CN114539201A - Preparation method of siber linking agent - Google Patents

Abstract

The invention provides a preparation method of a siber linking agent, which comprises the following steps: step 1, enabling o-fluorobenzoic acid and m-diphenylmethyl ether to perform Friedel-crafts reaction to obtain an intermediate; and 2, performing ring closing and demethylation reaction on the intermediate to obtain the siberian linking agent. According to the preparation method of the siberian linker provided by the embodiment of the invention, o-fluorobenzoic acid and m-phenyl dimethyl ether are used as raw materials, a Friedel-crafts reaction is firstly carried out, and then a ring closing and demethylation reaction is carried out to obtain a target compound.

Description

Preparation method of siber linking agent

Technical Field

The invention relates to the technical field of organic synthesis, in particular to a preparation method of a siberian linking agent.

Background

The polypeptide and protein medicines have the advantages of high activity, stable curative effect, small toxic and side effect, small dosage and the like, and have obvious curative effect and wide application prospect on cancers, autoimmune diseases, hypomnesis, mental disorder, hypertension, certain cardiovascular diseases, metabolism and other diseases, so the polypeptide and protein medicines are concerned by experts at home and abroad.

The polypeptide is an important bioactive substance and is widely applied to the fields of polypeptide drugs, polypeptide drug carriers, peptide foods, cosmetics and the like. Currently, chemical synthesis techniques for polypeptides include both liquid phase synthesis and solid phase synthesis. The solid phase method for synthesizing the polypeptide has the advantages of time saving, labor saving, material saving, convenience for automation and the like, becomes a conventional method for synthesizing the polypeptide, and is expanded to the fields of other organic matters such as nucleotide synthesis and the like.

On the other hand, the key step in solid phase synthesis is the attachment of the target molecule to a solid support, which can be achieved by a cleavable linker. The linker group can be regarded as a bifunctional protecting group, which is connected to the target molecule through an unstable bond (e.g., ester bond, amide bond, etc.) which is easy to cleave, and fixes the target molecule on the solid support through a relatively stable bond (e.g., carbon-carbon bond, ether bond, etc.). The choice of the ideal linking group is therefore directly linked to the success of the solid phase synthesis strategy.

Sieber Linker (siber Linker) is a peptide synthesis linking reagent with good effect, and the synthesis methods reported at present are summarized as follows:

1) o-methoxybenzoic acid and m-diphenylmethyl ether are subjected to Friedel-crafts reaction in polyphosphoric acid, and the intermediate is subjected to ring closure and demethylation reaction with pyridine hydrochloride at a high temperature of 190 ℃ (Han, Bontems, etc., Journal of Organic Chemistry,1996, vol.61, #18, p.6326-6339), and the reaction equation is shown in the following formula (1):

however, this method has disadvantages in that the first reaction system has a large viscosity, is difficult to handle at room temperature, and has a low yield; the reaction temperature of the second step is too high, so that the method is not suitable for industrial scale-up production.

2) Under the catalysis of ytterbium trifluoromethanesulfonate hydrate, the o-hydroxybenzoic acid and the m-diphenol react with each other in a microwave manner to obtain the siberian linking agent. The reaction equation is shown in the following formula (2):

however, the method seems to be simple, raw materials are easy to obtain, but the catalyst is expensive, so that the production cost is overhigh, the yield obtained by experiments is not high, and the obtained crude product is difficult to purify.

Disclosure of Invention

In view of the above, the present invention aims to provide a preparation method of a seebeck linker, which is low in cost, good in operability, free from high temperature operation and suitable for safe scale-up production.

In order to solve the technical problems, the invention adopts the following technical scheme:

the preparation method of the siber linking agent comprises the following steps:

step 1, enabling o-fluorobenzoic acid and m-diphenylmethyl ether to perform Friedel-crafts reaction to obtain an intermediate;

and 2, performing ring closing and demethylation reaction on the intermediate to obtain the siberian linking agent.

Further, the friedel-crafts reaction is carried out in a solvent under the action of a lewis acid.

Further, the Lewis acid is one or more of anhydrous aluminum trichloride, anhydrous ferric chloride and anhydrous ferric bromide.

