CN108440623A - A kind of preparation method and products thereof of capecitabine intermediate - Google Patents

A kind of preparation method and products thereof of capecitabine intermediate Download PDF

Info

Publication number
CN108440623A
CN108440623A CN201810309106.8A CN201810309106A CN108440623A CN 108440623 A CN108440623 A CN 108440623A CN 201810309106 A CN201810309106 A CN 201810309106A CN 108440623 A CN108440623 A CN 108440623A
Authority
CN
China
Prior art keywords
preparation
capecitabine
reaction
flurocytosine
solvent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201810309106.8A
Other languages
Chinese (zh)
Inventor
潘先文
黄雄鸠
何伟
彭磊
唐丽昌
唐建宗
王珑霖
李凤莲
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chongqing Sansheng Industry Ltd By Share Ltd
Original Assignee
Chongqing Sansheng Industry Ltd By Share Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Chongqing Sansheng Industry Ltd By Share Ltd filed Critical Chongqing Sansheng Industry Ltd By Share Ltd
Priority to CN201810309106.8A priority Critical patent/CN108440623A/en
Publication of CN108440623A publication Critical patent/CN108440623A/en
Pending legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07HSUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H19/00Compounds containing a hetero ring sharing one ring hetero atom with a saccharide radical; Nucleosides; Mononucleotides; Anhydro-derivatives thereof
    • C07H19/02Compounds containing a hetero ring sharing one ring hetero atom with a saccharide radical; Nucleosides; Mononucleotides; Anhydro-derivatives thereof sharing nitrogen
    • C07H19/04Heterocyclic radicals containing only nitrogen atoms as ring hetero atom
    • C07H19/06Pyrimidine radicals
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07HSUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H1/00Processes for the preparation of sugar derivatives
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07HSUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
    • C07H1/00Processes for the preparation of sugar derivatives
    • C07H1/06Separation; Purification
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07BGENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
    • C07B2200/00Indexing scheme relating to specific properties of organic compounds
    • C07B2200/07Optical isomers

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biochemistry (AREA)
  • Biotechnology (AREA)
  • General Health & Medical Sciences (AREA)
  • Genetics & Genomics (AREA)
  • Molecular Biology (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

Abstract

The present invention relates to a kind of preparation methods of capecitabine intermediate; the capecitabine intermediate is 2 '; 3 ' two O acetyl group, 5 ' deoxidation, 5 fluorine cytidine; 5 Flucytosines are placed in solvent; 1,2,3 three O acetyl group, 5 deoxyribose is added; under stirring, adds lewis acid and carry out catalysis reaction;Sodium bicarbonate is added in the reaction solution obtained after completion of the reaction and water quenching is gone out, then detaches, crystallizes obtained capecitabine intermediate.5 Flucytosines need not be protected using silylation in the preparation method of the present invention, and directly with 1, glycosylation reaction occurs for 2,3 O triacetyls, 5 deoxyribose, reduces reaction step, shortens the reaction time;Energy consumption is reduced, production efficiency is improved, reduces the generation of waste, has saved resource;And obtained capecitabine intermediate purity is high, α type content of isomer is small, or even without detection, optical purity of products is up to 99.8% or more.

