JPH0459789A - New cyclonucleoside, its production and antiviral agent containing the same - Google Patents

Abstract

NEW MATERIAL:The cyclonucleosides expressed by formula I (R1 is H, NH2 or OH; R3 is H or NH2). EXAMPLE:8,3'-S-cyclo-2',3'-dideoxyadenosine. USE:An antiviral agent stable to acid and useful as a remedy for viral diseases such as AIDS. PREPARATION:The compound of formula I can be produced by reacting a 8-bromo-2'-deoxynucleoside of formula II (R3 is trityl or dimethoxytrityl; R4 is methanesulfonyl, p-toluenesulfonyl or trifluoromethanesulfonyl) with thiourea in the presence of a catalytic amount of p-toluenesulfonic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to novel cyclonucleosides having antiviral activity, a method for producing the same, and an antiviral agent using the same.

[Conventional technology]

In recent years, the development of therapeutic drugs for various viral diseases has attracted attention. In particular, acquired immunodeficiency syndrome (AID)
S) has become a major social problem. Human immunodeficiency virus (HIV) is a type of retrovirus.
) is known to be caused by infection. An effective treatment for this has not yet been established. Currently, the only approved therapeutic agent is a nucleoside derivative called azidothymidine (AZT). The action of this drug is that the viral DNA is oxidized by reverse transcriptase.
It is thought that by inhibiting the synthesis of A, it suppresses the proliferation of HIV.

However, it has been reported that long-term administration of AZT causes side effects such as bone marrow suppression. In addition, AZT-resistant HI
The emergence of V strain has also been reported, and the emergence of even more effective antiviral agents is desired.

Currently, various drugs are being investigated, among which dideoxycytidine (d d e) and dideoxyinosine (
Dideoxynucleosides such as ddI) have high anti-HIV
Reported to be active. In particular, ddl is currently undergoing clinical trials, and its excellent anti-HIV activity has been confirmed so far.

[Problem to be solved by the invention]

Although ddl has high expectations as an AIDS treatment drug due to its excellent anti-HIV effect, it is also known to have some drawbacks. One of them is the acid instability of dideoxypurine nucleosides, typified by ddl. In the case of AIDS treatment, oral administration is preferable because the drug must be taken for the rest of one's life. However, acid-labile d
DL poses a problem of being degraded by gastric juice, and requires the combined use of antacids.

An object of the present invention is to provide a novel nucleoside having antiviral activity that is stable against acids.

[Means to solve the problem]

The present inventors have conducted extensive research to develop novel nucleosides that have antiviral activity that is stable against acids, and as a result, they have invented cyclonucleosides represented by the general formula [I].

(In the formula, R3 is -H, -NH2 or -OH.

(R2 represents -H1 or -NH2) The present invention provides a method for producing a cyclonucleoside represented by [I].

The 8-bromo-2'-deoxynucleosides (general formula [■]), which is a raw material for the compound of the present invention, are of the general formula [I[[]
It can be easily synthesized from the 2'-deoxynucleosides shown below.

p.

(In the formula, R1 and R2 are the same as [I, R3 is a trityl group or dimethoxytrityl group, R4 is a methanesulfonyl group, p-toluenesulfonyl group, or trifluoromethanesulfonyl group] 8-bromo- A general formula characterized by reacting 2'-deoxynucleosides with thiourea in the presence of a catalytic amount of p-1-luenesulfonic acid (wherein R3 and R2 are the same as the general formula [I]), that is, the general formula [I[2'-deoxynucleosides represented by [] are suspended in a pH 4 sodium acetate buffer, bromine water or a methanol solution of bromine is added thereto, and the mixture is stirred at room temperature for several hours. . Bromine is 1. Add S to 3 times the mole. By neutralizing the reaction solution, crude crystals of the corresponding 8-bromo derivative are precipitated. Crystals are obtained by dissolving this in aqueous hydrochloric acid and neutralizing it again after treatment with activated carbon.

The 8-bromo derivative thus obtained is reacted with trityl chloride or dimethoxytrityl chloride in pyridine at room temperature for several days to protect the hydroxyl group at the 5' position. The amount of trityl chloride or dimethoxytrityl chloride added is 1.2 to 2 moles. The reaction is almost quantitative. For isolation, the pyridine solvent is evaporated and then partitioned with CH (13-H20), and the CHCl3 layer is concentrated to dryness. Proceed to the next step without purification.

Next, the obtained 8-bromo derivative protected at the 5' position is reacted with methanesulfonyl chloride, P-toluenesulfonyl chloride, or trifluoromethanesulfonyl chloride in pyridine at room temperature. The amount of reagent added is 1.5 to 3 times the mole. After evaporating the reaction solution, the 8-bromo-2'-deoxynucleosides of the general formula [I1], which are the raw materials of the present invention, can be obtained with good efficiency by partitioning the reaction solution with CHC13H20 and separating and purifying the CHC73 layer using a silica gel column. You can get it with

8-Bromo-2 of the general formula [nl] thus obtained
By reacting ′-deoxynucleosides with thiourea in the presence of a catalytic amount of p-toluenesulfonic acid, S-
At the same time as the cyclo-isomer is produced, the protecting group at the 5' position is removed to easily obtain the compound of the present invention (general formula [I]). The amount of thiourea added is 1.5 to 3 equivalents.

Suitable reaction catalysts include alcohol catalysts such as methanol and ethanol, DMF, DMSO, and acetonyl. The reaction conditions are 60-150°C for several hours.

The compound of the present invention synthesized in this manner can be easily purified by conventional purification methods, such as column chromatography, recrystallization, or a combination thereof.

〔Example〕

Next, examples of the present invention will be shown.