Further, the step 1 comprises:

step 11, dissolving o-fluorobenzoic acid in a solvent, and adding m-phenyl dimethyl ether into the solvent to obtain a mixed solution;

and 12, slowly adding anhydrous aluminum trichloride into the mixed solution at the temperature of below 10 ℃, and reacting at room temperature for 4-8 hours after the addition is finished to obtain the intermediate.

Further, the step 1 further comprises:

and step 13, after the reaction is finished, quenching the reaction system by using ice water, and separating, washing and concentrating the product to obtain a concentrated intermediate.

Further, in the step 2, the ring closing and demethylation reaction is carried out under the action of strong acid.

Still further, the strong acid is one or more of hydrobromic acid, hydrofluoric acid, hydroiodic acid, and concentrated hydrochloric acid.

Further, the step 2 includes:

and adding a hydrobromic acid aqueous solution into the intermediate, heating to 80-100 ℃ under the protection of nitrogen, reacting for 6-12 hours, and performing ring closing and demethylation reactions to obtain the siberian linker.

Further, in the step 2, after the reaction is finished, concentration is performed, and the obtained solid is recrystallized by ethanol to refine the siber linker.

The technical scheme of the invention at least has one of the following beneficial effects:

according to the preparation method of the siberian linker provided by the embodiment of the invention, o-fluorobenzoic acid and m-phenyl dimethyl ether are used as raw materials, a Friedel-crafts reaction is firstly carried out, and then a ring closing and demethylation reaction is carried out to obtain a target compound.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.

First, the preparation method of the siber linker according to the embodiment of the present invention is specifically described, which includes the following steps:

step 1, carrying out Friedel-crafts reaction on o-fluorobenzoic acid and m-diphenylmethyl ether to obtain an intermediate.

That is, the invention takes o-fluorobenzoic acid and m-diphenylmethyl ether as starting materials to carry out Friedel-crafts reaction to obtain an intermediate.

A specific chemical reaction formula is shown in the following formula (3):

further, the friedel-crafts reaction is carried out in a solvent under the action of a lewis acid. The existence of Lewis acid can catalyze and promote the Friedel-crafts reaction.

In particular, it is preferred to use a strong lewis acid, such as one or more of anhydrous aluminum trichloride, anhydrous ferric chloride, anhydrous ferric bromide.

Further, the step 1 may include:

step 11, dissolving o-fluorobenzoic acid in a solvent, and adding m-phenyl dimethyl ether into the solvent to obtain a mixed solution;

and 12, slowly adding anhydrous aluminum trichloride into the mixed solution at the temperature of below 10 ℃, and reacting at room temperature for 4-8 hours after the addition is finished to obtain the intermediate.

That is, o-fluorobenzoic acid is firstly dissolved in a solvent, for example, dichloromethane, then m-xylylene ether is dissolved in the solvent, after the o-fluorobenzoic acid and the m-xylylene ether are uniformly mixed, anhydrous aluminum trichloride is slowly added into the mixed solution at the temperature of below 10 ℃ as a catalyst to catalyze the friedel-crafts reaction, and after the catalyst is added, the friedel-crafts reaction can be smoothly carried out at room temperature to obtain an intermediate. Therefore, the reaction condition is simple, the raw materials are low in price, the operability is strong, and the expanded production is easy.

Further, the step 1 further comprises:

and step 13, after the reaction is finished, quenching the reaction system by using ice water, and separating, washing and concentrating the product to obtain a concentrated intermediate.

That is, after the friedel-crafts reaction is completed, the reaction system is separated, washed, concentrated, and the concentrated intermediate is used for the subsequent reaction. On one hand, the method is favorable for avoiding unnecessary side reactions, on the other hand, the method is favorable for reducing the difficulty of purifying the product, improving the yield and the like.

And 2, performing ring closing and demethylation reaction on the intermediate to obtain the siberian linking agent.

That is, after obtaining the intermediate, the intermediate is further subjected to a ring closure and demethylation reaction to obtain a target product, i.e., a siberian linker.

The reaction formula is shown as the following formula (4):

further, in the step 2, the ring closing and demethylation reaction is carried out under the action of strong acid.

