阅读说明：本技术 一种亚精胺的制备方法 (Preparation method of spermidine ) 是由 姜珍华 黄陈赛 邵昌尧 吴�荣 章明 许传昊 司洪福 许延想 周法政 闫浩磊 于 2021-11-08 设计创作，主要内容包括：本发明涉及有化合物制备技术领域,尤其是一种亚精胺的制备方法,包括如下步骤：S1、以4-二甲氨基吡啶为催化剂,2-吡咯烷酮和二碳酸二叔丁酯在有机溶剂中反应,得到1-(叔丁氧基羰基)-2-吡咯烷酮；S2、将所得的1-(叔丁氧基羰基)-2-吡咯烷酮溶于溶剂中,加入至1,3-丙二胺溶液中,搅拌反应至反应结束,经后处理后得到[3-(3-氨基-丙氨甲酰基)丙基]-氨基甲酸叔丁酯；S3、溶于溶剂中,经还原剂还原,再经后处理得到[4-(3-氨基-丙氨基)丁基]-氨基甲酸叔丁酯；S4、溶于溶剂,滴入盐酸反应脱保护基,反应后,进一步处理得到亚精胺。本发明使用原料吡咯烷酮、1,3-丙二胺等均为常见化工原料,成本较低、反应条件相对温和,反应中安全隐患较低。(The invention relates to the technical field of compound preparation, in particular to a preparation method of spermidine, which comprises the following steps: s1, reacting 2-pyrrolidone and di-tert-butyl dicarbonate in an organic solvent by taking 4-dimethylaminopyridine as a catalyst to obtain 1- (tert-butoxycarbonyl) -2-pyrrolidone; s2, dissolving the obtained 1- (tert-butoxycarbonyl) -2-pyrrolidone in a solvent, adding the solution into a 1, 3-propanediamine solution, stirring for reaction until the reaction is finished, and carrying out post-treatment to obtain [3- (3-amino-propylcarbamoyl) propyl ] -carbamic acid tert-butyl ester; s3, dissolving in a solvent, reducing by a reducing agent, and carrying out post-treatment to obtain [4- (3-amino-propylamino) butyl ] -tert-butyl carbamate; s4, dissolving in a solvent, dripping hydrochloric acid to react and remove a protecting group, and further processing after the reaction to obtain spermidine. The raw materials of pyrrolidone, 1, 3-propane diamine and the like used in the invention are common chemical raw materials, the cost is low, the reaction condition is relatively mild, and the potential safety hazard in the reaction is low.)

1. A method for preparing spermidine, which is characterized by comprising the following steps: the method comprises the following steps:

s1, reacting 2-pyrrolidone and di-tert-butyl dicarbonate in an organic solvent by taking 4-dimethylaminopyridine as a catalyst, and processing to obtain 1- (tert-butoxycarbonyl) -2-pyrrolidone after the reaction is finished;

s2, dissolving the obtained 1- (tert-butoxycarbonyl) -2-pyrrolidone in a solvent, adding the solution into a 1, 3-propanediamine solution, stirring to react until the reaction is finished, and carrying out post-treatment to obtain [3- (3-amino-propylcarbamoyl) propyl ] -carbamic acid tert-butyl ester;

s3 and [3- (3-amino-propylamino) propyl ] -tert-butyl carbamate are dissolved in a solvent, reduced by a reducing agent and subjected to post-treatment to obtain [4- (3-amino-propylamino) butyl ] -tert-butyl carbamate;

s4 and [4- (3-amino-propylamino) butyl ] -tert-butyl carbamate are dissolved in an organic solvent, hydrochloric acid is dripped in to react to remove a protecting group, the pH value is adjusted by alkali after the reaction is finished, the reaction product is further processed to obtain the non-purified spermidine, and the pure spermidine product is further obtained by reduced pressure rectification.

2. The method for producing spermidine according to claim 1, wherein: in the step S1, the organic solvent is one or more of methyl tert-butyl ether, tetrahydrofuran, and acetonitrile.

3. The method for producing spermidine according to claim 1, wherein: in the step S1, the molar ratio of the catalyst 4-dimethylaminopyridine to the pyrrolidone is 1: 5 to 1: 20.

4. the method for producing spermidine according to claim 1, wherein: in the step S1, the molar ratio of the 2-pyrrolidone to the di-tert-butyl dicarbonate is 5: 5 to 5: 6.