Description

A kind of preparation method and products thereof of capecitabine intermediate
Technical field
The invention belongs to pharmaceutical drug substance synthesis technical field, it is related to preparation method and its production of a kind of capecitabine intermediate Product.
Background technology
Capecitabine (capecitabine) the entitled 5 '-deoxidation -5- of chemistry fluoro- N- [(amoxy) carbonyl] cytidine, be by The oral nucleosides series antineoplastic medicament of Roche (Roche) drugmaker research and development.It is absorbed rapidly through intestinal mucosa after oral, then in liver Dirty that inactive intermediate 5'- deoxidation -5' fluorine cytidines are converted by Carboxylesterase, the cytidine through liver and tumor tissues after is de- The effect of ammonia enzyme is converted into 5'- deoxidation -5' floxuridines, is finally fluorouracil through thymidine phosphorylase catalysis in tumor tissues (5-FU) and work.It is pernicious to be clinically mainly used for treatment metastatic colorectal cancer, breast cancer, colon cancer and gastric cancer etc. Tumour.According to statistics, global capecitabine bulk pharmaceutical chemicals market demand in 2016 is about 200 tons, and only domestic market is as high as 50 tons, Market demand is very big.
There are many route of capecitabine synthesis report, but in existing technology and the factors such as raw material supply, capecitabine Preparation method mainly using 5-flurocytosine as starting material, with 1 after being protected using silylation, 2,3-O- triacetyl -5- Glycosylation reaction occurs under lewis acidic catalysis for deoxyribose, and aminoacylation then occurs with n-amyl chlorocarbonate, Most capecitabine is obtained through hydrolysis afterwards.Synthetic route is as follows:
And the most complicated reaction of this route is glycosylation reaction, the hydrolysis of aminoacylates and ester group is all easier to, therefore 2 ', 3 '-two-O- acetyl group -5 '-deoxidation -5- fluorine cytidines are the important intermediates of the synthesis of nucleoside antineoplastic capecitabine.
The route needs that silylating reagent HMDS (hexamethyldisilazane), Silanization reaction process is used to also need to use Higher boiling such as toluene equal solvent, and need to generate a large amount of ammonias during Silanization reaction big to environmental hazard.But current document The preparation method of report be required for first use silylation protection 5-flurocytosine after with 1,2,3-O- triacetyl -5- deoxidation cores Glycosylation reaction occurs for sugar, if it is possible to save silylation protection, 5-flurocytosine is directly with 1,2,3-O- triacetyls Glycosylation reaction occurs for base -5- deoxyriboses, will greatly reduce the manufacturing cost of capecitabine, while decreasing environment dirt Dye.So there is an urgent need for a kind of new methods prepared by new capecitabine important intermediate.
Invention content
In view of this, the purpose of the present invention is to provide a kind of preparation method of simple capecitabine important intermediate, And the obtained purity of this method is high and its micro α types isomers or the capecitabine midbody compound without α type isomers.
In order to achieve the above objectives, the present invention provides the following technical solutions:
1. a kind of preparation method of capecitabine intermediate, the capecitabine intermediate is 2 ', 3 '-two-O- acetyl group- 5 '-deoxidation -5- fluorine cytidines, structure are shown in formula I:
The preparation method comprises the following steps:
1) 5-flurocytosine (formula II) is placed in solvent, 1,2,3-, tri--O- acetyl group -5- deoxyribose (formulas is added III) it, under stirring, adds lewis acid and carries out catalysis reaction;
2) sodium bicarbonate is added in the reaction solution obtained after completion of the reaction and water quenching is gone out, then detaches, crystallizes obtained capecitabine Intermediate.
Its reaction equation is as follows:
Further, the solvent is dichloromethane or dichloroethanes.
Further, the molal weight ratio of the 5-flurocytosine and 1,2,3- tri--O- acetyl group -5- deoxyriboses is 1:1 ~1.5.
Further, the molal weight ratio of the 5-flurocytosine and 1,2,3- tri--O- acetyl group -5- deoxyriboses is 1:1 ~1.05.
Further, the mass ratio of the volume of solvent and 5-flurocytosine is 2~20ml:1g.
Further, the lewis acid is butter of tin, titanium tetrachloride, ferric trichloride or zinc chloride.
Further, the lewis acid is butter of tin.
