KR100699099B1 - 1-?-halo-2,2-difluoro-2-deoxy-d-ribofuranose derivatives and process for the preparation thereof - Google Patents

Abstract

The present invention relates to a 1-α-halo-2,2-difluoro-2-deoxy-D-ribofuranose derivative represented by the following Chemical Formula 1 and a method for preparing the same, and to 1-α-halo of the present invention. Ribofuranose derivatives are obtained in the solid state and can be usefully used as intermediates for the preparation of gemcitabine.

Where

이고, R ¹ is benzoyl or

ego,

이고,R ² is

ego,

R ³ is phenyl unsubstituted or substituted with one or more groups selected from the group consisting of cyano, halogen, carboalkoxy, toluene, nitro, C _1-2 alkoxy, C _1-2 alkyl and dialkyl amino,

X is Cl, Br or I.

Description

1-α-halo-2,2-difluoro-2-deoxy-D-ribofuranose derivatives and preparation method thereof {1-α-HALO-2,2-DIFLUORO-2-DEOXY-D-RIBOFURANOSE DERIVATIVES AND PROCESS FOR THE PREPARATION THEREOF}

The present invention is a novel 1-α-halo-2,2-difluoro-2-deoxy-D-ribofuranose derivative, which can be usefully used as an intermediate for the preparation of gemcitabine, the preparation thereof A method and compounds useful as intermediates in the preparation thereof.

Gemcitabine is an anticancer agent widely used to treat Non Small Cell Lung Cancer (NSCLC), a nucleoside with ribofuranose skeleton, and stereochemically in the 1-position of ribofuranose. cytosine) has a structure oriented in the β-position.

Gemcitabine can be prepared using lactol compound (I), as shown in Scheme 1 below, wherein the 1-hydroxy group of lactol compound (I) is difficult to directly glycosylation with cytosine Therefore, 1a) the intermediate compound (II) may be prepared by introducing a highly reactive leaving group (L), and then 2a) glycosylation of the activated intermediate compound (II).

Wherein P is a hydroxy protecting group and L means a leaving group.

To in Scheme 1, glycosylation reaction 2a) is so mainly proceeds by the S _N 2 displacement reaction mechanism and the cytosine base, such as gemcitabine and a nucleoside β- oriented in position to produce a yield of a leaving group ( It is important to obtain α-anomers with high purity where L) is oriented in the α-position.

Therefore, a method of stereoselectively introducing a leaving group to the 1-position of ribofuranose has been continuously studied.

For example, US Pat. Nos. 4,526,988 and 5,453,499 disclose 1-α-halo-ribofuranose derivatives incorporating halo leaving groups.

US Pat. No. 4,526,988 discloses 1-acetate derivatives by reacting the 1-hydroxy group of lactol compound (III) with acetic anhydride or another source of acetyl group in the presence of at least one equivalent of an acid scavenger as shown in Scheme 2 below. A process for preparing 1-halo anomer (V) is described by preparing IV) and then slowly adding hydrogen bromide or hydrogen chloride gas at a low temperature of about −50 to 0 ° C. However, this method has a problem in that the yield of α-halo anomer obtained due to low stereoselectivity is low.

Wherein R 'is a hydroxy protecting group, Ac is acetyl and X is bromo or chloro.

On the other hand, U. S. Patent No. 5,453, 499 discloses that the [alpha] -haloomer (VII) is reacted with a halide source in an inert solvent as shown in Scheme 3: A method of producing at a high ratio of 1 to 10: 1 is described.

Wherein X is a hydroxy protecting group such as benzoyl and the like, R 'is sulfonate and Y is halide.

However, the starting material β-sulfonate anomer (Compound VI) is prepared from the corresponding 1-hydroxy compound, for example as described in US Pat. No. 5,401,861, wherein α-sulfonate anomer and β-sulfo Nate anomers are produced in a ratio of 1: 4, so considering the process of purely separating the β-sulfonate anomers from the α- and β-mixtures, the α-halo anomers in Scheme 3 may be 9: 1 to 10: Even if obtained at a high ratio of 1 (α-anomer: β-anomer), the stereoselective ratio of obtaining the final α-halo anomer (VII) from the 1-hydroxy compound is only about 3: 1. . In addition, since the reaction product α-halo anomer (VII) having a benzoyl group or the like introduced as a 3- and 5-hydroxy group protecting group is obtained in an oil phase, the separation efficiency is low and uneconomical to purify it, which is not suitable for mass production. There is a problem of using a column chromatography method. In particular, the oil phase obtained has a problem in that it is difficult to handle or store unlike a solid in general, and a method of preparing gemcitabine using 1-α-halo anomer has not been developed in various ways.

Accordingly, it is an object of the present invention to provide a 1-α-halo-D-ribofuranose derivative which is obtained in a solid phase and is highly purified by simple methods such as recrystallization.

Another object of the present invention is to provide a method for preparing the compound in stereoselective, high purity and high yield.