5. the method for producing spermidine according to claim 1, wherein:

in the step S2, the solvent is one or more of tetrahydrofuran, acetonitrile, n-heptane, n-hexane, and petroleum ether.

6. The method for producing spermidine according to claim 1, wherein: in the step S2, the molar ratio of 1- (tert-butoxycarbonyl) -2-pyrrolidone to 1, 3-propanediamine is 5: 6 to 5: 10.

7. the method for producing spermidine according to claim 1, wherein: in the above step S3, at least any one of the following is satisfied:

the solvent is tetrahydrofuran or toluene;

the reducing agent is any one of borane tetrahydrofuran, borane dimethylsulfide complex, a combination of Lewis acid and sodium borohydride and red aluminum, wherein the Lewis acid comprises any one of boron trifluoride, zinc chloride, aluminum chloride and magnesium chloride.

8. The method for producing spermidine according to claim 1, wherein: in the above step S3, the molar ratio of [3- (3-amino-propylcarbamoyl) propyl ] -carbamic acid tert-butyl ester to the reducing agent is 10: 11 to 10: 25.

9. the method for producing spermidine according to claim 1, wherein: in the above step S4, at least any one of the following is satisfied:

the organic solvent is methanol or ethanol;

in the step of adjusting the pH by using the alkali, the alkali for adjusting the pH is selected from one of sodium hydroxide, potassium carbonate and strong-base anion exchange resin.

Technical Field

The invention relates to the field of organic chemical synthesis, in particular to a method for realizing industrial production and purification and industrial production of high-purity spermidine under low-cost and mild reaction conditions, and especially relates to a preparation method of spermidine.

Background

Spermidine is a polyamine that is widely distributed in the body and can inhibit neuronal NO synthase, bind and precipitate DNA, and can also be used to purify DNA binding proteins and stimulate the activity of T4 polynucleotide kinase. It is involved in many biological processes in the body, such as regulation of cell proliferation, cell aging, organ development, immunity, and cancer.

The cooperation of scientists in germany and austria on 1/9 in 2013 indicates that spermidine can prevent the onset of senile dementia. Spermidine can be obtained by chemical synthesis methods other than extraction from wheat germ, but the chemical synthesis methods in the prior art have many problems.

For example: the application number of the plake pharmaceutical science and technology limited company in Tianjin in 2012 is CN201210138708.4, the patent name is: the invention discloses a method for synthesizing spermidine, which comprises the steps of preparing spermidine by using benzyloxycarbonyl as a protecting group, wherein the total reaction is 5 steps, firstly preparing 1, 4-butanediamine protected by benzyloxycarbonyl, then carrying out addition reaction on the butanediamine and acrylonitrile, finally reducing cyano groups in addition products, and removing the benzyloxycarbonyl protection to obtain the spermidine, wherein the total yield is 30%, and the product purity is 99.5%. The method uses Raney nickel and expensive palladium carbon to carry out high-pressure hydrogenation reduction in the last two steps, requires special equipment under reaction conditions, has high production cost, and has the following specific reaction formula:

。

the following steps are repeated: the patent application number applied in 2018 by Sichuan university is CN201810833825.X, and the patent name is: the invention of the process for the preparation of spermidine also provides in the patent application a process for the preparation of spermidine comprising the following steps: a. reacting compound I amino propanol and butyrolactone serving as raw materials in a solvent; b. compound (I)Reducing with lithium aluminum hydride to obtain the compound(ii) a c. Compound (I)Adding alkali and di-tert-butyl dicarbonate to react to protect hydroxyl to obtain the compound(ii) a d. Compound (I)Adding ligand and phthalimide to react to obtain a compound(ii) a e. Dissolving the compound V in a solvent, adding hydrazine hydrate for reaction, obtaining a compound VI after the reaction is finished, and further rectifying the compound VI to obtain a pure spermidine productThe total yield is 35%, and the product purity is 98%. According to analysis, the method takes aminopropanol and butyrolactone as raw materials to react, and then the spermidine is obtained through the steps of reduction, amino protection and the like. The method has five steps, and a dangerous reagent lithium aluminum hydride is used in the step of reducing the amide, so that the scale-up production is difficult; in addition, the phthalimide is removed by hydrazine hydrate after the amino group is introduced, the reaction is safe and has high risk, the raw materials such as aminopropanol and the like are expensive, the overall cost is high, and the specific reaction formula is as follows:

。

of course, the conventional methods for producing spermidine are not limited to the above two methods, but the conventional methods for producing spermidine generally have problems such as high raw material cost, severe reaction conditions, and potential safety hazard.

