JPH0710899A - Compound useful for producing 2'-alkylidene-cytidine derivative - Google Patents

Abstract

PURPOSE:To obtain the subject new compound is good yield, useful as an intermediate capable of providing a 2'-alkylidenecytidine derivative useful for antitumor agents, antiviral agents, etc. CONSTITUTION:A compound of formula I (R<1> is H, halogen or lower alkyl, R<3> is acyl; R<4> is protecting group of hydrogen), e.g. 3',5'- O-(tetraisopropyldisiloxane-1,3-diyl)-2'-keto-N<4>-benzoylcytidine. The compound of formula I is obtained by introducing protecting groups into an amino group of a compound of formula II and OH groups at 3' position and 5' position in a sugar part of the compound of formula II to provide a compound of formula III and then oxidizing OH at 2' position of sugar part of the compound of formula III.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a synthetic intermediate useful for producing a 2'-alkylidene cytidine derivative.

[0002]

2. Description of the Related Art 2'-Alkylidene pyrimidine nucleosides are novel compounds developed by the present inventors and are expected to be developed as antitumor agents or antiviral agents (JP-A-63-63). 230699). The preparation of the 2'-alkylidene cytidine derivative described in JP-A-63-230699 is carried out by using a uridine derivative as a raw material, and using a Wittig reagent, an alkylidene reaction at the sugar moiety 2'position, a sugar moiety 3'position and It consisted of each reaction step of removing the protecting group protecting the 5'-hydroxyl group and amination reaction of the 4-position of the base moiety.

[0003]

However, the above-mentioned conventional method has a problem that the reaction step is long and the isolation yield of the final product is low.

[0004]

Means for Solving the Problems As a result of trying the preparation of a 2'-alkylidene cytidine derivative using various compounds, the present inventors have found that if a compound represented by the formula (II) is used as a starting compound, The present invention has been completed by discovering that a 2'-alkylidene cytidine derivative can be obtained in good yield.

[0005]

[Chemical 3]

[In the formula, R ¹ represents a hydrogen atom, a halogen atom or a lower alkyl group, R ³ represents an acyl group, and R ⁴ represents a hydroxyl-protecting group. That is, the present invention relates to a compound represented by the above formula (II), which is useful as a synthetic intermediate in the production of a 2′-alkylidene cytidine derivative (hereinafter abbreviated as “the compound of the present invention”). Hereinafter, the present invention will be described in detail.

The compound of the present invention is represented by the above formula (II). In the formula, examples of the halogen atom for R ¹ include iodine, bromine, chlorine and fluorine halogen atoms. Examples of the lower alkyl group for R ¹ include methyl, ethyl, propyl, and isopropyl alkyl groups having 1 to 3 carbon atoms.

Examples of the acyl group of R ³ include acetyl, chloroacetyl, dichloroacetyl, trichloroacetyl,
Aliphatic acyl groups such as trifluoroacetyl, methoxyacetyl, propionyl, n-butyryl, isobutyryl, (E) -2-methyl-2-butenoyl, pentanoyl, pivaloyl, benzoyl, o- (dibromomethyl) benzoyl, p-phenyl Benzoyl, 2,4,6-trimethylbenzoyl, p-trioil, p-anisoyl,
Examples thereof include aromatic acyl groups such as p-halobenzoyl, p-nitrobenzoyl, p-methoxybenzoyl and the like.

The protecting group for R ⁴ may be any group commonly used as a protecting group for a hydrogen group, and examples thereof include acyl groups such as acetyl, propionyl, butyryl, benzoyl, naphthoyl, ethylidene, propylidene, isopropylidene, benzylidene, Acetal or ketal type protecting groups such as cyclohexylidene, cyclopentylidene, methoxymethylidene, ethoxymethylidene, dimethoxymethylidene, benzyl, p-methoxybenzyl, 3,4-dimethoxybenzyl, diphenylmethyl, triphenylmethyl, α Or an alkyl group such as β-naphthylmethyl, α-naphthyldiphenylmethyl, trimethylsilyl, t-butyldimethylsilyl, methyldiisopropylsilyl, triisopropylsilyl, tetraisopropyldisiloxyl, etc. It can be exemplified lil group.

In the compound of the present invention, for example, a protecting group is introduced into the amino group of the base moiety of the cytidine derivative and the hydroxyl groups at the 3'-position and 5'-position of the sugar moiety, and subsequently the hydroxyl group at the 2'-position of the sugar moiety is subjected to an oxidation reaction. It can be prepared by The reaction process is shown below as a reaction formula.