Another object of the present invention is to provide a compound useful as an intermediate in the preparation of the compound.

In order to achieve the above object, the present invention provides a 1-α-halo-2,2-difluoro-2-deoxy-D-ribofuranose derivative of the general formula (1):

Formula 1

Where

이고, R ¹ is benzoyl or

ego,

이고,R ² is

ego,

R ³ is phenyl unsubstituted or substituted with one or more groups selected from the group consisting of cyano, halogen, carboalkoxy, toluene, nitro, C _1-2 alkoxy, C _1-2 alkyl and dialkyl amino,

X is Cl, Br or I.

In order to achieve the above another object, in the present invention

1) reducing the 1-oxo ribose compound of Formula 2 to prepare a lactol compound of Formula 3;

2) reacting the lactol compound obtained in step 1) with a halophosphate compound of formula 4 in the presence of a base to prepare a 1-phosphate furanose derivative of formula 5; And

3) reacting the compound obtained in step 2) with a halide source and recrystallizing

Provided is a method for preparing 1-α-halo-2,2-difluoro-2-deoxy-D-ribofuranose derivative of Formula 1, comprising:

Formula 1

Wherein R ¹ , R ² , R ³ and X are as defined above and R ⁴ is methyl, ethyl or phenyl, preferably phenyl.

In order to achieve the above another object, the present invention provides a 1-phosphate furanose derivative of formula (5) useful as an intermediate in the preparation of 1-α-halo-D-ribofuranose derivative of formula (1):

Formula 1

Formula 5

Wherein R ¹ , R ² , R ⁴ and X are as defined above.

Hereinafter, the present invention will be described in more detail.

In the ribofuranose derivative of Formula 1, R ³ is preferably 2-phenyl or 4-phenyl.

Ribofuranose derivative of the general formula (1) of the present invention is characterized in that the biphenyl carbonyl group is introduced as a protecting group of 3-hydroxy. In addition, a biphenylcarbonyl group may be selectively introduced as a protecting group of 5-hydroxy.

Due to such a structural feature, the ribofuranose derivative of the present invention is obtained in a solid phase, and thus can be obtained with high purity of 99.5% or more through a simple purification process such as recrystallization.

Gemcitabine with the cytosine oriented in the β-position can be prepared by combining the 1-α-halo-ribofuranose derivative of Formula 1 with cytosine through a glycosylation reaction known in the art.

The purity of the α-halo compound is very important when proceeding to the next glycosylation reaction using the 1-halo compound. If the opposite isomer of β-halo compound is mixed without purification, the stereoselectivity of the glycosylation reaction is inversely reduced in proportion to the amount, resulting in β-nucleoside, that is, gemcitabine in a very low yield. The purity of the α-halo compound is important, and when glycosylation is carried out using the high-purity α-halo compound according to the present invention, the desired β-nucleoside gemcitabine is 2 to 3 times by the conventional method. It can be obtained with a high ratio of 4 to 14 times, which is significantly improved compared to that, and thus gemcitabine can be produced at low cost.

In addition, since the compound of Formula 1 according to the present invention is present in a solid phase, it does not discolor or decompose even if left in the air for a long time, and has stability enough to maintain high purity. It can solve the problem.

Method for preparing a compound of Formula 1 according to the present invention is as shown in Scheme 4.

Wherein R ¹ , R ² , R ³ , R ⁴ and X are as defined above.

When the overall process of the production method of the present invention as shown in Scheme 2 is outlined, 1) the 1-oxoribose compound of the formula (2) is reduced by a conventional method to the α-anomer and β- 2) A 1-phosphate containing β-anomer of Formula 5 at a higher ratio of 10 times by reacting the obtained lactol compound with a halo phosphate compound of Formula 4 in the presence of a base. 3) 1-halo-2-deoxy-2,2-difluoro- of the final target compound of the present invention by preparing a furanose derivative and then reacting the obtained 1-phosphate furanose derivative with a halide source. D-ribofuranose derivatives may be prepared in a state where the α-anomer is contained at a high ratio of 99.5% or more.

According to the above-described manufacturing process, the present invention has a leaving structure of a new structure in order to prepare the α-halo anomer of the formula (1) containing a high proportion of α-anomer, of the general formula (5) The technical feature is the use of novel 1-phosphate furanose derivatives as precursors.

Further, in a step for producing a 1-phosphate furanose derivative of formula (5) from raktol compound of formula (3) it is selectively generated by more than 10 times the rate of β- phosphate cyano meoga α- anomeric phosphate, the state (in situ) When the next reaction proceeds, the α-halo anomer of Formula 1 is produced at the same ratio as that of the β-phosphate anomer in the previous step (more than 10 times of the β-halo anomer).

Therefore, it is much improved compared to the conventional method of producing the α-halo anomer in the ratio of 3: 1 (α-anomer: β-anomer) from the lactol compound, and the α-anomer is 10 times or more than the β-anomer. There is an advantage that can be obtained α-halo anomer contained.

