Preparation method of prodrug intermediate of thymidine phosphorylase inhibitor
阅读说明：本技术 一种胸苷磷酸化酶抑制剂的前药中间体的制备方法 (Preparation method of prodrug intermediate of thymidine phosphorylase inhibitor ) 是由 宋艳民 陈勇 张超 李静简 于 2020-12-29 设计创作，主要内容包括：本申请涉及胸苷磷酸化酶抑制剂的前药中间体制备领域,公开了一种胸苷磷酸化酶抑制剂的前药中间体的制备方法,其包括以下步骤：(1)在硫脲的混合醇碱溶液中加入氰乙酸乙酯,回流反应5～6小时,降温结晶,过滤,用乙醇/二氧六环混合液洗涤；(2)将吡啶和氨水混合,加入兰尼镍、ZnSO-4和步骤(1)的所得物,在65～75℃下加热反应7～8小时,趁热过滤,降温结晶,过滤,洗涤；(3)将步骤(2)的所得物加入混合碱溶液中,在45～55℃下缓慢加入2-溴乙醛,反应4～5小时,降温结晶,过滤,洗涤,干燥。根据本申请的制备方法提高了胸苷磷酸化酶抑制剂的前药中间体4-羟基吡咯并[2,3-d]嘧啶的总收率。(The application relates to the field of preparation of prodrug intermediates of thymidine phosphorylase inhibitors, and discloses a preparation method of a prodrug intermediate of a thymidine phosphorylase inhibitor, which comprises the following steps: (1) adding ethyl cyanoacetate into a mixed alcohol alkali solution of thiourea, carrying out reflux reaction for 5-6 hours, cooling, crystallizing, filtering, and washing with an ethanol/dioxane mixed solution; (2) mixing pyridine and ammonia water, adding Raney nickel and ZnSO 4 And (2) heating the obtained product in the step (1) at 65-75 ℃ for reaction for 7-8 hours, filtering while hot, cooling for crystallization, filtering, and washing; (3) and (3) adding the product obtained in the step (2) into a mixed alkali solution, slowly adding 2-bromoacetaldehyde at the temperature of 45-55 ℃, reacting for 4-5 hours, cooling, crystallizing, filtering, washing and drying. The preparation method improves the prodrug intermediate 4-hydroxypyrrolo [2,3-d ] of thymidine phosphorylase inhibitor]Overall yield of pyrimidine.)
1. A method for preparing a prodrug intermediate of a thymidine phosphorylase inhibitor comprising the steps of:
(1) synthesis of 2-mercapto-4-amino-6-hydroxypyrimidine
Dissolving thiourea in a mixed alcohol alkali solution, slowly adding ethyl cyanoacetate at room temperature, carrying out reflux reaction at 75-85 ℃ for 5-6 hours, cooling and crystallizing after the reaction is finished, filtering, and washing with an ethanol/dioxane mixed solution, wherein the mixed alcohol alkali solution comprises a potassium ethoxide with the concentration of 0.75-0.80 mol/L, a lithium ethoxide solute with the concentration of 0.03-0.05 mol/L, and an ethanol and dioxane solvent with the volume ratio of 10 (1.0-1.2), and the molar ratio of the thiourea, the ethyl cyanoacetate and the potassium ethoxide is (1.25-1.5) to 1 (1.7-2.0);
(2) synthesis of 4-amino-6-hydroxypyrimidines
The volume ratio was (0.2-0.3) mixing 10 of pyridine and 25-28 mass percent of ammonia water to obtain a mixed amine solvent, and adding Raney nickel and ZnSO4And (2) heating the obtained product in the step (1) at 65-75 ℃ for reaction for 7-8 hours, filtering while the product is hot after the reaction is finished, cooling for crystallization, filtering, and washing with water, wherein the mixed amine solvent, the Raney nickel and the ZnSO are4And the weight ratio of the product obtained in the step (1) can be (15-20): 0.2-0.3): 0.06-0.08): 1;
(3) synthesis of 4-hydroxypyrrolo [2,3-d ] pyrimidines
Adding the obtained substance in the step (2) into a mixed alkali solution, slowly adding 2-bromoacetaldehyde at the temperature of 45-55 ℃, reacting for 4-5 hours, cooling and crystallizing after the reaction is finished, filtering, washing with water, and drying, wherein the mixed alkali solution contains KHCO with the concentration of 1.35-1.50 mol/L3And LiOH aqueous solution with the concentration of 0.40-0.50 mol/L, wherein the weight ratio of the obtained substance in the step (2), 2-bromoacetaldehyde and mixed alkali solution is 1 (1.5-2.0) to 10-12.
