Liquid phase synthesis method of semeglutide side chain key intermediate

Abstract

The invention discloses a liquid phase synthesis method of a semeglutide side chain key intermediate. According to the invention, a compound represented by a formula (III) is used as a starting material, and is subjected to carboxyl activation to prepare a compound represented by a formula (IV). And condensing the compound of the formula (IV) and the compound of the formula (V) to prepare a compound of a formula (VI). The preparation method comprises the following steps: carrying out carboxyl activation on a compound as shown in a formula (VI) to prepare a compound as shown in a formula (VII), and condensing the compound as shown in the formula (VII) and a compound as shown in a formula (VIII) to prepare a compound as shown in a formula (II). The invention provides the method for liquid-phase synthesis of the semeglutide side chain key intermediate, the method is short in production period and mild in reaction condition, racemization of glutamic acid is effectively inhibited, the prepared key intermediate is high in purity, no racemization isomer impurity is generated, the yield is high, the total yield reaches 85%, and the method is suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the field of polypeptide synthesis, and particularly relates to a key intermediate of the side chain of semaglutide. Background Art

[0002] Semaglutide Injection (trade name OZEMPIC) is developed by Novo Nordisk. It is a GLP hypoglycemic drug for the treatment of type 2 diabetes in adults, administered by subcutaneous injection once a week. It was approved by the FDA for market on December 6, 2017, but has not been launched in China yet. Indications: OZEMPIC is designated as an adjunct to diet and exercise to improve blood glucose control in patients with type 2 diabetes. Its chemical structure is as follows:

[0003]

[0004] Its key intermediate of the side chain consists of one molecule of monobutyl octadecanedioate, one molecule of L-glutamic acid 1-tert-butyl ester, and one molecule of 17-amino-10-oxo-3,6,12,15-tetraoxa-9-azapentadecanoic acid. Its chemical structure is as follows:

[0005]

[0006] Currently, Patent CN110423251A discloses a preparation method of the compound of formula (II), and the route is as follows:

[0007]

[0008] In the reaction route of this patent, NaH is used, which has safety problems in production, the synthesis method is cumbersome, the reaction steps are long, and the intermediate is not easy to purify.

[0009] Patent CN111269137A discloses a preparation method of the compound of formula (II), and the route is as follows:

[0010]

[0011] The reaction route of this patent is relatively long, there are many steps of protection and deprotection, the intermediate is not easy to purify, and NaH is used in the reaction, which has safety problems in production.

[0012] In addition, patents such as CN101133082A and CN109369798A are all for the solid-phase synthesis of the compound of formula (I), with relatively high costs and not suitable for industrial production. Summary of the Invention

[0013] The purpose of the present invention is to provide a new method for preparing the compound of formula (II). The steps of this method are as follows

[0014] Step a: In the presence of a condensation reagent and a carboxyl activating reagent, a compound of formula (III) is used to prepare a carboxylic acid active ester compound of formula (IV);

[0015] Step b: After condensation of the compound of formula (IV) and the compound of formula (V), a compound of formula (VI) is prepared;

[0016] Step c: After carboxyl activation of the compound of formula (VI), a compound of formula (VII) is prepared;

[0017] Step d: After condensation of the compound of formula (VII) and the compound of formula (VIII), a compound of formula (II) is prepared.

[0018] One of the synthetic routes of the present invention is as follows:

[0019]

[0020] This method may further include the following steps:

[0021] In the presence of a condensation reagent and a carboxyl activating reagent, a compound of formula (III) is used to prepare a carboxylic acid active ester compound of formula (IV).

[0022] According to one aspect of the method of the present invention, the above-mentioned condensation reagent is selected from dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC), 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), preferably dicyclohexylcarbodiimide (DCC).

[0023] According to one aspect of the method of the present invention, the above-mentioned carboxyl activating reagent is selected from N-hydroxysuccinimide (HOSu), N-hydroxy-5-norbornene-2,3-dicarboximide (HONB), 1-hydroxybenzotriazole (HOBt), 1-hydroxy-7-azabenzotriazole (HOAt), preferably N-hydroxysuccinimide (HOSu).

