Method for preparing bifunctional amide

Abstract

Disclosed in the present invention is a method for preparing a bifunctional amide. Specifically, the method comprises the following step: in the presence of an alkali reagent, a solvent and an activating reagent, reacting compound (1) with compound (2), so as to obtain compound (3). The preparation method of the present invention involves a rapid reaction and mild reaction conditions, has high selectivity, a high yield, and products that are easily separated, and is suitable for industrial promotion.

Description

A method for preparing a bifunctional amide Technical Field

[0001] This invention relates to the field of organic synthesis, and more specifically to a method for preparing a bifunctional amide. Background Technology

[0002] In recent years, pharmaceutical researchers have discovered that long-chain compounds can be used to modify bioactive peptides, thereby improving their drug activity. For example, semaglutide, a drug used to treat diabetes, has a side chain as shown in the following formula:

[0003] According to literature reports, the presence of this side chain allows smegglutinin to bind more tightly to the target protein, thereby enhancing its drug activity.

[0004] The side chain of smegglutide is formed by the condensation of two molecules of 8-amino-3,6-dioxanoic acid, one molecule of glutamic acid, and one molecule of monobutyl octadecanoate. In existing technologies, the reaction of condensing two molecules of 8-amino-3,6-dioxanoic acid mostly uses condensing reagents such as DCC, DIC, HoBt / EDC, HUTA, or compounds such as N-hydroxysuccinimide esters. Although these compounds can achieve the condensation reaction well, they tend to generate trimers or polymers that are difficult to purify and remain in the target compound, causing difficulties in subsequent drug production.

[0005] Therefore, there is an urgent need in the field for a highly selective method for preparing smegglutinin side chains that allows for easy product separation.

[0006] Summary of the Invention

[0007] To address the above problems, this invention provides a method for preparing amides that is rapid, has mild reaction conditions, high selectivity, high yield, and easy product separation.

[0008] In a first aspect of the invention, a method for preparing a bifunctional amide is provided, the method comprising the following steps: reacting compound 1 with compound 2 in the presence of a base reagent, solvent A, and an activating reagent to obtain compound 3.

[0009] G1 is selected from the following group:

[0010] A 1 and A 1 Each is independently selected from the following groups: -NH-, -CH2-;

[0011] A 2 and A 2 Each is independently selected from the following group: -(CH2) p-、-(OCH2CH2) q -; where p is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16; q is 1, 2, 3, 4, 5 or 6; and A1 and A2 can be optionally replaced by 1 or 2 R5;

[0012] Each R5 is independently selected from the following group: C 1-4 Alkyl-OC(O)-, HOOC-;

[0013] A 3 Selected from the following group: chemical bonds, -NHCO-A 1 '-A 2 '-、-CONH-A 1 '-A 2 '-;

[0014] R3 is selected from the following group: hydroxyl group, C 1-10 Alkoxy;

[0015] PG1 and PG2 are each independently protected by an H or amino group; and PG1 and PG2 are not simultaneously protected by H.

[0016] PG3 is a carboxyl protecting group;

[0017] The activating agent is compound 4:

[0018] Among them, R4 is selected from the following group: C 1-6 Alkyl, C 3-7 cycloalkyl, C 6-10 Aryl, 5-7 quinone heteroaryl;

[0019] X is Br or Cl;

[0020] The amino protecting group is selected from the group consisting of: Boc, Fmoc, Trt, Cbz, Bn, and PMB.

[0021] The carboxyl protecting group is selected from the following group: C 1-6 Alkyl, benzyl.

[0022] In another preferred embodiment, A 1 It is CH2.

[0023] In another preferred embodiment, A 2 Selected from the following groups: -OCH2CH2-, -(OCH2CH2)2-, -(CH2)2-, -(CH2) 15 -

[0024] In another preferred embodiment, A 1 'For CH2.

[0025] In another preferred embodiment, A 2 Selected from the following groups: -OCH2CH2-, -(OCH2CH2)2-, -(CH2)2-.

[0026] In another preferred embodiment, A 3 ' is a chemical bond.

[0027] In another preferred embodiment, A 3 'is -NHCO-CH2-(OCH2CH2)2-.

[0028] In a preferred embodiment, R5 is Boc or -COOH.