For example, the strong acid may be one or more of hydrobromic acid, hydrofluoric acid, hydroiodic acid, and concentrated hydrochloric acid. Hydrobromic acid is preferred because of its relatively high stability, low operating conditions, and favorable yield.

Further, the step 2 comprises:

and adding a hydrobromic acid aqueous solution into the intermediate, heating to 80-100 ℃ under the protection of nitrogen, reacting for 6-12 hours, and performing ring closing and demethylation reactions to obtain the siberian linker.

In addition, after the reaction is finished, concentration can be carried out, and the obtained solid is recrystallized by ethanol so as to refine the siber linker.

The production method of the present invention will be described in further detail with reference to specific examples.

Example 1:

adding 140.1g of o-fluorobenzoic acid and 1000ml of dichloromethane into a 2L three-neck flask, adding 138.2g of m-xylylene ether, cooling to 5-10 ℃, slowly adding 133.3g of anhydrous aluminum trichloride into the three-neck flask, gradually releasing a large amount of heat in the system, controlling the temperature below 10 ℃, slowly adding the aluminum trichloride, gradually separating out a tan solid from a tan clear liquid in the system, removing an ice bath, reacting at room temperature for 6 hours, and monitoring by TLC that the o-fluorobenzoic acid is almost consumed.

After the reaction is finished, cooling to below 5 ℃, slowly adding the system into 500g of ice water, quenching the reaction, wherein a large amount of heat and gas escape, quenching, adding 500ml of 6N hydrochloric acid, stirring for 10 minutes, separating, washing the obtained organic phase once with 500ml of saturated sodium bicarbonate, separating, washing once with 500ml of saturated sodium chloride solution, separating, drying the organic phase with anhydrous magnesium sulfate, decoloring with activated carbon, performing suction filtration to obtain a light yellow liquid, spinning the light yellow liquid until a large amount of white solid is separated out, adding 2L of petroleum ether into the light yellow liquid, performing ice bath pulping for 1 hour, performing suction filtration to obtain a white solid, and performing vacuum drying to obtain 210g of an intermediate (the single-step molar yield is 80.7%, and the melting point is about 80 ℃).

210g of intermediate and 1200g of hydrobromic acid aqueous solution are added into a 2L three-neck flask, the temperature is raised to 95 ℃ under the protection of nitrogen, the reaction lasts for about 8 hours, the solid gradually dissolves into yellow clear liquid in the reaction period, and the color of the system becomes darker and darker along with the lengthening of the reaction time.

TLC monitoring, confirming no intermediate and finishing the reaction. The system was concentrated to precipitate a large amount of beige solid crude product. Heating, refluxing and dissolving the crude product by 1500ml of ethanol, decoloring by active carbon, performing suction filtration to obtain filtrate, cooling to room temperature, adding 3000ml of water, pulping, performing suction filtration to obtain off-white to white solid, and performing vacuum drying to obtain 145.5g of a product (the single step molar yield is 85.1%, the HPLC (high performance liquid chromatography) is 98.6%, and the melting point is 251 and 253 ℃).

The reaction product was characterized by nmr and the data were as follows:

HNMR(400MHz,DMSO)：δ6.89(d,1H)，δ6.92(dd,1H)，δ7.46(td,1H)，δ7.63(d,1H)，δ7.77(td,1H)，δ8.02(d,1H)，δ8.12(dd,1H)，δ11(br,OH)

example 2:

140.1g of o-fluorobenzoic acid and 1000ml of tetrahydrofuran are added into a 2L three-neck flask, 138.2g of m-xylylene ether is added into the o-fluorobenzoic acid, the temperature is reduced to 5-10 ℃, 133.3g of anhydrous aluminum trichloride is slowly added into the o-fluorobenzoic acid, a large amount of heat is gradually released in the system, the temperature is controlled below 10 ℃, the aluminum trichloride is slowly added, a tawny solid is gradually separated out from a tawny clear liquid in the system, an ice bath is removed, the reaction is carried out at room temperature for 6 hours, and TLC monitors that the o-fluorobenzoic acid is almost completely consumed.