[0024] According to one aspect of the method of the present invention, the reaction molar ratio of the above-mentioned condensation reagent and carboxyl activating reagent is selected from 1.0:1.0, 1.2:1.2, 1.5:1.5, 1.8:1.8, 2.0:2.0, 3.0:3.0, preferably 1.5:1.5.

[0025] According to one aspect of the method of the present invention, the above-mentioned reaction temperature is selected from -5 to 5°C, 5 to 15°C, 15 to 25°C, 25 to 35°C, preferably 15 to 25°C.

[0026] According to one aspect of the method of the present invention, the above-mentioned reaction time is selected from 8h, 16h, 24h, 36h, 48h, preferably 24h.

[0027] According to one aspect of the method of the present invention, the above reaction solvent is selected from dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, N-methylpyrrolidone, ethyl acetate, 1,4-dioxane, preferably dichloromethane.

[0028] The compound of formula (IV) and the compound of formula (V) are condensed under basic conditions to obtain the compound of formula (VI).

[0029] According to one aspect of the method of the present invention, the above base is selected from triethylamine, diisopropylethylamine, N-methylmorpholine, sodium carbonate, sodium bicarbonate, potassium carbonate, preferably diisopropylethylamine.

[0030] According to one aspect of the method of the present invention, the equivalent of the above base is selected from 1 to 5 equivalents, preferably 3 equivalents.

[0031] According to one aspect of the method of the present invention, the equivalent of the compound of formula (V) is selected from 1 to 5 equivalents, preferably 2 equivalents.

[0032] According to one aspect of the method of the present invention, the above reaction temperature is selected from -5 to 5 °C, 5 to 15 °C, 15 to 25 °C, 25 to 35 °C, preferably 15 to 25 °C.

[0033] According to one aspect of the method of the present invention, the above reaction time is selected from 8 h, 16 h, 24 h, 36 h, 48 h, preferably 24 h.

[0034] According to one aspect of the method of the present invention, the above reaction solvent is selected from dichloromethane, tetrahydrofuran, acetone, ethyl acetate, acetonitrile, methyl tert-butyl ether, preferably tetrahydrofuran.

[0035] The compound of formula (VI) is prepared in the presence of a condensing agent and a carboxyl activating agent to obtain the carboxylic acid active ester compound of formula (VII).

[0036] According to one aspect of the method of the present invention, the above condensing agent is selected from dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC), 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), preferably dicyclohexylcarbodiimide (DCC).

[0037] According to one aspect of the method of the present invention, the above carboxyl activating agent is selected from N-hydroxysuccinimide (HOSu), N-hydroxy-5-norbornene-2,3-dicarboximide (HONB), 1-hydroxybenzotriazole (HOBt), 1-hydroxy-7-azabenzotriazole (HOAt), preferably N-hydroxysuccinimide (HOSu).

[0038] According to one aspect of the method of the present invention, the reaction molar ratio of the above condensation reagent and carboxyl activating reagent is selected from 1.0:1.0, 1.2:1.2, 1.5:1.5, 1.8:1.8, 2.0:2.0, 3.0:3.0, preferably 1.5:1.5.

[0039] According to one aspect of the method of the present invention, the above reaction temperature is selected from -5 to 5 °C, 5 to 15 °C, 15 to 25 °C, 25 to 35 °C, preferably 15 to 25 °C.

[0040] According to one aspect of the method of the present invention, the above reaction time is selected from 8 h, 16 h, 24 h, 36 h, 48 h, preferably 24 h.

[0041] According to one aspect of the method of the present invention, the above reaction solvent is selected from dichloromethane, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, N-methylpyrrolidone, ethyl acetate, 1,4-dioxane, preferably dichloromethane.

[0042] The compound of formula (VII) and the compound of formula (VIII) are condensed under basic conditions to obtain the compound of formula (II).

[0043] According to one aspect of the method of the present invention, the above base is selected from triethylamine, diisopropylethylamine, N-methylmorpholine, sodium carbonate, sodium bicarbonate, potassium carbonate, preferably diisopropylethylamine.