2. The process for producing a prodrug intermediate of thymidine phosphorylase inhibitor as claimed in claim 1, wherein the temperature-decreasing crystallization in step (1) is carried out by cooling the reaction system to a temperature of-5 to-10 ℃ to precipitate crystals.
3. The method of claim 1, wherein the washing in step (1) is performed with a mixture of ethanol and dioxane at a volume ratio of 10:1.5 and a temperature of-5 to-10 ℃.
4. The method of claim 3, wherein the washing is performed 2 to 3 times with 1/10 to 1/8 volumes of the mixed alcohol-base solution.
5. The method for preparing the prodrug intermediate of thymidine phosphorylase inhibitor according to claim 1, wherein the step (2) comprises filtering the solution while hot, washing the residue 1-2 times with 1/10-1/8 water at 65-75 ℃ and in a volume of the mixed amine solvent, and combining the eluate with the filtrate.
6. The method for producing a prodrug intermediate of a thymidine phosphorylase inhibitor as claimed in claim 1, wherein the temperature-lowering crystallization in step (2) is carried out by cooling the reaction system to 0 to 5 ℃ to precipitate crystals.
7. The method for preparing the prodrug intermediate of thymidine phosphorylase inhibitor as claimed in claim 1, wherein the washing in step (2) is performed 2-3 times by using 1/10-1/8 volume of water at 0-5 ℃.
8. The method for producing a prodrug intermediate of a thymidine phosphorylase inhibitor as claimed in claim 1, wherein the temperature-lowering crystallization in step (3) is carried out by cooling the reaction system to 0 to 5 ℃ to precipitate crystals.
9. The method for preparing the prodrug intermediate of thymidine phosphorylase inhibitor as claimed in claim 1, wherein the washing in step (3) is performed 2-3 times by using 1/8-1/6 water at 0-5 ℃ and in volume of the mixed alkali solution.
10. The method of claim 1, wherein the drying in step (3) is performed at 70-80 ℃ for 4-5 hours.
Technical Field
The application relates to the field of preparation of prodrug intermediates of thymidine phosphorylase inhibitors, and more particularly relates to a preparation method of prodrug intermediates of thymidine phosphorylase inhibitors.
Background
Thymidine Phosphorylase (TP), an important enzyme in the synthesis and degradation of pyrimidine nucleosides, is also a newly discovered angiogenic factor. TP is expressed in a plurality of solid tumor tissues, the activity of the TP is closely related to the sensitivity of tumor cells to fluorouracil drugs, and the effects of inducing angiogenesis and resisting apoptosis are closely related to the growth and metastasis of tumors, in particular to the angiogenesis of tissues of gastric cancer, colorectal cancer, breast cancer and cervical cancer. Thymidine phosphorylase inhibitors have therefore been developed by those skilled in the art for the treatment of cancer.
4-hydroxypyrrolo [2,3-d ]]Pyrimidine is a very important prodrug intermediate of a xanthine oxidase activated thymidine phosphorylase inhibitor, and the medical significance and application value of exploring and optimizing the synthetic method of the pyrimidine are very great. 4-hydroxypyrrolo [2,3-d ]]Pyrimidine, english name: pyrrolo [2,3-d ]]pyrimidin-4-ol, molecular formula: c6H5N3O, molecular weight: 135.1234, relative density: 1.62g/cm3CAS number: 3680-71-5. It has both enol and keto tautomers, as shown below:
chinese patent application CN101830904A discloses a preparation method of 4-chloro-pyrrolopyrimidine, which takes ethyl cyanoacetate, thiourea, 2-chloroacetaldehyde and the like as raw materials, synthesizes and obtains the 4-hydroxy-pyrrolopyrimidine through three-step reaction, and then passes through POCl3And (4) chlorination to obtain the target product 4-chloro pyrrolopyrimidine. Wherein, the synthesis process of the 4-hydroxypyrrolopyrimidine is simple to operate, but the yield still has a space for further improvement.
Accordingly, it would be desirable to develop a process for preparing 4-hydroxypyrrolo [2,3-d ] pyrimidine, a prodrug intermediate of thymidine phosphorylase inhibitors, in higher yields.