[0029] In another preferred embodiment, R3 is selected from the group consisting of: hydroxyl groups, C... 1-6 Alkyl group.

[0030] In a preferred embodiment, R3 is selected from the group consisting of: hydroxyl groups, C... 1-4 Alkyl group.

[0031] In a preferred embodiment, R4 is selected from the group C 1-4 Alkyl, C 5-7 Cycloalkyl, phenyl, 5-7 heteroaryl.

[0032] In a preferred embodiment, the activating agent is selected from the group consisting of: Or a combination thereof.

[0033] In a preferred embodiment, PG1 is selected from the group consisting of: Boc, Fmoc, Trt, and Cbz;

[0034] The PG2 is H.

[0035] In another preferred embodiment, the carboxyl protecting group is selected from the group consisting of: C 1-4 Alkyl or benzyl. In another preferred embodiment, the carboxyl protecting group is tert-butyl.

[0036] In a preferred embodiment, compound 1 is selected from the group consisting of:

[0037] The definitions of PG1 and PG2 are as described above.

[0038] In a preferred embodiment, compound 2 is selected from the group consisting of:

[0039] R3 is defined as described above.

[0040] In a preferred embodiment, the alkaline reagent is selected from the group consisting of triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, N,N'-diisopropylethylamine, diisopropylmethylamine, methylcyclohexylamine, methylmorpholine, DABCO, DBU, dicyclohexylamine, N,N,N',N'-tetramethylethylenediamine, 1,1,3,3-tetramethylguanidine, DMAP, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or combinations thereof.

[0041] In a preferred embodiment, solvent A is selected from the group consisting of tetrahydrofuran, 2-methyltetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, methyl tert-butyl ether, diisopropyl ether, 1,4-dioxane, 1,3-dioxane, diethylene glycol dimethyl ether, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, tert-butyl acetate, dimethyl carbonate, benzene, toluene, xylene, chlorobenzene, dichloromethane, chloroform, dichloroethane, acetone, butanone, 3-methyl-2-butanone, acetonitrile, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, isobutanol, n-pentanol, sec-pentanol, 3-pentanol, tert-pentanol, isopentanol, or combinations thereof.

[0042] In a preferred embodiment, solvent B is also present in the reaction;

[0043] Solvent B is selected from the group consisting of tetrahydrofuran, 2-methyltetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, methyl tert-butyl ether, diisopropyl ether, 1,4-dioxane, 1,3-dioxane, diethylene glycol dimethyl ether, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, tert-butyl acetate, dimethyl carbonate, benzene, toluene, xylene, chlorobenzene, dichloromethane, dichloroethane, acetone, butanone, 3-methyl-2-butanone, acetonitrile, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, isobutanol, n-pentanol, sec-pentanol, 3-pentanol, tert-pentanol, isopentanol, or combinations thereof.

[0044] In another preferred embodiment, the solvent B is a mixed solution of dichloromethane and methanol; wherein the volume ratio of dichloromethane to methanol is (1-5):1; preferably (1-3):1; more preferably (1-2):1.

[0045] In a preferred embodiment, the method includes the following steps: adding compound 1, an alkaline reagent, and an activating reagent sequentially to solvent A, and finally reacting it with compound 2 or a solution thereof to obtain reaction solution 3.

[0046] In another preferred embodiment, the reaction temperature is 20–30°C.

[0047] In another preferred embodiment, the method includes the following steps: adding compound 1 to solvent A; adding an alkaline reagent at 0–10°C and reacting at 20–30°C for 0.5–1 h; adding an activating reagent at 0–10°C and reacting at 20–30°C for 1–3 h; and obtaining reaction solution 1.

[0048] Compound 2 was added to solvent B to obtain reaction solution 2;

[0049] Mix reaction solution 1 and reaction solution 2 at 0–10°C and react at 20–30°C for 2–6 hours to obtain reaction solution 3.

[0050] In another preferred embodiment, the reaction temperature is 0–10°C.

[0051] In another preferred embodiment, the method includes the following steps: adding compound 1 to solvent A; adding an alkaline reagent at 0–10°C and reacting at 20–30°C for 0.5–1 h; adding an activating reagent at 0–10°C and reacting at 20–30°C for 1–3 h; and obtaining reaction solution 1.

