CN117886748A

CN117886748A - Quinoline amino acid conjugate and preparation method and application thereof

Info

Publication number: CN117886748A
Application number: CN202410018337.9A
Authority: CN
Inventors: 孙华; 温廷婕; 杨灏; 范瑜
Original assignee: Tianjin University of Science and Technology
Current assignee: Tianjin University of Science and Technology
Priority date: 2024-01-05
Filing date: 2024-01-05
Publication date: 2024-04-16

Abstract

The invention belongs to the technical field of synthesis and drug application of novel compounds, and discloses a novel quinoline amino acid conjugate, wherein the quinoline amino acid conjugate is a quinoline-3-amino acid conjugate and derivatives thereof, a quinoline-6-amino acid conjugate and derivatives thereof, or a quinoline-5-amino acid conjugate and derivatives thereof. The invention synthesizes and discovers that the quinoline amino acid conjugate compound has good activities of losing weight, reducing blood fat and relieving fatty liver. Can inhibit pancreatic lipase activity in vitro and reduce the lipid content of cells induced by high fat; in addition, in vivo level, the composition can reduce the weight of obese hyperlipidemia mice, improve various fat contents and body fat rates in vivo, reduce hyperlipidemia symptoms of serum and liver, improve liver and spleen indexes and the like. Therefore, the quinoline amino acid conjugate synthesized by the invention has wide prospect in the aspects of preparing medicines for losing weight, reducing blood fat and relieving fatty liver and application.

Description

Quinoline amino acid conjugate and preparation method and application thereof

Technical Field

The invention belongs to the technical field of synthesis and pharmaceutical application of novel compounds, and in particular relates to a quinoline amino acid conjugate, a preparation method and application thereof, including compound synthesis, activity research and application.

Background

In 1834, runge first obtained a mixed quinoline from coal tar, the name of which was derived from quinine, an antimalarial drug isolated from cinchona bark. Quinoline exists widely in nature and is one of the important frameworks for new drug design. Many quinoline compounds are important drugs or intermediates, have various pharmacological activities such as antibiosis, antitumor, antivirus and the like, and are attracting attention in drug research.

Ghorab et al synthesize quinoline-containing heterocycles that can exert antitumor activity through a variety of mechanisms, such as cMet kinase inhibition, carbonic anhydrase inhibition, VEGFR inhibition, tubulin inhibition, and the like. Sun Ning et al synthesized benzoindoloquinoline derivatives and found inhibitory activity against Staphylococcus aureus and enterococcus faecalis. Fakh et al synthesized a number of mono-and polysubstituted quinolines and screened for antiprotozoal or anti-HIV-1 activity, and the results indicate that the compounds exhibit good inhibition against Lactobacillus amazonensis, lactobacillus infantis and HIV-1.

By searching, the following publications related to the present patent application are found:

1. Patent 1: yu Peng, sun Hua, and the like, a 3-aryl isoquinoline and 4-aryl quinoline derivative, and a preparation method and application thereof, and application number 201910085622.1. The invention discloses an application of 3-aryl isoquinoline and 4-aryl quinoline derivatives in antidiabetic treatment, wherein the main derivatization strategy is to introduce aryl at the 3 position of isoquinoline parent nucleus and aryl at the 4 position of quinoline parent nucleus through Suzuki coupling reaction, and the alpha-glucosidase inhibition activity of the product is researched, the derivative structure is essentially different from that of the invention, the invention is an amino acid derivative of quinoline, and the activity research is lipid-lowering activity.

2. Patent 2: sun Hua, et al, application number 202011100324.4, a new application of isoquinoline and quinoline derivatives in the preparation of hypolipidemic agents. The invention discloses a 3-aryl isoquinoline derivative, a 4-aryl quinoline derivative and a 3-substituted phenyl hydrogenated isoquinoline derivative, the structure of the compound is essentially different from that of the invention, the invention is an amino acid derivative of quinoline, the structure is brand new, the physicochemical properties are different, and the protection scope is also different.