[0044] According to one aspect of the method of the present invention, the equivalent of the above base is selected from 1 to 5 equivalents, preferably 3 equivalents.

[0045] According to one aspect of the method of the present invention, the equivalent of the compound of formula (VIII) is selected from 1 to 5 equivalents, preferably 2 equivalents.

[0046] According to one aspect of the method of the present invention, the above reaction temperature is selected from -5 to 5 °C, 5 to 15 °C, 15 to 25 °C, 25 to 35 °C, preferably 15 to 25 °C.

[0047] According to one aspect of the method of the present invention, the above reaction time is selected from 8 h, 16 h, 24 h, 36 h, 48 h, preferably 24 h.

[0048] According to one aspect of the method of the present invention, the above reaction solvent is selected from dichloromethane, tetrahydrofuran, acetone, ethyl acetate, acetonitrile, methyl tert-butyl ether, preferably tetrahydrofuran.

[0049] The present invention uses the compound of formula (III) as the starting material. After carboxyl activation, the compound of formula (IV) is prepared. After condensation of the compound of formula (IV) and the compound of formula (V), the compound of formula (VI) is prepared. After carboxyl activation of the compound of formula (VI), the compound of formula (VII) is prepared. After condensation of the compound of formula (VII) and the compound of formula (VIII), the compound of formula (II) is prepared. The raw materials used in this method are easily available, the synthetic route is short, the conditions are mild, the yield is high, the product quality is good, and it is suitable for industrial production. Description of the Drawings

[0050] Figure 1 It is the liquid phase detection spectrum of intermediate (II);

[0051] Figure 2 It is the isomer detection spectrum of intermediate (II);

[0052] Figure 3 It is the liquid phase detection spectrum of intermediate (II);

[0053] Figure 4 It is the isomer detection spectrum of intermediate (II). Detailed Description of the Invention

[0054] Example 1 Preparation of the Compound of Formula (IV)

[0055]

[0056] Take 74 g of the compound of formula (III), 61.8 g of DCC, 34.4 g of HOSu, 1000 mL of dichloromethane, react at 15 - 25 °C for 24 hours, filter, wash the filtrate with 1000 mL of 10% sodium bisulfate solution, 1000 mL of saturated sodium bicarbonate solution, and 1000 mL of saturated brine respectively. The dichloromethane layer is dried, filtered, and concentrated to obtain a off-white solid of the compound of formula (IV) with a purity of 98.6% and a yield of 95%.

[0057] Example 2 Preparation of the Compound of Formula (IV)

[0058] Take 100 g of the compound of formula (III), 83.5 g of DCC, 46.6 g of HOSu, 1500 mL of dichloromethane, react at 15 - 25 °C for 24 hours, filter, wash the filtrate with 1500 mL of 10% sodium bisulfate solution, 1500 mL of saturated sodium bicarbonate solution, and 1500 mL of saturated brine respectively. The dichloromethane layer is dried, filtered, and concentrated to obtain a off-white solid of the compound of formula (IV) with a purity of 98.8% and a yield of 96%.

[0059] Example 3 Preparation of the Compound of Formula (VI)

[0060]

[0061] Take 46.7 g of the compound of formula (IV), 40.6 g of the compound of formula (V), 500 mL of tetrahydrofuran, 38.7 g of diisopropylethylamine, and react at 15 - 25 °C for 24 hours. Concentrate the reaction solution. Add 500 mL of dichloromethane and 500 mL of 10% sodium bisulfate solution to the concentrate, stir and separate the layers. Wash the dichloromethane layer with 500 mL of saturated sodium bicarbonate solution and 500 mL of saturated brine respectively. Dry, filter, and concentrate the dichloromethane layer. Add isopropyl ether to the concentrate for crystallization, filter, and dry to obtain a white solid of the compound of formula (VI) with a purity of 99.2% and a yield of 95%.