[0011]

[Chemical 4]

[In the formula, R ¹ , R ³ and R ⁴ have the same meanings as described above. The introduction of the protective groups represented by R ³ and R ⁴ into the cytidine derivative may be carried out according to the method usually used for the protective group used. For example, the introduction of the acyl group represented by R ³ is carried out by introducing 1 to 5 moles of an acylating agent (an acid anhydride or acid chloride of the acid corresponding to R ³⁾ to 1 mole of the cytidine derivative.
In a reaction solvent (for example, pyridine, picoline, diethylaniline, dimethylaminopyridine, dimethylformamide, acetonitrile, tetrabutylamine, triethylamine, etc., alone or as a mixed solvent) at a reaction temperature of 0 to 50 ° C. for about 1 to 30 hours. Can be carried out. Further, the introduction of the hydroxyl-protecting group represented by R ⁴ will be described by taking the silyl protecting group as an example.
It can be carried out by using 1 to 3 moles of the silylating agent to 1 mole of the cytidine derivative and reacting under the same reaction conditions as the acylation.

Next, the cytidine derivative [compound (A)] having a protecting group thus prepared is subjected to an oxidation reaction to obtain the compound of the present invention. As the method for oxidizing the 2'-hydroxyl group of the compound (A), chromic acid oxidation using a chromic acid-pyridine-acetic anhydride complex (Method A), or activated dimethyl sulfoxide generated by oxalyl chloride-dimethyl sulfoxide or the like is used. The activated dimethyl sulfoxide oxidation (Method B) used can be used. The oxidation reaction is carried out in the presence of 1 to 10 mol of the oxidizing agent per mol of the compound, in the case of Method A, -10 ° C to room temperature, and in the case of Method B,
It can be carried out by reacting at 80 to -10 ° C for about 1 to 10 hours.

The compound of the present invention thus prepared is
The nucleoside can be isolated and purified by an appropriate combination of conventional isolation and purification methods (for example, various chromalographic methods such as ion exchange and adsorption, recrystallization method, etc.). As a method for preparing a 2′-alkylidene cytidine derivative, for example, a compound represented by the formula (I), from the compound of the present invention, the compound of the present invention is subjected to an alkylidene-forming reaction using a Wittig reagent, and after reaction, represented by R ³ and R ⁴ . It is possible to employ a method of removing the protecting group.

[0015]

[Chemical 5]

[Wherein R ¹ represents a hydrogen atom, a halogen atom or a lower alkyl group, and R ² represents a hydrogen atom or a lower alkyl group (note that the halogen atom or the lower alkyl group has the same meaning as described above). To). ] The Wittig reagent that can be used in the above method is
Formula: (C ₆ H ₅₎ (wherein, R ² is the same as _{defined.) 3 P = CH-R} 2 is an alkylidene phosphorane represented by,
Specific examples thereof include triphenylphosphine methylene, triphenylphosphine ethylene, triphenylphosphine propylene, and the like.

[0017] Wittig reagent used in the reaction, immediately prior to use _{formula: [(C 6 H 5)} 3 P + -CH 2 -R 2] X - ( wherein, R ² are as defined above, X ^- is A triphenylphosphonium compound represented by a halogen ion such as Br ⁻ or I ⁻ (eg, methyltriphenylphosphonium bromide, methyltriphenylphosphonium iodide, ethyltriphenylphosphonium bromide, etc.) and a strong alkali (eg, , Potassium hydride, sodium hydride, n-butyllithium, sodium methoxide, potassium-t-butoxide, sodium amide, etc.) are preferably used according to a conventional method. The amount of the Wittig reagent used can be appropriately selected from 1 to 3 mol per 1 mol of the compound of the present invention.

In the alkylideneation reaction using such Wittig reagent, the compound of the present invention and the Wittig reagent are reacted at a reaction temperature in a solvent (for example, tetrahydrofuran, dioxane, ether, benzene, dimethyl sulfoxide, etc., alone or in a mixed solvent). 0-30 at 30-30 ° C.
It can be carried out by reacting for about 5 to 20 hours. Further, in the above-mentioned alkylideneation reaction, a phosphonium salt of a Wittig intermediate which is a reaction intermediate in the reaction solution [the structure of the intermediate is not clear, but it is considered to have the structure shown below from the reaction mode thereof] To be

[0019]

[Chemical 6]

(Wherein R ¹ , R ² , R ³ , R ⁴ and X have the same meanings as defined above)], the above intermediate may be optionally added to a reaction solvent (eg, tetrahydrofuran, dioxane, A strong alkali (eg, potassium hydride, sodium hydride, n-) in ethyl ether, benzene, dimethyl sulfoxide, etc. alone or in a mixed solvent).
Butyl lithium, sodium methoxide, potassium-t
-Butoxide, sodium amide, etc.) to recover as a 2'-alkylidene cytidine derivative having a protecting group.