Further, the 5-flurocytosine and lewis acidic molar ratio are 1:0.8~2.0.
Further, the temperature of the catalysis reaction is 10~40 DEG C.
Further, the temperature of the catalysis reaction is 10~20 DEG C.
Further, the molar ratio of the sodium bicarbonate and 5-flurocytosine is 6:1.
Further, the solvent of the crystallization is methanol, absolute ethyl alcohol, isopropanol, ethyl acetate, isopropyl acetate or methyl One or more mixing in tertbutyl ether.
Further, the solvent of the crystallization is isopropanol.
2. the capecitabine intermediate obtained by the preparation method described in any of the above item.
The beneficial effects of the present invention are:1. 5-flurocytosine (formula II) need not use silicon in the synthetic method of the present invention Alkyl is protected, directly with 1 under methylene chloride or dichloroethanes effect, 2,3-O- triacetyl -5- deoxyribose (formulas III) glycosylation reaction occurs, reduces reaction step, shortens the reaction time;2. Silanization reaction needs under the high temperature conditions It carries out, therefore reduces energy consumption, improve production efficiency, reduce Material Cost, while reducing the generation of waste, save Resource;3. by obtained 99.5% or more capecitabine intermediate (Formulas I) purity of preparation method of the present invention, α type isomers Content is less than 0.1%, or even without detection, optical purity of products is up to 99.8%.
Description of the drawings
In order to keep the purpose of the present invention, technical solution and advantageous effect clearer, the present invention provides following attached drawing and carries out Explanation:
Fig. 1 is that the HPLC of 1 gained capecitabine intermediate of embodiment analyzes collection of illustrative plates;
Fig. 2 is that the HPLC of 2 gained capecitabine intermediate of embodiment analyzes collection of illustrative plates;
Fig. 3 is that the HPLC of 3 gained capecitabine intermediate of embodiment analyzes collection of illustrative plates;
Fig. 4 is that the HPLC of 4 gained capecitabine intermediate of embodiment analyzes collection of illustrative plates;
Fig. 5 is that the HPLC of 5 gained capecitabine intermediate of embodiment analyzes collection of illustrative plates.
Specific implementation mode
Below in conjunction with attached drawing, the preferred embodiment of the present invention is described in detail.It is not specified in embodiment specific The experimental method of condition, usually according to conventional conditions or according to the manufacturer's recommendations.
Embodiment 1:
5-flurocytosine (20.0g, 155mmol) is suspended in 200mL dichloromethane, addition is added 1 under room temperature, 10~20 DEG C 2,3- tri--O- acetyl group -5- deoxyriboses (40.3g, 155mmol), control of temperature, quickly stirring is lower is added dropwise tetrachloro Change the dichloromethane solution that titanium (40.3g, 155mmol) is dissolved in 100mL, continues to react 4h at 10~20 DEG C after dripping off.Carbon is added Sour hydrogen sodium (78.1g, 930mmol), is slowly added dropwise water 10g, continues stirring 3 hours, filtering, filter cake dichloromethane after dripping off (40mL × 2) are washed, and filtrate washed once with saturated sodium bicarbonate aqueous solution 200mL, and organic phase is dry with anhydrous sodium sulfate 20g Dry, filtering, filtrate decompression is concentrated into syrupy shape, and residue obtains capecitabine intermediate with 120mL recrystallisation from isopropanol 44.1g, white powder, yield 86.5%, purity 99.6%, maximum single miscellaneous 0.10%, α types isomers are not detected.Fig. 1 is real Apply the HPLC analysis collection of illustrative plates of 1 gained capecitabine intermediate of example.
Embodiment 2:
5-flurocytosine (20.0g, 155mmol) is suspended in 200mL dichloroethanes, 1,2,3- is added under room temperature 10~20 DEG C three-O- acetyl group -5- deoxyriboses (40.3g, 155mmol), control of temperature, quickly stirring is lower is added dropwise titanium tetrachloride (40.3g, 155mmol) is dissolved in the dichloroethane solution of 100mL, continues to react 4h at 10~20 DEG C after dripping off.Bicarbonate is added Sodium (78.1g, 930mmol), is slowly added dropwise water 10g, continues stirring 3 hours, filtering, filter cake dichloroethanes (40mL after dripping off × 2) it washs, filtrate washed once with saturated sodium bicarbonate aqueous solution 200mL, and organic phase is dried with anhydrous sodium sulfate 20g, mistake Filter, filtrate decompression are concentrated into syrupy shape, and residue obtains capecitabine intermediate 45.0g with 120mL recrystallisation from isopropanol, white Powder, yield 85.2%, purity 99.0%, maximum single miscellaneous 0.25%, α types isomers 0.05%.Fig. 2 is 2 gained of embodiment The HPLC of capecitabine intermediate analyzes collection of illustrative plates.
