阅读说明：本技术 一种硫酸沙丁胺醇中间体的合成方法 (Synthetic method of salbutamol sulfate intermediate ) 是由 孙玉琴 杨卫民 于 2021-01-21 设计创作，主要内容包括：本发明公开了一种硫酸沙丁胺醇中间体的合成方法,以水杨醛为原料,通过付克酰基化、还原、丙叉保护和N的烷基化的三步反应,每步反应收率60％以上得到目标产品沙丁胺醇中间体。本发明采用上述一种硫酸沙丁胺醇中间体的合成方法,反应步骤少,后处理简便,产物纯度高。(The invention discloses a synthesis method of a salbutamol sulfate intermediate, which takes salicylaldehyde as a raw material, and obtains the target product salbutamol intermediate through three steps of reactions of friedel-crafts acylation, reduction, propylidene protection and N alkylation, wherein the reaction yield of each step is more than 60%. The synthesis method of the salbutamol sulfate intermediate has the advantages of few reaction steps, simple and convenient post-treatment and high product purity.)

1. A synthetic method of a salbutamol sulfate intermediate is characterized in that the synthetic reaction route is as follows:

2. the method for synthesizing the salbutamol sulfate intermediate as claimed in claim 1, wherein the intermediate I is synthesized according to the following formula:

during reaction, adding aluminum trichloride and dichloromethane into a reaction bottle, dropwise adding a mixed solution of bromoacetyl chloride and dichloromethane at 10-15 ℃, heating to 30 ℃, stirring for 30min, dropwise adding a mixed solution of salicylaldehyde and dichloromethane, heating to 35 ℃ after dropwise adding, and keeping the temperature and stirring for 24 h; monitoring reaction by TLC, adding a small amount of reaction liquid into water, adjusting pH to 1 by concentrated hydrochloric acid, adding DCM, and taking an organic phase;

cooling the reaction liquid to 20 ℃, slowly adding crushed ice and dichloromethane, controlling the temperature within 25 ℃, adding concentrated hydrochloric acid after dripping, stirring for 30min, and separating liquid; extracting the water phase twice with dichloromethane, combining the organic phases, purifying and washing once, and washing once with saturated sodium chloride solution; drying the organic phase with anhydrous magnesium sulfate, filtering, and concentrating the filtrate below 38 deg.C to dryness;

adding ethyl acetate and n-hexane, heating to 35-38 deg.C, stirring for 30min, slowly cooling to room temperature, stirring for 30min, continuing ice water bath for 30min, vacuum filtering, and filtering to obtain filter cake containing ethyl acetate: and eluting with a mixed solution of n-hexane and 1:1, and vacuum-drying at 40 ℃ to obtain the intermediate I.

3. The method for synthesizing the salbutamol sulfate intermediate according to claim 1, wherein the intermediate II is synthesized according to the following formula:

during reaction, adding glacial acetic acid into a reaction bottle, cooling to 20 ℃, adding sodium borohydride in batches, stirring at 25 ℃ for 1h, and separating out a white solid; adding the intermediate I in batches, reacting for 1h at 25 ℃, and monitoring the reaction completion by TLC;

adding purified water, stirring, adjusting pH to 1-2 with concentrated hydrochloric acid, stirring at 25 deg.C for 30min, adding ethyl acetate, stirring, and separating; adding ethyl acetate into the water phase for extraction, combining the organic phases, and washing twice by using a saturated sodium chloride solution; drying the organic phase with anhydrous sodium sulfate, filtering, and concentrating at 55 deg.C to obtain solid;

adding dichloromethane, stirring, heating to 35 ℃, stirring for 1h, cooling to room temperature, stirring for 1h, stirring in an ice-water bath for 1h, leaching a filter cake with dichloromethane, and vacuum drying at 45 ℃ to obtain an intermediate II.

