CN118239891A

CN118239891A - Method for preparing N- (5-pyrimidine methyl) -2-pyridine amine compound

Info

Publication number: CN118239891A
Application number: CN202211656962.3A
Authority: CN
Inventors: 焦体; 王志会
Original assignee: Purpana Beijing Technologies Co Ltd
Current assignee: Purpana Beijing Technologies Co Ltd
Priority date: 2022-12-22
Filing date: 2022-12-22
Publication date: 2024-06-25

Abstract

The invention discloses a preparation method for preparing N- (5-pyrimidine methyl) -2-pyridine amine compounds and intermediates thereof. The preparation method of the N- (5-pyrimidine methyl) -2-pyridine amine compound intermediate has the following synthetic route: . The invention also provides two methods for preparing the N- (5-pyrimidine methyl) -2-pyridine amine compounds, which respectively adopt the following synthetic routes: route one, Route two,

Description

Method for preparing N- (5-pyrimidine methyl) -2-pyridine amine compound

Technical Field

The invention relates to the field of preparation of pesticide intermediates, in particular to a method for preparing N- (5-pyrimidine methyl) -2-pyridine amine compounds and intermediates thereof.

Technical Field

The preparation of N- (5-pyrimidinylmethyl) -2-pyridineamines is achieved by reacting 2-aminopyridine with different pyrimidine structures or pyrimidine structure precursors.

Chinese patent CN108373468a (2018-08-07) reports a method for synthesizing N-2-pyridine-5-pyrimidine methylamine by direct nucleophilic substitution of 2-aminopyridine and 5-bromomethyl pyrimidine. The method involves the substitution of aromatic amine and primary bromo-compound, has more side reactions, is unfavorable for purification and high price for producing 5-bromomethyl pyrimidine, is not easy to obtain, has high cost and the like, is not easy to generate, and has the following synthetic route:

Patent WO 2019/86447 (syngeneta) reports a route to the synthesis of N-2-pyridin-5-pyrimidinemethylamine by removing Boc protection after nucleophilic substitution with 5-chloromethylpyrimidine under NaH as base. The route has single product and high yield, but involves protection and deprotection of amino groups and has higher cost.

Dupond corporation (WO 2019/173173A1, WO2017/189339A 1) reports that after synthesizing an imine from 2-aminopyridine and 5-formylpyrimidine, the imine is reacted with sodium bisulfite or methanol, respectively, to give a product that is added to the imine, and then reduced by NaBH4 to give N-2-pyridine-5-pyrimidinemethylamine. The route has higher yield and fewer byproducts. However, the reaction route is long, a large amount of three wastes are generated, the environment is not protected, the market price of the 5-formyl pyrimidine is high, and the synthesis method is not basically reported at present.

Chinese patent CN111454247a (2020-07-28) reports nucleophilic substitution reactions with 2-aminopyridine and 2-bromomethylmalonate followed by the construction of pyrimidine rings on malonate fragments. The route involves substitution of aromatic amine and primary bromide, has more side reactions, and faces pyrimidine ring construction in the latter stage of synthesis, with higher overall cost.

In general, the existing synthesis methods all take 2-aminopyridine as raw materials, and the main problems are that how to connect 2-aminopyridine and pyrimidine ring parts together, the overall cost of the method for constructing pyrimidine ring is high, and the synthesis of 5-substituted pyrimidine faces the problems that the cost of 5-formyl pyrimidine is high, the selectivity of 2-aminopyridine and primary halogenide substitution is difficult to control, the route of nitrogen atom Boc protection in 2-aminopyridine is high, and the reductive amination side reaction of 2-aminopyridine and 5-formyl pyrimidine is difficult to control. Thus, there is a need to find methods in synthetic routes to reduce the cost of 5-formyl pyrimidine and how to increase the reductive amination yields of 2-aminopyridine with 5-formyl pyrimidine.