[0052] Compound 2 was added to solvent B to obtain reaction solution 2;

[0053] Mix reaction solution 1 and reaction solution 2 at 0-10℃ and react at 0-10℃ for 2-10 hours to obtain reaction solution 3.

[0054] In a preferred embodiment, the method further includes the following post-processing steps: adding an aqueous solution and an organic solvent to the reaction solution 3 formed by the reaction of compound 1 and compound 2 for extraction, washing, drying, and concentration to obtain compound 3.

[0055] In a preferred embodiment, the aqueous solution is selected from the group consisting of: aqueous sodium carbonate solution, aqueous potassium carbonate solution, aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, or combinations thereof.

[0056] In another preferred embodiment, the aqueous solution is a 10-20 wt% sodium carbonate aqueous solution; preferably a 12-18 wt% sodium carbonate aqueous solution.

[0057] In another preferred embodiment, the organic solvent is selected from the group consisting of dichloromethane, trichloromethane, tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, etc., or combinations thereof.

[0058] In another preferred embodiment, the extraction includes the following steps: first, adding 10-20 wt% sodium carbonate aqueous solution to reaction solution 3 to adjust the pH to 9-10; then adding an organic solvent and collecting the organic phase.

[0059] In another preferred embodiment, the method further includes the following post-processing steps: adding an aqueous solution to the reaction solution formed by the reaction of compound 1 and compound 2, concentrating, performing chromatography, and concentrating again to obtain compound 3.

[0060] In another preferred embodiment, the method further includes the following post-processing step: concentrating the reaction solution after the reaction of compound 1 and compound 2 is completed, performing chromatography, and concentrating again to obtain compound 3.

[0061] In a preferred embodiment, the molar ratio of compound 1 to compound 2 is 1:(0.9 to 2.0); preferably 1:(1.0 to 1.5).

[0062] In another preferred embodiment, the molar ratio of compound 1 to the activating agent is 1:(0.9 to 2.0); preferably 1:(0.9 to 1.3).

[0063] In another preferred embodiment, the molar ratio of compound 1 to the base reagent is 1:(1.0 to 5.0); preferably 1:(1.0 to 2.0).

[0064] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Detailed Implementation

[0065] Through long-term and in-depth research and extensive screening, the inventors have developed a novel method for preparing amides. Specifically, the inventors activate the carboxyl group by forming a mixed anhydride from a carboxylic acid and an acyl chloride under the action of an organic base, which then reacts with another molecule containing a 1° or 2° amino group to form an amide bond, thereby yielding the amide compound. The method of this invention features rapid reaction, mild reaction conditions, high selectivity, high yield, and easy product separation. Based on these characteristics, the applicant has completed this invention.

[0066] the term

[0067] Unless otherwise specified, when describing divalent groups, the left-to-right writing form is intended to also include the right-to-left writing form.

[0068] In this invention, the term "C" 1-10 "C" refers to a number of carbon atoms, either 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. 3-6 "" refers to having 3, 4, 5 or 6 carbon atoms, and so on.

[0069] In this invention, the term "alkyl" refers to a saturated linear or branched hydrocarbon moiety, such as the term "C". 1-4"Alkyl" refers to a straight-chain or branched alkyl group having 1, 2, 3 or 4 carbon atoms, and includes, without limitation, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl; preferably ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl.

[0070] In this invention, the term "alkoxy" refers to -O-alkyl, and examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, isopropoxy, tert-butoxy, etc.

[0071] Preparation of bifunctional amides

[0072] This invention provides a method for preparing bifunctional amides. The method can be used for the amide condensation reaction of bifunctional monomers. No polypolymer byproducts are generated during the reaction. The product composition is simple and suitable for industrial production.

[0073] The method of the present invention includes the following steps: in the presence of an alkaline reagent, solvent A, and an activating reagent, compound 1 reacts with compound 2 to obtain compound 3.

[0074] G1 is selected from the following group:

[0075] A 1 and A 1 Each is independently selected from the following groups: -NH-, -CH2-;

[0076] A 2 and A 2 Each is independently selected from the following group: -(CH2) p -、-(OCH2CH2) q -; where p is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16; q is 1, 2, 3, 4, 5 or 6; and A1 and A2 can be optionally replaced by 1 or 2 R5;

[0077] Each R5 is independently selected from the following group: C 1-4 Alkyl-OC(O)-, HOOC-;

[0078] A 3 Selected from the following group: chemical bonds, -NHCO-A 1 '-A 2 '-、-CONH-A 1 '-A 2 '-;

[0079] R3 is selected from the following group: hydroxyl group, C 1-10 Alkoxy;

[0080] PG1 and PG2 are each independently protected by an H or amino group; and PG1 and PG2 are not simultaneously protected by H.