4. The method for synthesizing the salbutamol sulfate intermediate according to claim 1, wherein the intermediate III is synthesized according to the following reaction formula:

during reaction, adding the intermediate II into a reaction bottle, adding acetone and p-toluenesulfonic acid, and cooling; dripping 2-methoxypropene at 0-5 ℃, and controlling the temperature to be 0-5 ℃; after the dripping is finished, the temperature is preserved for 1h, and the TLC monitoring is carried out; adding N-benzyl tert-butylamine, heating to 55 ℃, reacting for 22h, and monitoring by TLC; cooling to 25 deg.C, stirring for 10-20min, vacuum filtering, and concentrating the filtrate; evaporating to dryness to obtain oily substance, adding ethyl acetate/n-hexane (1:20) and silica gel, heating to 55 deg.C, and stirring for 1 hr; performing suction filtration, adding the filter cake into a reaction bottle, adding ethyl acetate/n-hexane (1:20), heating to 55 ℃, stirring for 30min, performing suction filtration, adding the filter cake into the reaction bottle, adding ethyl acetate/n-hexane (1:20), stirring for 30min, performing suction filtration, combining filtrates, and concentrating at 45 ℃ to dryness to obtain a solid;

adding methanol, stirring, heating to 55 deg.C until the solid is completely dissolved, cooling to 20 deg.C, and stirring for 1 h; cooling to 0-5 deg.C, stirring for 4 hr, vacuum filtering, leaching the filter cake with 0-5 deg.C methanol, and vacuum drying at 45 deg.C.

Technical Field

The invention relates to the technical field of chemical pharmacy, in particular to a synthetic method of a salbutamol sulfate intermediate.

Background

Salbutamol sulfate belongs to adrenal gland, can selectively act on receptors on bronchial smooth muscle to produce a rapid bronchodilatory effect, is used for treating bronchial asthma, Chronic Obstructive Pulmonary Disease (COPD), asthmatic tracheitis and bronchospasm of emphysema patients, and has good curative effect.

In the prior art, the synthesis conditions of salbutamol are harsh, the yield is low, the three wastes pollution is serious, and the cost is higher. Shenkansai et al, which utilizes chiral (salon) Co to catalyze a terminal epoxy compound to prepare chiral levalbuterol hydrochloride, have a yield of about 20%, but have many steps, which is not suitable for large-scale industrial production.

At present, the synthetic route using salicylaldehyde as a raw material is reported to be the simplest, but bromoacetyl chloride and Pd-C are expensive, and the number of times of applying Pd-C is greatly reduced for discontinuous synthesis, so that the cost is increased.

Disclosure of Invention

The invention aims to provide a synthetic method of a salbutamol sulfate intermediate, which has the advantages of few reaction steps, simple and convenient post-treatment and high product purity.

In order to achieve the purpose, the invention provides a synthetic method of a salbutamol sulfate intermediate, which comprises the following synthetic reaction route:

preferably, the synthesis reaction of the intermediate I is as follows:

during reaction, adding aluminum trichloride and dichloromethane into a reaction bottle, dropwise adding a mixed solution of bromoacetyl chloride and dichloromethane at 10-15 ℃, heating to 30 ℃, stirring for 30min, dropwise adding a mixed solution of salicylaldehyde and dichloromethane, heating to 35 ℃ after dropwise adding, and keeping the temperature and stirring for 24 h; monitoring reaction by TLC, adding a small amount of reaction liquid into water, adjusting pH to 1 by concentrated hydrochloric acid, adding DCM, and taking an organic phase;

cooling the reaction liquid to 20 ℃, slowly adding crushed ice and dichloromethane, controlling the temperature within 25 ℃, adding concentrated hydrochloric acid after dripping, stirring for 30min, and separating liquid; extracting the water phase twice with dichloromethane, combining the organic phases, purifying and washing once, and washing once with saturated sodium chloride solution; drying the organic phase with anhydrous magnesium sulfate, filtering, and concentrating the filtrate below 38 deg.C to dryness;

adding ethyl acetate and n-hexane, heating to 35-38 deg.C, stirring for 30min, slowly cooling to room temperature, stirring for 30min, continuing ice water bath for 30min, vacuum filtering, and filtering to obtain filter cake containing ethyl acetate: and eluting with a mixed solution of n-hexane and 1:1, and vacuum-drying at 40 ℃ to obtain the intermediate I.

