JP3023804B2 - Method for producing 3'-deoxy-3'-fluorothymidine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing 3'-deoxy-3'-fluorothymidine which itself has an antiviral action and an antitumor action.

[0002]

2. Description of the Related Art In recent years, it has been known that nucleosides exhibit various physiological activities, and a large number of natural and unnatural nucleosides have been synthesized. Among these nucleosides, 3'-deoxy-3'-fluorothymidine, which is noted for exhibiting anti-AIDS virus activity, is synthesized by 3'-mesylthymidine or 2,3 '
Anhydrothymidine and potassium hydrogen fluoride or ammonium fluoride in ethylene glycol solvent in 19
By heating and reacting at 1 ° C. for 10 to 90 minutes, the yield is 10
A method of synthesizing 3′-deoxy-3′-fluorothymidine at １４14% (Japanese Patent Publication No. 48-10472), reacting thymidine and 4-chlorobenzoyl chloride in a pyridine solvent at 5 to 20 ° C. 5'- at 80% rate
After (4-chlorobenzoyl) thymidine, 5′-
(4-Chlorobenzoyl) thymidine was treated with diethylaminosulfotrifluoride and -78 in a methylene chloride solvent.
And reacted at a yield of 19.9% with 3′-deoxy-3′-
Method for synthesizing fluorothymidine [JP-A-1-6832]
No. 5], 3'-deoxy-3'-fluorothymidine and 3'-deoxy-3'- are reacted by heating 2,3'-anhydrothymidine and hydrofluoric acid at 150 ° C for 90 minutes in a triethylamine solvent. A method of obtaining a mixture of fluoro-5'-mesylthymidine in a yield of 19% [Zeits
lift fur Chemie, Vol. 23, No. 3
35 (1983)], 2,3'-anhydro-
5′-mesylthymidine was reacted with hydrofluoric acid and aluminum fluoride in a dioxane solvent at 170 ° C. to give a yield of 61 ′.
% Of 3'-deoxy-3'-fluoro-5'-mesylthymidine, followed by demesylation with sodium hydroxide to synthesize 3'-deoxy-3'-fluorothymidine with a yield of 46%. Method [Journal fur
Praktische Chemie, vol. 315, p. 895 (1973)]. However, these methods have problems such as low yield, use of expensive reagents, poor reproducibility, and difficulty in purification, and are not suitable as industrial production methods. The synthesis of this addition, the 5'-position hydroxyl group of thymidine mesyl group is acid-resistant protective group (CH ₃ SO ₃ -) After protected, the 3'-position by fluorination with hydrofluoric acid 3 '-Deoxy-3'-fluoro-5'-mesylthymidine (hereinafter abbreviated as "5'-mesylated"), followed by demesylation to give 3'-deoxy-3'-fluorothymidine. Are known. The demesylation reaction, which is one of the steps of this synthesis method, is usually performed under alkaline conditions using alkali hydroxide, but the 5′-mesylated compound easily reacts with alkali hydroxide in its structural formula. Since it contains fluorine, the demesylation reaction using this alkali hydroxide cannot be employed. Therefore, as the demesylation reaction of the 5'-mesylated product, 5'-acetyl-3'-deoxy-3'-fluorothymidine (hereinafter, referred to as "5'-acetyl-3'-deoxy-3'-fluorothymidine" in which mesyl group is substituted with acetyl group using potassium acetate in acetic anhydride) 5′-acetylated product ”), followed by deacetylation to obtain 3′-deoxy-3′-fluorothymidine [Nucleic Acid Ch
chemistry part I, pp. 299-302 (1978)].

[0003]

The conventional acetylation reaction of the 5'-mesylated compound in acetic anhydride uses about 100 times the amount of acetic anhydride with respect to the 5'-mesylated compound and requires a long time. Due to the heating, the reactants are markedly colored, by-products are formed in large amounts, and the yield of the 5'-acetylated product is extremely low.
Therefore, purification requires an inefficient column chromatography method, and it is difficult to industrially produce a large amount of 5'-acetylated product.