After the reaction is finished, cooling to below 5 ℃, concentrating to remove tetrahydrofuran, adding 1000ml of ethyl acetate into the system, slowly dropwise adding 500g of ice water, quenching the reaction, wherein a large amount of heat and gas escape, quenching, adding 500ml of 6N hydrochloric acid, stirring for 10 minutes, separating, washing the obtained organic phase once with 500ml of saturated sodium bicarbonate, separating, washing once with 500ml of saturated sodium chloride solution, separating, drying the organic phase with anhydrous magnesium sulfate, decolorizing with activated carbon, performing suction filtration to obtain a light yellow liquid, rotating until a large amount of white solid is separated out, adding 2L of petroleum ether into the light yellow liquid, performing ice bath pulping for 1 hour, performing suction filtration to obtain a white solid, and performing vacuum drying to obtain 193g of an intermediate (the single-step molar yield is 74.2%, and the melting point is about 79 ℃).

193g of intermediate and 1200g of hydrobromic acid aqueous solution are added into a 2L three-neck flask, the temperature is raised to 95 ℃ under the protection of nitrogen, the reaction lasts for about 8 hours, solid gradually dissolves into yellow clear liquid in the reaction period, and the color of the system becomes darker and darker along with the lengthening of the reaction time.

TLC monitoring, confirming no intermediate and finishing the reaction. The system was concentrated to precipitate a large amount of beige solid crude product. Heating, refluxing and dissolving the crude product by 1500ml of ethanol, decoloring by active carbon, performing suction filtration to obtain filtrate, cooling to room temperature, adding 3000ml of water, pulping, performing suction filtration to obtain off-white to white solid, and performing vacuum drying to obtain 133.7g of a product (the single step molar yield is 85.1%, the HPLC (high performance liquid chromatography) is 98.5%, and the melting point is 250 ℃ and 252 ℃).

The reaction product was characterized by nmr and the data were as follows:

HNMR(400MHz,DMSO)：δ6.89(d,1H)，δ6.92(dd,1H)，δ7.46(td,1H)，δ7.63(d,1H)，δ7.77(td,1H)，δ8.02(d,1H)，δ8.12(dd,1H)，δ11(br,OH)

example 3:

140.1g of o-fluorobenzoic acid and 1000ml of ethyl acetate are added into a 2L three-neck flask, 138.2g of m-xylylene ether is added into the o-fluorobenzoic acid, the temperature is reduced to 5-10 ℃, 133.3g of anhydrous aluminum trichloride is slowly added into the o-fluorobenzoic acid, the system gradually releases a large amount of heat, the temperature is controlled below 10 ℃, the aluminum trichloride is slowly added, a tan solid is gradually separated out from a tan clear solution of the system, the ice bath is removed, the reaction is carried out at room temperature for 6 hours, and the o-fluorobenzoic acid is almost completely consumed under TLC monitoring.

After the reaction is finished, cooling to below 5 ℃, slowly adding the system into 500g of ice water, quenching the reaction, wherein a large amount of heat and gas escape, quenching, adding 500ml of 6N hydrochloric acid, stirring for 10 minutes, separating, washing the obtained organic phase once with 500ml of saturated sodium bicarbonate, separating, washing once with 500ml of saturated sodium chloride solution, separating, drying the organic phase with anhydrous magnesium sulfate, decoloring with activated carbon, performing suction filtration to obtain a light yellow liquid, spinning the light yellow liquid until a large amount of white solid is separated out, adding 2L of petroleum ether into the light yellow liquid, performing ice bath pulping for 1 hour, performing suction filtration to obtain a white solid, and performing vacuum drying to obtain 205g of an intermediate (the single-step molar yield is 78.8%, and the melting point is about 79 ℃).

205g of intermediate and 1200g of hydrobromic acid aqueous solution are added into a 2L three-neck flask, the temperature is raised to 95 ℃ under the protection of nitrogen, the reaction lasts for about 8 hours, the solid gradually dissolves into yellow clear liquid in the reaction period, and the color of the system becomes darker and darker along with the lengthening of the reaction time.