Disclosure of Invention

Aiming at the defects of complex process, high synthesis cost and more side reaction products in the preparation of N- (5-pyrimidine methyl) -2-pyridine amine compounds in the prior art. The invention firstly solves the problem that the cost for synthesizing 5-formylpyrimidine is high in the prior art, therefore, the invention firstly provides a novel method for synthesizing substituted formylpyrimidine, which reduces the synthesis cost of substituted 5-formylpyrimidine, and the intermediate synthesized by the method can improve the yield and purity of the product and reduce the cost of the whole N- (5-pyrimidinylmethyl) -2-pyridinylamine compound synthesis process, the process route is environment-friendly, the energy consumption can be greatly reduced, the method is more suitable for industrial production, and the product has stronger market competitiveness.

The invention provides a novel synthesis method of substituted formyl pyrimidine, which adopts the following technical scheme: step (1), synthesizing methoxy methyl acrylate and orthoformate in the presence of ammonia gas to obtain a compound of a formula I; step (2), reacting the compound of formula I with a Wilsmeier reagent to obtain a compound of formula II, wherein the structures of the compounds of formula I and formula II are as follows: The orthoformate structure is: RC (OEt) ₃, where R is H or C ₁-C₆ alkyl.

The specific synthetic route is as follows:

The invention also provides a method for preparing the N- (5-pyrimidinylmethyl) -2-pyridinamine compound (formula VI), which comprises the following steps:

step one), reacting a compound of formula II with ethylene glycol to prepare a compound of formula III;

step two), dechlorinating the compound of the formula III under the condition of hydrogen to obtain a compound of the formula IV;

Step three), preparing the compound of the formula IV and 2-aminopyridine to obtain a compound of the formula V,

Step four), preparing a compound of a formula VI by the compound of the formula V under the action of a reducing agent, wherein the structures of the formula II, the formula III, the formula IV, the formula V and the formula VI are as follows:

wherein R is H or C ₁-C₆ alkyl.

The invention also provides another method for preparing the N- (5-pyrimidinylmethyl) -2-pyridinamine compound (formula VI), which comprises the following steps:

step a, preparing a compound of a formula II and 2-aminopyridine to obtain a compound of a formula VII;

step b, preparing the compound of the formula VII under the action of a reducing agent to obtain the compound of the formula VI,

Wherein, formula II has the structure:

The structure of formula VII is as follows:

The structure of formula VI is as follows: Wherein R is H or C ₁-C₆ alkyl.

The beneficial effects are that:

1. according to the invention, the methyl methoxyacrylate is used as a starting material to synthesize the 4-hydroxy pyrimidine intermediate, and the 4-hydroxy pyrimidine is used as a key intermediate to synthesize the compound shown in the formula II, so that the amount of chloro reagent required to be consumed in the synthesis of the 5-formyl pyrimidine from the 4, 6-dihydroxy pyrimidine in the traditional method and the cost in the hydrodechlorination step are reduced, and the cost occupied by pyrimidine ring synthesis in the whole synthesis period is reduced;

2. The selectivity in the dechlorination step can be improved by adopting 4-chloro-5-pyrimidine aldehyde to form glycol acetal and then carrying out hydrodechlorination, so that the side reaction of aldehyde reduction in the traditional process is effectively avoided;

3. the N- (5-pyrimidinyl methyl) -2-pyridinamine compound is prepared by adopting the reduction of the product of the reaction of the 5-pyrimidinyl glycol acetal and the 2-aminopyridine, so that the product singleness in the reductive amination step can be improved, and byproducts can be effectively avoided;

4. The imine product is prepared by condensing 4-chloro-5-pyrimidine aldehyde and 2-aminopyridine, the hydrodechlorination and imine hydrogenation reaction are continuously realized in one pot, the construction of pyrimidine ring parts and the connection of two molecular fragments are concentrated into one-step reaction, the concentration of the reaction in the process flow is improved, the post-treatment process of the intermediate process is reduced, and the yield of the whole process is improved, so that the whole production cost is reduced.

Detailed Description

The following describes the present invention in further detail with reference to examples. For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated elements and steps without excluding the presence of other material elements or steps.

In addition, numerous specific details are set forth in the following description in order to provide a better illustration of the invention.

It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In some embodiments, materials, methods, means, etc. well known to those skilled in the art are not described in detail in order to highlight the gist of the present invention.

Hereinafter, embodiments of the present invention are described in detail. However, these embodiments are exemplary, the invention is not limited thereto, and the invention is defined by the scope of the claims.

In the present invention, room temperature refers to about "20 ℃ to 25 ℃ unless otherwise specified.