Embodiment 3:
5-flurocytosine (20.0g, 155mmol) is suspended in 200mL dichloromethane, 1,2,3- is added under room temperature 10~20 DEG C three-O- acetyl group -5- deoxyriboses (40.3g, 155mmol), control of temperature, quickly stirring is lower is added dropwise titanium tetrachloride (40.3g, 155mmol) is dissolved in the dichloromethane solution of 100mL, continues to react 4h at 10~20 DEG C after dripping off.Bicarbonate is added Sodium (78.1g, 930mmol), is slowly added dropwise water 10g, continues stirring 3 hours, filtering, filter cake dichloromethane (40mL after dripping off × 2) it washs, filtrate washed once with saturated sodium bicarbonate aqueous solution 200mL, and organic phase is dried with anhydrous sodium sulfate 20g, mistake Filter, filtrate decompression are concentrated into syrupy shape, and residue obtains capecitabine intermediate 41.7g with 200mL re-crystallizing in ethyl acetate, in vain Color powder, yield 84.7%, purity 99.5%, maximum single miscellaneous 0.25%, α types isomers are not detected.Fig. 3 is 3 institute of embodiment The HPLC for obtaining capecitabine intermediate analyzes collection of illustrative plates.
Embodiment 4:
5-flurocytosine (20.0g, 155mmol) is suspended in 200mL dichloromethane, 1,2,3- is added under room temperature 10~20 DEG C three-O- acetyl group -5- deoxyriboses (40.3g, 155mmol), control of temperature, quickly stirring is lower is added dropwise titanium tetrachloride (40.3g, 155mmol) is dissolved in the dichloromethane solution of 100mL, continues to react 4h at 10~20 DEG C after dripping off.Bicarbonate is added Sodium (78.1g, 930mmol), is slowly added dropwise water 10g, continues stirring 3 hours, filtering, filter cake dichloromethane (40mL after dripping off × 2) it washs, filtrate washed once with saturated sodium bicarbonate aqueous solution 200mL, and organic phase is dried with anhydrous sodium sulfate 20g, mistake Filter, filtrate decompression are concentrated into syrupy shape, and residue is warming up to 80 DEG C with 200mL isopropyl acetates and is beaten 0.5 hour, is cooled to 0 DEG C crystallization 1 hour, filtering are dried to obtain capecitabine intermediate 46.2g, yield 86.5%, and purity 99.3% is maximum single miscellaneous 0.19%, α type isomers are not detected.Fig. 4 is that the HPLC of 4 gained capecitabine intermediate of embodiment analyzes collection of illustrative plates.
Embodiment 5:
5-flurocytosine (200.0g, 1.55mol) is suspended in 2L dichloromethane, 1,2,3- is added under room temperature 10~20 DEG C three-O- acetyl group -5- deoxyriboses (403.0g, 1.55mol), control of temperature, quickly stirring is lower is added dropwise four chlorinations Titanium (403.0g, 1.55mol) is dissolved in the dichloromethane solution of 1L, continues to react 4h at 10~20 DEG C after dripping off.Bicarbonate is added Sodium (781.0g, 9.3mol), is slowly added dropwise water 100g, continues stirring 3 hours, filtering, filter cake dichloromethane (0.4L after dripping off × 2) it washs, filtrate washed once with saturated sodium bicarbonate aqueous solution 2.0L, and organic phase is small with anhydrous sodium sulfate 200g dryings 1 When, filtering, filtrate decompression is concentrated into syrupy shape, and residue obtains capecitabine intermediate 452g with 2.0L recrystallisation from isopropanol, White powder, yield 88.6%, purity 99.7%, maximum single miscellaneous 0.11%, α types isomers are not detected.Fig. 5 is embodiment 5 The HPLC of gained capecitabine intermediate analyzes collection of illustrative plates.
Reaction temperature may be controlled to 10~40 DEG C, preferably 10~20 DEG C in the preparation method of the present invention, if warm Spend it is high can generate more impurity, temperature crosses that low reaction is relatively slow and reaction is incomplete.
Finally illustrate, preferred embodiment above is merely illustrative of the technical solution of the present invention and unrestricted, although logical It crosses above preferred embodiment the present invention is described in detail, however, those skilled in the art should understand that, can be Various changes are made to it in form and in details, without departing from claims of the present invention limited range.