In addition, in the conventional method, α-halo anomer was obtained in the oil phase by using benzoyl as a 3,5-hydroxy group protecting group, but in the present invention, biphenylcarbonyl is used as a 3-hydroxy and / or 5-hydroxy protecting group. By using the compound of the series it is possible to obtain the α-halo anomer of the formula (1) as a solid, can be obtained in a high order of 99.5% or more through a simple purification process to proceed to the glycosylation reaction using the desired β -Nucleosides can be produced at a high ratio of 4 to 14 times that of the α-nucleoside, which is significantly improved over the prior art.

Specifically, in the step 1) of Scheme 2, the 1-oxo ribose compound of Chemical Formula 2 is reduced by the method as described in US Pat. Nos. 4,526,988 and 5,464,826 to the lactol compound of Formula 3 Can be prepared.

The starting material of the 1-oxo ribose compound of formula (2) is protected by the bihydroxycarbonyl group of the 3-hydroxy group of the compound of formula 6 and then hydrolyzed to a solid 3R- carboxylate enantiomer of formula (7) It may be produced by a method comprising the step of obtaining.

Wherein R ² is as defined above, R ⁴ is methyl or ethyl, R ⁵ is C _1-3 alkyl, and M is ammonium (NH ₄ ), sodium or potassium.

Examples of the solvent used in the reduction reaction may include tetrahydrofuran, diethyl ether, dioxane, and the like, and the reducing agent may be lithium aluminum hydride, diisobutyl aluminum hydride, lithium tri-tert-butoxy aluminohydride, and the like. Ride, preferably lithium tri-tert-butoxyaluminohydride, and it is preferable to add a reducing agent at -50 to -20 ℃ and then heated to room temperature to react for 1 to 2 hours.

In this step, the lactol compound of formula 3, α- anomer and β-anomer are produced in a ratio of about 1: 1 to 2: 1 by weight, each isomer is separated or not separated using column chromatography method The next step reaction can proceed.

In step 2), the 1-phosphate furanose derivative of formula 5 can be prepared by reacting the lactol compound of formula 3 obtained in step 1) with a halophosphate compound of formula 4 in the presence of a base, wherein the β-phosphate anomer It is produced at a higher ratio 10 times higher than the α-phosphate anomer.

As the phosphate leaving group according to the present invention, dimethyl phosphate, diethyl phosphate or diphenyl phosphate may be used, of which diphenyl phosphate leaving group is most preferred.

The desired β-phosphate anomer is recrystallized and separated in water, ethanol, propanol, isopropanol, n-butanol, ethyl acetate and a mixed solvent thereof, preferably isopropanol or a water-isopropanol mixed solvent, and then It is possible to proceed with the next step reaction as it is in a mixture with the α-phosphate anomer without proceeding or separating the step reaction.

In this step, the halophosphate compound of Formula 4 is preferably used in an amount of 1.1 to 1.5 molar equivalents relative to the amount of the lactol compound of Formula 3, and the halophosphate compound of Formula 4 is purchased as a reagent, or described in Biochem. Preps. , 1, 50 (1951)] or J. Chem. Soc. , 2921 (1949). In addition, 4-dimethylaminopyridine or 4-pyrrolidinopyridine can be used as a catalyst to promote the reaction.

The free acid produced as the reaction proceeds may be removed using a base such as pyridine, triethylamine, tributylamine, diisopropylethyl amine, methylpiperidine, preferably triethylamine, wherein the base Is preferably used in an amount of 1.2 to 2.0 molar equivalents relative to the amount of the lactol compound represented by formula (3).

Benzene, toluene, acetonitrile, tetrahydrofuran, ethyl acetate, methylene chloride, chloroform or ethyl acetate, preferably toluene, are used as the reaction solvent, and the reaction temperature is -25 to 50 ° C, and the reaction time is 2 to 10 hours is preferred.

Further, in step 3), the 1-phosphate furanose derivative of formula 5 is reacted with a halide source and then recrystallized to yield 1-halo-2,2-difluoro-2-deoxy-D-ribofuranose of formula 1 Derivatives can be prepared, whereby high purity α-halo anomers containing less than 0.5% of β-halo anomers can be obtained.

Halide sources in the present invention include 1.0M HCl / acetic acid solution, 30% -HBr / acetic acid solution, 30% -HBr / propionic acid solution, trialkylsilyl halide, lithium halide, sodium halide, cesium halide, potassium halide, tetraalkylammonium Halide or trialkylsilyl halide-lithium halide mixture, preferably 30% -HBr / acetic acid solution, 30% -HBr / propionic acid solution, tetrabutylammonium iodide, tetrabutylammonium bromide, trimethylsilyl iodide, tri Methylsilyl bromide, trimethylsilyl chloride or trimethylsilyl chloride-lithium bromide mixtures can be used and the halide source is 5 to 30 molar equivalents, preferably 10 to 10, based on the amount of the 1-phosphate furanose derivative of formula (5). Preference is given to using in an amount of 20 molar equivalents.