The percentage of the present invention is not particularly limited and generally refers to weight percent.

The invention provides a preparation method of a compound of a formula II, which comprises the following steps:

step (1), synthesizing methoxy methyl acrylate and orthoformate in the presence of ammonia gas to obtain a compound of a formula I;

Step (2), reacting the compound of formula I with a Wilsmeier reagent to obtain a compound of formula II, wherein the structures of the compounds of formula I and formula II are as follows: The orthoformate structure is:

RC (OEt) ₃, where R is H or C ₁-C₆ alkyl.

The specific synthetic route is as follows:

in the reaction step (1), the methoxy methyl acrylate and the orthoformate are reacted in the presence of ammonia, wherein the ammonia may be pure NH ₃ which is liquid or gas, or may be NH ₃ which is dissolved in an organic solvent, and the organic solvent is an alcohol solvent, a halogenated alkane solvent, an aromatic hydrocarbon solvent, preferably an alcohol solvent, and most preferably one of methanol, ethanol and propanol.

Further, in the reaction step (1), the molar ratio of the methoxy methyl acrylate, the orthoformate and the ammonia gas is as follows: 1 (1-2): 1-5, preferably 1 (1-1.5): 1-2. Wherein, the orthoformate is preferably one of methyl orthoformate and ethyl orthoformate and isopropyl orthoformate. The reaction temperature in the step (1) is 25-50 ℃, preferably 30-40 ℃ and the reaction time is 1-10, preferably 2-5h.

The reaction step (2) comprises the reaction of the compound of the formula I with a Wilsmeier reagent to obtain the compound of the formula II. Wherein the Vilsmeier reagent is prepared from formylating reagent and acid halide, and the formylating reagent is preferably one of DMF, N, N-diethyl formamide and N-methyl-N-ethyl formamide; the acid halide is selected from one of phosphorus oxychloride, phosphorus oxybromide, thionyl chloride, oxalyl chloride, gas phosgene or solid phosgene, wherein the molar ratio of the formylating reagent to the acid halide is 1:1-1.5. The reaction temperature in step (2) is 20 to 60℃and preferably 30 to 40 ℃.

wherein R is H or C ₁-C₆ alkyl.

The specific synthetic route is as follows:

Wherein R is H or C ₁-C₆ alkyl, preferably H, methyl, ethyl and isopropyl.

Wherein the compound of formula II is prepared by the preparation method provided by the invention.

Further, in the step one), the compound of formula II and ethylene glycol are reacted in the presence of a catalyst to form a compound of formula III, wherein the catalyst is preferably an acidic catalyst, the acidic catalyst is preferably one of p-toluenesulfonic acid, pyridine p-toluenesulfonate, benzenesulfonic acid, trifluoromethanesulfonic acid, methanesulfonic acid, sulfuric acid and hydrogen chloride, and more preferably one of p-toluenesulfonic acid, pyridine p-toluenesulfonate, benzenesulfonic acid, trifluoromethanesulfonic acid and methanesulfonic acid, and the molar ratio of the compound of formula II to the catalyst is 1: 0.005-2.50, preferably 1:0.01-2.20; most preferably 1:0.05-1.0.

Further, the molar ratio of the compound of formula II to the ethylene glycol used in the above reaction step one) is 1:1-2, preferably 1:1-1.5. The reaction is carried out in a solvent, wherein the solvent is preferably benzene solvent, namely toluene and xylene, and the reaction temperature is 100-150 ℃, preferably 100-110 ℃.

Further, in the second reaction step), the compound of formula III and hydrogen are subjected to hydrogenation reduction reaction in the presence of a catalyst to generate a compound of formula IV, wherein the catalyst is one of nickel and Pd/C, and Pd/C is preferably 1% -20% Pd/C, more preferably 5% Pd/C, 10% Pd/C, 15% Pd/C and 20% Pd/C; the hydrogenation reaction is carried out in a solvent, wherein the solvent is one or more of an alcohol solvent, a benzene solvent, water and a hydrocarbon solvent, the alcohol solvent is preferably methanol and ethanol, and the benzene solvent is preferably toluene and xylene; the hydrocarbon solvent is preferably pentane or hexane, more preferably one of methanol and toluene. The pressure of the hydrogen reduction reaction is 0.1 to 5MPa, preferably 1 to 2.5MPa.