Claims (10)

1. a kind of preparation method of capecitabine intermediate, which is characterized in that the capecitabine intermediate is 2 ', 3 '-two-O- Acetyl group -5 '-deoxidation -5- fluorine cytidines, structure are shown in formula I:
The preparation method comprises the following steps:
1) 5-flurocytosine is placed in solvent, 1,2,3-, tri--O- acetyl group -5- deoxyriboses is added, under stirring, add road Lewis acid carries out catalysis reaction;
2) sodium bicarbonate is added in the reaction solution obtained after completion of the reaction and water quenching is gone out, then detaches, crystallizes among obtained capecitabine Body.
2. preparation method according to claim 1, which is characterized in that the solvent is dichloromethane or dichloroethanes.
3. preparation method according to claim 1, which is characterized in that the 5-flurocytosine and 1,2,3- tri--O- acetyl The molal weight ratio of base -5- deoxyriboses is 1:1~1.5.
4. preparation method according to claim 1, which is characterized in that the volume of solvent and the mass ratio of 5-flurocytosine are 2~20ml:1g.
5. preparation method according to claim 1, which is characterized in that the lewis acid be butter of tin, titanium tetrachloride, Ferric trichloride or zinc chloride.
6. preparation method according to claim 1, which is characterized in that the 5-flurocytosine and lewis acidic molar ratio It is 1:0.8~2.0.
7. preparation method according to claim 1, which is characterized in that the temperature of the catalysis reaction is 10~40 DEG C.
8. preparation method according to claim 1, which is characterized in that the molar ratio of the sodium bicarbonate and 5-flurocytosine It is 6:1.
9. preparation method according to claim 1, which is characterized in that the solvent of the crystallization is methanol, absolute ethyl alcohol, different One or more mixing in propyl alcohol, ethyl acetate, isopropyl acetate or methyl tertiary butyl ether(MTBE).
10. the capecitabine intermediate obtained by claim 1~9 any one of them preparation method.
CN201810309106.8A 2018-04-09 2018-04-09 A kind of preparation method and products thereof of capecitabine intermediate Pending CN108440623A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810309106.8A CN108440623A (en) 2018-04-09 2018-04-09 A kind of preparation method and products thereof of capecitabine intermediate

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810309106.8A CN108440623A (en) 2018-04-09 2018-04-09 A kind of preparation method and products thereof of capecitabine intermediate

Publications (1)

Publication Number Publication Date
CN108440623A true CN108440623A (en) 2018-08-24

Family

ID=63198929

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810309106.8A Pending CN108440623A (en) 2018-04-09 2018-04-09 A kind of preparation method and products thereof of capecitabine intermediate

Country Status (1)

Country Link
CN (1) CN108440623A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111377988A (en) * 2018-12-30 2020-07-07 山东新时代药业有限公司 Capecitabine intermediate
CN113321693A (en) * 2021-05-25 2021-08-31 神隆医药(常熟)有限公司 Preparation method of capecitabine intermediate suitable for industrial production