Disclosure of Invention
[ problem ] to
Aiming at the defects in the prior art, one object of the application is to provide a preparation method of a prodrug intermediate of a thymidine phosphorylase inhibitor, wherein the method has the advantages of stable reaction and simple and convenient operation, and particularly, the total yield of 4-hydroxypyrrolo [2,3-d ] pyrimidine is further improved and can reach more than 75%.
[ solution ]
In order to achieve the above objects, according to one embodiment of the present application, there is provided a method for preparing a prodrug intermediate of a thymidine phosphorylase inhibitor, comprising the steps of:
(1) synthesis of 2-mercapto-4-amino-6-hydroxypyrimidine
Dissolving thiourea in a mixed alcohol-alkali solution, slowly adding ethyl cyanoacetate at room temperature, carrying out reflux reaction at 75-85 ℃ for 5-6 hours, cooling and crystallizing after the reaction is finished, filtering, and washing with an ethanol/dioxane mixed solution, wherein the mixed alcohol-alkali solution comprises potassium ethoxide with the concentration of 0.75-0.80 mol/L, lithium ethoxide solute with the concentration of 0.03-0.05 mol/L, and an ethanol-dioxane solvent with the volume ratio of 10 (1.0-1.2), and the molar ratio of the thiourea, the ethyl cyanoacetate and the potassium ethoxide can be (1.25-1.5): 1 (1.7-2.0);
(2) synthesis of 4-amino-6-hydroxypyrimidines
Mixing pyridine with the volume ratio of (0.2-0.3): 10 with ammonia water with the mass concentration of 25-28% to obtain a mixed amine solvent, and adding Raney nickel (Raney Ni) and ZnSO4And (2) heating the obtained product in the step (1) at 65-75 ℃ for reaction for 7-8 hours, filtering while the product is hot after the reaction is finished, cooling for crystallization, filtering, and washing with water, wherein the mixed amine solvent, the Raney nickel and the ZnSO are4And the weight ratio of the product obtained in the step (1) can be (15-20): 0.2-0.3): 0.06-0.08): 1;
(3) synthesis of 4-hydroxypyrrolo [2,3-d ] pyrimidines
Adding the product obtained in the step (2) into a mixed alkali solution, slowly adding 2-bromoacetaldehyde at 45-55 ℃, reacting for 4-5 hours, cooling and crystallizing after the reaction is finished, filtering, washing with water, drying, wherein,the mixed alkali solution is KHCO with the concentration of 1.35-1.50 mol/L3And LiOH aqueous solution with the concentration of 0.40-0.50 mol/L, wherein the weight ratio of the obtained substance in the step (2), 2-bromoacetaldehyde and mixed alkali solution is 1 (1.5-2.0) to 10-12.
In the application, the reaction conditions and the material ratio of each step are further optimized and adjusted, the utilization rate and the conversion rate of reactants are improved, the occurrence of side reactions is reduced, products in the intermediate step can be put into the next step without being fully purified, and the product loss in each step can be reduced comprehensively, so that the final prodrug intermediate 4-hydroxypyrrolo [2,3-d ] pyrimidine of the target thymidine phosphorylase inhibitor is obtained with very high total yield.
The step (1) is a pyrimidine ring closure reaction, wherein under the action of alkali, two amino groups of thiourea can respectively attack carbonyl carbon and cyano carbon of ethyl cyanoacetate, and nucleophilic reaction is carried out to bond and form a pyrimidine ring. In the reaction, the mixed alkali of potassium ethoxide and lithium ethoxide is used for catalyzing the reaction, and the mixed solvent of ethanol and dioxane is also used, and the reaction conditions are adaptively adjusted, so that the reaction can be promoted to be fully carried out, the generation of byproducts is reduced, and the mixed solvent is favorable for precipitating more products during cooling crystallization after the reaction is finished. In addition, the step (1) can be put into the next reaction through simple crystallization and washing without drying and further purification, so that the loss of the product can be further reduced.
Preferably, the temperature-reducing crystallization in the step (1) is to cool the reaction system to-5 to-10 ℃ to precipitate crystals. At the above temperature, the crystallization of the product 2-mercapto-4-amino-6-hydroxypyrimidine can be promoted as much as possible, while the residual reactants thiourea and ethyl cyanoacetate and a small amount of by-products can still remain in the reaction solution. When the temperature is higher, the residual product in the mother liquor is correspondingly higher, and when the temperature is further reduced, the impurities cannot be separated out in a large amount.