[0062] Preparation of the compound of formula (VI) in Example 4

[0063] Take 100 g of the compound of formula (IV), 86.9 g of the compound of formula (V), 1000 mL of tetrahydrofuran, 82.9 g of diisopropylethylamine, and react at 15 - 25 °C for 24 hours. Concentrate the reaction solution. Add 1000 mL of dichloromethane and 1000 mL of 10% sodium bisulfate solution to the concentrate, stir and separate the layers. Wash the dichloromethane layer with 500 mL of saturated sodium bicarbonate solution and 1000 mL of saturated brine respectively. Dry, filter, and concentrate the dichloromethane layer. Add isopropyl ether to the concentrate for crystallization, filter, and dry to obtain a white solid of the compound of formula (VI) with a purity of 99.5% and a yield of 95%.

[0064] Preparation of the compound of formula (VII) in Example 5

[0065]

[0066] Take 55.6 g of the compound of formula (VI), 30.9 g of DCC, 17.2 g of HOSu, 600 mL of dichloromethane, and react at 15 - 25 °C for 24 hours. Filter, and wash the filtrate with 600 mL of 10% sodium bisulfate solution, 600 mL of saturated sodium bicarbonate solution, and 600 mL of saturated brine respectively. Dry, filter, and concentrate the dichloromethane layer to obtain a white solid of the compound of formula (IV) with a purity of 98.8% and a yield of 96%.

[0067] Preparation of the compound of formula (VII) in Example 6

[0068] Take 100 g of the compound of formula (VI), 55.6 g of DCC, 31.0 g of HOSu, 1000 mL of dichloromethane, and react at 15 - 25 °C for 24 hours. Filter, and wash the filtrate with 1000 mL of 10% sodium bisulfate solution, 1000 mL of saturated sodium bicarbonate solution, and 1000 mL of saturated brine respectively. Dry, filter, and concentrate the dichloromethane layer to obtain a white solid of the compound of formula (IV) with a purity of 98.2% and a yield of 95%.

[0069] Synthesis of the Compound of Formula (II) in Example 7

[0070]

[0071] Take 65.2 g of the compound of formula (VII), 61.5 g of the compound of formula (VIII), 650 mL of tetrahydrofuran, and 38.7 g of diisopropylethylamine, and react at 15 - 25 °C for 24 hours. Concentrate the reaction solution. Add 650 mL of dichloromethane and 500 mL of 10% sodium bisulfate solution to the concentrate, stir and separate the layers. Wash the dichloromethane layer with purified water until the pH is neutral. Dry the dichloromethane layer, filter, and concentrate to obtain a slightly yellow oily substance of the compound of formula (II) with a purity of 99.46%, no isomers detected, and a yield of 97%. Its HPLC spectrum is as shown in Figure 1 shown, and the isomer detection spectrum is as shown in Figure 2 shown.

[0072] Synthesis of the Compound of Formula (II) in Example 8

[0073] Take 200 g of the compound of formula (VII), 188.9 g of the compound of formula (VIII), 2000 mL of tetrahydrofuran, and 118.7 g of diisopropylethylamine, and react at 15 - 25 °C for 24 hours. Concentrate the reaction solution. Add 2000 mL of dichloromethane and 2000 mL of 10% sodium bisulfate solution to the concentrate, stir and separate the layers. Wash the dichloromethane layer with purified water until the pH is neutral. Dry the dichloromethane layer, filter, and concentrate to obtain a slightly yellow oily substance of the compound of formula (II) with a purity of 99.39%, no isomers detected, and a yield of 97%. Its HPLC spectrum is as shown in Figure 3 shown, and the isomer detection spectrum is as shown in Figure 4 shown

[0074] The present invention provides a method for the liquid-phase synthesis of the key intermediate of the side chain of semaglutide. This method has a short production cycle, mild reaction conditions, effectively inhibits the racemization of glutamic acid, the obtained key intermediate has high purity, no generation of racemic isomer impurities, high yield, and the total yield reaches 85%, which is suitable for industrial production.

