CN106831917B

CN106831917B - Preparation method of decitabine intermediate

Info

Publication number: CN106831917B
Application number: CN201611190810.3A
Authority: CN
Inventors: 陈之峰; 张庆捷
Original assignee: Lianyungang Hengyun Pharmaceutical Co ltd
Current assignee: Lianyungang Hengyun Pharmaceutical Co ltd
Priority date: 2016-12-21
Filing date: 2016-12-21
Publication date: 2020-05-19
Anticipated expiration: 2036-12-21
Also published as: CN106831917A

Abstract

the invention relates to a preparation method of a decitabine intermediate, which comprises the step of coupling a silicon etherate of 5-azacytosine with protected ribose under the action of a catalyst to obtain a nucleoside coupling product with enriched β configuration.

Description

Preparation method of decitabine intermediate

Technical Field

The invention relates to the field of medicines, and particularly relates to a preparation method of a decitabine intermediate.

Background

Decitabine is a natural nucleoside-2-deoxycytidine analogue synthesized in 1964, and has the effect of inducing DNA (deoxyribonucleic acid) to reduce methylation in myelodysplastic syndrome patients, thereby achieving the effects of controlling cell differentiation and proliferation and realizing the medicinal treatment significance of the decitabine.

Decitabine as a specific DNA methylation transferase inhibitor can reverse the DNA methylation process, induce the tumor cells to differentiate into normal cells or induce the tumor cells to die. In tumor cells, decitabine is phosphorylated by deoxycytidine kinase and binds to DNA in the form of phosphate. The combination of high-concentration decitabine can inhibit DNA synthesis, thereby inducing cell death and playing a role in cytotoxicity; the combination of decitabine with low concentration can replace cytosine in tumor cells to be covalently combined with DNA methyltransferase, so that the DNA methyltransferase is inactivated but does not cause cell death. It can not inhibit DNA synthesis in vitro, but induce hypomethylation in tumor cells, and has the function of maintaining the differentiation and proliferation control of gene-related cells. Non-proliferating cells are relatively insensitive to the drug.

The antitumor activity of decitabine is not only due to its specific DNA methyltransferase inhibitory effect, but other mechanisms of action are under study. Decitabine can induce local chromosomal recombination of certain genes, increase the release of histone deacetylase-1 in cells, and relieve the inhibition effect of p21WAF 1. Decitabine and histone deacetylase inhibitor are combined for application, so that chromosome recombination can be enhanced, and non-methylation-cause silent inactivated cancer suppressor genes can be activated.

The preparation process of decitabine is disclosed in many patents, and generally, ribose is etherified, then hydroxyl protection is carried out to obtain closed sugar, coupling with silicon etherate of 5-azacytosine is realized through a series of reactions, and finally deprotection is carried out to obtain decitabine. For coupling reactions using blocked sugars, only a few documents on the reactive sites of sugars disclose that the group at the reactive site can be methoxy and that the protecting group must be a specific group, for example WO2009086687 discloses a method for preparing decitabine, a typical technical solution of which is: 2-deoxy-D-ribose is used as a raw material to prepare an intermediate 1-methoxy-2-deoxy-3, 5-di-O-fluorenylmethoxycarbonyl acyl-D-furan ribose, the intermediate 1- (2-deoxy-3, 5-di-O-acyl-D-ribose) -4-amino-1, 3, 5-s-triazine-2-ketone is obtained by directly reacting with silicon etherate of 5-azacytosine, and decitabine is obtained by removing acyl substituent.

As is known, decitabine is an β isomer, but α and beta isomers are usually obtained during preparation, and one important reason is that the content ratio of the beta-isomer in a coupling reaction product as an intermediate directly influences the content ratio of the beta-decitabine in subsequent purification and subsequent products.

WO2010129211 also discloses the same route, which has high purity but beta form content of about 50%, CN101560233 has examples in which beta form is 59.7% to 39.7%, but the ratio is not high, and the working up process of this example is not detailed enough, it is not clear whether the above-mentioned ratio is measured directly from the end product of the reaction or from the product after purification, WO2008101448 of the same idea is more directly used for preparing α type product.

Disclosure of Invention

the invention overcomes the defects of the prior art and provides a novel method for enriching β configuration intermediates, which does not need to convert alkoxy groups at reaction sites into other groups and has higher proportion of β configuration in products.

on one hand, the invention discloses a preparation method of a decitabine intermediate, which comprises the steps of coupling a silicon etherate of 5-azacytosine with a raw material shown as a formula I under the action of a catalyst to obtain a nucleoside coupling product with enriched β configuration, wherein the coupling product is the decitabine intermediate,

the Pg refers to a hydroxyl protecting group, R is any substituent which does not hinder the coupling reaction in the field, and the enriched beta configuration is β configuration which is conventionally understood in the field, and the α configuration is more than 1.