Preferably, the washing of the step (1) is carried out by using a mixed solution of ethanol and dioxane with a volume ratio of 10:1.5 and a temperature of-5 to-10 ℃. By adopting the mixture solution with the mixture ratio and the temperature for washing, the loss of the product 2-mercapto-4-amino-6-hydroxypyrimidine can be reduced as much as possible while impurities are washed off to the maximum extent.
More preferably, the washing is performed 2 to 3 times by using the mixed solution of 1/10 to 1/8 in volume of the mixed alcohol-alkali solution. The mixed liquid with the volume and the dosage can effectively wash impurities in the crystals.
The step (2) is a reduction removal reaction of sulfydryl, Raney nickel is used as a catalyst, ammonia is used as a hydrogen donor, and the sulfydryl is reduced into hydrogen sulfide to be removed. In the reaction, pyridine and ZnSO are added to further improve the removal effect of sulfydryl and reduce the influence on hydroxyl and amino in molecules4The hydrogen supply capability of the ammonia and the reduction activity of the catalyst are adjusted, so that the effects of improving the reaction conversion rate and reducing side reactions are achieved. In addition, the step (2) can be put into the next reaction through simple crystallization and washing without drying and further purification, so that the loss of the product can be further reduced.
Preferably, the hot filter residue in the step (2) is washed by 1/10-1/8 water with the temperature of 65-75 ℃ and the volume of the mixed amine solvent for 1-2 times, and the leacheate is combined with the filtrate. The residue after the reaction is washed with hot water, so that the product adhering to the residue can be washed out as much as possible.
Preferably, the temperature reduction crystallization in the step (2) is to cool the reaction system to 0-5 ℃ to precipitate crystals. At the temperature, the crystallization of the product 4-amino-6-hydroxypyrimidine can be promoted to be separated out as much as possible, and the residual reactant 2-mercapto-4-amino-6-hydroxypyrimidine and a small amount of by-products can still be remained in the reaction solution and are finally removed by filtration. When the temperature is higher, the residual product in the mother liquor is correspondingly higher, and when the temperature is further reduced, the impurities cannot be separated out in a large amount, and the system has the risk of icing.
Preferably, the washing in the step (2) is carried out for 2-3 times by using 1/10-1/8 water with the temperature of 0-5 ℃ and the volume of the mixed amine solvent. By washing with water at the above temperatures, volumes and amounts, the loss of the product 4-amino-6-hydroxypyrimidine can be minimized while maximizing the washing away of impurities.
And (3) pyrrole cyclization reaction, wherein under the action of alkali, the amino group of 4-amino-6-hydroxypyrimidine can attack the carbonyl group of 2-bromoacetaldehyde, and the alpha-carbon of 2-bromoacetaldehyde attacks a pyrimidine ring, so that bonding is carried out to form a fused heterocyclic ring of pyrrolopyrimidine. In this reaction, KHCO is used3The mixed alkali with LiOH is used for catalytic reaction, the ring formation conversion rate is high, the side reaction is less, and after the reaction is finished, impurities can be effectively removed through simple treatment, so that a final product with high purity is obtained.
Preferably, the temperature reduction crystallization in the step (3) is to cool the reaction system to 0-5 ℃ to precipitate crystals. At the above temperature, the crystallization of the product 4-hydroxypyrrolo [2,3-d ] pyrimidine can be promoted as much as possible, and the residual reactant and a small amount of by-products can still remain in the reaction solution and are finally removed by filtration. When the temperature is higher, the residual product in the mother liquor is correspondingly higher, and when the temperature is further reduced, the impurities cannot be separated out in a large amount, and the system has the risk of icing.
Preferably, the washing in the step (3) is carried out for 2-3 times by using 1/8-1/6 water with the temperature of 0-5 ℃ and the volume of the mixed alkali solution. By washing with water at the above temperatures, volumes and amounts, the loss of product can be minimized while maximizing the washing away of impurities.
Preferably, the drying in the step (3) is drying at 70-80 ℃ for 4-5 hours. Under such dry conditions, the moisture in the product can be sufficiently removed while avoiding thermal decomposition of the crystals.
[ advantageous effects ]
In summary, the present application has the following beneficial effects:
according to the preparation method of the prodrug intermediate of the thymidine phosphorylase inhibitor, conditions and material ratios of all steps are fully optimized, the utilization rate and the conversion rate of reactants are improved, side reactions are reduced, the operation is simple and convenient, and the total yield of a target product, namely 4-hydroxypyrrolo [2,3-d ] pyrimidine is finally improved (more than 75%).