(1) 8.3'-3-Cyclo-2',3'-dideoxyadenosine 5.0 g (19.9 mmol I) of 2'-deoxyadenosine was suspended in 100 ml of pH 4 sodium acetate buffer and heated to room temperature. Upper bromine 2.4m1 (
45.8 mmol) dissolved in methanol] 00 ml
was added dropwise and stirred. After 2 hours, I ran out of raw materials, so
After treating excess bromine with an aqueous sodium thiosulfate solution,
When neutralized to pH 7 with caustic soda, crude crystals were precipitated. After filtration, it was dissolved in an aqueous hydrochloric acid solution and treated with activated carbon, and then neutralized again to pH 7 with caustic soda, resulting in 8-bromo-2'-
Crystals of deoxyadenosine precipitate and are filtered out.
When dried after washing with water, 3.0g of pale yellow powder (45,7
%)was gotten.

Next, 3.0 g of the above 8-bromo derivative (9,1 mmo
1) was dissolved in 30 ml of pyridine, 3.8 g (13,4++ll1 ol) of trityl chloride was added, and the reaction was carried out at room temperature for 2 days. For isolation, pyridine was evaporated, extracted with CHCl3-H2O system, and concentrated to dryness.

Since the reaction is progressing almost quantitatively, proceed to the next step without purification.

8-Bromo-5'-trityl- thus obtained
Dissolve 2'-deoxyadenosine in 50ml of pyridine and add 6.4g of p-)luenesulfonyl chloride under water cooling.
(33.6n+mol) was added dropwise. After the dropwise addition was completed, the temperature was returned to room temperature and the reaction was carried out for 2 days. After evaporating the reaction solvent, extraction was performed using a CHC/3-H2O system, and the extract was separated and purified using column chromatography.

The obtained crude crystals were crystallized from ethanol to give 2-72 g of crystals of 8-bromo-5'-trityl-3'-p-toluenesulfonyl-2'-deoxyadenosine (3,
7m+nol) was obtained.

2.72 g (3.7 n+mol) of the above compound were suspended in 15 ml of ethanol and 0.43 g (5 mol) of the above compound was suspended in 15 ml of ethanol.
, 6+n+nol) and p-toluenesulfonic acid 5■ (2
, 9x 10-2+nmol) and heated under reflux. After 3 hours, upon cooling, crystals precipitated. Recrystallization was performed from ethanol water to obtain compound 8.3'-8 of the present invention.
-Cyclo-2',3'-dideoxyadenosine 200■
(0.75m+l1ol) was obtained.

' H-NMR (DMSO-d6) Figure IIR (KB
r) Figure 2 FAR-)IRMs (m#); Calculated value (CIDH1
IN5023↓H) 266,0712 Actual value 266,0701 (2) Regarding acid stability Dissolve compound 20 of the present invention in pure water and add 100 ml.
Mess up to. Transfer 1 ml of this to a 25 ml volumetric flask, make up the volume with a phosphate buffer solution of pH 7.4, and use this as the starting concentration.

Prepare a 25 ml volumetric flask by adding a certain amount of pi (7,4) phosphate buffer in advance.Next, add 1 ml of concentrated hydrochloric acid to 99 ml of the above sample solution and mix quickly. 1, 1. Then 2.
5. Take 1 ml of the solution at 10.15 and 30 minutes, transfer it to a volumetric flask containing any buffer solution, and adjust the pH.
Make up the volume to 25+nl with 7.4 phosphate buffer.

Quantification was performed using HPLC (column, ODS-80TM).

Detection was carried out at 25411m). Note that the starting materials were subjected to concentration correction. Similar operations are done for comparison.
I also went to dl. The results are shown in Table 1.

Table 1: Acid stability (3) Anti-inflammatory activity Tests were conducted using Rous sarcoma virus (RSV), a type of retrovirus. The antiviral test was performed using primary culture cells (Chick Embryo Fi
brolgsf) for about 30 minutes. Then, add the sample diluted in stages and add 4 to 7
Days later, the stage at which cell transformation due to R8V infection was inhibited was determined using a microscope. The results are shown in Table 2.

Table 2 Antiviral effect [Effect of the invention] As explained above, the present invention is stable against acids (Table 1) and is a novel antiviral agent (Table 2
) is provided. Therefore, it is extremely effective as a therapeutic agent for viral diseases such as AIDS.

[Brief explanation of drawings]

FIG. 1 shows the NMR of the example substance of the present invention, and FIG. 2 shows the IR of the same. Procedural amendment (Contents of self-amendment dated September 13, 1990 and antiviral agent using the same) The following matters are corrected in the specification of the present application. "Derivative" has been corrected to "8-bromo derivative J." 2. On the bottom line of page 1 of the specification, "reaction catalyst" has been corrected as "reaction solvent." 3. On lines 9-10 of the same page, "alcohol "Catalyst" has been corrected to "alcohol solvent." 4. On lines 10-11 of the same page, "acetonyl" has been corrected to "acetonitrile J." 5. On page 12, line 6 from the bottom of the specification, "Resistance" has been corrected. 6. In the second line from the bottom of the same page.

Claims (3)

[Claims] (1) General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] (In the formula, R_1 is -H, -NH_2 or -OH, R_
2 represents -H or -NH_2) Cyclonucleosides represented by: (2) The following general formula [II] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [II] (In the formula, R_1 and R_2 are the same as [I], R_3
represents a trityl group or a dimethoxytrityl group, and R_4 represents a methanesulfonyl group, a p-toluenesulfonyl group, or a trifluoromethanesulfonyl group. 1. A method for producing cyclonucleosides represented by the general formula [I], which comprises reacting 8-bromo-2'-deoxynucleosides represented by the following with thiourea in the presence of a catalytic amount of p-toluenesulfonic acid. (3) An antiviral agent containing a cyclonucleoside represented by the general formula [I] as an active ingredient.