[0004]

Means for Solving the Problems The inventors of the present invention have studied the efficient acetylation of the 5'-mesylated compound, and as a result, have found that the 5'-mesylated compound and an alkali metal acetate, amine acetates and acetates Focusing on the fact that acetylation proceeds easily in a solvent that dissolves both acetylation reagents selected from the group consisting of ammonium, acetic anhydride is required by selecting an aprotic solvent as the reaction solvent. No acetylation conditions of the present invention have been found.
That is, according to the present invention, as shown in the following formula, the raw material 5′-
The mesylate is reacted with an acetylating reagent selected from the group consisting of alkali metal acetate, amine acetates and ammonium acetate in an aprotic polar solvent to give a 5′-acetylated form, and then the 5′-acetylated form is obtained. 3'-deoxy-3 '
-To obtain fluorothymidine. (Below)

[0005]

Embedded image 3'-deoxy-3'-fluorothymidine

[0006] The 5'-mesylated product as a raw material of the present invention is
Nucleic Acid Chemistry Pa
rt I, page 299 (1978), thymidine was reacted with mesyl chloride in a pyridine solvent to give 3 ′, 5′-dimesylthymidine, and then sodium hydroxide in an ethanol solvent. Reacting to 2,3′-anhydro-5′-mesylthymidine,
Subsequently, it can be obtained by reacting with aluminum fluoride in a 0.1% dihydrofluoric acid solvent under heating. The acetylation reagent used in the present invention is an alkali metal acetate, amine acetates and ammonium acetate. Specifically, lithium acetate, sodium acetate, potassium acetate and the like are used as the alkali metal acetate, and acetic acid = tetraacetic acid is used as the amine acetate. Examples thereof include tetraalkylammonium acetic acid such as methylammonium, acetic acid = tetraethylammonium, acetic acid = tetrapropylammonium, and acetic acid = tetrabutylammonium. As the reaction solvent, an aprotic polar solvent is used, and examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, and hexamethylphosphoric triamide, but are not limited thereto. The acetylation reaction of the 5'-mesylated compound of the present invention requires a minimum equimolar amount of the acetylating reagent with respect to the 5'-mesylated compound, and usually the optimal amount is 1.4 to 3 moles. Use of an excessive amount of the acetylating reagent is not preferable because the reaction system becomes acidic.
The amount of the aprotic polar solvent may be any as long as the 5′-mesylated compound is dissolved, and the reaction proceeds even if a part of the acetylating reagent is in a suspended state. It is preferably equal to or greater than the body weight (weight). The reaction may be carried out at a temperature of 50 ° C. or higher and at a temperature not higher than the boiling point of the reaction solvent. If the temperature is lower than 50 ° C., the progress of the acetylation reaction is extremely slow, and the reaction product may be colored near the boiling point of the reaction solvent.
~ 130 ° C is the most preferred temperature range. The reaction time varies depending on the reaction temperature, the type of the reaction solvent, and the type of the acetylating reagent, but requires 110 to 120 minutes at 110 ° C. After completion of the reaction, the reaction product may be used as it is for the deacetylation reaction in the next step, or may be used for the deacetylation reaction in the form of a reaction concentrate in which the reaction solvent has been removed from the reaction product under reduced pressure. In addition, the 5'-acetylated product is extracted from the reaction product or the reaction concentrate with an organic solvent, and the solvent obtained by distilling off the solvent is used as it is, or the concentrate is deacetylated after purification treatment such as decolorization treatment with activated carbon. It can also be used for the reaction. Next, the thus obtained 5′-acetylated product is subjected to a known acetyl group elimination reaction, for example, leaving or stirring at 0 ° C. to room temperature in ammonia-saturated methanol [Nucleic Acid Chemistry].
Part I, p. 299 (1978)]. After completion of the reaction, decolorization treatment is performed with activated carbon to obtain crude 3′-deoxy-3′-fluorothymidine as off-white crystals, and further purification treatment such as recrystallization using water, lower alcohol, or ethyl acetate is performed, or the reaction is performed. After distilling off the reaction solvent from the liquid under reduced pressure, the residue is treated with a synthetic adsorbent to adsorb 3′-deoxy-3′-fluorothymidine, and then eluted with an alcohol-water mixture, and the solvent is distilled off, water, lower grade Purification by recrystallization using alcohol to obtain 3'-deoxy-3'-fluorothymidine having a purity of 99.8% or more in white powder or white granular crystals in a high yield of 70% or more. It is.