Further, in the second reaction step), a base may be added during the hydrogenation reaction, where the base is an inorganic base or an organic base, the inorganic base is preferably one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, the organic base is preferably one of methylamine, dimethylamine, triethylamine, isopropylamine and pyridine, and the reaction temperature is 20-80 ℃, preferably 40-60 ℃.

Further, the compound in the formula IV in the step III) reacts with 2-aminopyridine to generate a compound in the formula V, and the step III) is carried out in a solvent, wherein the solvent is halogenated alkane, and the halogenated alkane is one of dichloromethane, chloroform and dichloroethane; the reaction temperature is 10-50 ℃, preferably room temperature. The molar ratio of IV compound to 2-aminopyridine is 1:1-1.5, preferably 1:1-1.2.

Further, the compound of formula V in the fourth reaction step) is reacted in the presence of a reducing agent to form a compound of formula VI, wherein the reducing agent comprises a metal reducing agent and hydrogen, and the metal reducing agent comprises sodium borohydride and potassium borohydride, but is not limited thereto. The molar ratio of the compound of formula V to the reducing agent is: 1:1-5, preferably 1:1 to 1.5; the reaction is carried out in an organic solvent, wherein the organic solvent is one of tetrahydrofuran, methyltetrahydrofuran, ethylene glycol and methanol, and preferably methanol, tetrahydrofuran and methyltetrahydrofuran; the reaction temperature of the reaction is 0 to 50 ℃, preferably 15 to 30 ℃.

Wherein formula VII is as follows: Wherein R is H or C1-C6 alkyl, and formula II and formula VI are as above.

The specific synthetic route is as follows:

wherein R is H or C ₁-C₆ alkyl, preferably H, methyl and ethyl.

Further, the compound of formula II in the reaction step a is reacted with aminopyridine to obtain a compound of formula VII, wherein the reaction is performed in a solvent, the solvent is halogenated alkane, and the halogenated alkane is one of dichloromethane, chloroform and dichloroethane. The molar ratio of the compound of formula II to 2-aminopyridine is 1:1-2, preferably 1:1-1.3.

Further, the compound of formula VII in the above reaction step b is reacted with a metal reducing agent or hydrogen to prepare the compound of formula VI, wherein the metal reducing agent includes sodium borohydride and potassium borohydride, but is not limited thereto. When the metal reducing agent is selected for the reduction reaction with the VII compound, the molar ratio of the compound of formula VII to the metal reducing agent is 1:1-1.5, preferably 1:1-1.2, the product of the reduction of the compound of formula VII with a metal reducing agent is then dechlorinated under hydrogen conditions to give the compound of formula VI, the dechlorination hydrogenation preferably being carried out in the presence of a catalyst which is nickel, pd/C, wherein Pd/C is preferably 1-20% Pd/C, more preferably 5% Pd/C, 10% Pd/C. More preferably, the compound of formula VII is reacted directly with hydrogen to form the compound of formula VI, wherein formula VII and hydrogen are reduced in the presence of a catalyst which is nickel, pd/C, wherein Pd/C is preferably 1-20% Pd/C, more preferably 5% Pd/C; the catalyst is used in an amount of 0.01 to 0.03mol, preferably 0.01 to 0.02mol, relative to 1mol of the compound of formula VII; the hydrogenation reaction temperature is 10-50 ℃, preferably 10-20 ℃.

The present invention will be described in detail by examples.

In the following examples, all materials used were commercially available unless otherwise specified

Wherein the contents (purity) of the reactants and products are measured by liquid chromatography (AGI LENT HPLC 1260).

The conversion and selectivity of the reaction were calculated by the following formula:

Conversion= (molar amount of raw material charged-molar amount of raw material remaining in product)/molar amount of raw material charged x 100%.

Selectivity = actual molar amount of target product/theoretical molar amount of target product x 100%

In addition, the compound represented by the following formula (II) is prepared by the method disclosed in WO 9708163.