Preferably, R of said formula I is selected from unsaturated hydrocarbyl groups, such as C1-C6, which may be phenyl or alkynyl groups, such as ethynyl.

Preferably, Pg of said formula I is any suitable group protecting the hydroxyl group on the D-ribofuranose from unwanted reactions, commonly an acyl group such as acetyl.

By way of example, formula I is 1-propargyloxy-2-deoxy-3, 5-di-O-acetyl-D-ribofuranose (Pg is acetyl, R is ethynyl), 1-benzyloxy-2-deoxy-3, 5-di-O-acetyl-D-ribofuranose. The formula I can be prepared by reacting 2-deoxy-D-ribofuranose with etherified 1-hydroxyl and hydroxyl protecting agent by conventional method, such as 1-propargyloxy-2-deoxy-3, 5-di-O-acetyl-D-ribofuranose, the preparation method can be seen in WO 2009074076.

Preferably, the catalyst is trifluoromethanesulfonic acid.

Preferably, the molar ratio of the catalyst to the feedstock of formula I is from 0.1 to 0.3:1, such as 0.2: 1.

Preferably, the temperature of the coupling reaction is from-5 ℃ to 100 ℃, such as from-5 ℃ to 0 ℃.

Preferably, the solvent for the coupling reaction is acetonitrile.

Preferably, the silicon etherate is 2, 4-bis- (trimethylsilyl) -5-azacytosine.

on the other hand, the invention also discloses a method for further preparing decitabine, which comprises the steps of carrying out deprotection on an intermediate (coupling product with enriched beta configuration) prepared by any one of the methods to obtain the decitabine, carrying out deprotection to obtain the decitabine, wherein the reaction comprises directly carrying out deprotection and carrying out deprotection on part of groups after modification, and the deprotection can be carried out by adopting a conventional method, for example, when Pg is acyl, alkali is adopted for hydrolysis, the alkali can be sodium methoxide, and the solvent can be methanol.

The invention has the beneficial effects that:

1. the alkoxy groups at the reaction sites do not need to be converted into other groups, and the β configuration proportion in the product is higher, so that the technical bias is overcome;

2. the method improves the selectivity of the reaction, and leads the ratio of β configuration to α configuration in the coupling product to be more than 2, which is very surprising for the reaction;

3. the invention has simple post-treatment and other operations, obviously improved yield and higher product purity.

Detailed Description

In order to better illustrate the present invention and the effects obtained, the following description is given with reference to specific examples, but the scope of the present invention is not limited to the specific embodiments of the examples.

Example 1:

0.4mol of 1-propargyloxy-2-deoxy-3, 5-di-O-acetyl-D-ribofuranose, 0.5mol of 2, 4-di- (trimethylsilyl) -5-azacytosine are dissolved in 3L of acetonitrile, the temperature is controlled to 0 ℃, 80mmol of trifluoromethanesulfonic acid is added, the reaction is kept at 0 ℃ and stirred, HPLC monitors until the reaction is complete (about 24 hours), the reaction mixture is quenched and washed 3L in 3 portions with saturated aqueous sodium bicarbonate solution, the organic layer is directly separated after standing and layering, dried using molecular sieves and then dried under vacuum to obtain 125g of solid, which is identified as 1- (2-deoxy-3, 5-di-O-acetyl-D-ribose) -4-amino-1, 3, 5-s-sym-triazin-2-one with a total purity of HPLC (α + β configuration) of 90%, wherein β configuration α configuration is 3.0.

¹H-NMR(DMSO-d⁶)，δ：2.1(s,6H),2.2-3.1(m,2H),4.1(m,1H)，4.3(m,1H),4.8(m,1H),5.1-5.3(m,1H),6.1(q,1H),7.5(s,1H)，7.6(s,1H),8.4(s,1H)

Example 2:

0.4mol of 1-benzyloxy-2-deoxy-3, 5-di-O-acetyl-D-ribofuranose, 0.5mol of 2, 4-di- (trimethylsilyl) -5-azacytosine was dissolved in 3L of acetonitrile, the temperature was controlled to 0 ℃, 80mmol of trifluoromethanesulfonic acid was added, the reaction was maintained at 0 ℃ and stirred, HPLC monitored until the reaction was complete (about 24 hours), the reaction mixture was quenched with saturated aqueous sodium bicarbonate (3L, 3 times), the reaction mixture was washed, the organic layer was directly separated after standing for separation, dried using a molecular sieve and then evaporated to dryness under vacuum to obtain 125g of a solid, and the nuclear magnetic data were essentially the same as in example 1 and identified as 1- (2-deoxy-3, 5-di-O-acetyl-D-ribose) -4-amino-1, 3, 5-s-triazin-2-one with a total purity of HPLC (. alpha. + β configuration) of 84%, wherein the. α configuration is 2.0.