[0007]

The present invention will be illustrated below by way of examples. Example 13 3.22 g (10 mmol) of '-deoxy-3'-fluoro-5'-mesylthymidine are dissolved in 10 ml of dimethylsulfoxide. 1.64 g (20 mmol) of sodium acetate was added to this solution, and the mixture was heated with stirring at 110 ° ± 5 ° C. for 10 minutes. After completion of the reaction, dimethyl sulfoxide was distilled off from the reaction mixture under reduced pressure to obtain about 5 g of a pale brown oil as a residue. This light brown oil is 5'-
Acetyl-3'-deoxy-3'-fluorothymidine gave the same retention time in high performance liquid chromatography and the same Rf value in thin layer chromatography as the standard. Also, in the nuclear magnetic resonance spectrum, the peak at a δ value of 3.25 ppm attributed to the mesyl group disappeared, and the δ value attributable to the acetyl group of 2.09 ppm.
Was confirmed to be 5'-acetyl-3'-deoxy-3'-fluorothymidine. Next, 60 ml of an ammonia-saturated methanol solution was added to the pale brown oil, and the mixture was stirred at room temperature for about 2 hours, and then methanol was distilled off under reduced pressure to obtain a pale red brown oil. 10 ml of water was added to the reddish-brown oil and dissolved by heating.
Activated carbon is added to decolorize, and filtered while hot. Add this to hot water 1
After washing with 0 ml, water is distilled off under reduced pressure together with the filtrate. After adding 10 ml of water to the residue and dissolving by heating, the mixture was allowed to stand at room temperature overnight to obtain 2.0 g (8.2 mmol) of 3'-deoxy-3'-fluorothymidine as white granular crystals. 82% yield.

Analytical values (1) 3'-deoxy-3'-fluoro-5'-mesylthymidine Melting point: 165 to 166 ° C. ¹ H-nuclear magnetic resonance spectrum (DMSO-d ₆ ) δ (ppm) = 1.77 _{(s, 3H, CH 3)} 2.39 (m, 2H, H-2 '× 2) 3.25 (s, 3H, CH 3 SO 2 -) 4.38 (m, 1H, H-4') 4.42 (m, 2H, H-5 '× 2) 5.37 (dd, JHH = 4.0HZ, JHF = 52.2Hz, 1H, H-3') 6.24 (dd, J = 8. 6HZ, J = 6.0HZ, 1H, H-1 ′) 7.51 (s, 1H, 6-H) 11.40 (brS, 1H,> NH) ¹³ C-nuclear magnetic resonance spectrum (DMSO-d ₆ ) δ (ppm) = 11.94 ( CH 3) 36.08 (d, J = 20.7HZ, 2'-C) 36.76 (CH 3 SO 2 -) 68.83 (d, J = 1.2 HZ, 5'-C) 81.39 (d, J = 26.9 HZ, 4'-C) 84.45 (1'-C) 93.86 (d, J = 176.6 HZ, 3'-C) C) 110.37 (5-C) 135.88 (6-C) 150.80 (2-C) 160.98 (4-C)

(2) 5′-acetyl-3′-deoxy-3′-fluorothymidine Melting point: 99-100 ° C. ¹ H-nuclear magnetic resonance spectrum (DMSO = d ₆ ) δ (ppm) = 1.90 (d) , J = 1.22HZ, 3H, CH 3) 2.09 (s, 3H, CH 3 CO-) 2.23 (m, 1H, 2'-H) 2.62 (m, 1H, 2'-H 4.36 (m, 2H, 5'-H) 4.37 (m, 1H, 4'-H) 5.18 (dd, JHH = 5.3Hz, JHF = 51.6Hz, 3'-H) 6.30 (dd, J = 8.8 Hz, J = 55 Hz, 1′-H) 7.22 (d, J = 1.22 Hz, 6-H) 9.21 (brS, 1H,> NH) ¹³ C - nuclear magnetic resonance spectrum _{(DMSO-d 6) δ (} ppm) = 12.43 (CH 3) 20.55 (CH 3 CO-) 38.12 (d, J = 21.3HZ, 2'-C) 3.44 (d, J = 10.2 Hz, 5'-C) 82.37 (d, J = 26.7 Hz, 4'-C) 85.47 (1'-C) 93.44 (d, J) = 180.6HZ, 3'-C) 111.57 (5-C) 134.83 (6-C) 150.41 (2-C) 163.82 (4-C) 170.32 (CH 3 CO- )