Halide sources are used as neat solutions when 1.0M HCl / acetic acid solution, 30% -HBr / acetic acid solution, 30% -HBr / propionic acid is used, and other halide sources are methylene chloride, dibromoethane, It is preferable to dissolve in a solvent such as dichloroethane, chloroform, tetrahydrofuran, 1,4-dioxane, acetonitrile, N, N-dimethylformamide, N, N-dimethylacetamide and the like.

Methylene chloride, dibromoethane, dichloroethane, chloroform and the like are used as the reaction solvent, and the reaction may be performed at a temperature of 0 to 50 ° C., preferably 10 to 30 ° C., for 30 minutes to 24 hours.

The 1-halo anomer obtained through the above process is a mixture in which α-anomer is present at a ratio of 10-fold or more of β-anomer. From this, β-halo is obtained through recrystallization to obtain α-halo anomer in a pure state. The anomer must be removed.

As the recrystallization solvent, at least one selected from the group consisting of methanol, ethanol, isopropanol, acetonitrile and water, preferably isopropanol or isopropanol-water mixed solvent, and 1-? The halo anomer can be obtained with high purity of 99.5% or more containing 0.5% or less of β-anomer.

The method for preparing 1-α-halo anomer of Formula 1 using the 1-phosphate furanose derivative of Formula 5 of the present invention has not been reported so far, and the total yield after the three-step reaction is 65 From 75%, it can be seen that very high compared to the existing method (about 45% total yield).

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

을 의미한다. In the following Preparation Examples and Examples, -OCOBiPh, or BiPhOCO- is

Means.

In the case of HPLC, YMC hydrosphere C18 (4.6 ㅧ 150 mm, 5 μm) column was used for the compound of Formula 5, and Capcellpak MG C18 (4.6 ㅧ 150 mm, 5 μm) column was used for the compound of Formula 5. As the eluate, the compound of formula 5 was mixed with phosphate buffer and methanol at 17:83 (v / v), and the compound of formula 1 was mixed with phosphate buffer and methanol at 1: 4 (v / v). One solution was used each. In addition, the phosphate buffer solution was dissolved in 900 ml of NaH ₂ PO _{4 in} 900 ml of purified water, the pH was adjusted to 2.5 with phosphoric acid and purified water was added so that the total volume was 1 L.

Preparation Example 1 Preparation of D-erythro-2-deoxy-2,2-difluoro-pentofuranos-1-ulose-5-benzoyl-3- (4-phenyl) benzoate (Compound 2)

15.0 g of D-erythro-2-deoxy-2,2-difluoropentofuranose-1-ulose-3- (4-phenyl) benzoate was dissolved in 150 ml of methylene chloride, and 6.9 ml of pyridine was stirred with stirring. Dropwise at room temperature. 7.4 ml of benzoyl chloride dissolved in 40 ml of methylene chloride was slowly added to the reaction mixture while maintaining 5 to 10 ° C., and then reacted at room temperature for 7 hours, followed by neutralization of 105 ml of 1N hydrochloric acid. Water was added to the reaction mixture, the organic layer was separated, washed sequentially with 100 ml each of saturated sodium bicarbonate and brine, and the organic layer was dried over magnesium sulfate and filtered. The filtrate was distilled off under reduced pressure to give a white solid. The obtained solid was recrystallized with an ether-hexane mixture (5: 1, v / v) to give 16.8 g of a white solid title compound (yield: 86%).

¹ H-NMR (300MHz, CDCl ₃ ): 4.90 ~ 4.75 (ddd, 2H), 5.10 (dd, 1H), 5.87 (ddd, 1H), 7.65 ~ 7.50 (m, 5H), 7.78 ~ 7.67 (m, 3H ), 7.81 (d, 2H), 8.13 (d, 2H), 8.23 (d, 2H)

Melting Point (m.p): 130 ~ 131 ℃

Preparation Example 2 Preparation of D-erythro- 2 -deoxy-2,2-difluoro-pentofuranos-1-ulose-3,5-di- (4-phenyl) benzoate (Compound 2)

20 g of D-erythro-2-deoxy-2,2-difluoropentofuranose-1-ulose-3- (4-phenyl) benzoate are dissolved in 300 ml of chloroform, and 9.5 ml of pyridine is stirred at room temperature. Then, 10.1 ml of benzoyl chloride dissolved in 55 ml of chloroform was added to the reaction solution. After 6 hours of reaction at room temperature, 140 ml of 1N hydrochloric acid was added to neutralize the reaction solution. The organic layer was washed sequentially with 150 ml of water, sodium bicarbonate and brine, and the water contained in the organic layer was removed with magnesium sulfate, and then the solvent was removed under reduced pressure to obtain a white white solid. The obtained solid was recrystallized with an ethyl acetate-hexane mixture (3: 1, v / v) to give 21.8 g (yield: 72%) of the title compound as a white solid.

