WO2013044714A1

WO2013044714A1 - New method for preparing d-isoglutamyl-d-tryptophan

Info

Publication number: WO2013044714A1
Application number: PCT/CN2012/080754
Authority: WO
Inventors: 曾国良; 陆永章; 黄怀; 刘建; 马亚平; 袁建成
Original assignee: 深圳翰宇药业股份有限公司
Priority date: 2011-09-26
Filing date: 2012-08-30
Publication date: 2013-04-04
Also published as: CN102417474A; CN102417474B

Abstract

A preparation method of D-isoglutamyl-D-tryptophan (D-iGlu-D-Trp-OH) comprises the following steps: (A) activating R¹-D-Glu-OR² under an HONb condition, to obtain R¹-D-Glu(ONb)-OR² (II); condensing with D-Trp-OR² in an alkaline condition, to obtain R¹-D-Glu(D-Trp-OR²)-OR² (IV), and purifying the product through crystallization; and (C) removing protection groups R¹ and R² through hydrogenation, to obtain D-iGlu-D-Trp-OH (V).

Description

A new method for the preparation of D-isoglutamyl-D-tryptophan

This application claims priority to Chinese Patent Application filed on Sep. 26, 2011, to the Chinese Patent Office, Application No. 201110288091.X, entitled "D-Isoglutamyl-D-Tryptophan Preparation" The entire contents of which are incorporated herein by reference. Technical field

The present invention relates to a process for the preparation of a dipeptide, and more particularly to a process for the preparation of D-iGlu-D-Trp-OH. Background technique

D-isoglutamine-D-tryptophan, English chemical name: (R-amino-S-i R -l-carboxy-S- lH-indoU-yDethylaminc -S-oxopentanoic acid, another il

H-D-y-Glu-D-Trp-OH, H-D-iGlu-D-Trp-OH, iDD or D-iEW, is a synthetic blood-regulating dipeptide with a molecular weight of 333.34, CAS registration number: 186087-26-3. Has the following chemical structure (1):

US 5736519 uses Boc-D-Glu-OH and D-Trp-OH as raw materials, and is decondensed by DCC to obtain a mixture of D-Glu-D-Trp-OH and D-iGlu-D-Trp-OH. . Finally, D-Glu-D-Trp-OH was isolated by Sephadex SP-PEA ion exchange chromatography column.

D-iGlu-D-Trp-OH, yield 12.25%. An obvious feature of this synthesis method is that the reaction is not selective, and D-Glu-D-Trp-OH and D-iGlu-D-Trp-OH are obtained, which reduces the synthesis yield and the difficulty of purification. increase. WO2008064465 points out that there are still three shortcomings in this method. 1. The following by-products (Compound 3, Compound 4) may be produced during the DCC condensation process.

2. Boc-D-iGlu-D-Trp-OH deprotection requires elevated temperature and requires more toxic pyridine. An increase in temperature may result in the formation of an N-tert-butylfluorene derivative (Compound 5), and in addition, the peptide may also be cyclized to give a diimide (Compound 6).

3. The coupling reaction can only produce a mixture of Boc-D-Glu-D-Trp-OH and Boc-D-iGlu-D-Trp-OH, in order to enrich D-iGlu-D-Trp-OH, multiple times Separation cycle, low efficiency, not suitable for large-scale production.

The carboxy protecting group in the synthetic method described in WO2008064465 employs a benzyl group or an alkyl group of 1 to 4 C atoms, and thus relates to the problem of deprotection with an alkali. The advantages of the method: 1. The α-carboxyl protection of Glu avoids the formation of Boc-D-Glu-D-Trp-OH, and the reaction is selective. 2. The impurity by-product (compound 7, compound 8) produced by HOBt used in the coupling process can be purified by crystallization to obtain a monoammonium salt, which does not need to be purified by HPLC.