(3) 3′-deoxy-3′-fluorothymidine Melting point: 177 to 179 ° C. ¹ H-nuclear magnetic resonance spectrum (DMSO-d ₆ ) δ (ppm) = 1.77 (d, J = 1. _{1HZ, CH 3) 2.30 (m} , 2H, H-2 '× 2) 3.64 (m, 2H, H-5' × 2) 4.13 (td, JHH = 4.0HZ, JHF = 27 0.8HZ, 1H, H-4 ') 5.29 (dd, JHH = 4.0HZ, JHF = 54.2Hz, 1H, H-3') 6.20 (dd, J = 5.9HZ, J = 9) .1HZ, 1H, H-1 ') 7.69 (d, J = 1.1Hz, 1H, H-6) 11.31 (brS, 1H,> NH) ^13C- nuclear magnetic resonance spectrum (DMSO-d ₆ ) δ (ppm) = 12.16 (CH ₃ ) 36.94 (d, J = 20.3 Hz, 2'-C) 60.94 (d, J = 11.1 Hz, 5'-C) 8 (1′-C) 84.94 (d, J = 23.0 HZ, 4′-C) 95.03 (d, J = 174.4 HZ, 3′-C) 110.00 (5-C) 136. 04 (6-C) 150.82 (2-C) 164.03 (4-C) Specific application rate [α] (26 ° / D) -7.0 ° (c = 1.0, DMSO)

Example 2 3.22 g (10 mmol) of 3'-deoxy-3'-fluoro-5'-mesylthymidine are dissolved in 10 ml of N, N-dimethylformamide. 1.96 g (20 mmol) of potassium acetate was added to this solution, and 110 ° ± 5 ° C.
For 60 minutes with stirring. After completion of the reaction, N, N-dimethylformamide was distilled off under reduced pressure.
The mixture was extracted twice with 50 ml of ethyl acetate.
The ethyl acetate layer was washed twice with 30 ml of water, dried over anhydrous sodium sulfate, then, ethyl acetate was distilled off under reduced pressure, and the residue was dissolved in methanol. Activated carbon (1.4 g) was added to this solution, followed by decolorization and filtration. The filtrate was concentrated to give a residue. After treating the residue with ammonia-saturated methanol in the same manner as in Example 1, purification operation was carried out, and 1.8 g (7.38 mMo) of 3′-deoxy-3′-fluorothymidine as white granular crystals was obtained.
1) was obtained. Yield 73.8%. The analytical value is the same as that of 3′-deoxy-3′-fluorothymidine obtained in Example 1.

Example 3 644 g (2 mol) of 3'-deoxy-3'-fluoro-5'-mesylthymidine are dissolved in 1 liter of N, N-dimethylformamide. 308 g (4 mol) of ammonium acetate was added to this solution, and the mixture was heated with stirring at 110 ° ± 5 ° C. for 2 hours. After completion of the reaction, N, N-dimethylformamide was distilled off from the reaction mixture under reduced pressure to obtain about 1 kg of a brown oily substance as a residue. This brown oil was prepared according to Example 1.
From the results of high performance liquid chromatography, thin layer chromatography and nuclear magnetic resonance spectrum similar to those described above, it was confirmed that the product was 5′-acetyl-3′-deoxy-3′-fluorothymidine. Next, 6 liters of an ammonia-saturated methanol solution was added to the brown oil, and the mixture was stirred at room temperature for about 2 hours.
kg. Next, the brown oily substance was dissolved in 10 liters of water, and the solution was added to the synthetic adsorbent Sepabeads SP207.
The solution is passed through 10 liters (registered trademark) and adsorbed. Next, 30 liters of water are passed through this synthetic adsorbent to wash the same,
The mixture is eluted and washed by sequentially passing 30 liters of a mixed solution of 30% methanol and water and 10 liters of methanol. The methanol-water mixture eluate was concentrated to dryness under reduced pressure to obtain about 450 g of a white solid of crude crystals of 3′-deoxy-3′-fluorothymidine as a residue. Next, 2 liters of water was added to the white solid, and the mixture was heated and dissolved under stirring. The mixture was stirred overnight at room temperature to obtain 410 g (1.68 mol) of 3'-deoxy-3'-fluorothymidine as white powdery crystals. Yield 84%. The analytical value is the same as that of 3′-deoxy-3′-fluorothymidine obtained in Example 1.