Therefore, there is a need to provide a new method for preparing spermidine by a convenient and low-cost route, so as to better solve the problems of the prior art.

Disclosure of Invention

In order to solve one of the above problems, the present invention aims to: provides a technical scheme for solving the problems of purification of the industrial production of the high-purity spermidine and realization of the industrial production after easy amplification by using easily available raw materials, lower cost and mild reaction conditions.

In order to realize the purpose of the invention, the specific technical scheme adopted is as follows: a method for preparing spermidine with molecular formula C₇H₁₉N₃The chemical structural formula is as follows:the method comprises the following steps:

s1, taking 4-dimethylamino pyridine (DMAP) as a catalyst, reacting pyrrolidone (a) and di-tert-butyl dicarbonate in an organic solvent, desolventizing after complete reaction, and carrying out aftertreatment to obtain a compound b, wherein the specific reaction formula is as follows:；

s2, stirring the compound b and 1, 3-propane diamine in an organic solvent to react until the reaction is finished, extracting by weak acid aqueous solution, washing impurities by the organic solvent, adjusting pH by alkali, adding salting out, extracting the product by the organic solvent, and removing the solvent under reduced pressure to obtain a compound c, wherein the specific reaction formula is as follows:；

s3, dissolving the compound c in an organic solvent, reducing by a reducing agent, and carrying out post-treatment steps such as quenching, washing and the like to obtain a compound d, wherein the specific reaction formula is as follows:；

s4, dissolving the compound d in a solvent, carrying out acid catalysis, carrying out reaction to remove a protecting group, adjusting the pH value by alkali after the reaction is finished, further processing to obtain an unpurified compound e, and further carrying out vacuum rectification to obtain a pure spermidine product, wherein the specific reaction formula is as follows:。

in any of the above embodiments, preferably, in step S1, the organic solvent used in the reaction step may be a single organic solvent or a mixed solvent, such as acetonitrile, tetrahydrofuran, or methyl tert-butyl ether; further, if a water-immiscible solvent such as methyl t-butyl ether is used, it can be directly subjected to the post-treatment water-washing step without being subjected to desolventizing under reduced pressure.

In any of the above schemes, it is preferable that in the above step S1, the reaction temperature is comprised between 10 ℃ and 20 ℃ or between 20 ℃ and 30 ℃ and the reaction time is comprised between 2 hours and 10 hours.

In any of the above embodiments, preferably, in step S1, the post-treatment method includes washing with a weak acid aqueous solution, washing with a weak base aqueous solution, and desolventizing under reduced pressure to dryness, wherein the weak acid includes citric acid and ammonium chloride; the weak base includes sodium bicarbonate, sodium carbonate, and potassium bicarbonate.

In any of the above embodiments, preferably, in step S1, the molar ratio of the catalyst 4-Dimethylaminopyridine (DMAP) to the pyrrolidone is 1: 5 to 1: 20.

in any of the above embodiments, preferably, in step S1, the molar ratio of 2-pyrrolidone to di-tert-butyl dicarbonate is 5: 5 to 5: 6.

in any of the above embodiments, preferably, in step S2, the solvent is one or more of tetrahydrofuran, acetonitrile, n-heptane, n-hexane, and petroleum ether.

In any of the above embodiments, it is preferable that in step S2, the molar ratio of compound b, 1- (tert-butoxycarbonyl) -2-pyrrolidone to 1, 2-propanediamine, is 5: 6 to 5: 10.

in any of the above schemes, preferably, in step S2, the organic solvent used in the reaction step includes acetonitrile, tetrahydrofuran, n-heptane, n-hexane, and petroleum ether, the organic solvent used for impurity washing includes dichloromethane, ethyl acetate, isopropyl acetate, and the like, and the organic solvent used for product extraction includes 2-methyltetrahydrofuran, dichloromethane, and n-butanol.

In any of the above embodiments, it is preferable that, in step S2, the weak acid aqueous solution includes an aqueous solution of citric acid and an aqueous solution of ammonium chloride.