The thus-prepared 2'-alkylidene cytidine derivative having a protecting group may be optionally isolated and purified by the same isolation and purification means as the above-mentioned compound of the present invention, and then subjected to the reaction for removing the protecting group. . The removal of the protecting group can be carried out by appropriately selecting the removal method usually used for the used protecting group. For example, the acyl group of R ³ can be removed by an alkaline hydrolysis method using methanol-ammonia (1: 1), concentrated ammonia or the like, and when a silyl group is used as a protective group for the hydroxyl group of R ^4. The silyl group can be removed by treatment with ammonium fluoride or an acidic or alkaline hydrolysis method.

The thus obtained 2'-alkylidene cytidine derivative is a conventional nucleoside isolation and purification means (various chromatographic methods such as adsorption or ion exchange,
Recrystallization method, etc.) can be appropriately combined and isolated and purified.

[0023]

INDUSTRIAL APPLICABILITY The compound of the present invention is more useful than known compounds in that the desired 2'-alkylidene cytidine derivative can be obtained in good yield.

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples and application examples. Example 3 ′, 5′-O- (tetraisopropyldisiloxane-1,3-diyl) -2′-keto-N ⁴ -benzoylcytidine [Formula (II): R ¹ = hydrogen, R ³ = benzoyl, R ⁴ = tetraisopropyldisiloxane-1,3-
Production of diyl] 1) 3 ', 5'- O- ( tetraisopropyldisiloxane-1,3-diyl) -N ⁴ - benzo Irushi cytidine

5 g of N ⁴ -benzoylcytidine (20.6
mmol) in 50 ml of pyridine,
7.1 ml (22.6 mmol) of 1,3,3-dichlorotetraisopropyldisiloxane was added, and the mixture was reacted with stirring at 0 ° C. for 3 hours and then at room temperature for 3 hours with stirring. After the reaction, ice water was added to the reaction solution, the solvent was evaporated under reduced pressure, the obtained residue was dissolved in ethyl acetate, and the solution was partitioned with water three times. The organic layer was dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The residue was adsorbed on a silica gel column (5 x 10 cm) and eluted with a mixed solvent of 33% ethyl acetate-hexane to give the target compound fraction, which was concentrated under reduced pressure and concentrated at 3 ', 5'-O- (tetrahydrofuran. Isopropyldisiloxane-
1,3-diyl) -N ⁴ - to give an amorphous powder 7.3g benzo Irushi cytidine (86% yield).

Elemental analysis: Calculated value (%) as C ₂₈ H ₄₈ N ₃ O ₇ Si.H ₂ O C: 55.32%, H: 7.46%,
N: 6.91% Actual value (%) C: 55.54%, H: 7.41%,
N: 6.99%

2) 3 ', 5'-O- (tetraisopropyldisiloxane-1,3-diyl) -2'-keto-N ⁴
- Synthesis of chromium trioxide benzo Irushi cytidine _{(CrO 3) 5g (40mmol)} , pyridine 8.3 ml (80 mmol) and acetic anhydride 5ml
(40 mmol) was mixed and dissolved in 110 ml of methylene chloride to obtain a chromic acid complex solution. To this, 3 ', 5'-O- (tetraisopropyldisiloxane-
1,3-diyl) -N ⁴ - benzo Irushi cytidine 5.9g
(10 mmol) was dissolved and reacted with stirring at room temperature for 1 hour. After the reaction, 500 ml of ethyl acetate was added dropwise to the reaction solution, and the solution was passed through a silica gel column (6 × 1.5 cm) to obtain a filtrate. The collected filtrate was dried under reduced pressure and the residue was adsorbed on a silica gel column (3.0 × 21 cm) to give 25%.
It was eluted with a mixed solvent of ethyl acetate-hexane and crystallized from ethyl acetate-hexane to give 3 ', 5'-O- (tetraisopropyldisiloxane-1,3-diyl) -2'-.
4.6 g of keto-N ⁴ -benzoylcytidine (yield 78
%) Was obtained.

Melting point: 135 to 137 ° C. Elemental analysis: Calculated value (%) as C ₂₈ H ₄₁ N ₃ O ₇ Si ₂ C: 57.21%, H: 7.03%,
N: 7.15% Actual measurement value (%) C: 57.08%, H: 7.12%,
N: 7.01%