¹ H-NMR (300MHz, CDCl ₃ ): 4.72 ~ 4.79 (m, 2H), 5.03 (q, 1H), 5.84 ~ 5.76 (m, 1H), 7.48 ~ 7.44 (m, 6H), 7.72 ~ 7.60 (m , 8H), 8.15-8.07 (m, 4H)

Melting Point (m.p): 137 ~ 139 ℃

Example 1 1-α-Bromo-2-deoxy-2,2-difluoro-D-rifurfuranosyl-3-benzoyl-5- (4-phenyl) benzoate (Compound 1; R ¹ = Benzoyl, R ² = 4-biphenylcarbonyl)

Step 1) Preparation of 2-deoxy-2,2-difluoro-D-rifurfuranosyl-3-benzoyl-5- (4-phenyl) benzoate (Compound 3)

13.5 g of lithium tri-tert-butoxyaluminohydride was dissolved in 160 ml of tetrahydrofuran, stirred at room temperature for 30 minutes, and then cooled to -40 ° C. 20 g of D-erythro-2-deoxy-2,2-difluoro-pentofuranos-1-ulose-5-benzoyl-3- (4-phenyl) benzoate obtained in Preparation Example 1 was added with tetrahydro. The solution dissolved in 80 ml of furan was added dropwise to the reaction mixture, and then slowly warmed to room temperature and reacted for about 2 hours. Upon completion of the reaction, 220 ml of 1N hydrochloric acid was added to the reaction solution to quench excess lithium tri-tert-butoxyaluminohydride and to separate the tetrahydrofuran layer. The aqueous layer was extracted with 220 ml of ether, combined with tetrahydrofuran layers, washed successively with 220 ml of water, saturated sodium bicarbonate and brine, dried over magnesium sulfate, filtered, and the filtrate was removed under reduced pressure to remove the solvent. The residue was then purified by column chromatography. Isolation gave 18.3 g (yield: 91%) of the title compound as a pale yellow syrup.

¹ H-NMR (300MHz, CDCl ₃ ): 3.89 ~ 3.91 (d, 1H), 4.61 ~ 4.81 (m, 2H), 5.31 ~ 5.92 (m, 2H), 7.26 ~ 7.70 (m, 10H), 8.05 ~ 8.16 (m, 4H)

Step 2) Preparation of 2-deoxy-2,2-difluoro-D-rifurfuranosyl-3-benzoyl-5- (4-phenyl) benzoyl-1β-diphenylphosphate (Compound 5)

18.3 g of 2-deoxy-2,2-difluoro-D-ribofuranosyl-3-benzoyl-5- (4-phenyl) benzoate obtained in step 1 was dissolved in 146 ml of toluene and 6.7 ml of triethylamine. ml was added in one portion, and then 12.4 ml of diphenyl chlorophosphate was added dropwise by diluting in 37 ml of toluene. After 4 hours, 48 ml of 1N hydrochloric acid was added to neutralize the residual triethylamine, the toluene layer was separated, and the aqueous layer was extracted with 48 ml of ether. The extracted organic layer was combined with the toluene layer, washed sequentially with water, saturated sodium bicarbonate and brine, and then the organic layer was separated, dried over magnesium sulfate, filtered and the solvent of the filtrate was concentrated under reduced pressure. The resulting solid mixture was analyzed using a quantum nuclear magnetic resonance ( ¹ H-NMR) instrument, and it was confirmed that α-phosphate and β-phosphate anomers were produced in a ratio of 10.6. The mixture was recrystallized in an isopropanol-water mixed solvent (mix ratio: 3: 1, v / v) to give 26.5 g (yield: 87%) of the title compound as a white solid.

¹ H-NMR (300 MHz, CDCl ₃ ): 4.56-4.25 (m, 3 H), 5.80 (m, 1 H), 5.95 (t, 1 H), 7.44-6.98 (m, 16 H), 7.51 (d, 2 H), 7.57 (d, 2H), 7.89 (d, 2H), 8.01 (d, 2H)

Melting Point (m.p): 101 ~ 103 ℃

HPLC purity (area%): α-phosphate anomer 1.76%, β-phosphate anomer 98.24%

Step 3) Preparation of 1-α-Bromo-2-deoxy-2,2-difluoro-D-rifurfuranosyl-3-benzoyl-5- (4-phenyl) benzoate (Compound 1)

To 80.5 ml of 30% -HBr / acetic acid, 2-deoxy-2,2-difluoro-D-ribofuranosyl-3-benzoyl-5- (4-phenyl) benzoyl-1β- obtained in step 2 22.8 g of diphenylphosphate were added and reacted at room temperature for 6 hours. After the reaction, 400 ml of methylene chloride was added to the reaction mixture, and the mixture was diluted. The diluted solution was slowly poured into 500 ml of ice water, the aqueous layer was removed, and the methylene chloride layer was washed again with ice water, and subsequently washed with saturated sodium bicarbonate and brine. The methylene chloride layer was dried over magnesium sulfate, filtered and the filtrate was concentrated under reduced pressure. The resulting solid mixture was analyzed using a ¹ H-NMR instrument to confirm that α-bromo anomer and β-bromo anomer were produced at a ratio of 10.7: 1. The mixture was recrystallized in isopropanol to give 17.0 g (yield: 82%) of the title compound as a white solid.