Example 3:

0.4mol of 1-propargyloxy-2-deoxy-3, 5-di-O-acetyl-D-ribofuranose, 0.5mol of 2, 4-bis- (trimethylsilyl) -5-azacytosine were dissolved in 3L of acetonitrile, the temperature was controlled to-5 ℃, 40mmol of trifluoromethanesulfonic acid was added, the reaction was stirred and HPLC monitored until the reaction was complete (about 24 hours), the reaction mixture was quenched with saturated aqueous sodium bicarbonate (3L, used 3 times), washed, allowed to stand for demixing, the organic layer was separated directly, dried using molecular sieves and then evaporated to dryness under vacuum to give 121g of a solid, which was identified as 1- (2-deoxy-3, 5-di-O-acetyl-D-ribose) -4-amino-1, 3, 5-s-triazin-2-one in substantially the same data as in example 1 as 1 in total purity of HPLC (α + β configuration) of 88%, wherein β configuration is 2.7.

Example 4:

0.4mol of 1-propargyloxy-2-deoxy-3, 5-di-O-acetyl-D-ribofuranose, 0.5mol of 2, 4-di- (trimethylsilyl) -5-azacytosine are dissolved in 3L of acetonitrile, the temperature is controlled to-5 ℃, 120mmol of trifluoromethanesulfonic acid is added, the reaction is kept at 0 ℃ and stirred, HPLC monitors until the reaction is complete (about 24 hours), the reaction mixture is quenched with saturated aqueous sodium bicarbonate (3L, used 3 times), the reaction mixture is washed, the organic layer is separated directly after settling, dried using molecular sieves and then evaporated to dryness under vacuum to obtain 128g of a solid, the nuclear magnetic data are essentially the same as in example 1 and are identified as 1- (2-deoxy-3, 5-di-O-acetyl-D-ribose) -4-amino-1, 3, 5-s-triazin-2-one, the total purity of HPLC (α + β configuration) is 90%, wherein the β configuration is 2.8.

Example 5:

dissolving 12.8g of the solid obtained in example 4 in 50ml of methanol, adding 50mmol of sodium methoxide, stirring at room temperature for 1 hour, performing suction filtration, cooling the filtrate to 0 ℃, stirring for 1 hour to fully separate out the solid, performing suction filtration, recrystallizing the obtained solid with 50ml of methanol, and drying to obtain 4.8g of white solid, wherein the purity of the decitabine is detected to reach 95%, and the yield is 74% (calculated by the molar weight of β configuration materials before and after the reaction).

Claims

1. the preparation method of the decitabine intermediate comprises the steps of coupling a silicon etherate of 5-azacytosine with a raw material shown as a formula I under the action of a catalyst to obtain a nucleoside coupling product with enriched beta configuration, wherein the catalyst is trifluoromethanesulfonic acid;

wherein Pg is acetyl and R is C₁-C₆The unsaturated hydrocarbon group of (1) is phenyl or ethynyl, and the silicon etherate of 5-azacytosine is 2, 4-bis- (trimethylsilyl) -5-azacytosine.

2. The method of claim 1, wherein formula I is 1-propargyloxy-2-deoxy-3, 5-di-O-acetyl-D-ribofuranose or 1-benzyloxy-2-deoxy-3, 5-di-O-acetyl-D-ribofuranose.

3. The process of claim 1, wherein the molar ratio of the catalyst to the feedstock of formula I is from 0.1 to 0.3: 1.

4. The process of claim 1, wherein the molar ratio of the catalyst to the feed of formula I is 0.2: 1.

5. The process of claim 1, wherein the temperature of the coupling reaction is from-5 ℃ to 100 ℃.

6. The process of claim 1, wherein the temperature of the coupling reaction is from-5 ℃ to 0 ℃.

7. The process of claim 1, wherein the solvent for the coupling reaction is acetonitrile.

8. A process for the preparation of decitabine comprising deprotecting a coupling product intermediate prepared according to any one of claims 1 to 7 to give decitabine.

9. The method of claim 8, wherein the deprotection reaction is performed using a base.

10. The process of claim 9, wherein the base is sodium methoxide.