Detailed Description
In order to make the present application more clearly understood by those skilled in the art, the present application will be described in further detail with reference to the following examples, but it should be understood that the following examples are only preferred embodiments of the present application, and the scope of the present application as claimed is not limited thereto.
Sources of materials
Thiourea, available from Shanghai Aladdin Biotechnology Ltd,
ethyl cyanoacetate, potassium ethoxide, lithium ethoxide (1M ethanol solution), 2-bromoacetaldehyde, available from bailing technologies ltd, beijing,
raney nickel, available from Beijing Jinruimeixiang technologies, Inc.,
ZnSO4pyridine, ammonia water (25-28%) and KHCO3LiOH, from the national pharmaceutical group.
< example >
Example 1
The prodrug intermediate 4-hydroxypyrrolo [2,3-d ] pyrimidine of thymidine phosphorylase inhibitors was prepared using the following preparation method according to the present application:
(1) synthesis of 2-mercapto-4-amino-6-hydroxypyrimidine
90.84g (1.1934mol) of thiourea is dissolved in 2.12L of mixed alcohol alkali solution (comprising solute of potassium ethoxide with concentration of 0.75mol/L and lithium ethoxide with concentration of 0.04mol/L and solvent of ethanol and dioxane with volume ratio of 10: 1.2), 100.00g (0.8840mol) of ethyl cyanoacetate is slowly added at room temperature, reflux reaction is carried out for 5.5 hours at 80 ℃, after the reaction is finished, the mixture is cooled to-5 ℃ to precipitate crystals, filtered, and washed for 2 times by 0.25L of ethanol/dioxane mixed solution with volume ratio of 10:1.5 and temperature of-5 ℃ to obtain 117.70g of product;
(2) synthesis of 4-amino-6-hydroxypyrimidines
Pyridine with the volume ratio of 0.25:10 and ammonia water with the mass concentration of 25% -28% are mixed to obtain a mixed amine solvent, 2240g (2500mL) of the mixed amine solvent is taken, 23.54g of Raney nickel and 9.42g of ZnSO are added into the mixed amine solvent4And (2) heating the obtained product in the step (1) at 75 ℃ for reaction for 7.5 hours, filtering the hot reaction product after the reaction is finished, washing the filter residue with water at 75 ℃ and the volume of 250mL for 2 times, combining the leacheate with the filtrate, cooling to 3 ℃ to separate out crystals, filtering, and washing with water at 3 ℃ and the volume of 250mL for 2 times to obtain 84.18g of product;
(3) synthesis of 4-hydroxypyrrolo [2,3-d ] pyrimidines
The resultant of step (2) was added to 842g (750mL) of a mixed alkali solution containing KHCO at a concentration of 1.50mol/L3And an aqueous solution of LiOH with a concentration of 0.45 mol/L), 151.53g of 2-bromoacetaldehyde were slowly added at 45 ℃ and then reacted for 4.5 hours, cooled to 0 ℃ after completion of the reaction to precipitate crystals, filtered, washed 2 times with water having a temperature of 0 ℃ and a volume of 100mL, and dried at 75 ℃ for 4.5 hours, thereby obtaining 96.68g of a final product, 4-hydroxypyrrolo [2,3-d ] (a final product) as a reaction product]Pyrimidine (purity 99.23%, total yield 80.31%).