[0081] PG3 is a carboxyl protecting group;

[0082] The activating agent is compound 4:

[0083] Among them, R4 is selected from the following group: C 1-6 Alkyl, C 3-7 cycloalkyl, C 6-10 Aryl, 5-7 quinone heteroaryl;

[0084] X is Br or Cl;

[0085] The amino protecting group is selected from the group consisting of: Boc, Fmoc, Trt, Cbz, Bn, PMB; the carboxyl protecting group is selected from the group consisting of: C 1-6 Alkyl, benzyl.

[0086] This invention employs an activating reagent to activate hydroxyl groups. The activated hydroxyl groups can selectively react with monomers rather than dimers, thereby controlling the formation of polymers. In the prior art, the preparation of amide compounds using carbodiimide condensing reagents (such as DCC, DIC, etc.) is a conventional method. However, these condensing reagents generate numerous byproducts during application, such as urea byproducts that are difficult to remove by conventional purification methods through self-rearrangement reactions, and polypeptide byproducts formed by further reactions between the reactants and the generated dimers.

[0087] The applicant unexpectedly discovered that using acyl chloride as an activating agent not only avoids the urea byproducts generated by the rearrangement of the condensation reagent itself, but also allows the reactants to react selectively with the monomers at room temperature, avoiding the formation of polypeptide byproducts. More preferably, the present invention first activates the carboxyl group of compound 1, and then adds compound 2 to react, thus avoiding the activation of the carboxyl group of compound 2, thereby preventing further condensation reactions and the formation of polymers.

[0088] abbreviations

[0089] Boc: tert-Butoxycarbonyl

[0090] Fmoc: fluorenemethyloxycarbonyl

[0091] Trt: Triphenylmethyl

[0092] Cbz: benzyloxycarbonyl

[0093] Bn: Benzyl

[0094] PMB: p-Methoxybenzyl

[0095] DABCO: Triethylenediamine

[0096] DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene

[0097] DMA: Dimethylacetamide

[0098] The main advantages of this invention are:

[0099] 1. The preparation method of the present invention is rapid, highly selective, does not require high or low temperature, reacts under normal pressure, and the product is easy to separate with high yield.

[0100] 2. The preparation method of the present invention is easy to operate, the production process is simple and easy to scale up, and it has significant practical value compared with existing processes.

[0101] 3. The present invention uses acyl chloride as an activating reagent, which not only avoids the byproduct problem caused by carbodiimide condensation reagents, but also selectively activates reactants and improves reaction yield, which has significant advantages.

[0102] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, were generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, percentages and parts are weight percentages and parts by weight.

[0103] Example 1: Screening of the amount of alkaline reagent and reactants

[0104] Prepare reaction flask R1. Add 2g of compound 1a (1.0 eq) to 16mL of dichloromethane under nitrogen protection. Start stirring and cool to 0-5℃, stirring until dissolved. Add a base reagent dropwise while maintaining the temperature at 0-10℃, stirring the reaction mixture at room temperature for 30-40 minutes. Add the activating reagent 2,2-dimethylbutyryl chloride dropwise while maintaining the temperature at 0-10℃ to form the reaction solution.

[0105] Prepare reaction flask R2. Add 2-(2-(2-aminoethoxy)ethoxy)acetic acid (compound 2a) to a mixed solvent of dichloromethane:methanol = 3 v / w: 2 v / w (6 mL: 4 mL) and stir until dissolved. Control the temperature at 0-10℃. Add the reaction solution from R1 dropwise to R2. After the addition is complete, stir the reaction at room temperature for 4 hours.

[0106] The obtained reaction solution was analyzed using HPLC.

[0107] Table 1. Amounts of base reagent and reactants used (calculated based on compound 2a)

[0108] Therefore, it can be seen that the product conversion rate is the highest when the base reagent is N,N-diisopropylethylamine and the ratio of compound 2a:base reagent:activating reagent:compound 1a is 1:1.3:1.0:1.3. Therefore, the following examples all adopt this condition.