EXAMPLE 14 Synthesis of hydroxypyrimidine

In a 500ml four-mouth bottle with mechanical stirring, a thermometer and a condenser, 0.1mol of methyl methoxyacrylate, 0.11mol of trimethyl orthoformate and a methanol solvent containing 0.12mol of ammonia gas are added, the reaction is carried out for 3 hours at 30-40 ℃, after the liquid phase detection is qualified, the temperature is reduced to room temperature, the methanol is removed under reduced pressure, and the compound 4-hydroxypyrimidine is obtained, wherein the purity is 98%, and the yield is 90% (calculated by taking the methyl methoxyacrylate as a reference).

EXAMPLE 24 Synthesis of chloro-5-formylpyrimidine

In a 500ml four-mouth bottle with mechanical stirring, a thermometer and a condenser, 0.1mol of 4-hydroxy pyrimidine, 0.11mol of DMF and 0.12mol of sulfoxide chloride are added for reaction for 3 hours at the temperature of 30-40 ℃, after the liquid phase detection is qualified, the temperature is reduced to room temperature, and the compound 4-chloro-5-formyl pyrimidine is obtained, the purity is 98%, and the yield is 90% (calculated by taking 4-hydroxy pyrimidine as a reference).

EXAMPLE 34 Synthesis of chloro-5- (1, 3-dioxolan-2-yl) pyrimidine

In a four-mouth bottle with mechanical stirring, a thermometer and a condenser, 0.1mol of 4-chloro-5-formylpyrimidine, 0.01mol of p-toluenesulfonic acid, 100g of toluene and 0.13mol of glycol are added, the mixture is heated and refluxed for 3 hours, after liquid phase detection is qualified, the temperature is reduced to room temperature, and toluene is recovered by reduced pressure distillation, thus obtaining 4-chloro-5- (1, 3-dioxolan-2-yl) pyrimidine with purity of 90% and yield of 95% (calculated by taking 4-chloro-5-formylpyrimidine as a reference).

EXAMPLE 45 Synthesis of- (1, 3-Dioxolan-2-yl) pyrimidine

In a 500ml autoclave, 0.1mol of compound 4-chloro-5- (1, 3-dioxolan-2-yl) pyrimidine, 0.001mol of 10% Pd/C,100g of methanol and nitrogen are added for three times, hydrogen is filled, the pressure is kept at 2MPa, the temperature is heated to 40-60 ℃ for reaction for 3 hours, after liquid phase detection is qualified, the temperature is reduced to room temperature, the catalyst is filtered and removed for application, and methanol is recovered by reduced pressure distillation, so that the purity of 5- (1, 3-dioxolan-2-yl) pyrimidine is 90%, and the yield is 90% (calculated by taking 4-chloro-5- (1, 3-dioxolan-2-yl) pyrimidine as a reference).

Example 52 Synthesis of- ((pyridin-2-ylamino) (pyrimidin-5-yl) methoxy) ethanol

To a 500ml four-necked flask equipped with a mechanical stirrer, a thermometer and a condenser tube, 0.1mol of 5- (1, 3-dioxolan-2-yl) pyrimidine, 0.1mol of 2-aminopyridine, 100g of dichloroethane, and room temperature were added for reaction for 10 hours, and after passing the liquid phase detection, 2- ((pyridin-2-ylamino) (pyrimidin-5-yl) methoxy) ethanol was recovered by distillation under reduced pressure, and the purity was 90% and the yield was 95% (based on 5- (1, 3-dioxolan-2-yl) pyrimidine).

EXAMPLE 6 Synthesis of N- ((pyrimidin-5-yl) methyl) pyridin-2-amino group

To a four-necked flask equipped with a mechanical stirrer, a thermometer and a condenser, 0.1mol of 2- ((pyridin-2-ylamino) (pyrimidin-5-yl) methoxy) ethanol, 0.1mol of sodium borohydride, 100g of methanol and room temperature reaction were added, after passing the liquid phase detection, the methanol was recovered by distillation under reduced pressure to obtain N- ((pyrimidin-5-yl) methyl) pyridin-2-amino with a purity of 95% and a yield of 95% (calculated on the basis of 2- ((pyridin-2-ylamino) (pyrimidin-5-yl) methoxy) ethanol).