Example 2
The prodrug intermediate 4-hydroxypyrrolo [2,3-d ] pyrimidine of thymidine phosphorylase inhibitors was prepared using the following preparation method according to the present application:
(1) synthesis of 2-mercapto-4-amino-6-hydroxypyrimidine
84.11g (1.1050mol) of thiourea is dissolved in 2.10L of mixed alcohol-base solution (comprising 0.80mol/L potassium ethoxide, 0.03mol/L lithium ethoxide solute and 10:1.1 volume ratio of ethanol to dioxane solvent), 100g (0.8840mol) of ethyl cyanoacetate is slowly added at room temperature, reflux reaction is carried out for 6 hours at 75 ℃, cooling is carried out to-10 ℃ after the reaction is finished to precipitate crystals, filtering is carried out, and washing is carried out for 3 times by using 0.21L of ethanol/dioxane mixed solution with 10:1.5 volume ratio and-10 ℃ to obtain 120.23g of product;
(2) synthesis of 4-amino-6-hydroxypyrimidines
Body to be fixedPyridine with the volume ratio of 0.2:10 is mixed with ammonia water with the mass concentration of 25-28 percent to obtain a mixed amine solvent, 2400g (2610mL) of the mixed amine solvent is taken, 36.07g of Raney nickel and 8.42 g of ZnSO are added into the mixed amine solvent4And (2) heating the obtained product in the step (1) at 65 ℃ for 8 hours, filtering while the product is hot after the reaction is finished, washing the filter residue with water at 65 ℃ and 270mL in volume for 2 times, combining the leacheate with the filtrate, cooling to 0 ℃ to separate out crystals, filtering, and washing with water at 2 ℃ and 270mL for 2 times to obtain 84.14g of product;
(3) synthesis of 4-hydroxypyrrolo [2,3-d ] pyrimidines
The resultant of step (2) was added to 1010g (880mL) of a mixed alkali solution containing KHCO at a concentration of 1.35mol/L3And an aqueous solution of LiOH with a concentration of 0.50 mol/L), 159.87g of 2-bromoacetaldehyde were slowly added at 55 ℃ and then reacted for 4 hours, cooled to 0 ℃ after completion of the reaction to precipitate crystals, filtered, washed 3 times with water having a temperature of 2 ℃ and a volume of 120mL, and dried at 70 ℃ for 5 hours, thereby obtaining 97.92g of a final product, 4-hydroxypyrrolo [2,3-d ]]Pyrimidine (purity 99.05%, overall yield 81.19%).
Example 3
The prodrug intermediate 4-hydroxypyrrolo [2,3-d ] pyrimidine of thymidine phosphorylase inhibitors was prepared using the following preparation method according to the present application:
(1) synthesis of 2-mercapto-4-amino-6-hydroxypyrimidine
100.94g (1.3260mol) of thiourea is dissolved in 1.88L of mixed alcohol alkali solution (comprising solute of potassium ethoxide with concentration of 0.80mol/L and lithium ethoxide with concentration of 0.05mol/L and solvent of ethanol and dioxane with volume ratio of 10: 1.2), 100.00g (0.8840mol) of ethyl cyanoacetate is slowly added at room temperature, reflux reaction is carried out for 5.5 hours at 80 ℃, after the reaction is finished, the mixture is cooled to minus 7 ℃ to precipitate crystals, filtered, and washed for 3 times by 0.20L of ethanol/dioxane mixed solution with volume ratio of 10:1.5 and temperature of minus 7 ℃ to obtain 118.96g of product;
(2) synthesis of 4-amino-6-hydroxypyrimidines
The volume ratio is 0.3:10Mixing pyridine with ammonia water with the mass concentration of 25-28% to obtain a mixed amine solvent, taking 2141g (2330mL) of the mixed amine solvent, adding 35.69g of Raney nickel and 7.14 g of ZnSO into the mixed amine solvent4And (2) heating the obtained product in the step (1) at 70 ℃ for reaction for 7 hours, filtering the hot reaction product after the reaction is finished, washing the filter residue 1 time by using water with the temperature of 70 ℃ and the volume of 250mL, combining the leacheate with the filtrate, cooling to 2 ℃ to separate out crystals, filtering, and washing 2 times by using water with the temperature of 2 ℃ and the volume of 240mL to obtain 82.34g of product;
(3) synthesis of 4-hydroxypyrrolo [2,3-d ] pyrimidines
The resultant of step (2) was added to 906g (790mL) of a mixed alkali solution containing KHCO at a concentration of 1.40mol/L3And an aqueous solution of LiOH with a concentration of 0.40 mol/L), 139.98g of 2-bromoacetaldehyde was slowly added at 50 ℃ and then reacted for 5 hours, cooled to 0 ℃ after completion of the reaction to precipitate crystals, filtered, washed 3 times with water having a temperature of 1 ℃ and a volume of 100mL, and dried at 80 ℃ for 4 hours, thereby obtaining 94.82g of a final product, 4-hydroxypyrrolo [2,3-d ]]Pyrimidine (purity 99.34%, total yield 78.86%).
