阅读说明：本技术 一种吲哚-3-甲醇的绿色制备工艺 (Environment-friendly preparation process of indole-3-methanol ) 是由 安珂 赵浪 于 2021-11-15 设计创作，主要内容包括：本发明提供一种吲哚-3-甲醇的绿色制备工艺,包括以下步骤：S1、将吲哚分散溶解在DEF中,再加入甲基磺酰氯作为催化剂,加入催化剂时控制温度在30～50℃,然后升温至80～90℃进行反应,反应完成后加水,过滤,得到吲哚-3-甲醛；S2、将S1制备的吲哚-3-甲醛分散溶解在乙醇中,再加入硼氢化钠作为催化剂,然后升温至30～50℃进行反应,反应完成后过滤,滤液浓缩得到吲哚-3-甲醇粗品；S3、将吲哚-3-甲醇粗品用乙醇重结晶,得到含量和纯度均大于99％的吲哚-3-甲醇,收率达到90％以上。该方法具有绿色、环保、成本低、产率高、时间短适用于工业化生产,符合绿色生产工艺。(The invention provides a green preparation process of indole-3-methanol, which comprises the following steps: s1, dispersing and dissolving indole in DEF, adding methylsulfonyl chloride as a catalyst, controlling the temperature at 30-50 ℃ when adding the catalyst, then heating to 80-90 ℃ for reaction, adding water after the reaction is finished, and filtering to obtain indole-3-formaldehyde; s2, dispersing and dissolving the indole-3-formaldehyde prepared in the S1 in ethanol, adding sodium borohydride serving as a catalyst, heating to 30-50 ℃ for reaction, filtering after the reaction is finished, and concentrating the filtrate to obtain a crude indole-3-methanol product; s3, recrystallizing the indole-3-methanol crude product with ethanol to obtain indole-3-methanol with the content and purity both greater than 99%, wherein the yield is more than 90%. The method has the advantages of environmental protection, low cost, high yield, short time, suitability for industrial production and accordance with the green production process.)

1. A green preparation process of indole-3-methanol is characterized by comprising the following steps:

s1, dispersing and dissolving indole in DEF, adding methylsulfonyl chloride as a catalyst, controlling the temperature at 30-50 ℃ when adding the catalyst, then heating to 80-90 ℃ for reaction, adding water after the reaction is finished, and filtering to obtain indole-3-formaldehyde;

s2, dispersing and dissolving the indole-3-formaldehyde prepared in the S1 in ethanol, adding sodium borohydride serving as a catalyst, heating to 30-50 ℃ for reaction, filtering after the reaction is finished, and concentrating the filtrate to obtain a crude indole-3-methanol product;

s3, recrystallizing the indole-3-methanol crude product with ethanol to obtain purified indole-3-methanol.

2. The green process of claim 1, wherein in S1, the mass ratio of indole to DEF to methylsulfonyl chloride is 1: 3-5: 1.1 to 1.5.

3. The green preparation process of indole-3-methanol according to claim 1, wherein the reaction time in S1 is 2-3 h.

4. The green process for preparing indole-3-methanol according to claim 1, wherein S1 further comprises a filtrate treatment step; the specific operation of the filtrate treatment process is as follows:

concentrating the filtrate by stages, collecting DEF for reuse, adding alkali solution into the residual concentrated solution, and neutralizing the hydrogen chloride generated by the reaction.

5. The green preparation process of indole-3-methanol according to claim 1, wherein in S2, the mass ratio of indole-3-carbaldehyde to sodium borohydride is 1: 0.4 to 0.5.

6. The green preparation process of indole-3-methanol according to claim 1, wherein in S2, the mass ratio of indole-3-carbaldehyde to ethanol is 1: 2.

7. The green preparation process of indole-3-methanol according to claim 1, wherein the reaction time in S2 is 2-3 h.

Technical Field

The invention relates to the technical field of organic chemical synthesis, in particular to a green preparation process of indole-3-methanol.