Preferably, the synthesis reaction formula of the intermediate II is as follows:

during reaction, adding glacial acetic acid into a reaction bottle, cooling to 20 ℃, adding sodium borohydride in batches, stirring at 25 ℃ for 1h, and separating out a white solid; adding the intermediate I in batches, reacting for 1h at 25 ℃, and monitoring the reaction completion by TLC;

adding purified water, stirring, adjusting pH to 1-2 with concentrated hydrochloric acid, stirring at 25 deg.C for 30min, adding ethyl acetate, stirring, and separating; adding ethyl acetate into the water phase for extraction, combining the organic phases, and washing twice by using a saturated sodium chloride solution; drying the organic phase with anhydrous sodium sulfate, filtering, and concentrating at 55 deg.C to obtain solid;

adding dichloromethane, stirring, heating to 35 ℃, stirring for 1h, cooling to room temperature, stirring for 1h, stirring in an ice-water bath for 1h, leaching a filter cake with dichloromethane, and vacuum drying at 45 ℃ to obtain an intermediate II.

Preferably, the synthesis reaction formula of the intermediate III is as follows:

during reaction, adding the intermediate II into a reaction bottle, adding acetone and p-toluenesulfonic acid, and cooling; dripping 2-methoxypropene at 0-5 ℃, and controlling the temperature to be 0-5 ℃; after the dripping is finished, the temperature is preserved for 1h, and the TLC monitoring is carried out; adding N-benzyl tert-butylamine, heating to 55 ℃, reacting for 22h, and monitoring by TLC; cooling to 25 deg.C, stirring for 10-20min, vacuum filtering, and concentrating the filtrate; evaporating to dryness to obtain oily substance, adding ethyl acetate/n-hexane (1:20) and silica gel, heating to 55 deg.C, and stirring for 1 hr; performing suction filtration, adding the filter cake into a reaction bottle, adding ethyl acetate/n-hexane (1:20), heating to 55 ℃, stirring for 30min, performing suction filtration, adding the filter cake into the reaction bottle, adding ethyl acetate/n-hexane (1:20), stirring for 30min, performing suction filtration, combining filtrates, and concentrating at 45 ℃ to dryness to obtain a solid;

adding methanol, stirring, heating to 55 deg.C until the solid is completely dissolved, cooling to 20 deg.C, and stirring for 1 h; cooling to 0-5 deg.C, stirring for 4 hr, vacuum filtering, leaching the filter cake with 0-5 deg.C methanol, and vacuum drying at 45 deg.C.

Therefore, the synthesis method of the salbutamol sulfate intermediate has the following technical effects:

(1) the synthesis process of the invention has no high-temperature high-pressure reaction, few reaction steps and simple and convenient post-treatment, and is beneficial to realizing the industrialization of the production of the salbutamol sulfate.

(2) The synthesis method has the advantages of high product yield, short steps and low impurity content.

The technical solution of the present invention is further described in detail by the following examples.

Detailed Description

The embodiments of the present invention will be further explained below.

A synthetic method of a salbutamol sulfate intermediate comprises the following synthetic reaction route:

(1) synthesis of intermediate I

During reaction, 136.5g of aluminum trichloride and 300mL of dichloromethane are added into a 1L reaction bottle, 96.7g of mixed solution of bromoacetyl chloride and 50mL of dichloromethane is dropwise added at 10-15 ℃, the temperature is increased to 30 ℃, stirring is carried out for 30min, 50g of mixed solution of salicylaldehyde and 50mL of dichloromethane is dropwise added, the temperature is increased to 35 ℃ after dropwise addition, and stirring is carried out for 24h under heat preservation. The reaction was monitored by TLC (small amount of reaction mixture was taken, water was added, concentrated HCl adjusted to pH 1, DCM was added, organic phase was taken).