[0075] It should be noted that the above preferred embodiments are only used to illustrate the technical concept and characteristics of the present invention. The purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for synthesizing a key intermediate compound of the side chain of semaglutide of formula (II), characterized in that, The synthetic route of the compound of formula (II) is as follows: Step a: In the presence of a condensation reagent and a carboxyl activating reagent, the compound of formula (III) is used to prepare the carboxylic acid active ester of formula (IV); Step b: After the condensation of the compound of formula (IV) and the compound of formula (V), the compound of formula (VI) is prepared; Step c: After the carboxyl group of the compound of formula (VI) is activated, the compound of formula (VII) is prepared; Step d: After the condensation of the compound of formula (VII) and the compound of formula (VIII), the compound of formula (II) is prepared.

2. The synthesis method of the key intermediate compound of the side chain of semaglutide of formula (II) according to claim 1, characterized in that, The condensation reagent is selected from dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and the carboxyl activating reagent is selected from N-hydroxysuccinimide, N-hydroxy-5-norbornene-2,3-dicarboximide, 1-hydroxybenzotriazole, 1-hydroxy-7-azabenzotriazole. The reaction molar ratio of the condensation reagent and the carboxyl activating reagent is selected from 1.0:1.0, 1.2:1.2, 1.5:1.5, 1.8:1.8, 2.0:2.0, 3.0:3.

0.

3. The synthesis method of the key intermediate compound of the side chain of semaglutide of formula (II) according to claim 2, characterized in that, The condensation reagent is dicyclohexylcarbodiimide, the carboxyl activating reagent is N-hydroxysuccinimide, the reaction molar ratio of the condensation reagent and the carboxyl activating reagent is 1.5:1.5, and the reaction temperature of step a is 15-25 °C.

4. The synthesis method of the key intermediate compound of the side chain of semaglutide of formula (II) according to claim 3, characterized in that, In step b, the compound of formula (IV) and the compound of formula (V) are condensed under alkaline conditions to prepare the compound of formula (VI), and the base is selected from triethylamine, diisopropylethylamine, N-methylmorpholine, sodium carbonate, sodium bicarbonate, potassium carbonate.

5. The synthesis method of the key intermediate compound of the side chain of semaglutide of formula (II) according to claim 4, characterized in that, The base is diisopropylethylamine, the diisopropylethylamine is 3 equivalents, the compound of formula (V) is 2 equivalents, and the reaction temperature is 15-25 °C.

6. The synthesis method of the key intermediate compound of the side chain of semaglutide of formula (II) according to claim 5, characterized in that, In step c, in the presence of a condensation reagent and a carboxyl activating reagent, the compound of formula (VI) is used to prepare the carboxylic acid active ester of formula (VII).

7. The synthesis method of the key intermediate compound of the side chain of semaglutide of formula (II) according to claim 6, characterized in that, The condensation reagent is selected from dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, preferably dicyclohexylcarbodiimide, and the carboxyl activating reagent is selected from N-hydroxysuccinimide, N-hydroxy-5-norbornene-2,3-dicarboximide (HONB), 1-hydroxybenzotriazole (HOBt), 1-hydroxy-7-azabenzotriazole. The reaction molar ratio of the condensation reagent and the carboxyl activating reagent is selected from 1.0:1.0, 1.2:1.2, 1.5:1.5, 1.8:1.8, 2.0:2.0, 3.0:3.

0.

8. The synthesis method of the key intermediate compound of the side chain of semaglutide of formula (II) according to claim 7, characterized in that, The condensation reagent is dicyclohexylcarbodiimide (DCC), the carboxyl activating reagent is N-hydroxysuccinimide, the reaction molar ratio of the condensation reagent and the carboxyl activating reagent is 1.5:1.5, and the reaction temperature is 15-25 °C.

9. The synthesis method of the key intermediate formula (II) compound of the side chain of semaglutide according to claim 8, characterized in that, In step d, the compound of formula (VII) and the compound of formula (VIII) are condensed under basic conditions to obtain the compound of formula (II). The base is diisopropylethylamine, the amount of the base is 3 equivalents, the amount of the compound of formula (VIII) is 2 equivalents, and the reaction temperature is 15-25 °C.

10. The synthesis method of the key intermediate compound of the side chain of semaglutide of formula (II) according to claim 1, characterized in that, The synthetic route for the synthesis of the key intermediate of the side chain of semaglutide, the compound of formula (II), is as follows:

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