[0109] Example 2: Preparation of compound 3a (activating agent: 2,2-dimethylbutyryl chloride)

[0110] Prepare a three-necked flask R1. Add 2-[2-(tert-butoxycarbonylamino)ethoxy]ethoxyacetic acid (compound 1a) (20.0 g, 76.0 mmol, 1.0 eq) to 160 mL of dichloromethane under nitrogen protection, start stirring, and cool to 0-5 °C, stirring until dissolved. Add N,N-diisopropylethylamine (12.8 g, 98.8 mmol, 1.3 eq) dropwise at 0-10 °C, stirring at room temperature (20-30 °C) for 30-40 min. Add 2,2-dimethylbutyryl chloride (10.2 g, 76.0 mmol, 1.0 eq) dropwise at 0-10 °C, stirring at room temperature for 2 h. Monitor the reaction by TLC until complete.

[0111] Prepare reaction flask R2. Add 2-(2-(2-aminoethoxy)ethoxy)acetic acid (compound 2a) (16.1 g, 98.8 mmol, 1.3 eq) to a mixed solvent of dichloromethane:methanol = 3 v / w: 2 v / w (60 mL: 40 mL) and stir until dissolved. Maintain the temperature at 0-10 °C. Add the reaction solution from R1 dropwise to R2. After the addition is complete, react at room temperature for 4 h. Prepare a 16 wt% sodium carbonate aqueous solution and add it dropwise to R2, adjusting the pH to pH = 9-10. Add dichloromethane to R2 and extract the organic phase to obtain a pale yellow oily liquid product, namely compound 3a (27.6 g, 88.9%).

[0112] 1 H NMR (400MHz, DMSO-d6) δ13.23–12.04(m,1H),7.64(t,J=5.8Hz,1H),6.76(t,J=5.7Hz,1H),4.01(s,2H),3.86(s, 2H), 3.62–3.48 (m, 8H), 3.41 (dt, J=19.7, 6.0Hz, 4H), 3.27 (q, J=5.9Hz, 2H), 3.07 (q, J=6.0Hz, 2H), 1.36 (s, 9H). LCMS:[M+H] + : 409.45, measured value: 409.30.

[0113] Example 3: Preparation of Compound 3 (Activating agent: 2-methyl-2-phenylpropionyl chloride)

[0114] 3.1 Preparation of the activating reagent 2-methyl-2-phenylpropionyl chloride

[0115] Prepare a three-necked flask, add α,α-dimethylphenylacetic acid (50 g, 0.3 mol, 1.0 eq) and thionyl chloride (39.8 g, 0.33 mol, 1.1 eq), heat to an internal temperature of 85 °C, and maintain the temperature for 1.5 h. TLC shows that the starting material reacts completely. Remove excess thionyl chloride by distillation of n-heptane (250 mL, 5 v / w) to obtain 2-methyl-2-phenylpropionyl chloride (41.5 g, 74.46%), a pale yellow oily liquid. 1 H NMR (400MHz, DMSO-d6) δ7.33 (s, 5H), 1.46 (s, 6H). LCMS:[M+H] + :183.65, measured value:183.45.

[0116] 3.2 Preparation of compound 3a

[0117] Prepare a three-necked flask R1. Add 10.0 g (0.038 mol) of 2-[2-(tert-butoxycarbonylamino)ethoxy]ethoxyacetic acid (compound 1a) to dichloromethane under nitrogen protection, start stirring, and cool to 0-5°C, stirring until dissolved. Add N,N-diisopropylethylamine (6.4 g, 0.0494 mol, 1.3 eq) dropwise at 0-10°C, stirring for 30-40 min. Add 6.94 g (0.038 mol, 1.0 eq) dropwise at 0-10°C, stirring for 2 h. Monitor the reaction by TLC until complete.