Example 4 322 g (1 mol) of 3'-deoxy-3'-fluoro-5'-mesylthymidine was added to dimethyl sulfoxide 500.
266 g (2 mol) of tetramethylammonium acetate to this solution.
Heat under stirring for minutes. After completion of the reaction, dimethyl sulfoxide was distilled off from the reaction mixture under reduced pressure to obtain about 500 g of a brown oily substance as a residue. This brown oil was confirmed to be 5'-acetyl-3'-deoxy-3'-fluorothymidine from the results of high-performance liquid chromatography, thin-layer chromatography, and nuclear magnetic resonance spectrum similar to those in Example 1. . Next, 3 liters of an ammonia-saturated methanol solution was added to the brown oily substance, and the mixture was stirred at room temperature for about 2 hours.
0 g was obtained. Next, the brown oil was dissolved in 5 liters of water, and then the synthetic adsorbent Diaion HP20 (registered trademark) 5 was added.
Pass through the liter to adsorb. Next, this synthetic adsorbent was treated in the same manner as in Example 3 to obtain 195 g (0.80 mol) of 3′-deoxy-3′-fluorothymidine as white powdery crystals.
1) was obtained. Yield 80%. The analysis value was 3 'obtained in Example 1.
The same as -deoxy-3'-fluorothymidine.

Comparative Example 3 0.5 g (1.6 mmol) of 3'-deoxy-3'-fluoro-5'-mesylthymidine was dissolved in 60 ml of acetic anhydride, and 0.5 g (5.1 mm) of potassium acetate was added to this solution.
ol) and heated with stirring at 130-135 ° C for 2 hours. After completion of the reaction, acetic anhydride was distilled off under reduced pressure, and the dark reddish brown residue was dissolved in 125 ml of chloroform, washed with 100 ml of water, and the chloroform layer was washed with 0.1 ml of activated carbon.
Treat with 1 g to decolorize and dry over magnesium sulfate. Then, chloroform was distilled off to obtain 0.73 g of a reddish brown oily substance as a residue. As a result of analyzing the reddish-brown oil by high-performance liquid chromatography, 27 peaks were detected, of which 5′-acetyl-3′-deoxy-3′-
The content of fluorothymidine was 20% (area ratio).

[0015]

Industrial Applicability The process for producing 3'-deoxy-3'-fluorothymidine of the present invention is useful as a compound having antiviral and antitumor effects by itself, and particularly, 3'- which is an anti-AIDS drug. Deoxy-3'-azidothymidine (A
3'- which shows stronger anti-AIDS virus activity than ZT)
Deoxy-3'-fluorothymidine can be supplied stably in a large amount in a high yield, and is suitable as an industrial production method.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigeki Higuchi 1-168-1, Nisshincho, Omiya-shi, Saitama A-308 (72) Inventor Junko Tanaka 5-17-4 Shimo, Kita-ku, Tokyo (58) Field (Int. Cl. ⁷ , DB name) C07H 19/073 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A process for producing 3′-deoxy-3′-fluorothymidine, comprising the steps of: 3′-deoxy-3′-fluoro-5′-mesylthymidine in an aprotic polar solvent.
Reacting with an acetylating reagent selected from the group consisting of alkali metal acetate, amine acetates and ammonium acetate to obtain 5'-acetyl-3'-deoxy-3'-fluorothymidine; Deacetylating -3'-deoxy-3'-fluorothymidine to obtain 3'-deoxy-3'-fluorothymidine. .