Background

Indole-3-carbinol is one of the simplest natural active alkaloids, and is naturally derived from cruciferous vegetables such as cabbage, cauliflower, cabbage, radish, and the like. The cruciferous vegetables contain rich ghuo active ingredients, and researches show that the cruciferous vegetables have a very good effect on preventing tumors. Epidemiological studies have found that frequent consumption of these vegetables can greatly reduce the risk of esophageal cancer, gastric cancer, lung cancer, uterine cancer, colon cancer, and the like.

At present, the extract of Brassicaceae such as indole-3-methanol has been used as an important food additive for health foods in countries in Europe, America and Japan where health foods are developed. According to statistics, the annual output amount of indole-3-methanol in China is more than 20 tons. At present, the international market price is about 80-100 Meijin/kg, and if the cruciferous vegetables are directly extracted, the cost is too high. Therefore, the establishment of the indole-3-methanol synthesized by common chemical raw materials and having high content, small impurity and no harmful solvent residue has great economic value.

The synthesis of indole-3-methanol is not reported in foreign documents, and according to market research, no factory is used to produce the product in foreign countries. Nearly 80 reports of indole-3-methanol are reported by the Chinese knowledge, but most of them are pharmacological and clinical researches. Only two groups report about synthesis, and the synthesis route is that indole is used as a raw material to synthesize indole-3-formaldehyde, and then indole-3-methanol is obtained through further hydrogenation reduction.

The method uses the dangerous chemical POC1 in the synthesis of indole-3-formaldehyde₃A large amount of excessive DMF, and a large amount of byproducts such as phosphate and the like generated in the reaction, which causes great burden to the environment and is not suitable for large-scale production. Reducing indole-3-carbaldehyde to indole-3-carbinol in a toluene system. Although the efficiency of the reducing agent is high, the reduction cost is too high, and the use of a toluene system causes great harm to the health of workers in large-scale production due to too high toxicity.

Disclosure of Invention

In order to solve the problems, the invention aims to provide an environment-friendly, low-cost and simple-process green preparation process of indole-3-methanol, which has the advantages of green, environment-friendly, low cost, high yield and short time, is suitable for industrial production and conforms to the green production process.

In order to achieve the above object, the technical solution of the present invention is as follows.

A green preparation process of indole-3-methanol comprises the following steps:

s1, dispersing and dissolving indole in DEF, adding methylsulfonyl chloride as a catalyst, controlling the temperature at 30-50 ℃ when adding the catalyst, then heating to 80-90 ℃ for reaction, adding water after the reaction is finished, and filtering to obtain indole-3-formaldehyde;

s2, dispersing and dissolving the indole-3-formaldehyde prepared in the S1 in ethanol, adding sodium borohydride serving as a catalyst, heating to 30-50 ℃ for reaction, filtering after the reaction is finished, and concentrating the filtrate to obtain a crude indole-3-methanol product;

s3, recrystallizing the indole-3-methanol crude product with ethanol to obtain purified indole-3-methanol.

Further, in S1, the mass ratio of indole, DEF, and methanesulfonyl chloride is 1: 3-5: 1.1 to 1.5.

Further, in S1, the reaction time is 2-3 h.

Further, in S1, a filtrate treatment step is further included; the specific operation of the filtrate treatment process is as follows:

concentrating the filtrate by stages, collecting DEF for reuse, adding alkali solution into the residual concentrated solution, and neutralizing the hydrogen chloride generated by the reaction.

Further, in S2, the mass ratio of indole-3-formaldehyde to sodium borohydride is 1: 0.4 to 0.5.

Further, in S2, the mass ratio of indole-3-carbaldehyde to ethanol was 1: 2.

Further, in S2, the reaction time is 2-3 h.