There is also a big problem with this method. D-Trp-OH is relatively easy to racemization, and deprotection with alkali may occur in the case of racemization, which is disadvantageous for subsequent purification. Summary of the invention

SUMMARY OF THE INVENTION The object of the present invention is to provide a high yield, high purity D-iGlu-D-Trp-OH synthesis method which overcomes the deficiencies of the prior art. The advantage of this method is that the route is short, the raw materials are cheap and easy to obtain, the synthesis process produces less impurities and is easy to purify. The total yield is over 48%, which can greatly reduce the cost of synthesis and purification.

The synthesis method described in the present invention is characterized by comprising the following steps:

(A^iD-Glu-OR ² is activated under HONb conditions to obtain R^-D-Glu ONb OR ² (II); II is initially purified and used;

O

,

One Q

: M O'

i

(8)

(11) condensing with D-Trp-OR ² under basic conditions to obtain R^D-Glu(D-Trp-OR ² )-OR ² (IV), which is purified;

(C) R'-D-Glu ( D-Trp-OR ² ) -OR ² ( IV ) Deprotection of protecting groups R ¹ and R by hydrogenation ^: obtaining D-iGlu-D-Trp-OH ( V )

Hydrogenation

(D) Purification.

Wherein R^-H, -C0 ₂ CH ₂ C ₆ H ₅ , -C0 ₂ CH ₂ C ₆ H ₄ Br, -C0 ₂ CH ₂ C ₆ H ₄ C1,

-C0 ₂ CH ₂ C ₆ H ₄ N0 ₂ , -C0 ₂ CH ₂ C ₆ H ₄ OCH; R ² = -CH ₂ C ₆ H ₅ , -CH ₂ C ₆ H ₄ Br,

-CH ₂ C ₆ H ₄ C1, -CH ₂ C ₆ H ₄ N0 ₂ , -CH ₂ C ₆ H ₄ OCH ₃ . Preferred:

- ':■'

■,,,, ■.( ,■, "Br

) , . . . . o, — f oc3⁄4 ', ,,, ”

More preferably: phenyl decyl ester group, i.e., -OBzl.

In the present invention, the amino group of D-glutamic acid is protected with R ¹ , the main chain carboxyl group is protected with R ² , and glutamic acid is activated by HONb to participate in the condensation reaction. The main chain carboxyl group of glutamic acid is protected by R ² , and the main purpose is to increase the selectivity of the reaction and reduce the purification step. In the present invention, the carboxyl group of D-tryptophan is protected with R ² . R ¹ and R ² simultaneously employ a hydrogenatable benzyloxycarbonyl group (or a benzyloxycarbonyl group in which the phenyl ring is substituted in the para position) and a benzyl ester (or a benzyl ester in which the phenyl ring is substituted in the para position) to reduce the deprotection step.

The solvent used in the activation of HONb on the R^-D-Glu-OR ² in the present invention may be a halogenated hydrocarbon such as: dichlorodecane, chloroform, 1,2-dichloroethane or tetrachloro Carbon, etc., or aliphatic hydrocarbons, such as acetonitrile, ethyl acetate, etc., or aromatic hydrocarbons, such as toluene, diphenylbenzene, nitrobenzene, various halogenated benzenes, etc., or ether solvents, such as: tetrahydrofuran, diethyl ether, The dioxane or the like may be carried out in a single solvent or in a mixture of any two or more thereof, preferably THF.

The condensation step of the present invention uses a condensing agent, and the coupling agent includes dicyclohexylcarbodiimide (DCC), hydrazine, Ν'-diisopropylcarbodiimide (DIC), 1-(3-diaminopropylpropyl). )-3-ethylcarbodiimide (EDC), benzene And triazole tetradecyltetrafluoroboric acid (TBTU).