TLC monitoring, confirming no intermediate and finishing the reaction. The system was concentrated to precipitate a large amount of beige solid crude product. Heating, refluxing and dissolving the crude product by 1500ml of ethanol, decoloring by active carbon, performing suction filtration to obtain filtrate, cooling to room temperature, adding 3000ml of water, pulping, performing suction filtration to obtain a white-like to white solid, and performing vacuum drying to obtain 142g of a product (the single step molar yield is 85.1%, the HPLC is 99.2%, and the melting point is 251-phase 253 ℃).

The reaction product was characterized by nmr and the data were as follows:

HNMR(400MHz,DMSO)：δ6.89(d,1H)，δ6.92(dd,1H)，δ7.46(td,1H)，δ7.63(d,1H)，δ7.77(td,1H)，δ8.02(d,1H)，δ8.12(dd,1H)，δ11(br,OH)

example 4:

adding 140.1g of o-fluorobenzoic acid and 1000ml of acetone into a 2L three-neck flask, adding 138.2g of m-xylylene ether, cooling to 5-10 ℃, slowly adding 133.3g of anhydrous aluminum trichloride into the three-neck flask, gradually releasing a large amount of heat in the system, controlling the temperature below 10 ℃, slowly adding the aluminum trichloride, gradually separating out a tan solid from a tan clear liquid in the system, removing an ice bath, reacting at room temperature for 6 hours, and monitoring by TLC that the o-fluorobenzoic acid is almost consumed.

After the reaction is finished, cooling to below 5 ℃, concentrating to remove acetone, adding 1000ml of dichloromethane into the system, slowly and dropwise adding 500g of ice water, quenching the reaction, wherein a large amount of heat and gas escape, quenching, adding 500ml of 6N hydrochloric acid, stirring for 10 minutes, separating, washing the obtained organic phase once with 500ml of saturated sodium bicarbonate, separating, washing once with 500ml of saturated sodium chloride solution, separating, drying the organic phase with anhydrous magnesium sulfate, decolorizing with activated carbon, performing suction filtration to obtain a light yellow liquid, rotating until a large amount of white solid is separated out, adding 2L of petroleum ether into the light yellow liquid, performing ice bath pulping for 1 hour, performing suction filtration to obtain a white solid, and performing vacuum drying to obtain 201g of an intermediate (the single-step molar yield is 77.3%, and the melting point is about 80 ℃).

201g of intermediate and 1200g of hydrobromic acid aqueous solution are added into a 2L three-neck flask, the temperature is raised to 95 ℃ under the protection of nitrogen, the reaction lasts for about 8 hours, the solid gradually dissolves into yellow clear liquid in the reaction period, and the color of the system becomes darker and darker along with the lengthening of the reaction time.

TLC monitoring, confirming no intermediate and finishing the reaction. The system was concentrated to precipitate a large amount of beige solid crude product. Heating, refluxing and dissolving the crude product by 1500ml of ethanol, decoloring by active carbon, performing suction filtration to obtain filtrate, cooling to room temperature, adding 3000ml of water, pulping, performing suction filtration to obtain off-white to white solid, and performing vacuum drying to obtain 139.3g of a product (the single step molar yield is 85.1%, the HPLC (high performance liquid chromatography) is 98.8%, and the melting point is 251 and 253 ℃).

The reaction product was characterized by nmr and the data were as follows:

HNMR(400MHz,DMSO)：δ6.89(d,1H)，δ6.92(dd,1H)，δ7.46(td,1H)，δ7.63(d,1H)，δ7.77(td,1H)，δ8.02(d,1H)，δ8.12(dd,1H)，δ11(br,OH)

example 5:

adding 140.1g of o-fluorobenzoic acid and 1000ml of acetonitrile into a 2L three-neck flask, adding 138.2g of m-xylylene ether, cooling to 5-10 ℃, slowly adding 133.3g of anhydrous aluminum trichloride into the three-neck flask, gradually generating a large amount of heat in the system, controlling the temperature to be below 10 ℃, slowly adding the aluminum trichloride, gradually separating out a tawny solid from the tawny clear liquid in the system, removing an ice bath, reacting at room temperature for 6 hours, and monitoring by TLC that the o-fluorobenzoic acid is almost consumed.