¹ H-NMR (300MHz, CDC1 ₃ ): 8.19 (d, 2H), 8.06 (d, 2H), 7.73 (d, 2H), 7.63 (d, 2H), 7.64-7.41 (m, 6H), 6.56 ( d, 1H), 5.60 (dd. 1H)

Melting Point (m.p): 111 ~ 112 ℃

HPLC purity (area%): 99.74% of α-bromo anomer, 0.26% of β-bromo anomer

Example 2 1-α-Bromo-2-deoxy-2,2-difluoro-D-ribofuranosyl-3,5-di- (4-phenyl) benzoate (Compound 1; R ¹ = 4-biphenylcarbonyl, R ² = 4-biphenylcarbonyl)

Step 1) Preparation of 2-deoxy-2,2-difluoro-D-rifurfuranosyl-3,5-di- (4-phenyl) benzoate (Compound 3)

8.66 g of lithium tri-tert-butoxyaluminohydride was dissolved in 120 ml of tetrahydrofuran, stirred at room temperature for 30 minutes, and then cooled to -40 ° C. 15 g of D-erythro-2-deoxy-2,2-difluoro-pentofuranos-1-ulose-3,5-di- (4-phenyl) benzoate obtained in Preparation Example 2 was added to tetrahydrofuran. The solution dissolved in 100 ml was slowly added dropwise to the reaction solution, the temperature was raised to room temperature, and reacted for 1 hour. 142 ml of 1N hydrochloric acid was slowly added dropwise to the reaction solution to quench excess lithium tri-tert-butoxyaluminohydride and separate the organic layer. The aqueous layer was extracted with 150 ml of ether, combined with the organic layer, and the organic layer was washed successively with 150 ml each of water, saturated sodium bicarbonate and brine, dried over magnesium sulfate and filtered. The filtrate was removed under reduced pressure and the resulting solid was recrystallized in toluene to give 13.4 g (yield: 89%) of the title compound as a white solid.

¹ H-NMR (300MHz, CDCl ₃ ): 3.45 (s, 1H), 3.8 (s), 4.85 ~ 4.50 (m, 3H), 5.8 ~ 5.4 (m, 2H), 7.49 ~ 7.43 (m, 6H), 7.71 ~ 7.61 (m, 8H), 8.18 ~ 8.12 (m, 4H)

m.p: 156-158 ℃

Step 2) Preparation of 2-deoxy-2,2-difluoro-D-rifurfuranosyl-3,5-di- (4-phenyl) benzoyl-1β-diphenylphosphate (Compound 5)

13 g of 2-deoxy-2,2-difluoro-D-ribofuranosyl-3,5-di- (4-phenyl) benzoate obtained in step 1 was added to a mixed solvent of 130 ml of toluene and 100 ml of methylene chloride. After dissolving and adding 5.1 ml of triethylamine, 7.6 ml of diphenyl chlorophosphate was added dropwise at room temperature. After 5 hours, the solvent was removed under reduced pressure, and the resulting solid was dissolved in 130 ml of methylene chloride, and 65 ml of 1N hydrochloric acid was added thereto. The organic layer was separated, washed sequentially with water, sodium bicarbonate and brine and dried over magnesium sulfate. After the filtration, the solvent was removed under reduced pressure, and the resulting solid mixture was analyzed using a ¹ H-NMR instrument. As a result, it was confirmed that the α-phosphate anomer and the β-phosphate anomer were produced at a ratio of 1: 10.8. The mixture was recrystallized in isopropanol to give 15.6 g (yield: 83%) of the title compound as a white solid.

¹ H-NMR (300MHz, CDCl ₃ ): 4.70-4.40 (m, 3H), 5.90 (m, 1H), 6.08 (t, 1H), 7.70 ~ 7.08 (m, 24H), 8.15 ~ 8.04 (dd, 4H )

m.p: 145-147 ℃

HPLC purity (area%): α-phosphate anomer 1.29%, β-phosphate anomer 98.71%

Step 3) Preparation of 1-α-Bromo-2-deoxy-2,2-difluoro-D-rifurfuranosyl-3,5-di- (4-phenyl) benzoate (Compound 1)

13 g of 2-deoxy-2,2-difluoro-D-ribofuranosyl-3,5-di- (4-phenyl) benzoyl-1β-diphenylphosphate obtained in step 2 was added with 30% -HBr /. After dissolving in 83.2 ml of acetic acid and reacting at room temperature for 7 hours, 50 ml of ice water was poured into the reaction solution, and the precipitated solid was filtered. The obtained solid was analyzed using a ¹ H-NMR instrument, and it was confirmed that α-bromo anomer and β-bromo anomer were produced at a ratio of 10.9: 1. The solid was recrystallized in ethanol to give 8.45 g (yield: 83%) of the title compound as a white solid.