The condensation step of the present invention uses a solvent, the solvent is an organic solvent or water, and the organic solvent may be a halogenated hydrocarbon such as dichlorosilane, chloroform, 1,2-dichloroethane or carbon tetrachloride, or an aliphatic hydrocarbon. For example, acetonitrile, ethyl acetate, etc., or aromatic hydrocarbons: toluene, diphenylbenzene, nitrobenzene, various benzenes, etc. or ether solvents, such as: tetrahydrofuran, diethyl ether, dioxane, etc., the reaction can be in a single solvent It can also be carried out in a mixture of any two or more of them. It is preferably water.

The base used in the condensation step of the present invention is an organic base or an inorganic base. The organic base may be triethylamine, diethylamine or N-mercaptomorpholine or the like. The inorganic base may be sodium hydrogencarbonate, potassium hydrogencarbonate, sodium carbonate, potassium carbonate, sodium hydroxide or potassium hydroxide. It is preferably sodium hydrogencarbonate.

In the present invention, R^-D-Glu(D-Trp-OR ² ) -OR ² ( IV ) is purified by crystallization, and the crystallization solvent includes ethyl acetate, diethyl ether, tetrahydrofuran, dichlorodecane, trichlorodecane. , petroleum ether, n-hexane, n-heptane, etc. or a mixture of any two or more thereof. It is preferably ethyl acetate/petroleum ether. The HPLC purity of R^D-Glu(ϋ-Τ-OR ² ) -OR ² ( IV ) was 99.5%, the ee value was 99.9%, and the single impurity was <0.1%. Yield: 81.1%. No derivative of DCC was found in R^D-Glu(D-Trp-OR ² ) -OR ² ( IV ) after crystallization purification.

The hydrogenation step of the present invention can be carried out in two ways, catalytic hydrogenation and hydrogen transfer catalysis. The catalyst is used for catalytic hydrogenation. The catalyst includes Pd/C, Raney nickel, Pt, Pt/C, Pt0 ₂ , Pd(OH) ₂ , R/C, RhCl(PPh ₃ ) _{3 ,} etc., Pd/C, Rh/C or The Pt/C is a metal nanoparticle or oxide particle of Pd, Rh or Pt supported on carbon, and the carbon may be CNT (carbon nanotube) or a carbon thin film, or may be a carbon material such as activated carbon.

The catalytic hydrogenation can be carried out at room temperature or heating, and the temperature range is: 20-80 ° C; the hydrogen pressure can be l-10 Atm; the catalyst addition ratio is equivalent to 5-200% of the substrate mass. The preferred conditions are that the catalyst is Pd/C, the temperature is 20 ° C, the hydrogen gas pressure is lOAtm, and the catalyst addition ratio is equivalent to 100% of the substrate mass.

Hydrogen transfer catalysis does not use hydrogen directly, safe and easy to operate. The hydrogen donor involved in the reaction includes cyclohexene, Cyclohexadiene, citric acid, ammonium citrate, tetrahydronaphthalene, and the like. The reaction may be carried out using a single hydrogen donor or a mixture of any two or more of them. Preferred is citric acid.

The solvent used in the hydrogenation step of the present invention may be decyl alcohol, tetrahydrofuran, ethyl acetate, dioxane or the like or a mixture of any two or more thereof. Preferred is decyl alcohol.

The purification of D-iGlu-D-Trp-OH in the present invention can be obtained by crystallization. The crude aqueous solution of D-iGlu-D-Trp-OH obtained in the step (C) was adjusted to its isoelectric point, and D-iGlu-D-Trp-OH was precipitated in an aqueous solution, and the precipitate was filtered and dried in vacuo. Preferably, the crude D-iGlu-D-Trp-OH is dissolved in water, and an aqueous solution having a concentration of 5-200 mg/ml is disposed, and the pH of the solution is adjusted to its isoelectric point.

D-iGlu-D-Trp-OH is precipitated in an aqueous solution, and the precipitate is filtered and dried under vacuum.

D-iGlu-D-Trp-OH.

The purification of D-iGlu-D-Trp-OH in the present invention can be obtained by a washing method.