In any of the above embodiments, it is preferable that at least any one of the following is satisfied in step S3: the solvent is tetrahydrofuran or toluene; the reducing agent is any one of borane tetrahydrofuran, borane dimethylsulfide complex, a combination of Lewis acid and sodium borohydride and red aluminum, wherein the Lewis acid comprises any one of boron trifluoride, zinc chloride, aluminum chloride and magnesium chloride.

In any of the above embodiments, it is preferable that in the step S3, the molar ratio of the compound c to the reducing agent is 10: 11 to 10: 25.

in any of the above embodiments, it is preferable that at least any one of the following is satisfied in step S4: the organic solvent is methanol or ethanol or a mixed solvent formed by mixing the methanol and the ethanol; in the step of adjusting the pH by using the alkali, the alkali for adjusting the pH is selected from one of sodium hydroxide, potassium carbonate and strong-base anion exchange resin.

In any of the above embodiments, preferably, in step S4, the acid includes hydrochloric acid and trifluoroacetic acid.

In any of the above embodiments, preferably, in step S4, the further treatment is performed by desolventizing, filtering or resin adsorption to remove salt, and then desolventizing.

In any of the above schemes, it is preferable that in the above step S4, the vacuum distillation conditions are such that the distillation external temperature is strictly controlled at 142 ℃, and the fraction of 124 ℃ to 126 ℃ is collected under a vacuum of 12 mmHg.

Compared with the prior art, the invention has the following beneficial effects: 1. the raw materials used in the invention, such as pyrrolidone, 1, 3-propane diamine and the like, are common chemical raw materials, and are cheap and easily available;

the chemical raw materials have low cost, the reaction conditions are relatively mild, and the potential safety hazard in the whole reaction is low.

2. The reaction yield is ideal by the protection of tert-butyloxycarbonyl in S1, and can reach 94.2-98.8%.

3. In S2, excess 1, 3-propane diamine ring-opening pyrrolidone is carried out to obtain a compound c with a main chain structure of spermidine, the product is easily soluble in water under a weak acid condition, small polar impurities can be removed in a mode of washing and separating liquid by an organic solvent, the solubility of the compound c in water is reduced in a salting-out mode after pH is further adjusted, most propane diamine is removed by reduced pressure distillation after extraction by the organic solvent, the purification method is simple and effective, and the single-step yield range is 62.2-73.2%.

4. Reduction of the amide in the presence of a reducing agent in S3 affords the mono-Boc protected spermidine.

5. And (3) removing a tert-butyloxycarbonyl protecting group through acid catalysis in S4, and rectifying to obtain a spermidine product.

6. The combination yield range of the products prepared by the method reaches 62.1-79.5%, and the purity of the finished product spermidine can reach 99.6%.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.

When the method disclosed by the invention is used for realizing the preparation of spermidine, the synthetic route of spermidine is as follows:

。

example 1:

s1, synthesizing a compound b of the formula: 1- (tert-butoxycarbonyl) -2-pyrrolidone having the formula: c₉H₁₅NO₃185.22, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: adding pyrrolidone (255.1 g, 3.0mol, 1.0 eq) and acetonitrile (2.0L, 4-dimethylamino pyridine (18.3 g, 0.15mol, 0.05 eq) into a 3L reaction bottle, dropwise adding di-tert-butyl dicarbonate (654.7 g, 3.0mol, 1.0 eq) into a water bath, reacting for 5 hours at 20-30 ℃, concentrating to dry under reduced pressure at 40 ℃, adding 1175g of methyl tert-butyl ether for dissolving, washing with 137g of citric acid/1400 mL of aqueous solution, 40g of sodium bicarbonate/600 mL of aqueous solution and 40g of sodium chloride/600 mL of aqueous solution, removing the solvent from an organic phase, and obtaining 529.5g of a light yellow oily compound b after aftertreatment and purification, wherein the yield is 95.3%;

s2, synthesizing a compound c of the formula: [3- (3-amino-propylcarbamoyl) propyl group]-tert-butyl carbamate of formula: c₁₂H₂₅N₃O₃259.35, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: mixing 1, 3-propanediamine (80.0 g, 1.08 mol), compound b (100 g, 0.54 mol) and 400mL of acetonitrile, stirring at 20-25 ℃ for 24h, removing the solvent and the excess 1, 3-propanediamine under reduced pressure, adding the remaining system into 400mL of water, adjusting the pH to 5 with citric acid, extracting with dichloromethane M100 mL for 4 times, adding 60g of sodium chloride into the water layer, adjusting the pH to 10 with 30% aqueous solution of sodium hydroxide, extracting the aqueous phase with 150mL of 2-methyltetrahydrofuran 2, removing the solvent to obtain 102.5g of yellow oily matter (compound c) with the yield of 73.2%;