¹ H-NMR (300MHz, CDCl ₃ ): 4.89 ~ 4.22 (m.3H), 5.62 (dd, 1H), 6.55 (d, 1H), 7.73 ~ 7.42 (m, 14H), 8.63 ~ 8.11 (dd, 4H )

Melting Point (m.p): 151-153 ° C

HPLC purity (area%): α-bromo anomer 99.67%, β-bromo anomer 0.33%

Example 3 Preparation of 1-α-Bromo-2-deoxy-2,2-difluoro-D-rifurfuranosyl-3-benzoyl-5- (4-phenyl) benzoate

6.5 g of lithium tri-tert-butoxyaluminohydride was dissolved in 100 ml of tetrahydrofuran, stirred at room temperature for 30 minutes, and then cooled to -40 ° C. 10 g of D-erythro-2-deoxy-2,2-difluoro-pentofuranos-1-ulose-5-benzoyl-3- (4-phenyl) benzoate obtained in Preparation Example 1 was added to tetrahydrofuran. The solution dissolved in 50 ml was added dropwise to the reaction mixture, and gradually warmed to room temperature, and then reacted at the same temperature for 2 hours. When the reaction was completed, 120 ml of 1N hydrochloric acid was added to the reaction solution to decompose excess lithium tri-tert-butoxyaluminohydride remaining in the reaction solution, and the tetrahydrofuran layer was separated. The aqueous layer was extracted with 150 ml of ether and combined with a tetrahydrofuran layer, washed successively with 150 ml of water, saturated sodium bicarbonate and brine and dried over magnesium sulfate. After filtration the filtrate was removed under reduced pressure to give 10.5 g of syrupy residue.

100 ml of toluene was added to the syrupy residue to dissolve, 4.0 ml of triethylamine was added at once, and 6.4 ml of diphenyl chlorophosphate was diluted in 30 ml of toluene and added dropwise. After 4 hours of reaction, 30 ml of 1N hydrochloric acid was added to neutralize residual triethylamine, the toluene layer was separated, and the aqueous layer was extracted with 30 ml of ether. The extracted ether layer was combined with the toluene layer, washed sequentially with water, saturated sodium bicarbonate and brine, and dried over magnesium sulfate. Subsequently, after filtration, the solvent of the filtrate was removed under reduced pressure and 14.9 g of 1-phosphate mixture was obtained in syrup form. The mixture was analyzed using an H-NMR instrument to confirm that α-phosphate and β-phosphate anomers were produced in a ratio of 10.3.

Subsequently, 57.2 ml of 30% -HBr / acetic acid was added to the syrup-like 1-phosphate mixture, and the mixture was reacted at room temperature for 7 hours. After the reaction, 280 ml of methylene chloride was added to the reaction mixture, and the mixture was diluted. The diluted solution was poured into iced water, the methylene chloride layer was separated, washed with iced water, and washed with saturated sodium bicarbonate and brine continuously. The methylene chloride layer was dried over magnesium sulfate and filtered and the filtrate was concentrated under reduced pressure to give a solid. The obtained solid was analyzed using a ¹ H-NMR instrument, and it was confirmed that α-bromo anomer and β-bromo anomer were produced at a ratio of 10.5: 1. The mixture was recrystallized in isopropanol to give 8.0 g (total yield: 70%) of the title compound as a white solid.

¹ H-NMR and melting point data were the same as those of the compound according to step 4 of Example 1 above.

HPLC purity (area%): 99.51% of α-bromo anomer, 0.48% of β-bromo anomer

Example 4 Preparation of 1-α-iodo-2-deoxy-2,2-difluoro-D-ribofuranosyl-3-benzoyl-5- (4-phenyl) benzoate

5.6 ml of iodotrimethylsilane was added to 40 ml of methylene chloride, followed by 2-deoxy-2,2-difluoro-D-ribofuranosyl-5- (4-phenyl) obtained in Step 3 of Example 1. 1.8 g of benzoyl-3-benzoyl-1β-diphenylphosphate was added. The reaction was completed by stirring at room temperature for 0.5 hours. The reaction solution was slowly added dropwise to 100 ml of saturated sodium bicarbonate under ice cooling, stirred for 0.5 hour, and then separated from the methylene chloride layer. The methylene chloride layer was dried over magnesium sulfate and then concentrated under reduced pressure. The resulting solid was analyzed using a ¹ H-NMR instrument, and it was confirmed that α-iodo anomer and β-iodo anomer were produced at a ratio of 14.2: 1. The solid was recrystallized in isopropanol to give 1.36 g (yield 92%) of the title compound as an off white solid.