The crude D-iGlu-D-Trp-OH was dissolved in water, adjusted to pH 3.0 with acid, and evaporated to dryness. Ethanol or decyl alcohol was added to the residue, stirred vigorously, and the insoluble material was removed by filtration. The filtrate was evaporated and dried to give a white solid.

In the present invention, D-iGlu-D-Trp-OH can be purified by using an ion exchange resin.

The crude D-iGlu-D-Trp-OH was dissolved in water, adsorbed with an ionic resin, rinsed with deionized water, and then desorbed with dilute aqueous ammonia or dilute hydrochloric acid. Concentrated, lyophilized to give D-iGlu-D-Trp-OH.

An advantage of the present invention is that it does not have a racemization during the condensation process. The intermediate R^-D-Glu ( D-Trp-OR ² ) -OR ² ( IV ) can be purified by crystallization, product purity >99%, ee value >99%, single impurity <0.1%, does not contain existing DCC derivative impurities introduced by DCC as reported in the art. It is indicated that the impurities generated in this step can be controlled by means of crystallization. -D-Glu ( D-Trp-OR ² ) -OR ² ( IV ) is reduced by hydrogenation except for R^-D-Glu ( D-Trp-OR ² ) -OR ² ( IV ) No other impurities that are difficult to purify are produced outside. Therefore, by controlling the amount of impurities in -D-Glu (D-Trp-OR ² ) -OR ² ( IV ), the impurities in the subsequent products can be well controlled, and the purification cost of the subsequent steps can be reduced. The scheme has few steps and the raw materials are easily available. Compared with the methods reported in the literature, the synthesis yield of D-iGlu-D-Trp-OH is greatly improved, which is beneficial to cost saving. DRAWINGS

Figure 1 is a UV detector map of D-iGlu-D-Trp-OH purified by Amberlyst 15 resin; Figure 2: Ultraviolet detector map of D-iGlu-D-Trp-OH purified by GA4-X4 Resin. detailed description

The invention discloses a novel method for preparing D-isoglutamyl-D-tryptophan, and those skilled in the art can learn from the contents of the paper and appropriately improve the process parameters. It is to be noted that all such alternatives and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The method and the application of the present invention have been described by the preferred embodiments, and it is obvious that the method and application described herein may be modified or appropriately modified and combined without departing from the scope of the present invention. The technique of the present invention is applied.

In order to make those skilled in the art better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to specific embodiments. Example 1 : Synthesis of Z-D-Glu(ONb)-OBzl

ZD-Glu-OBzl (7.4 g, 20 mmol) and HONb (3.9 g, 22 mmol) were added to a 100 ml two-neck round bottom flask, which was stirred and dissolved with 50 mL of THF. DCC (4.5 g, 2.2 mmol) was dissolved in 10 mL of THF. The reaction mixture was filtered, the filtrate was concentrated by rotary evaporation to dryness with Et ₂ 0 / DCM residual oil was dissolved (V:: V = 5 1 ), filtered to remove insolubles lh after standing, the filtrate was concentrated by rotary evaporation to dryness after Dissolved in 10 mL of THF for use, hereinafter referred to as "activated ester THF solution". Example 2: Synthesis of ZD-Glu ( D-Trp-OBzl ) -OBzl