[0118] Prepare reaction flask R2. Add 2-(2-(2-aminoethoxy)ethoxy)acetic acid (compound 2a) (6.3 g, 0.0387 mol, 1.02 eq) to a mixed solvent of dichloromethane:methanol = 3 v / w: 2 v / w (30 mL: 20 mL) and stir until dissolved. Maintain the temperature at 0-10 °C. Add the reaction solution from R1 dropwise to R2. Prepare a 16 wt% sodium carbonate aqueous solution and add it dropwise to R2. Continue the reaction for 4 hours. TLC shows that the reaction is complete. Concentrate the solution and perform column chromatography with n-heptane:ethyl acetate (1:3). Concentrate under reduced pressure to obtain a pale yellow oily liquid product (6.7 g, 43.2%).

[0119] Example 4: Preparation of compound 3a (activating agent: pivaloyl chloride)

[0120] Prepare a three-necked flask R1. Add 10.0 g (0.038 mol, 1.0 eq) of 2-[2-(tert-butoxycarbonylamino)ethoxy]ethoxyacetic acid (compound 1a) to dichloromethane under nitrogen protection, start stirring, and cool to 0-5°C, stirring until dissolved. Add 6.4 g (0.0494 mol, 1.3 eq) of N,N-diisopropylethylamine dropwise at 0-10°C, stirring for 30-40 min. Add 4.58 g (0.038 mol, 1.0 eq) of tert-valeryl chloride dropwise at 0-10°C, stirring for 2 h. Monitor the reaction by TLC until complete.

[0121] Prepare reaction flask R2. Add 2-(2-(2-aminoethoxy)ethoxy)acetic acid (compound 2a) (7.4 g, 1.02 eq) to a mixed solvent of dichloromethane:methanol = 3 v / w: 2 v / w (30 mL: 20 mL) and stir until dissolved. Control the temperature at 0-10 °C. Add the reaction solution from R1 dropwise to R2 and continue the reaction for 4 hours. TLC shows that the reaction is complete. Concentrate the solution and perform column chromatography with n-heptane:ethyl acetate (1:3). Concentrate under reduced pressure to obtain a pale yellow oily liquid product, compound 3a (6.9 g, 44.5%).

[0122] Example 5

[0123] Derivatization reaction using 2,2-dimethylbutyryl chloride as a condensing agent 1

[0124] Prepare reaction flask R1. Add 20 g (66 mmol, 1.0 eq) of Boc-L-glutamic acid-1-tert-butyl ester (compound 1b) to dichloromethane (3 v / w 15 mL), under nitrogen protection, and start stirring. Cool to 0-5 °C and stir until dissolved. Add N,N-diisopropylethylamine (11.0 g, 85 mmol, 1.3 eq.) dropwise at 0-10 °C, and stir at room temperature for 30-40 min. Add 2,2-dimethylbutyryl chloride (8.9 g, 66 mmol, 1.0 eq.) dropwise at 0-10 °C, and stir at room temperature for 2 h. Monitor the reaction by TLC until complete.

[0125] Prepare reaction flask R2. Add 20.7 g (67 mmol, 1.02 eq) of 17-amino-10-oxo-3,6,12,15-tetraoxa-9-azaheptadecanoic acid (compound 2b) to a mixed solvent of dichloromethane:methanol = 3 v / w: 2 v / w (60 mL: 40 mL) and stir until dissolved. Maintain the temperature at 0-10 °C. Add the reaction solution from R1 dropwise to R2. Incubate the reaction at 0-10 °C for 6 hours. Concentrate the solution and separate and concentrate it using column chromatography with n-heptane:ethyl acetate (1:3) to obtain the product, compound 3b (12 g, 31.03%), a pale yellow solid. 1H NMR(400MHz,Chloroform-d)δ7.65(s,1H),7.35(s,1H),6.96(s,1H),6.75(s,1H),5.37(d,J=8.3Hz,1H),4.17(s,2H),4.02(s,2H),3.8 1–3.32(m,16H),2.32(dd,J=10.9,4.3Hz,2H),2.13(dtd,J=12.2,7.7,4.4Hz,1H),1.90(dq,J=15.1,7.6Hz,1H),1.45(d,J=9.0Hz,18H). LCMS:[M+H] + Measured value: 594.67; Actual value: 594.45.