Example 4
The prodrug intermediate 4-hydroxypyrrolo [2,3-d ] pyrimidine of thymidine phosphorylase inhibitors was prepared using the following preparation method according to the present application:
(1) synthesis of 2-mercapto-4-amino-6-hydroxypyrimidine
Dissolving 94.21g (1.23mol) of thiourea in 2.36L of mixed alcohol alkali solution (comprising a solute of potassium ethoxide with the concentration of 0.75mol/L and lithium ethoxide with the concentration of 0.05mol/L and a solvent of ethanol and dioxane with the volume ratio of 10: 1.1), slowly adding 100.00g (0.8840mol) of ethyl cyanoacetate at room temperature, carrying out reflux reaction at 75 ℃ for 5.5 hours, cooling to-10 ℃ after the reaction is completed to precipitate crystals, filtering, washing for 2 times by using 0.24L of ethanol/dioxane mixed solution with the volume ratio of 10:1.5 and the temperature of-10 ℃ to obtain 116.43g of product;
(2) synthesis of 4-amino-6-hydroxypyrimidines
Pyridine and mass in a volume ratio of 0.3:10Mixing 25-28% ammonia water to obtain mixed amine solvent, collecting 1753g (1900mL) of mixed amine solvent, adding 23.29g Raney nickel and 9.31 g ZnSO4And (2) heating the obtained product in the step (1) at 65 ℃ for 8 hours, filtering while the product is hot after the reaction is finished, washing the filter residue with water at 70 ℃ and with the volume of 200mL for 2 times, combining the leacheate with the filtrate, cooling to 5 ℃ to separate out crystals, filtering, and washing with water at 5 ℃ and with the volume of 200mL for 2 times to obtain 79.69g of product;
(3) synthesis of 4-hydroxypyrrolo [2,3-d ] pyrimidines
The resultant of step (2) was added to 956g (830mL) of a mixed base solution (containing KHCO at a concentration of 1.45 mol/L)3And an aqueous solution of LiOH with a concentration of 0.50 mol/L), 119.54g of 2-bromoacetaldehyde were slowly added at 55 ℃ and then reacted for 5 hours, cooled to 0 ℃ after completion of the reaction to precipitate crystals, filtered, washed 2 times with water having a temperature of 1 ℃ and a volume of 120mL, and dried at 75 ℃ for 5 hours, thereby obtaining 91.78g of a final product, 4-hydroxypyrrolo [2,3-d ]]Pyrimidine (purity 99.15%, overall yield 76.18%).
Example 5
The prodrug intermediate 4-hydroxypyrrolo [2,3-d ] pyrimidine of thymidine phosphorylase inhibitors was prepared using the following preparation method according to the present application:
(1) synthesis of 2-mercapto-4-amino-6-hydroxypyrimidine
Dissolving 87.48g (1.1492mol) of thiourea in 2.05L of mixed alcohol-base solution (containing 0.80mol/L potassium ethoxide, 0.03mol/L lithium ethoxide solute and 10:1.0 ethanol and dioxane solvent), slowly adding 100.00g (0.8840mol) of ethyl cyanoacetate at room temperature, then carrying out reflux reaction at 75 ℃ for 6 hours, cooling to-8 ℃ after the reaction is completed to precipitate crystals, filtering, washing for 3 times by using 0.22L of ethanol/dioxane mixed solution with 10:1.5 volume ratio and-8 ℃ to obtain 116.40g of product;
(2) synthesis of 4-amino-6-hydroxypyrimidines
Pyridine with the volume ratio of 0.3:10 and the mass concentration of 25-28 percent% ammonia water to obtain mixed amine solvent, and adding 1863g (2025mL) of mixed amine solvent, 23.30g of Raney nickel, 6.99 g of ZnSO4And (2) heating the obtained product in the step (1) at 75 ℃ for reaction for 7 hours, filtering the hot reaction product after the reaction is finished, washing the filter residue with water at 75 ℃ and the volume of 210mL for 2 times, combining the leacheate with the filtrate, cooling to 3 ℃ to separate out crystals, filtering, and washing with water at 3 ℃ and the volume of 210mL for 2 times to obtain 82.38g of product;
(3) synthesis of 4-hydroxypyrrolo [2,3-d ] pyrimidines
The resultant of step (2) was added to 824g (720mL) of a mixed alkali solution containing KHCO at a concentration of 1.40mol/L3And an aqueous solution of LiOH with a concentration of 0.35 mol/L), 164.76g of 2-bromoacetaldehyde were slowly added at 50 ℃ and then reacted for 5 hours, cooled to 2 ℃ after completion of the reaction to precipitate crystals, filtered, washed 2 times with water having a temperature of 2 ℃ and a volume of 100mL, and dried at 70 ℃ for 4.5 hours, thereby obtaining 93.71g of a final product, 4-hydroxypyrrolo [2,3-d ] (a final product) of]Pyrimidine (purity 99.27%, total yield 77.88%).