EXAMPLE 7 Synthesis of N- ((4-chloropyrimidin-5-yl) methylene) pyridin-2-amino group

To a 500ml four-necked flask equipped with a mechanical stirrer, a thermometer and a condenser tube, 0.1mol of 4-chloro-5-formylpyrimidine, 0.1mol of 2-aminopyridine, 100g of dichloroethane, and after reaction at room temperature for 10 hours and passing the liquid phase detection, recovery of dichloroethane by distillation under reduced pressure, N- ((4-chloropyrimidin-5-yl) methylene) pyridin-2-amino purity was 90% and yield was 95% (based on 4-chloro-5-formylpyrimidine).

EXAMPLE 8 Synthesis of N- (4-chloropyrimidin-5-yl) methyl) pyridin-2-amino group

Adding 0.1mol of 4-chloro-5-formylpyrimidine, 0.1mol of 2-aminopyridine and 100g of dichloroethane into a 500ml four-necked flask equipped with a mechanical stirring, a thermometer and a condenser tube, reacting at room temperature for 5 hours, recovering dichloroethane by reduced pressure distillation after passing liquid phase detection, continuously adding 100g of methanol, adding 0.1mol of sodium borohydride in batches, reacting at room temperature for 10 hours, recovering methanol by reduced pressure distillation after passing liquid phase detection, and obtaining ((4-chloropyrimidin-5-yl) methyl) pyridine-2-amino with purity of 91% and yield of 90% (calculated by taking 4-chloro-5-formylpyrimidine as a reference)

EXAMPLE 9 Synthesis of N- ((pyrimidin-5-yl) methyl) pyridin-2-amino group

In a 500ml autoclave, 0.1mo of N- (4-chloropyrimidin-5-yl) methyl) pyridin-2-amino, 0.001mol of 5% Pd/C,100g of methanol and nitrogen are added for three times, hydrogen is flushed, the pressure is kept at 2MPa, the reaction is carried out for 3 hours at 40-60 ℃, after the liquid phase detection is qualified, the temperature is reduced to room temperature, the catalyst is filtered and removed for application, and after methanol is recovered by reduced pressure distillation, N- ((pyrimidin-5-yl) methyl) pyridin-2-amino is obtained with the purity of 90 percent and the yield of 90 percent (calculated by taking N- (4-chloropyrimidin-5-yl) methyl) pyridin-2-amino as a reference.

EXAMPLE 10 Synthesis of N- ((pyrimidin-5-yl) methyl) pyridin-2-amino group

In a four-mouth bottle with mechanical stirring, a thermometer and a condenser, 0.1mol of 4-chloro-5-formylpyrimidine, 0.1mol of 2-aminopyridine, 100g of dichloroethane and 5h of reaction at room temperature are added, after the liquid phase detection is qualified, the dichloroethane is recovered by reduced pressure distillation, the product is transferred into a 500ml autoclave and 100g of methanol is added, 0.001mol of Pd/C nitrogen is replaced for 3 times, hydrogen is filled, the pressure is kept at 2MPa and 20-30 ℃ for reaction for 5h, after the liquid phase detection is qualified, the temperature is reduced to the room temperature, the catalyst is removed by filtration, and after the methanol is recovered by reduced pressure distillation, the N- (pyrimidine-5-yl) methyl) pyridine-2-amino is obtained, the purity is 91%, and the yield is 90% (calculated based on 4-chloro-5-formylpyrimidine).

EXAMPLE 11 Synthesis of 4-hydroxypyrimidine

Unlike example 1, triethyl orthoformate was used instead of trimethyl orthoformate, and the other conditions were unchanged, 4-hydroxypyrimidine was obtained in a purity of 97% and a yield of 88% (calculated on the basis of methyl methoxyacrylate).

EXAMPLE 12 Synthesis of 4-chloro-5- (1, 3-dioxolan-2-yl) pyrimidine

In contrast to example 3, the catalyst replaced p-toluenesulfonic acid with trifluoromethanesulfonic acid, and the other conditions were unchanged, the purity of 4-chloro-5- (1, 3-dioxolan-2-yl) pyrimidine was 97% and the yield was 90% (calculated on the basis of 4-chloro-5-formyl pyrimidine).