The invention has the beneficial effects that:

1. the synthesis process route of the invention takes indole as a raw material, and obtains a product with high content and high purity through acylation, reduction and recrystallization. In the first step, the conventional phosphorus oxychloride is replaced by methylsulfonyl chloride, and hydrogen chloride generated in the reaction process is absorbed by alkali liquor to form industrial sodium chloride and sodium sulfate; and in the second step, ethanol is used for replacing toluene, so that great harm to the health of workers in the large-scale production process can be prevented, and the by-product sodium metaborate in the reduction process can be put into the market again after treatment, so that a large amount of solid waste is avoided.

2. The process directly uses the methylsulfonyl chloride to replace the existing phosphorus oxychloride in the first step, the methylsulfonyl chloride is stable in supply and low in value, and the investment cost can be reduced.

3. The reaction system in the second step of the process is ethanol, sodium metaborate is removed through post-treatment, the indole-3-methanol can be directly obtained through concentration and crystallization, and the indole-3-methanol with high content and high purity can be obtained through recrystallization by using the ethanol. Because ethanol is one of the most environment-friendly raw materials for producing the medical raw material intermediate, the health risk of workers can be reduced, and the solvent residue in the product is ethanol which is most acceptable for the medical and health-care product raw materials and is greatly superior to toluene, methanol, ethyl acetate and the like in the prior art. The above processes are all excellent industrial production routes from the aspects of economy, environment and occupational health.

4. In the second step of the process, sodium borohydride is used for replacing an expensive catalyst, namely nickel, for catalytic hydrogenation, so that the investment cost can be further reduced.

5. The method has the advantages of environmental protection, low cost, high yield and short time, is suitable for industrial production, and accords with the green production process.

Drawings

FIG. 1 is a synthesis scheme of the green preparation process of indole-3-methanol provided by the present invention.

FIG. 2 is a report of purity analysis of indole-3-methanol obtained in example 1 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

Example 1

A green preparation process of indole-3-methanol comprises the following steps:

s1 preparation of indole-3-carbaldehyde

Taking 150g of indole into a 1000mL three-necked bottle, adding 600g of DEF (N, N-diethylformamide), stirring, dispersing and dissolving, then slowly dropwise adding 175g of methylsulfonyl chloride into a reaction system, controlling the temperature at 50 ℃ when adding a catalyst, heating to 90 ℃ after dropwise adding, stirring for reaction for 3 hours, then adding 3 times of water by volume, stirring to separate out a solid, and filtering to obtain indole-3-formaldehyde with the yield of 95.0%.

Concentrating the filtrate in stages, collecting DEF, recycling the collected DEF, adding the concentrated residual solution into a liquid caustic soda sodium hydroxide solution for neutralizing hydrogen chloride generated in the reaction process, and absorbing the hydrogen chloride by liquid caustic soda to form industrial sodium chloride and sodium sulfate.

S2, preparation of indole-3-methanol crude product

Adding 100g of indole-3-formaldehyde into a 1000mL three-necked bottle, adding 200g of ethanol, stirring at room temperature for dispersion and dissolution, then adding 45g of sodium borohydride, slowly heating to 45 ℃, reacting for 2 hours, performing HPLC (high performance liquid chromatography) tracking detection on the indole-3-formaldehyde without raw material, then filtering, collecting sodium metaborate as a filter cake, and concentrating the filtrate to obtain a crude indole-3-methanol product.

S3, purification

The crude indole-3-methanol obtained in S2 was recrystallized from ethanol to give purified indole-3-methanol in 95.2% yield and 99.0% purity, the purity analysis results are shown in FIG. 2.

Example 2

A green preparation process of indole-3-methanol is basically the same as that of example 1, except that 165g of methylsulfonyl chloride is slowly added dropwise into a reaction system in S1, the temperature is controlled at 30 ℃ when a catalyst is added, the temperature is raised to 90 ℃ after the dropwise addition, and the reaction is stirred for 3 hours.

Example 3

A green preparation process of indole-3-methanol is basically the same as that of example 1, except that 190g of methylsulfonyl chloride is slowly dropped into a reaction system in S1, the temperature is controlled at 40 ℃ when a catalyst is added, the temperature is raised to 80 ℃ after dropping, and the mixture is stirred and reacts for 3 hours.