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008145403A1 (en) * 2007-06-01 2008-12-04 Synthon B.V. Processes related to making capecitabine
CN101812104A (en) * 2010-04-20 2010-08-25 江苏吴中苏药医药开发有限责任公司 New method for continuously operating to synthesize capecitabine
CN102993253A (en) * 2012-12-18 2013-03-27 浙江先锋科技有限公司 Preparation method of 2',3'-bi-O-acetyl-5'-deoxy-5-fulurocytidine
CN104926900A (en) * 2014-03-22 2015-09-23 上海创诺制药有限公司 Method for preparing Capecitabine intermediate represented by formula I

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008145403A1 (en) * 2007-06-01 2008-12-04 Synthon B.V. Processes related to making capecitabine
CN101812104A (en) * 2010-04-20 2010-08-25 江苏吴中苏药医药开发有限责任公司 New method for continuously operating to synthesize capecitabine
CN102993253A (en) * 2012-12-18 2013-03-27 浙江先锋科技有限公司 Preparation method of 2',3'-bi-O-acetyl-5'-deoxy-5-fulurocytidine
CN104926900A (en) * 2014-03-22 2015-09-23 上海创诺制药有限公司 Method for preparing Capecitabine intermediate represented by formula I

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111377988A (en) * 2018-12-30 2020-07-07 山东新时代药业有限公司 Capecitabine intermediate
CN111377988B (en) * 2018-12-30 2023-06-27 鲁南制药集团股份有限公司 Capecitabine intermediate
CN113321693A (en) * 2021-05-25 2021-08-31 神隆医药(常熟)有限公司 Preparation method of capecitabine intermediate suitable for industrial production

Similar Documents

Publication Publication Date Title
CN101007812B (en) Antibacterial drugs cefoxitin preparation process
CN104095857B (en) The application in preparing anti-hepatic fibrosis medicines of the diethylamine derivative of Cleistanone Cleistanone
CN103896855B (en) The synthetic method of the fluoro-6-chlorine of a kind of 4-(1-bromoethyl)-5-pyrimidine
CN106256824A (en) A kind of preparation method of high-purity De Lasha star meglumine salt
CN108440623A (en) A kind of preparation method and products thereof of capecitabine intermediate
CN102395591B (en) Method for preparing prasugrel
CN106365986A (en) Compounds and preparation methods thereof, and uses of compounds in synthesis of brivaracetam
CN103145636B (en) 1,4-diacyl-3,6-diphenyl-1,4-dihydrotetrazine compound as well as preparation method and application thereof
CN101376667B (en) Intermediate for synthesizing azidothimidine, preparation thereof and use in azidothimidine synthesis
González et al. A facile chemoselective deacetylation in the presence of benzoyl and p-bromobenzoyl groups using p-toluenesulfonic acid
CN106632265A (en) Preparation method of high-purity topiroxostat
CN104557891A (en) Quercetin derivative and preparation method and application thereof
CN103897004A (en) Synthesis method for capecitabine
CN107235921B (en) A kind of preparation method of Erlotinib
CN102659638B (en) Synthetic method of leonurine
CN107266304B (en) Novel synthesis method of natural product Salvianolic Acid F
CN103130855A (en) Preparation method of decitabine
CN102898439B (en) Preparation method of descarbamoyl cefuroxime lactone
CN103923135B (en) A kind of deuterated 5-hydroxyl color D-glucosamine glycoside derivates and preparation method thereof
CN104109182B (en) A kind of method preparing gemcitabine hydrochloride
CN101993464B (en) Preparation method of capecitabine
CN101845070A (en) Synthesis method of antineoplastic medicine capecitabine
CN106349145A (en) Method for preparing intelligence-improving medicine (S)-oxiracetam
CN102250175A (en) Preparation method of 2',3'-di-O-acetyl-5'-deoxy-5-fluorocytidine
CN107056724B (en) A kind of intermediate being used to prepare Erlotinib

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20180824