After the reaction is finished, cooling to below 5 ℃, concentrating to remove acetonitrile, adding 1000ml of dichloromethane into the system, slowly dropwise adding 500g of ice water, quenching the reaction, wherein a large amount of heat and gas escape, quenching, adding 500ml of 6N hydrochloric acid, stirring for 10 minutes, separating, washing the obtained organic phase once with 500ml of saturated sodium bicarbonate, separating, washing once with 500ml of saturated sodium chloride solution, separating, drying the organic phase with anhydrous magnesium sulfate, decolorizing with activated carbon, performing suction filtration to obtain a light yellow liquid, rotating until a large amount of white solid is separated out, adding 2L of petroleum ether into the light yellow liquid, performing ice bath pulping for 1 hour, performing suction filtration to obtain a white solid, and performing vacuum drying to obtain 195g of an intermediate (the single-step molar yield is 74.9%, and the melting point is about 79 ℃).

195g of intermediate and 1200g of hydrobromic acid aqueous solution are added into a 2L three-neck flask, the temperature is raised to 95 ℃ under the protection of nitrogen, the reaction lasts for about 8 hours, the solid gradually dissolves into yellow clear liquid in the reaction period, and the color of the system becomes darker and darker along with the lengthening of the reaction time.

TLC monitoring, confirming no intermediate and finishing the reaction. The system was concentrated to precipitate a large amount of beige solid crude product. Heating, refluxing and dissolving the crude product by 1500ml of ethanol, decoloring by active carbon, performing suction filtration to obtain filtrate, cooling to room temperature, adding 3000ml of water, pulping, performing suction filtration to obtain off-white to white solid, and performing vacuum drying to obtain 135.1g of a product (the single step molar yield is 85.1%, the HPLC (high performance liquid chromatography) is 98.9%, and the melting point is 250 ℃ and 252 ℃).

The reaction product was characterized by nmr and the data were as follows:

HNMR(400MHz,DMSO)：δ6.89(d,1H)，δ6.92(dd,1H)，δ7.46(td,1H)，δ7.63(d,1H)，δ7.77(td,1H)，δ8.02(d,1H)，δ8.12(dd,1H)，δ11(br,OH)

while the foregoing is directed to the preferred embodiment of the present invention, it will be appreciated by those skilled in the art that various changes and modifications may be made therein without departing from the principles of the invention as set forth in the appended claims.

Claims (9)

1. A preparation method of a siber linking agent is characterized by comprising the following steps:

step 1, enabling o-fluorobenzoic acid and m-diphenylmethyl ether to perform Friedel-crafts reaction to obtain an intermediate;

and 2, performing ring closing and demethylation reaction on the intermediate to obtain the siberian linking agent.

2. The process according to claim 1, wherein the Friedel-crafts reaction is carried out in a solvent under the action of a Lewis acid.

3. The preparation method of claim 2, wherein the Lewis acid is one or more of anhydrous aluminum trichloride, anhydrous ferric chloride and anhydrous ferric bromide.

4. The method for preparing according to claim 3, wherein the step 1 comprises:

step 11, dissolving o-fluorobenzoic acid in a solvent, and adding m-phenyl dimethyl ether into the solvent to obtain a mixed solution;

and 12, slowly adding anhydrous aluminum trichloride into the mixed solution at the temperature of below 10 ℃, and reacting at room temperature for 4-8 hours after the addition is finished to obtain the intermediate.

5. The method of claim 4, wherein the step 1 further comprises:

and step 13, after the reaction is finished, quenching the reaction system by using ice water, and separating, washing and concentrating the product to obtain a concentrated intermediate.

6. The method according to claim 1, wherein the ring-closing and demethylating reaction in step 2 is carried out by a strong acid.

7. The method according to claim 6, wherein the strong acid is one or more of hydrobromic acid, hydrofluoric acid, hydroiodic acid, and concentrated hydrochloric acid.

8. The method for preparing according to claim 7, wherein the step 2 comprises:

and adding a hydrobromic acid aqueous solution into the intermediate, heating to 80-100 ℃ under the protection of nitrogen, reacting for 6-12 hours, and performing ring closing and demethylation reactions to obtain the siberian linker.

9. The method according to claim 8, wherein in the step 2, after the reaction is completed, the reaction mixture is concentrated, and the obtained solid is recrystallized from ethanol to refine the siber linker.