Example 4

A green preparation process of indole-3-methanol is basically the same as that of example 1, except that 210g of methylsulfonyl chloride is slowly added dropwise into a reaction system in S1, the temperature is controlled at 50 ℃ when a catalyst is added, the temperature is raised to 85 ℃ after the dropwise addition, and the reaction is stirred for 2 hours.

Example 5

A green preparation process of indole-3-methanol is basically the same as that of example 1, except that 225g of methylsulfonyl chloride is slowly added dropwise into a reaction system in S1, the temperature is controlled at 50 ℃ when a catalyst is added, the temperature is raised to 90 ℃ after the dropwise addition, and the reaction is stirred for 2 hours.

Example 6

A green preparation process of indole-3-methanol is basically the same as that of example 1, except that in S1, 150g of indole is taken into a 1000mL three-necked bottle, 450g of DEF is added, and stirring, dispersing and dissolving are carried out.

Example 7

A green preparation process of indole-3-methanol is basically the same as that of example 1, except that in S1, 150g of indole is taken into a 1000mL three-necked bottle, 750g of DEF is added, and stirring, dispersing and dissolving are carried out.

Example 8

A green preparation process of indole-3-methanol is basically the same as that of example 1, except that 40g of sodium borohydride is added into S2, the temperature is slowly raised to 40 ℃, and the reaction is carried out for 3 hours.

Example 9

A green preparation process of indole-3-methanol is basically the same as that of example 1, except that 50g of sodium borohydride is added into S2, the temperature is slowly raised to 30 ℃, and the reaction is carried out for 3 hours.

Example 10

A green preparation process of indole-3-methanol is basically the same as that of example 1, except that 45g of sodium borohydride is added into S2, the temperature is slowly raised to 50 ℃, and the reaction is carried out for 2 h.

In the examples 1-10, the specific operation of recrystallizing the crude indole-3-methanol with ethanol is as follows:

heating and dissolving the indole-3-methanol crude product with absolute ethyl alcohol, then filtering the solution by a fine filter to a crystallizing tank, concentrating ethanol with a certain volume under reduced pressure, cooling and crystallizing the solution, filtering the solution, and drying the obtained product by a forced air drying oven to obtain a purified indole-3-methanol product, wherein the content and the purity of the purified indole-3-methanol product are both more than 99.0 percent.

The results of the amounts of the first step reaction and the yields in examples 1 to 7 are shown in Table 1.

TABLE 1 inventory and yield results for the first step reactions of examples 1-7

As can be seen from the results in Table 1, the yield substantially increases with the amount of the catalyst methanesulfonyl chloride, and after the amount of the catalyst is more than or equal to 175g, the yield is in the range of 93.4-95.0%. In addition, the amount of DEF also affects the yield of the first step, and the yield remains substantially constant after the amount of DEF is greater than or equal to 600 g.

The results of the amounts of the second-step reaction charge and the yields in examples 1, 8-10 are shown in Table 2.

TABLE 2 inventory and yield results for the second step reactions of examples 1, 8-10

As can be seen from the results in Table 2, in inventive example 1, when the amount of ethanol was 100g and the amount of sodium borohydride was 45g, the yield of the product was the highest, reaching 95.2%. In the embodiment 1 of the invention, the ethanol is used for replacing toluene in the prior art, and the product loss is serious and the yield is low due to high boiling point of the toluene; the ethanol adopted in the embodiment 1 of the invention has low boiling point, so that the loss of the product can be avoided, and the yield is relatively high.

In summary, the method for synthesizing indole-3-carbinol provided by the embodiment of the invention synthesizes the natural indole-3-carbinol active derivative by using common chemical raw materials. The aspects of reagent and raw materials used in the reaction are considered to be green, environment-friendly and efficient. The synthesis method adopted by the embodiment of the invention has the advantages of low raw material price, simple equipment, green and environment-friendly production procedure and great economic and social benefits.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.