EXAMPLE 13 Synthesis of 5- (1, 3-dioxolan-2-yl) pyrimidine

Unlike example 4, when 5% Pd/C was used instead of 10% Pd/C, the purity of 5- (1, 3-dioxolan-2-yl) pyrimidine was 85% and the yield was 80% (based on 4-chloro-5- (1, 3-dioxolan-2-yl) pyrimidine) was obtained under the same conditions.

Example 145 Synthesis of- (1, 3-Dioxolan-2-yl) pyrimidine

In contrast to example 4, 0.1mol of sodium hydroxide, an inorganic base, was added, and the other conditions were unchanged, to give 5- (1, 3-dioxolan-2-yl) pyrimidine having a purity of 84.5% and a yield of 80% (based on 4-chloro-5- (1, 3-dioxolan-2-yl) pyrimidine).

Example 155 Synthesis of- (1, 3-Dioxolan-2-yl) pyrimidine

In contrast to example 4, 0.1mol of triethylamine as an organic base was added thereto, and the other conditions were unchanged, whereby 5- (1, 3-dioxolan-2-yl) pyrimidine was obtained in a purity of 84% and a yield of 80% (based on 4-chloro-5- (1, 3-dioxolan-2-yl) pyrimidine).

EXAMPLE 16 Synthesis of N- ((pyrimidin-5-yl) methyl) pyridin-2-amino group

Unlike example 6, when the reaction temperature was increased from room temperature to 35℃and the other conditions were unchanged, N- ((pyrimidin-5-yl) methyl) pyridin-2-amino was obtained in a purity of 90% and in a yield of 90% (calculated on the basis of 2- ((pyridin-2-ylamino) (pyrimidin-5-yl) methoxy) ethanol).

EXAMPLE 17 Synthesis of N- ((4-chloropyrimidin-5-yl) methylene) pyridin-2-amino group

Unlike example 7, 0.12mol of 2-aminopyridine was substituted for 0.1mol of 2-aminopyridine, and N- ((4-chloropyrimidin-5-yl) methylene) pyridin-2-amino was obtained in a purity of 90% and a yield of 94.5% (based on 4-chloro-5-formyl pyrimidine) was obtained under otherwise unchanged conditions.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims

1. A process for the preparation of a compound of formula II comprising the steps of:

RC (OEt) ₃, where R is H or C ₁-C₆ alkyl.

2. The process according to claim 1, wherein the ammonia gas in step (1) is pure NH ₃, either liquid or gaseous, or NH ₃ dissolved in an organic solvent selected from the group consisting of alcohol solvents, halogenated alkane solvents, aromatic solvents, preferably alcohol solvents, most preferably one of methanol, ethanol and propanol.

3. The method according to claim 1 or 2, wherein the molar ratio of methyl methacrylate, orthoformate and ammonia gas in step (1) is: 1 (1-2): 1-5, preferably 1 (1-1.5): 1-2; the orthoformate is selected from one of methyl orthoformate and ethyl orthoformate, and isopropyl orthoformate; the reaction temperature in the step (1) is 25-50 ℃, preferably 30-40 ℃ and the reaction time is 1-10, preferably 2-5h.

4. The process according to claim 3, wherein the Vilsmeier reagent in step (2) is prepared from a formylating reagent selected from one of DMF, N, N-diethylformamide, N-methyl-N-ethylformamide and an acid halide; the acid halide is selected from one of phosphorus oxychloride, phosphorus oxybromide, thionyl chloride, oxalyl chloride, gas phosgene or solid phosgene.

5. A process for preparing a compound of formula VI comprising the steps of:

wherein R is H or C ₁-C₆ alkyl.

6. The process of claim 5, wherein in step one) the compound of formula II is reacted with ethylene glycol in the presence of a catalyst to form a compound of formula III, wherein the catalyst is an acidic catalyst selected from one of p-toluenesulfonic acid, pyridinium p-toluenesulfonate, benzenesulfonic acid, trifluoromethanesulfonic acid, methanesulfonic acid, sulfuric acid, and hydrogen chloride, more preferably one of p-toluenesulfonic acid, pyridinium p-toluenesulfonate, benzenesulfonic acid, trifluoromethanesulfonic acid, and methanesulfonic acid, and the molar ratio of the compound of formula II to the catalyst is 1: 0.005-2.50, preferably 1:0.01-2.20; most preferably 1:0.05-1.0.