Add D-Trp-OBzLHCl (6.6g, 20mmol) and NaHC03 (6.7g, mmol) to a 250ml two-necked in-situ flask, dissolve in 40mL deionized water, add 30mL THF and stir for 10min, slowly The activated ester THF solution prepared in Example 1 was added dropwise and stirred at room temperature for 4 h. After the reaction mixture was evaporated to dryness crystals crystals crystals crystals crystals The crude product was recrystallized twice with THF / petroleum ether (V:V = 10:1) to yield 10.5 g of ZD-Glu(D-Trp-OBzl)-OBzl white solid, HPLC: 99.5%, ee: 99.9%, single Miscellaneous <0.1%. Yield: 81.1%. ESI-MS: 648.2 (M+H+), 670.1 (M+Na+); 400-MHz lH NMR (DMSO-d6) 510.901 (s,lH, NH-indoel), 8.416 (d, 1 H, amide ), 7.855 ( d, lH, amide ), 7.533-6.992 ( m, 20H, CH-benzene ) , 5.158-5.003 (m, 6H, CH2-benzene methylene), 4.633 ( m, 1H, α-CH of D-Trp ), 4.192 ( m, 1H, a-CH of D-Glu ), 3.227-3.079 ( m, 2H, methylene of D-Trp ), 2.295-1.844 ( m, 4H, methylene of D-Glu ); 300-MHz 13C NMR (DMSO- D6) 5172.42-156.59 ( C=0, carboxyl or amide ) , 137.27-109.77 ( indoel of benzene ) 66.37-65.98 ( CH2 -benzene methylene ), 54.07-53.76 ( a-CH of AA ) , 31.63-26.87 ( methylene of AA). Example 3: Synthesis of ZD-Glu ( D-Trp-OBzl ) -OBzl

Add D-Trp-OBzLHCl (6.6g, 20mmol) and NaHC03 to a 250ml two-necked flask

(6.7 g, mmol), dissolved in 40 mL of deionized water, added with 30 mL of THF and stirred for 10 min, and slowly added dropwise the activated ester THF solution prepared in Example 1 and stirred at room temperature for 4 h. The reaction mixture was evaporated to dryness crystals crystals crystals crystals The crude product was recrystallized twice from ethyl acetate / petroleum ether (V:V = 8:1) to yield 10.5 g of ZD-Glu(D-Trp-OBzl)-OBzl white solid, HPLC: 99.2%, yield: 77.3% . Example 4:

Add ZD-Glu ( D-Trp-OBzl ) -OBzl ( l.Og, 1.5mmol ) to the reaction vessel, dissolve it with 50mL of decyl alcohol, add 1.0g of 10% Pd/C, pass hydrogen gas, keep the pressure at lAtm , heated to 80 ° C and stirred for 20 h. The reaction mixture was filtered to give a colourless solvent. HPLC>99.0%. Yield: 95. 0%. ESI-MS: 334.1 ( Μ+Η+ ) , 356.1 ( M+Na+ ); 500-MHz 3⁄4

NMR (DMSO-d ₆ ) 510.8670 ( s, lH, COOH ) , 8.1150 ( d, lH, amide ), 7.5185-6.9116

( m, 5H, CH- indoel ), 4.2464 ( m, 1H, α-CH of D-Trp ) , 3.2618 ( m, 1H, a-CH of D-Glu ), 3.2240-2.8872 ( m, 2H, methylene of D -Trp ), 2.2548-1.7970 (m, 4H, methylene of D-Glu ); 500-MHz ¹³ C NMR (DMSO-d ₆ ) 5178.528

(COOH) , 173.919 ( C=0, amide ) , 136.215-110.637 ( indoel ), 55.955 ( a-CH of D-Trp ), 54.441 ( a-CH of D-Glu ), 32.031 ( methylene of D-Trp ), 27.619-26.449

( methylene of D-Glu ). Example 5

Add ZD-Glu ( D-Trp-OBzl ) -OBzl ( l.Og, 1.5mmol ) to the reaction vessel, dissolve it with 50mL of decyl alcohol, add 1.0g of 10% Pd/C, and add hydrogen gas to maintain the pressure of lOAtm. Stir at 20 ° C for 20 h. The reaction mixture was filtered to give aq. HPLC>99.0%. Yield: 93.0% Example 6:

Add ZD-Glu ( D-Trp-OBzl ) -OBzl ( l.Og, 1.5 mmol ) to the reaction vessel, dissolve it with 50 mL of decyl alcohol, and add 2.0 g of 10% Pd/C, ammonium citrate (1.Og, 16 mmol). ), stirred at room temperature for 20 h. The reaction solution was filtered to give a colorless aqueous solution, which was concentrated, then filtered with EtOAc EtOAc HPLC>99.0%. Yield: 63.0%. Example 7

Add ZD-Glu ( D-Trp-OBzl ) -OBzl ( l.Og, 1.5 mmol ) to the reaction vessel, dissolve it in 50 mL of THF, and add 0.05 g of 10% Pd/C, citric acid (50 ml, 1.33 mol), room temperature. Stir for 20 h. The reaction solution was filtered to give a colorless aqueous solution, which was concentrated and filtered with ion-exchange resin ( AG 4-X4 Resin ). Freeze to dryness to a white solid. HPLC>99.0 Yield: 68.0% Example 8:

Weigh 10g of D-iGlu-D-Τ-ΟΗ crude product, add 50ml of deionized water, stir and dissolve, add 1mol / L HOAc aqueous solution, adjust the pH to 3.0, D-iGlu-D-Trp-OH precipitates in aqueous solution, The precipitate was filtered and dried in vacuo to give D-iGlu-D-Trp-OH. HPLC>99.0%. Yield: 54.0%. Example 9

Weigh 10 g of D-iGlu-D-Τ-ΟΗ crude, add 500 ml of deionized water, adjust the pH to 3.0 with hydrochloric acid, and steam to dryness. Ethanol or decyl alcohol was added to the residue, stirred vigorously, and the insoluble material was filtered off, and the filtrate was evaporated to give a white solid. HPLC>99.0%. Yield: 51.0%. Example 10

After 100 g of Amberlyst 15 resin was activated by a 1 mol/L aqueous solution of sulphuric acid for 4 h, it was washed to neutrality and placed in a 3.5*30 cm column. 10 g of D-iGlu-D-Trp-OH was dissolved in 100 ml of deionized water, and the sample was added at a rate of 10 ml/min. After the sample was applied, it was eluted with 400 ml of deionized water until the effluent pH=6, and then washed with 1.0% ammonia water. Off, HD-21-88 UV detector monitors and collects samples. An elution solution having an ultraviolet absorption value greater than 0.12 (Fig. 1) was obtained, and concentrated to obtain a white solid, which was recrystallized from deionized water to give 8.5 g of white crystal D-iGlu-D-Trp-OH, HPLC >99.5%. Yield: 85%. Example 11:

100g GA4-X4 Resin was activated by lmol/L NaOH solution for 4h, then washed to neutral, loaded into a 3.5 * 30cm column, added to the sample at 5ml / min elution rate, 10g D-iGlu-D-Trp-OH Dissolved in 100 ml of deionized water, loaded with 300 ml of deionized water to elute to pH=6, then eluted with 1.0% hydrochloric acid solution, and monitored and collected by HD-21-88 UV detector. Ultraviolet absorption An elution solution having a value greater than 0.134 (Fig. 2) was concentrated to give a white solid which was recrystallized from deionized water to give 8.8 g of white crystals of D-iGlu-D-Trp-OH, HPLC >99.9%. Yield: 88%. The novel method for the preparation of D-isoglutamyl-D-tryptophan proposed by the present invention has been described by way of examples, and it will be apparent to those skilled in the art that the D described herein can be made without departing from the spirit, scope and scope of the invention. A novel method of preparing isoglutamyl-D-tryptophan is modified or combined and modified to achieve the teachings of the present invention. It is to be understood that all such alternatives and modifications are obvious to those skilled in the art and are considered to be included in the spirit, scope and content of the invention.