And cooling the reaction liquid to 20 ℃, slowly adding 500g of crushed ice and 100mL of dichloromethane, controlling the temperature within 25 ℃, dropwise adding 50mL of concentrated hydrochloric acid, stirring for 30min, and separating the liquid. The aqueous phase was extracted twice with 200mL of dichloromethane. The combined organic phases were washed once with 200mL of purified water and once with 200mL of saturated sodium chloride solution. The organic phase is dried over anhydrous magnesium sulfate, filtered with suction, and the filtrate is concentrated to dryness at a temperature below 38 ℃. Adding 75mL of ethyl acetate and 75mL of n-hexane, heating to 35-38 ℃, stirring for 30min, slowly cooling to room temperature, stirring for 30min, continuing ice-water bath for 30min, performing suction filtration, and filtering a filter cake by using 20mL of ethyl acetate: the intermediate I is leached by mixed solution of n-hexane and 1:1 and dried in vacuum at 40 ℃ with the yield of 60 percent.

(2) Synthesis of intermediate II

During reaction, 80mL of glacial acetic acid is added into a 500mL reaction bottle, the temperature is reduced to 20 ℃, 3.5g of sodium borohydride is added in batches, the heat release of the sodium borohydride is violent in the dissolving process to generate hydrogen, and the mixture is stirred for 1h at 25 ℃ to separate out white solid. 15g of intermediate I were added in portions and reacted at 25 ℃ for 1 h. TLC monitored the reaction complete.

Adding 150mL of purified water, stirring, adjusting pH to 1-2 with concentrated hydrochloric acid, stirring at 25 deg.C for 30min, adding 200mL of ethyl acetate, stirring, and separating. The aqueous phase was extracted by adding 80mL of ethyl acetate. The combined organic phases were washed twice with 100mL of saturated sodium chloride solution. The organic phase is dried by anhydrous sodium sulfate, filtered by suction, and concentrated to dryness at 55 ℃ to obtain a solid. Adding 45mL of dichloromethane, stirring, heating to 35 ℃, stirring for 1h, cooling to room temperature, stirring for 1h, and stirring for 1h in an ice-water bath. Suction filtration and rinsing of the filter cake with 10mL dichloromethane. Vacuum drying at 45 ℃ to obtain an intermediate II with the yield of 70-80%.

(3) Synthesis of intermediate III

During reaction, 18g of the intermediate II is added into a reaction bottle, 90g of acetone and 0.09g of p-toluenesulfonic acid are added, and the temperature is reduced. 13.4g of 2-methoxypropene are added dropwise at 0 to 5 ℃. Controlling the temperature to be 0-5 ℃, keeping the temperature for reaction for 1h after finishing dripping, and monitoring by TLC. 26.25g N-benzyl tert-butylamine was added. The temperature was raised to 55 ℃. The reaction was carried out for 22h, monitored by TLC. Cooling to 25 deg.C, stirring for 10-20Min, vacuum filtering, and concentrating the filtrate. Evaporating to dryness to obtain oily substance, adding 180mL ethyl acetate/n-hexane (1:20) and 20.2g silica gel, heating to 55 deg.C, and stirring for 1 h. And (2) carrying out suction filtration, adding the filter cake into a reaction bottle, adding 180mL of ethyl acetate/n-hexane (1:20), heating to 55 ℃, stirring for 30min, carrying out suction filtration, adding the filter cake into the reaction bottle, adding 90mL of ethyl acetate/n-hexane (1:20), stirring for 30min, carrying out suction filtration, combining the filtrates, and concentrating at 45 ℃ to dryness to obtain a solid.

Adding 72g of methanol, stirring, heating to 55 ℃ until the solid is completely dissolved, cooling to 20 ℃, and stirring for 1 h. Cooling to 0-5 ℃, stirring for 4h, carrying out suction filtration, leaching a filter cake with 15mL of methanol with the temperature of 0-5 ℃, and carrying out vacuum drying on the obtained product at the temperature of 45 ℃. The yield is 70-80%.

Therefore, the synthesis method of the salbutamol sulfate intermediate has the advantages of few reaction steps, simple and convenient post-treatment and high product purity.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that modifications can be made by those skilled in the art without departing from the principle of the present invention, and these modifications should also be construed as the protection scope of the present invention.