[0126] Example 6

[0127] Derivatization reaction using 2,2-dimethylbutyryl chloride as a condensing agent 2

[0128] Prepare reaction flask R1. Add 2 g (0.0054 mol, 1.0 eq) of 18-(tert-butoxy)-18-oxooctadecanoic acid (compound 1c) to dichloromethane (3 v / w, 6 mL). Under nitrogen protection, start stirring and cool to 0-5 °C, stirring until dissolved. Add N,N-diisopropylethylamine (0.91 g, 0.0070 mol, 1.3 eq.) dropwise at 0-10 °C, stirring at room temperature for 30-40 min. Add 0.73 g (0.0054 mol, 1.0 eq.) dropwise at 0-10 °C, stirring at room temperature for 2 h. Monitor the reaction by TLC until complete.

[0129] Prepare reaction flask R2. Add 17-amino-10-oxo-3,6,12,15-tetraoxa-9-azaheptadecanoic acid (compound 2b) (1.70 g, 0.0055 mol, 1.02 eq.) to a mixed solvent of dichloromethane:methanol = 3 v / w: 2 v / w (6 mL: 4 mL) and stir until dissolved. Maintain the temperature at 0-10 °C. Add the reaction solution from R1 dropwise to R2. Incubate the reaction at 0-10 °C for 6 hours. Concentrate the solution and separate and concentrate it by column chromatography using n-heptane:ethyl acetate (1:3) to obtain the product, compound 3c (1.0 g, 28.04%), an off-white solid. 1H NMR(400MHz,Chloroform-d)δ7.19(t,J=5.9Hz,1H),6.40(t,J=5.8Hz,1H),4.16(s,2H),4.01(s,2H),3.81 –3.42(m,16H),2.19(t,J=7.6Hz,4H),1.59(dp,J=21.0,7.0Hz,4H),1.45(s,9H),1.25(d,J=10.6Hz,25H). LCMS:[M+H] + :661.89, measured value:661.55.

[0130] Example 7

[0131] Derivatization reaction using 2,2-dimethylbutyryl chloride as a condensing agent 3

[0132] Prepare reaction flask R1. Add 5 g (0.013 mol, 1.0 eq) of 18-(tert-butoxy)-18-oxooctadecanoic acid (compound 1c) to dichloromethane (5 v / w, 25 mL). Under nitrogen protection, start stirring and cool to 0-5 °C, stirring until dissolved. Add N,N-diisopropylethylamine (2.3 g, 0.018 mol, 1.3 eq.) dropwise at 0-10 °C, stirring for 30-40 min at room temperature. Add 1.8 g (0.013 mol, 1.0 eq.) dropwise at 0-10 °C, stirring for 2 h at room temperature. Monitor the reaction by TLC until complete.

[0133] Prepare reaction flask R2. Add L-glutamic acid (compound 2c) (2.58 g, 0.018 mol, 1.3 eq.) to a saturated sodium bicarbonate aqueous solution at 5 v / w (10 mL) and stir until dissolved. Maintain the temperature at 0-10℃. Add the reaction solution from R1 dropwise to R2. Incubate the reaction at 0-10℃ for 6 hours. Concentrate the solution and separate and concentrate it using column chromatography with n-heptane:ethyl acetate (1:3) + 0.5 wt% acetic acid to obtain the product, compound 3d (1.0 g, 14.9%), an off-white solid. 1 H NMR(400MHz,Chloroform-d)δ8.03(d,J=7.0Hz,1H),4.62(d,J=3.3Hz,2H),3.5 8(s,2H),2.33–2.08(m,2H),1.95(d,J=5.8Hz,4H),1.56(s,28H),1.19(s,9H). LCMS:[M+H] + :500.69, measured value:500.50.

[0134] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for preparing a bifunctional amide, characterized in that, The method includes the following steps: in the presence of a base reagent, solvent A, and an activating reagent, compound 1 reacts with compound 2 to obtain compound 3. G1 is selected from the following group: A 1 and A 1 Each is independently selected from the following groups: -NH-, -CH2-; A 2 and A 2 Each is independently selected from the following group: -(CH2) p -、-(OCH2CH2) q -; where p is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16; q is 1, 2, 3, 4, 5 or 6; and A is... 1 and A 2 It can be optionally bounded by 1 or 2 Rs 5 replace; Each R 5 Each of them independently selected from the following group: C 1-4 Alkyl-OC(O)-, HOOC-; A 3 Selected from the following group: chemical bonds, -NHCO-A 1 '-A 2 '-、-CONH-A 1 '-A 2 '-; R 3 Selected from the following group: hydroxyl, C 1-10 Alkoxy; PG1 and PG2 are each independently protected by an H or amino group; and PG1 and PG2 are not simultaneously protected by H. PG3 is a carboxyl protecting group; The activating agent is compound 4: Among them, R4 is selected from the following group: C 1-6 Alkyl, C 3-7 cycloalkyl, C 6-10 Aryl, 5-7 quinone heteroaryl; X is Br or Cl; The amino protecting group is selected from the group consisting of: Boc, Fmoc, Trt, Cbz, Bn, and PMB. The carboxyl protecting group is selected from the following group: C 1-6 Alkyl, benzyl.