Claims

Rights request

A method for preparing D-isoglutamyl-D-tryptophan, comprising the steps of:

(A) RLD-GIU-OR ² is activated under HONb conditions to give R^-D-Glu ONb OR ² (II); (B) R ¹ -D-Glu(ONb)-OR ² (II) is alkaline Condensation with D-Trp-OR ² under conditions

R^D-Glu ( D-Trp-OR ² ) -OR ² ( IV ), crystal purification;

(C) R'-D-Glu ( D-Trp-OR ² ) -OR ² (IV) by removal of the protecting groups R ¹ and R ² by hydrogenation, to obtain D-iGlu-D-Trp-OH (V);

(D) purification;

Wherein R -H, -C0 ₂ CH ₂ C ₆ H ₅ , -C0 ₂ CH ₂ C ₆ H ₄ Br, -C0 ₂ CH ₂ C ₆ H ₄ C1,

-C0 ₂ CH ₂ C ₆ H ₄ N0 ₂ , -C0 ₂ CH ₂ C ₆ H ₄ OCH; R ² = -CH ₂ C ₆ 3⁄4, -CH ₂ C ₆ H ₄ Br,

-CH ₂ C ₆ H ₄ C1, -CH ₂ C ₆ H ₄ N0 ₂ , -CH ₂ C ₆ H ₄ OCH ₃ .

2. The preparation method according to claim 1, wherein: a coupling agent is used in the step (B), and the coupling agent comprises dicyclohexylcarbodiimide (DCC), hydrazine, Ν'-diisopropyl Carbodiimide ( DIC ), 1-(3-diaminopropyl)-3-ethylcarbodiimide (EDC), benzotriazole tetradecyltetrafluoroborate

(TBTU).

The preparation method according to claim 1, wherein the product (D-Grp(D-Trp-OR ² ) -OR ² ( IV ) in the step ( Β ) is purified by crystallization, and the crystallization solvent comprises Ethyl acetate, diethyl ether, tetrahydrofuran, dichlorodecane, trichlorodecane, petroleum ether, n-hexane, n-heptane or a mixed solvent of any two or more thereof.

The preparation method according to claim 2, wherein the product -D-Glu ( D-Trp-OR ² ) -OR ² ( IV ) in the step (B) is purified by crystallization, and the crystallization solvent comprises Ethyl acetate, diethyl ether, tetrahydrofuran, dichlorodecane, trichlorodecane, petroleum ether, n-hexane, n-heptane or a mixed solvent of any two or more thereof.

The preparation method according to any one of claims 1 to 4, wherein: step (C) The catalyst is used, and the catalyst includes Pd/C, Raney nickel, Pt, Pt/C, Pt0 ₂ , Pd(OH) ₂ , Rh/C, RhCl(PPh ₃ ) ₃ .

The preparation method according to any one of claims 1 to 4, wherein the hydrogenation in the step (C) is catalytic hydrogenation, the hydrogenation pressure is l-10 Atm, and the catalyst is added in a ratio of 5-200 corresponding to the mass of the substrate. %, the temperature is 20-80 °C.

The preparation method according to any one of claims 1 to 4, wherein the hydrogenation in the step (C) is hydrogen transfer catalysis, and the hydrogen donor includes cyclohexene, cyclohexadiene, decanoic acid, Ammonium citrate, tetrahydronaphthalene or a mixture of any two or more thereof.

The preparation method according to claim 6, wherein the solvent is used in the step (C), and the solvent comprises decyl alcohol, tetrahydrofuran, ethyl acetate, dioxane or a mixture of two or more thereof. .

9. The preparation method according to claim 7, wherein: the solvent is used in the step (C), and the solvent comprises decyl alcohol, tetrahydrofuran, ethyl acetate, dioxane or a mixture of two or more thereof. .

The preparation method according to any one of claims 1 to 4, wherein the step (D) purification comprises the steps of: adjusting the crude aqueous solution of D-iGlu-D-Trp-OH obtained in the step (C) to The isoelectric point was rotary evaporated to dryness, decyl alcohol or ethanol was added, stirred vigorously, filtered, and the filtrate was concentrated to a solid.