Application Example Preparation of 2'-deoxy-2'-methylidene cytidine hydrochloride [Formula (I): R ¹ = hydrogen, R ² = hydrogen] 1) 3 ', 5'-O- (tetraisopropyl disiloxane-1,3-diyl) -2'-deoxy-2'-methylidene -N ⁴ - synthesis methyltriphenylphosphonium bromide benzo Irushi cytidine 10.7 g (30
mmol) in 60 ml of tetrahydrofuran,
Cool to −20 ° C. and add n-butyllithium solution 1
5.8 ml (25 mmol) was added dropwise and the reaction was allowed to stir for 1 hour. To this solution was added 3 ', 5'-O- (tetraisopropyldisiloxane-
1,3-diyl) -2'-keto -N ⁴ - benzo Irushi cytidine 2.9 g (5 mmol) mixture was reacted for 1 hour in a dropwise to -20 ° C. The obtained by dissolving a further 2 hours returned to room temperature The reaction was carried out with stirring. After the reaction, 50 ml of a 1N aqueous solution of ammonium bromide was added to the reaction solution, which was further partitioned with ethyl acetate. After partitioning, the organic layer was washed twice with water and dried over anhydrous sodium sulfate, then the solvent was distilled off under reduced pressure and the obtained residue was adsorbed on a silica gel column (2.4 × 20 cm), and 25% ethyl acetate-hexane was added. eluting with a mixture of 3 ', 5'-O- (tetraisopropyldisiloxane-1,3-diyl) -2'-deoxy-2'-methylidene -N ⁴ - amorphous powder benzo Irushi cytidine 0. 9 g
Got

In the above silica gel column, 6.
Fractions eluted with 25% ethanol-dichloromethane were collected and concentrated to dryness, and the resulting residue was dissolved in tetrahydrofuran 3
It was dissolved in 5 ml, 6.1 g of 60% powdered reagent of sodium hydride was added under an argon stream, and the mixture was stirred at room temperature for 3 hours. This was added with an aqueous solution of ammonium bromide in the same manner as above, partitioned with ethyl acetate-water, and further purified with a silica gel column to give 3 ', 5'-O- (tetraisopropyldisiloxane-1,3-diyl)-. 2'-deoxy-2 '
- methylidene -N ⁴ - to give an amorphous powder benzo Irushi cytidine 1.2 g (total 2.1 g, 72% yield).

Elemental analysis: Calculated value (%) as C ₂₉ H ₄₃ N ₃ O ₆ Si ₂ C: 59.46%, H: 7.40%,
N: 7.17% Actual measurement value (%) C: 59.39%, H: 7.52%,
N: 7.10%

2) 2'-deoxy-2'-methylidene-
N ⁴ - benzo Irushi cytidine 3 ', 5'-O- (tetraisopropyldisiloxane -
1,3-diyl) -2'-deoxy-2'-methylidene -N ⁴ - benzo Irushi cytidine 343 mg (1 mmol)
Was dissolved in 10 ml of tetrahydrofuran, and then 2.2 ml of 1N tributylammonium fluoride was added,
The mixture was reacted at 30 ° C. for 30 minutes with stirring. After neutralizing the reaction solution with acetic acid,
The solvent was evaporated under reduced pressure, and the obtained residue was developed on a silica gel column (1.6 × 30 cm, elution solvent: 8% ethanol-chloroform) and crystallized from ethyl ether-ethanol to give 2′-deoxy-2. '- methylidene -N ⁴ -
302 mg (yield 88%) of benzoyl cytidine was obtained.

Melting point: 300 ° C. or higher Elemental analysis: Calculated value (%) as C ₁₇ H ₁₇ N ₃ O ₅ C: 59.47%, H: 4.99%,
N: 12.24% Actual value (%) C: 59.28%, H: 5.05%,
N: 12.11%

3) Synthesis of 2'-deoxy-2'-methylidene cytidine hydrochloride 2'-deoxy-2'-methylidene-N ⁴ -benzoyl cytidine 139 mg (0.5 mmol) was dissolved in methanolic ammonia 10 ml, After reacting with stirring at room temperature for 6 hours, the solvent was distilled off under reduced pressure. The residue was developed with a silica gel column (1.6 × 10 cm, elution solvent: 20% ethanol-chloroform) to collect the target compound fraction, 1N hydrochloric acid (2 ml) was added, the solvent was evaporated under reduced pressure, and the residue was acetone. -Crystallized from methanol to give 2'-deoxy-2'-methylidene cytidine hydrochloride 115 mg (yield 8
3%) was obtained.

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[Procedure amendment]

[Submission date] June 15, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Compound useful for producing 2'-alkylidene cytidine derivative

Claims (2)

[Claims] 1. Formula (II): [In the formula, R ¹ represents a hydrogen atom, a halogen atom or a lower alkyl group, R ³ represents an acyl group, and R ⁴ represents a hydrogen group-protecting group. ] The compound represented by. 2. Formula (I): [In the formula, R ¹ represents a hydrogen atom, a halogen atom or a lower alkyl group, and R ² represents a hydrogen atom or a lower alkyl group. ] The compound of Claim 1 used for the synthesis | combination of the 2'-alkylidene cytidine derivative represented by these.