s3, synthesizing a compound d of the formula: [4- (3-amino-propylamino) butyl group]-tert-butyl carbamate of formula: c₁₂H₂₇N₃O₂245.36, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: dissolving a compound c (78 g, 0.3 mol) in 1000mL of tetrahydrofuran, under the protection of nitrogen, dropwise adding a 50% borane tetrahydrofuran solution (168 g, 0.6 mol) at 0 +/-5 ℃ under an ice bath, heating to 30 ℃, preserving heat for 16h, dropwise adding methanol 600mL under the ice bath for quenching reaction, and concentrating in a water bath at 45 ℃ under reduced pressure to obtain a compound d;

s4, synthesizing a compound e of the formula: n- (3-aminopropyl) -1, 4-butanediamine, spermidine, has the formula: c₇H₁₉N₃145.25, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: dissolving the compound d (0.3 mol) in the last step in 450mL of methanol, dripping hydrochloric acid (250 mL, 3 mol) into an ice-water bath, stirring for 4h, and reducingRemoving methanol under pressure, adjusting the pH value to be =12 by using 40% sodium hydroxide aqueous solution, removing dryness under reduced pressure, adding 300mL of tetrahydrofuran for extraction, filtering, concentrating the filtrate to be dry, further rectifying under reduced pressure, and collecting fractions at 124-126 ℃ under the vacuum of 12mmHg to obtain a compound e, namely 34.6g of spermidine, wherein the yield is 79.5% and the gas phase purity is 99.5%.

Example 2:

s1, synthesizing a compound b of the formula: 1- (tert-butoxycarbonyl) -2-pyrrolidone having the formula: c₉H₁₅NO₃185.22, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: adding pyrrolidone (255.1 g, 3.0mol, 1.0 eq) and tetrahydrofuran (1.8L, 4-dimethylamino pyridine (18.3 g, 0.15mol, 0.05 eq) into a 3L reaction bottle, dropwise adding di-tert-butyl dicarbonate (720.2 g, 3.3mol, 1.1 eq) into a water bath, reacting for 5 hours at 20-30 ℃, concentrating under reduced pressure at 40 ℃ until the solution is dried, adding 1175g of methyl tert-butyl ether for dissolving, washing with 137g of citric acid/1400 mL of aqueous solution, 40g of sodium bicarbonate/600 mL of aqueous solution and 40g of sodium chloride/600 mL of aqueous solution, removing the solvent from the organic phase, and obtaining 533.9g of a light yellow oily compound b after aftertreatment and purification, wherein the yield is 96.1%;

s2, synthesizing a compound c of the formula: [3- (3-amino-propylcarbamoyl) propyl group]-tert-butyl carbamate of formula: c₁₂H₂₅N₃O₃259.35, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: mixing 1, 3-propanediamine (60.0 g, 0.81mol, 1.5 eq), compound b (100 g, 0.54mol, 1.0 eq) and 700mL of n-heptane, stirring at 20-25 ℃ for 30h, removing the solvent and excess 1, 3-propanediamine under reduced pressure, adding the rest system into 400mL of water, adjusting pH to =5 with citric acid, extracting for 3 times with 100mL of ethyl acetate, adding 60g of sodium chloride into the water layer, adjusting pH to =10 with 30% aqueous solution of sodium hydroxide, extracting the water phase with 150mL of 2-methyltetrahydrofuran 2, removing the solvent to obtain yellow oily liquid95.2g of substance (compound c), yield 68.0%;

s3, synthesizing a compound d of the formula: [4- (3-amino-propylamino) butyl group]-tert-butyl carbamate of formula: c₁₂H₂₇N₃O₂245.36, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: dissolving a compound c (78 g, 0.3 mol) in 1000mL of tetrahydrofuran, under the protection of nitrogen, dropwise adding 10N borane dimethyl sulfide complex (60 mL, 0.6 mol) at the temperature of 0 +/-5 ℃ under ice bath, naturally raising the temperature to 30 ℃, preserving the temperature for 16h, dropwise adding methanol 600mL under ice bath for quenching reaction, and carrying out water bath decompression concentration at 45 ℃ until the mixture is dried to obtain a compound d;