¹ H-NMR (300 MHz, CDCl ₃ ): 8.24 (d, 2H), 8.06 (d, 2H), 7.74 (d, 2H), 7.66 (d, 2H), 7.64-7.43 (m, 6H), 6.93 ( d, 1H), 5.60 (dd. 1H), 4.86-4.68 (m, 3H)

HPLC purity (area%): α-iodo anomer 99.81%, β-iodo anomer 0.18%

Comparative Example 1 : Preparation of 1 -α-iodo-2-deoxy-2,2-difluoro-D-ribofuranosyl-3,5-dibenzoate

The title compound was prepared according to the method described in US Pat. No. 5,453,499 as follows.

To 1 g of 2-deoxy-2,2-difluoro-D-rifurfuranosyl-3,5-dibenzoyl-1-β- (p-bromobenzene) sulfonate, 80 ml of tetrahydrofuran and 80 ml Tetrabutylammonium iodide was added and measured by ¹ H-NMR spectroscopy at reflux temperature after about 3.5 hours to give the title compound containing α- and β-anomers in a ratio of 10: 1.

The reaction mixture was then cooled and diluted with dichloromethane and water to separate the α-anomer. The layers were separated and the organic layer was washed with 1N hydrochloric acid, sodium carbonate, saturated sodium chloride and water and then dried over magnesium sulfate. The resulting solution was concentrated to give an oily residue and chromatographed (silica gel, toluene / hexane 2: 1) to give 302 mg (yield: 45%) of the title compound.

¹ H-NMR (300 MHz, CDCl ₃ ): 8.12 (m, 4H), 7.72-7.4 (m, 6H), 6.92 (d, 1H), 5.60 (dd, 1H), 4.91-4.62 (m, 3H)

The 1-α-halo-2,2-difluoro-2-deoxy-D-ribofuranose derivative of the present invention is a structure in which a biphenylcarbonyl group is introduced as a 3-hydroxy protecting group, obtained in a solid state, It can be easily separated and obtained through a simple purification process such as recrystallization suitable for production, and can be usefully used as an intermediate for preparing gemcitabine.

In addition, the method for preparing 1-α-halo-2,2-difluoro-2-deoxy-D-ribofuranose derivatives according to the present invention is a novel 1-phosphate furanose containing β-anomer in high proportion. By using the derivatives, α-anomers of 1-halofuranos can be obtained with a high ratio of 10 times higher than the conventional method for β-anomers.

Claims (12)

1-α-halo-2,2-difluoro-2-deoxy-D-ribofuranose derivative of Formula 1 Formula 1

Where R ¹ is benzoyl or

ego, R ² is

ego, R ³ is phenyl unsubstituted or substituted with one or more groups selected from the group consisting of cyano, halogen, carboalkoxy, toluene, nitro, C _1-2 alkoxy, C _1-2 alkyl and dialkyl amino, X is Cl, Br or I. The method of claim 1, R ³ is 2-phenyl or 4-phenyl. The method of claim 1, Derivatives containing 0.5% or less of β-halo anomer. 1) reducing the 1-oxo ribose compound of Formula 2 to prepare a lactol compound of Formula 3; 2) reacting the lactol compound obtained in step 1) with a halophosphate compound of formula 4 in the presence of a base to prepare a 1-phosphate furanose derivative of formula 5; And 3) reacting the compound obtained in step 2) with a halide source and recrystallizing Method for preparing a 1-α-halo-2,2-difluoro-2-deoxy-D-ribofuranose derivative of Formula 1 comprising: Formula 1

Formula 2

Formula 3

Formula 4

Formula 5

Wherein R ¹ , R ² , R ³ and X are as defined in claim 1 and R ⁴ is methyl, ethyl or phenyl. The method of claim 4, wherein Wherein in step 2) the base is selected from the group consisting of pyridine, triethylamine, tributylamine, diisopropylethyl amine and methylpiperidine. The method of claim 5, Wherein the base is triethylamine. The method of claim 4, wherein In step 3) the halide source is 1.0M HCl / acetic acid solution, 30% -HBr / acetic acid solution, 30% -HBr / propionic acid solution, trialkylsilyl halide, lithium halide, sodium halide, cesium halide, potassium halide, tetraalkylammonium And halides and mixtures thereof. The method of claim 7, wherein Halide sources include 30% -HBr / acetic acid solution, 30% -HBr / propionic acid solution, tetrabutylammonium iodide, tetrabutylammonium bromide, trimethylsilyl iodide, trimethylsilyl bromide, trimethylsilyl chloride and trimethyl The silyl chloride-lithium bromide mixture. The method of claim 4, wherein Recrystallization in step 3) is carried out in a solvent selected from the group consisting of methanol, ethanol, isopropanol, acetonitrile, water and mixed solvents thereof. The method of claim 9, Recrystallization is carried out in an isopropanol or isopropanol-water mixed solvent. The method of claim 4, wherein Characterized in that in step 3) α-halo anomer is produced at least 99.5%. 1-phosphate furanos derivative of formula Formula 5

Where R ¹ is benzoyl or

Is, R ² is

Is, R ³ is 2-phenyl, 4-phenyl or substituted phenyl, R ⁴ is methyl, ethyl or phenyl.