7. The process of claim 6, wherein the molar ratio of the compound of formula II to ethylene glycol is 1:1-2, preferably 1:1-1.5, the reaction of the compound of formula II with ethylene glycol is carried out in a solvent which is a benzene-based solvent, preferably toluene and xylene, at a temperature of 100-150 ℃, preferably 100-110 ℃.

8. The process of claim 5, wherein in step two), the compound of formula III is hydrogenated with hydrogen in the presence of a catalyst selected from the group consisting of nickel and Pd/C, preferably 1% to 20% Pd/C, more preferably 5% Pd/C, 10% Pd/C, 15% Pd/C and 20% Pd/C to produce the compound of formula IV; the hydrogenation reaction is carried out in a solvent, wherein the solvent is one or more of an alcohol solvent, a benzene solvent and a hydrocarbon solvent, the alcohol solvent is preferably methanol and ethanol, and the benzene solvent is preferably toluene and xylene; the hydrocarbon solvent is preferably pentane or hexane, more preferably one of methanol and toluene.

9. The preparation method according to claim 8, wherein a base can be added in the hydrogenation reaction and reduction process, the base is an inorganic base or an organic base, the inorganic base is preferably one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, the organic base is preferably one of methylamine, dimethylamine, triethylamine, isopropylamine and pyridine, and the reaction temperature is 20-80 ℃, preferably 40-60 ℃.

10. The method according to claim 5, wherein the compound of formula IV is reacted with 2-aminopyridine to form the compound of formula V in a solvent, wherein the solvent is a halogenated alkane, and the halogenated alkane is one of dichloromethane, chloroform, and dichloroethane; the reaction temperature is 10-50 ℃.

11. The process of claim 5, wherein in step four) the compound of formula V is reacted in the presence of a reducing agent to form a compound of formula VI, wherein the reducing agent comprises a metal reducing agent selected from one of sodium borohydride and potassium borohydride and hydrogen, and wherein the molar ratio of the compound of formula V to the reducing agent is 1:1-5, preferably 1:1 to 1.5; the reaction is carried out in an organic solvent, wherein the organic solvent is one of tetrahydrofuran, methyltetrahydrofuran, ethylene glycol and methanol, and preferably methanol, tetrahydrofuran and methyltetrahydrofuran; the reaction temperature of the reaction is 0 to 50 ℃, preferably 15 to 30 ℃.

12. A process for preparing a compound of formula VI comprising the steps of:

Wherein the structures of formula II, formula VI and formula VII are as follows

Wherein R is H or C ₁-C₆ alkyl.

13. The preparation method according to claim 12, wherein the compound of formula II in step a is reacted with aminopyridine to obtain a compound of formula VII, the reaction is performed in a solvent, the solvent is halogenated alkane, and the halogenated alkane is one of dichloromethane, chloroform and dichloroethane; the molar ratio of the compound of formula II to 2-aminopyridine is 1:1-2, preferably 1:1-1.3.

14. The process of claim 13, wherein step b comprises preparing the compound of formula VI with a metal reducing agent or hydrogen, wherein the metal reducing agent comprises sodium borohydride, potassium borohydride.

15. The process of claim 14, wherein the molar ratio of compound of formula VII to metal reducing agent is 1:1-1.5, preferably 1:1-1.2.

16. The process according to claim 15, wherein the product of the reduction of the compound of formula VII with the metal reducing agent is dechlorinated under hydrogen to form the compound of formula VI, and the dechlorination hydrogenation is carried out in the presence of a catalyst which is nickel, pd/C, wherein Pd/C is preferably 1-20% Pd/C, more preferably 5% Pd/C, 10% Pd/C.

17. The process of claim 14, wherein the compound of formula VII is reacted directly with hydrogen to form the compound of formula VI, wherein the formula VII and hydrogen are reduced in the presence of a catalyst which is nickel, pd/C, wherein Pd/C is preferably 1-20% Pd/C, more preferably 5% Pd/C; the catalyst is used in an amount of 0.01 to 0.03mol, preferably 0.01 to 0.02mol, relative to 1mol of the compound of formula VII; the hydrogenation reaction temperature is 10-50 ℃, preferably 10-20 ℃.