s4, synthesizing a compound e of the formula: n- (3-aminopropyl) -1, 4-butanediamine, spermidine, has the formula: c₇H₁₉N₃145.25, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: dissolving the compound D (0.3 mol) in the last step in 450mL of methanol, dripping hydrochloric acid (250 mL, 3 mol) into an ice water bath, stirring for 4 hours, evaporating to dryness under reduced pressure, adding 300 g of purified water, eluting by a D201 strongly basic anion resin column, concentrating to dryness under reduced pressure at 60 ℃, eluting a product with tetrahydrofuran, filtering, precipitating the filtrate under reduced pressure, rectifying the residue, collecting fractions at 124-126 ℃ under vacuum of 12mmHg, and obtaining 32.8g of spermidine, wherein the yield is 75.5%, and the gas phase purity is 99.6%.

Example 3:

s1, synthesizing a compound b of the formula: 1- (tert-butoxycarbonyl) -2-pyrrolidone having the formula: c₉H₁₅NO₃185.22, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: pyrrolidone (255.1 g, 3.0mol, 1.0 eq), methyl tert-butyl ether 2.0L, 4-dimethyl ammoniaAdding pyridine (36.65 g, 0.3mol, 0.1 eq) into a 3L reaction bottle, dropwise adding di-tert-butyl dicarbonate (720.2 g, 3.3mol, 1.1 eq) into a water bath, reacting for 3h at 20-30 ℃, adding 250g of ammonium chloride/1400 mL of aqueous solution and 40g of sodium bicarbonate/600 mL of aqueous solution, removing a solvent from an organic phase, and purifying to obtain 523.4g of a light yellow oily compound b after aftertreatment, wherein the yield is 94.2%;

s2, synthesizing a compound c of the formula: [3- (3-amino-propylcarbamoyl) propyl group]-tert-butyl carbamate of formula: c₁₂H₂₅N₃O₃259.35, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: mixing 1, 3-propanediamine (80.0 g, 1.08mol, 2.0 eq), compound b (100 g, 0.54mol, 1.0 eq) and 400mL of tetrahydrofuran, stirring at room temperature for 30h, removing the solvent and excess 1, 3-propanediamine under reduced pressure, adding the remaining system to 400mL of water, adjusting pH to =5 with citric acid, extracting 4 times with 100mL of dichloromethane, adding 60g of sodium chloride to the aqueous layer, adjusting pH to =10 with 30% aqueous sodium hydroxide solution, extracting the aqueous phase with 150mL of 2-methyltetrahydrofuran 2, removing the solvent to obtain 91.0g of a yellow oil (compound c) with a yield of 65.0%;

s3, synthesizing a compound d of the formula: [4- (3-amino-propylamino) butyl group]-tert-butyl carbamate of formula: c₁₂H₂₇N₃O₂245.36, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: dissolving a compound c (78 g, 0.3 mol) in 1000mL of tetrahydrofuran, adding sodium borohydride (17.0 g, 0.45 mol) under the protection of nitrogen, controlling the temperature to be 0 +/-5 ℃ in an ice bath, dropwise adding boron trifluoride tetrahydrofuran (168 g, 0.6 mol), continuing to keep the temperature and stirring for 2 hours after adding, heating to 40 ℃, keeping the temperature for 12 hours, dropwise adding methanol 600mL in the ice bath to carry out quenching reaction, and concentrating and drying in 45 ℃ water bath under reduced pressure to obtain a compound d;

s4, synthesizing a compound e of the formula: n- (3-aminopropyl)) -1, 4-butanediamine, spermidine, of formula: c₇H₁₉N₃145.25, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: dissolving the compound d (0.3 mol) in the last step in 450mL of methanol, dripping hydrochloric acid (250 mL and 3 mol) into an ice water bath, stirring for 4 hours, evaporating to dryness under reduced pressure, adjusting the pH to =12 with potassium hydroxide, stirring for 2 hours at 40 ℃, removing the dryness under reduced pressure, adding 300mL of tetrahydrofuran for extraction, filtering, concentrating the filtrate to dryness, rectifying under reduced pressure, collecting 124-126 ℃ fractions under the vacuum of 12mmHg, and obtaining 32.1g of spermidine, wherein the yield is 73.8%, and the gas phase purity is 99.1%.