Example 6
The prodrug intermediate 4-hydroxypyrrolo [2,3-d ] pyrimidine of thymidine phosphorylase inhibitors was prepared using the following preparation method according to the present application:
(1) synthesis of 2-mercapto-4-amino-6-hydroxypyrimidine
Dissolving 97.57g (1.2818mol) of thiourea in 2.30L of mixed alcohol-base solution (comprising a solute of potassium ethoxide with the concentration of 0.75mol/L and lithium ethoxide with the concentration of 0.04mol/L and a solvent of ethanol and dioxane with the volume ratio of 10: 1.2), slowly adding 100.00g (0.8840mol) of ethyl cyanoacetate at room temperature, then carrying out reflux reaction at 85 ℃ for 5 hours, cooling to-10 ℃ after the reaction is finished to precipitate crystals, filtering, washing for 3 times by using 0.24L of ethanol/dioxane mixed solution with the volume ratio of 10:1.5 and the temperature of-10 ℃ to obtain 117.68g of product;
(2) synthesis of 4-amino-6-hydroxypyrimidines
Pyridine with the volume ratio of 0.3:10 is mixed with ammonia water with the mass concentration of 25-28 percentTo obtain a mixed amine solvent, 2002g (2175mL) of the mixed amine solvent was taken, and 35.31g of Raney nickel and 8.24 g of ZnSO were added thereto4And (2) heating the obtained product in the step (1) at 65 ℃ for 8 hours, filtering the hot filtered residue after the reaction is finished, washing the filtered residue 1 time by using water with the temperature of 65 ℃ and the volume of 230mL, combining the leacheate with the filtrate, cooling to 0 ℃ to separate out crystals, filtering, and washing 3 times by using water with the temperature of 2 ℃ and the volume of 220mL to obtain 82.37g of product;
(3) synthesis of 4-hydroxypyrrolo [2,3-d ] pyrimidines
The resultant of step (2) was added to 906g (790mL) of a mixed alkali solution (containing KHCO at a concentration of 1.35 mol/L)3And an aqueous solution of LiOH with a concentration of 0.45 mol/L), 131.79g of 2-bromoacetaldehyde were slowly added at 45 ℃ and then reacted for 5 hours, cooled to 0 ℃ after completion of the reaction to precipitate crystals, filtered, washed 3 times with water having a temperature of 1 ℃ and a volume of 100mL, and dried at 70 ℃ for 5 hours, thereby obtaining 92.71g of a final product, 4-hydroxypyrrolo [2,3-d ]]Pyrimidine (purity 99.19%, total yield 76.98%).
Comparative example 1
80.74g of 4-hydroxypyrrolo [2,3-d ] pyrimidine (purity 99.20%, overall yield 67.05%) as a final product was obtained in the same manner as in example 1, except that the same volume of an ethanol solution of sodium ethoxide at a concentration of 0.80mol/L was used in place of the mixed alcoholic base solution in step (1) and the crystals were washed with ethanol.
Comparative example 2
Except that ammonia water with the same volume and the mass concentration of 25-28 percent is adopted to replace the mixed amine solvent in the step (2), and ZnSO is not added4Otherwise, 83.17g of a final product, 4-hydroxypyrrolo [2,3-d ], was obtained in the same manner as in example 1]Pyrimidine (purity 99.15%, overall yield 69.03%).
Comparative example 3
78.98g of 4-hydroxypyrrolo [2,3-d ] pyrimidine (purity 99.25%, total yield 65.62%) as a final product was obtained in the same manner as in example 1, except that the mixed alkali solution was replaced with an aqueous sodium acetate solution of the same volume and concentration of 2.00mol/L in step (3) and 2-chloroacetaldehyde was used in place of 2-bromoacetaldehyde, and the reaction was carried out at 70 ℃.
As can be seen from the above examples 1 to 6 and comparative examples 1 to 3, the present application greatly improves the overall yield of 4-hydroxypyrrolo [2,3-d ] pyrimidine, a prodrug intermediate of thymidine phosphorylase inhibitor, by optimizing the reaction and post-treatment conditions of the respective steps; in contrast, in comparative examples 1 to 3, the total yield is significantly reduced after replacing the technical scheme of the present application in each step.
The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.