) of 3'-dideoxyribofuranoside,
40 ml of anhydrous ethanol, 0.20 g (6.00 mmol) of anhydrous hydrazine
And refluxed for 1 hour to react.

After the completion of the reaction, the temperature is returned to room temperature, and ethanol is distilled off using a rotary evaporator, and unreacted hydrazine is distilled off while adding ethanol to azeotrope. Crystallize to obtain white foil flake crystals.

The crystals were dried under reduced pressure (50 ° C, 0.1 mmHg, 10h) to give 6-
Hydrazinopurine-9-β-D-2 ', 3'-dideoxyribofuranoside was obtained. 97.5% yield.

Colorless foil flake crystal Melting point 84 ° C 1H NMR spectrum (DMSO-d6); δ 1.58 to 2.70 (4H, m, C2 'and C3'-H) 2.70 to 3.81 (2H, m, C5'-H) 3.81 to 4.38 (1H, m, C4'-H ) 5.48 (4H, broad S, C5'-OH and C6-NHNH 2) 6.25 (1H, t, C1'-H) 8.24 (1H, s, C8-H) 8.36 ( 1H, m, C2-H) MS spectrum (FAB-MS; m / z ) M + 1 251 (C10H14O2N6 + 1 as) Rf value (Silica Gel HF 254) 0.16 [ n-BuOH / AcOH / H 2 O = 4/1/1 Production Example 2 2-amino-6-hydrazinopurine-9-β-D-
Synthesis of 2 ', 3'-dideoxyribofuranoside 1.34 g (5.0%) of 2-amino-6-chloropurine-2', 3'-dideoxyribofuranoside was placed in a 100 ml eggplant flask.
mmol), anhydrous ethanol 100 ml, anhydrous hydrazine 0.32 g (1
0.0 mmol) and refluxed for 1 hour to react.

After completion of the reaction, when the temperature is slowly returned to room temperature, white crystals precipitate.

This is collected by vacuum filtration and washed well with cold ethanol. The crystals were dried under reduced pressure (50 ° C., 0.1 mmHg, 10 h) to give 2-amino-6-hydrazinopurine as a white powder.
9-β-D-2 ′, 3′-dideoxyribofuranoside was obtained. Yield 98%.

White microcrystal Melting point 165 ° C 1H NMR spectrum (DMSO-d6); δ 1.69 to 2.70 (4H, m, C2 ′ and C3′-H) 3.25 to 3.78 (2H, m, C5′-H) 3.78 to 4.41 (1H , m, C4'-H) 5.35 (4H, broad S, C5'-OH and C6-NHNH 2) 5.96 (2H, s, C6-NH 2) 6.04 (1H, t, C1'-H) 7.94 (1H , s, C8-H) MS spectrum (FAB-MS; m / z ) M + 1 266 (C10H14O2N6 + 1 as) Rf value (Silica Gel HF 254) 0.08 [ n-BuOH / AcOH / H 2 O = 4/1/1] (2) Antiviral test Antiviral data of representative compounds according to the present invention are shown below. The compound numbers are indicated by the numbers of the above examples which illustrate the preparation method in the examples of the present invention.

Test Example 1 The antiviral effect of the compound represented by the general formula [I] of the present invention was tested using Rous sarcoma virus (RSV).

Using primary cultured cells (Chich Embyo Fibrofast)
RSV infection was carried out for about 30 minutes. Then, a serially diluted sample was added, and after 4 to 7 days, it was determined by microscopy at which stage the transformation of cells due to SRV infection was suppressed. The results are shown in Table 1.

As shown in Table 1, the compound of the present invention has an excellent antiviral effect, and has very good solubility in water, so that the compound of the present invention is effective as a drug for treating viral diseases such as AIDS and hepatitis B. Clearly there is.

[Effects of the Invention] As described above, according to the present invention, a novel compound having an excellent antiviral action is provided. For example, it is extremely effective as a drug for treating viral diseases such as AIDS, hepatitis B and herpes.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI C07D 473/34 361 C07D 473/34 361 (58) Field surveyed (Int.Cl. ⁷ , DB name) C07D 473/16 C07D 473 / 34 361 A61K 31/52 CAPLUS (STN) REGISTRY (STN)

Claims (9)

(57) [Claims] 1. A compound of the general formula [I] (In the formula, X is a hydrogen atom or an amino group, and R is a hydrogen atom or any of an acetyl group, a propionyl group, a benzoyl group, or another acyl group of C1 to C20.) 2 ', 3'-dideoxypurine ribonucleosides. (2) 2-amino-6-hydrazinopurine-9-
β-D-2 ', 3'-dideoxyribofuranoside and 6
The compound according to claim 1, which is selected from -hydrazinopurine-9-β-D-2 ', 3'-dideoxyribofuranoside. 3. A compound of the general formula [II] Wherein X is a hydrogen atom or an amino group, Y is a halogen atom, and R is a hydrogen atom or any of an acetyl, propionyl, benzoyl or other C1-20 acyl group. Is treated with anhydrous hydrazine in an organic solvent to give a 2 ′, 3′-formula represented by the general formula [I].
A method for producing a nucleic acid derivative, comprising producing dideoxypurine ribonucleosides. (In the formula, X is a hydrogen atom or an amino group, and R is a hydrogen atom or any one of an acetyl group, a propionyl group, a benzoyl group, and other acyl groups of C1 to C20.) 4. An alcohol of methanol or ethanol which can dissolve the purine compound represented by the general formula [II] during the reaction and precipitate a reaction product after completion of the reaction, as the organic solvent used in the reaction according to claim 3. A method for producing 2 ', 3'-dideoxypurine nucleosides represented by the general formula [I], comprising using a system solvent. 5. An antiviral agent comprising as an active ingredient at least one of the 2 ', 3'-dideoxypurine nucleosides represented by the general formula [I] according to claim 1. 6. An antiretroviral agent comprising at least one of the 2 ', 3'-dideoxypurine nucleosides represented by the general formula [I] according to claim 1 as an active ingredient. 7. A therapeutic agent for acquired immunodeficiency syndrome (AIDS) comprising at least one of the 2 ', 3'-dideoxypurine nucleosides represented by the general formula [I] according to claim 1 as an active ingredient. And prophylactic drugs. 8. A drug for a dideoxy method experiment for genetic engineering, comprising at least one of the 2 ', 3'-dideoxypurine nucleosides represented by the general formula [I] according to claim 1 as an active ingredient. . 9. A reagent for a dideoxy method experiment for genetic engineering, comprising at least one of the 2 ', 3'-dideoxypurine nucleosides represented by the general formula [I] according to claim 1 as an active ingredient. .