Example 4:

s1, synthesizing a compound b of the formula: 1- (tert-butoxycarbonyl) -2-pyrrolidone having the formula: c₉H₁₅NO₃185.22, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: adding pyrrolidone (255.1 g, 3.0mol, 1.0 eq), acetonitrile (2.0L, 4-dimethylamino pyridine (73.3 g, 0.6mol, 0.2 eq) into a 3L reaction bottle, dropwise adding di-tert-butyl dicarbonate (654.7 g, 3.0mol, 1.0 eq) into a water bath, reacting for 2 hours at 10-20 ℃, concentrating to dry under reduced pressure at 40 ℃, adding 1175g of methyl tert-butyl ether for dissolving, washing with 137g of citric acid/1400 mL of aqueous solution, 40g of sodium bicarbonate/600 mL of aqueous solution and 40g of sodium chloride/600 mL of aqueous solution, removing the solvent from an organic phase, and obtaining 540.1g of a light yellow oily compound b after aftertreatment and purification, wherein the yield is 97.2%;

s2, synthesizing a compound c of the formula: [3- (3-amino-propylcarbamoyl) propyl group]-tert-butyl carbamate of formula: c₁₂H₂₅N₃O₃259.35, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: mixing 1, 3-propaneDiamine (80.0 g, 1.08mol, 2.0 eq), compound b (100 g, 0.54mol, 1.0 eq) and 500mL of tetrahydrofuran were mixed, stirred at room temperature for 30h, the solvent and excess 1, 3-propanediamine were removed under reduced pressure, the remaining system was added to 400mL of water, pH =5 was adjusted with citric acid, isopropyl acetate was extracted 3 times with 100mL, 60g of sodium chloride was added to the aqueous layer, pH =7 was adjusted with 30% aqueous sodium hydroxide, the aqueous phase was extracted with 150mL of dichloromethane 4, the solvent was removed to give 86.8g of a yellow oil (compound c), yield 62.1%;

s3, synthesizing a compound d of the formula: [4- (3-amino-propylamino) butyl group]-tert-butyl carbamate of formula: c₁₂H₂₇N₃O₂245.36, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: dissolving a compound c (78 g, 0.3 mol) in a mixed solvent of 300mL of toluene and 300mL of tetrahydrofuran, controlling the temperature to be 0 +/-5 ℃ in an ice bath under the protection of nitrogen, dropwise adding 70% of a red aluminum toluene solution (173.3 g, 0.6 mol), continuing to keep the temperature and stirring for 2 hours after the addition is finished, heating to 80 ℃, keeping the temperature for 20 hours, dropwise adding 500mL of a 25% ammonium chloride aqueous solution under the ice bath for quenching reaction, separating liquid after filtering, adding 200mL of methanol after the aqueous phase is decompressed and dried, fully scattering and filtering, and decompressing and drying the filtrate to obtain a compound d;

s4, synthesizing a compound e of the formula: n- (3-aminopropyl) -1, 4-butanediamine, spermidine, has the formula: c₇H₁₉N₃145.25, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: dissolving the compound d (0.3 mol) in the last step in 450mL of methanol, dripping hydrochloric acid (250 mL and 3 mol) into an ice water bath, stirring for 4 hours, evaporating to dryness under reduced pressure, adjusting the pH to 11-12 with potassium carbonate solid, stirring for 2 hours at 40 ℃, removing the dryness under reduced pressure, adding 300mL of tetrahydrofuran for extraction, filtering, concentrating the filtrate to dryness, rectifying under reduced pressure, collecting fractions at 124-126 ℃ under the vacuum of 12mmHg to obtain 29.8g of spermidine, wherein the yield is 69.4%, and the gas phase purity is 98.5%。

Example 5:

s1, synthesizing a compound b of the formula: 1- (tert-butoxycarbonyl) -2-pyrrolidone having the formula: c₉H₁₅NO₃185.22, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: adding pyrrolidone (255.1 g, 3.0mol, 1.0 eq), acetonitrile (2.0L, 4-dimethylamino pyridine (45.81 g, 0.375mol, 0.125 eq) into a 3L reaction bottle, dropwise adding di-tert-butyl dicarbonate (713.6 g, 3.27mol, 1.09 eq) into a water bath, reacting for 2 hours at 10-20 ℃, concentrating under reduced pressure at 40 ℃ to dry, adding 1175g of methyl tert-butyl ether to dissolve, washing with 137g of citric acid/1400 mL of aqueous solution, 40g of sodium bicarbonate/600 mL of aqueous solution and 40g of sodium chloride/600 mL of aqueous solution, removing the solvent from an organic phase, and obtaining 534.5g of a light yellow oily compound b after aftertreatment and purification, wherein the yield is 96.2%;