2. The method for preparing the amide according to claim 1, characterized in that, R5 is either Boc or -COOH.

3. The method for preparing the amide according to claim 1, characterized in that, The R3 is selected from the group consisting of: hydroxyl, C 1-4 Alkyl group.

4. The method for preparing the amide according to claim 1, characterized in that, The R4 is selected from the following group: C 1-4 Alkyl, C 5-7 Cycloalkyl, phenyl, 5-7 heteroaryl.

5. The method for preparing the amide according to claim 1, characterized in that, The activating agent is selected from the following group: Or a combination thereof.

6. The method for preparing the amide according to claim 1, characterized in that, The PG1 is selected from the following group: Boc, Fmoc, Trt, Cbz; The PG2 is H.

7. The method for preparing the amide according to claim 1, characterized in that, Compound 1 is selected from the group consisting of: The definitions of PG1 and PG2 are as described in claim 1.

8. The method for preparing the amide according to claim 1, characterized in that, Compound 2 is selected from the group consisting of: R3 is defined as described in claim 1.

9. The method for preparing the amide according to claim 1, characterized in that, The alkaline reagent is selected from the group consisting of: triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, N,N-diisopropylethylamine, diisopropylmethylamine, methylcyclohexylamine, methylmorpholine, DABCO, DBU, dicyclohexylamine, N,N,N',N'-tetramethylethylenediamine, 1,1,3,3-tetramethylguanidine, DMAP, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or combinations thereof.

10. The method for preparing the amide according to claim 1, characterized in that, Solvent A is selected from the group consisting of: tetrahydrofuran, 2-methyltetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, methyl tert-butyl ether, diisopropyl ether, 1,4-dioxane, 1,3-dioxane, diethylene glycol dimethyl ether, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, tert-butyl acetate, dimethyl carbonate, benzene, toluene, xylene, chlorobenzene, dichloromethane, chloroform, dichloroethane, acetone, butanone, 3-methyl-2-butanone, acetonitrile, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, isobutanol, n-pentanol, sec-pentanol, 3-pentanol, tert-pentanol, isopentanol, or combinations thereof.

11. The method for preparing the amide according to claim 1, characterized in that, Solvent B is also present in the reaction; Solvent B is selected from the group consisting of tetrahydrofuran, 2-methyltetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, methyl tert-butyl ether, diisopropyl ether, 1,4-dioxane, 1,3-dioxane, diethylene glycol dimethyl ether, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, tert-butyl acetate, dimethyl carbonate, benzene, toluene, xylene, chlorobenzene, dichloromethane, dichloroethane, acetone, butanone, 3-methyl-2-butanone, acetonitrile, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, isobutanol, n-pentanol, sec-pentanol, 3-pentanol, tert-pentanol, isopentanol, or combinations thereof.

12. The method for preparing the amide according to claim 1, characterized in that, The method includes the following steps: adding compound 1, an alkaline reagent, and an activating reagent sequentially to solvent A, and finally reacting it with compound 2 or its solution to obtain reaction solution 3.

13. The method for preparing the amide according to claim 12, characterized in that, The method further includes the following post-processing steps: adding an aqueous solution and an organic solvent to the reaction solution 3 formed by the reaction of compound 1 and compound 2 for extraction, washing, drying, and concentration to obtain compound 3.

14. The method for preparing the amide according to claim 12, characterized in that, The aqueous solution is selected from the group consisting of sodium carbonate aqueous solution, potassium carbonate aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, or a combination thereof.

15. The method for preparing the amide according to claim 1, characterized in that, The molar ratio of compound 1 to compound 2 is 1:(0.9 to 2.0); preferably 1:(1.0 to 1.5).

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