s2, synthesizing a compound c of the formula: [3- (3-amino-propylcarbamoyl) propyl group]-tert-butyl carbamate of formula: c₁₂H₂₅N₃O₃259.35, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: mixing 1, 3-propanediamine (60.0 g, 0.81mol, 1.5 eq), compound b (100 g, 0.54mol, 1.0 eq) and 500mL of tetrahydrofuran, stirring at room temperature for 30h, removing the solvent and excess 1, 3-propanediamine under reduced pressure, adding the remaining system into 400mL of water, adjusting the pH to =5 with citric acid, extracting 3 times with 100mL of isopropyl acetate, adding 60g of sodium chloride into the aqueous layer, adjusting the pH to =7 with 30% aqueous sodium hydroxide solution, extracting the aqueous phase with 150mL of dichloromethane 4, removing the solvent to obtain 89.9g of yellow oily matter (compound c) with a yield of 64.3%;

s3, synthesizing a compound d of the formula: [4- (3-amino-propylamino) butyl group]-tert-butyl carbamate of formula: c₁₂H₂₇N₃O₂Molecular weight of 245.36, chemistryThe structural formula is as follows:(ii) a The preparation method comprises the following steps: dissolving a compound c (78 g, 0.3 mol) in 1000mL of tetrahydrofuran, under the protection of nitrogen, dropwise adding a 50% borane tetrahydrofuran solution (168 g, 0.6 mol) at 0 +/-5 ℃ under an ice bath, heating to 30 ℃, preserving heat for 16h, dropwise adding methanol 600mL under the ice bath for quenching reaction, and concentrating in a water bath at 45 ℃ under reduced pressure to obtain a compound d;

s4, synthesizing a compound e of the formula: n- (3-aminopropyl) -1, 4-butanediamine, spermidine, has the formula: c₇H₁₉N₃145.25, the molecular weight is as follows:(ii) a The preparation method comprises the following steps: dissolving the compound d (0.3 mol) in the last step in 450mL of methanol, dripping hydrochloric acid (250 mL and 3 mol) into an ice water bath, stirring for 4 hours, evaporating to dryness under reduced pressure, adjusting the pH to be 11-12 by using potassium carbonate solid, stirring for 2 hours at 40 ℃, removing the dryness under reduced pressure, adding 300mL of tetrahydrofuran for extraction, filtering, concentrating the filtrate to dryness, rectifying under reduced pressure, collecting fractions at 124-126 ℃ under the vacuum of 12mmHg, and obtaining 31.1g of spermidine, wherein the yield is 72.4%, and the gas phase purity is 98.9%.

Experimental example:

taking practical application of the above method in preparing spermidine by a new material company as an example, the company records relevant data of products in the preparation process as shown in the following table after preparing spermidine by the above examples respectively (note: step 3 directly participates in the reaction of the next step 4 without purification, so the molar yield of step 3 and step 4 is two combined molar yields).

The patent with the patent application number of CN201210138708.4 has 5 synthesis steps, the total yield is 30 percent, the product purity is 99.5 percent, and multi-step dangerous reaction is involved; the total yield of 5 steps of patent application number CN201810833825.X is 35%, the product purity is 98%, the multiple steps relate to dangerous reaction, and the price of the raw material aminopropanol is high.

In conclusion, raw materials such as pyrrolidone and 1, 3-propane diamine used in the invention are common chemical raw materials, the price is low, the raw materials are easy to obtain, the reaction conditions are relatively mild, and the potential safety hazard in the whole reaction is low; the combined yield of the products prepared by the method reaches 62.1-79.5%, and the purity of the finished product spermidine can reach 99.6%, so that the problems in the prior art can be well solved.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; the modifications or the substitutions do not cause the essence of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of the present invention, and the technical solutions are all covered in the scope of the claims and the specification of the present invention; it will be apparent to those skilled in the art that any alternative modifications or variations to the embodiments of the present invention may be made within the scope of the present invention. The present invention is not described in detail, but is well known to those skilled in the art.