By contrast, the invention is essentially different from the above publications, the invention is a conjugate of quinoline and amino acid, which is a novel compound, and the synthesized quinoline amino acid conjugate and the derivative thereof are novel compounds through multi-path search. The structure differs greatly from the above publications, and the activity is not expected nor suggested. Therefore, the provision of a novel quinoline amino acid conjugate, a preparation method and application thereof in the aspects of losing weight, reducing blood fat and relieving fatty liver activity are motivations of the technical scheme of the invention.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a novel quinoline amino acid conjugate and a novel application thereof in preparing a medicine for reducing weight and/or reducing blood fat and/or relieving fatty liver.

The technical scheme adopted for solving the technical problems is as follows:

A quinoline amino acid conjugate is a quinoline-3-amino acid conjugate and derivatives thereof, a quinoline-6-amino acid conjugate and derivatives thereof, or a quinoline-5-amino acid conjugate and derivatives thereof.

Further, the quinoline-3-amino acid conjugate and the derivative thereof have the following structural general formula I:

wherein the connecting bridge is amine, ether, carbonyl, amide or a chain structure connected with the amine, the ether, the carbonyl, the amide or the chain structure, and the amino acid is 1-4 amino acids and derivatives thereof.

3. The method of preparing a quinoline-3-amino acid conjugate according to claim 2, wherein: the N-formyl-L-leucine and 3-aminoquinoline are directly condensed to obtain a compound 1, and the reaction route is as follows:

Or taking 3-aminoquinoline as a raw material, connecting N-tert-butoxycarbonyl-L-alanine through condensation reaction to obtain 2a, removing a protecting group to obtain a compound 2b, or connecting N-tert-butoxycarbonyl-beta-alanine to obtain 3a, removing the protecting group to obtain a compound 3b,2b or 3b, and connecting N-formyl-L-leucine through condensation reaction to obtain a compound 2 or 3, wherein the reaction route is as follows:

Or 3-aminoquinoline is used as a raw material, N- (9-fluorenylmethoxycarbonyl) -L-aspartic acid-4-tert-butyl ester is firstly connected through condensation reaction to obtain 4a or N- (9-fluorenylmethoxycarbonyl) -L-glutamic acid-5-tert-butyl ester is obtained to obtain 5a, a compound 4b or 5b is obtained after removal of a protecting group, N-formyl-L-leucine is connected through condensation reaction to obtain a compound 4c or 5c, and the protective group of the tert-butyl ester is removed to obtain 4 or 5, wherein the reaction route is as follows:

Or taking 3-carboxyl quinoline as a raw material, connecting N-tert-butoxycarbonyl ethylenediamine through a condensation reaction to obtain 6a, removing a protecting group to obtain a compound 6b, and connecting N-formyl-L-leucine through the condensation reaction to obtain the compound 6, wherein the reaction route is as follows:

or 3-hydroxyquinoline is used as a raw material, and reacts with bromoalkane to obtain tert-butyl isobutyrate 7a, a protecting group is removed to obtain a compound 7b, ethylenediamine is connected through condensation reaction, and then N-formyl-L-leucine is connected to obtain a compound 7, wherein the reaction route is as follows:

further, the quinoline-6-amino acid conjugate and the derivative thereof have the following structural general formula II:

The preparation method of the quinoline-6-amino acid conjugate comprises the steps of taking 6-aminoquinoline as a raw material, connecting N- (9-fluorenylmethoxycarbonyl) -L-aspartic acid-4-tert-butyl ester through condensation reaction to obtain 8a or connecting N-formyl-L-leucine through condensation reaction after removing protective groups to obtain a compound 8c or 9c after removing tert-butyl ester protective groups, wherein 8a or 9 is obtained after the condensation reaction is carried out on the compound and the N- (9-fluorenylmethoxycarbonyl) -L-glutamic acid-5-tert-butyl ester is obtained; the reaction route is as follows:

Or taking 6-aminoquinoline as a raw material, connecting N-tert-butoxycarbonyl-N- (9-fluorenylmethoxycarbonyl) -alpha-D-lysine through a condensation reaction to obtain 10a, removing a protecting group, connecting N-formyl-L-leucine through a condensation reaction to obtain a compound 10c, and removing a tert-butyl protecting group to obtain 10; the reaction route is as follows:

Or taking 6-hydroxyquinoline as a raw material, firstly connecting alpha-bromoisobutyric acid tert-butyl ester to obtain 11a, removing ester protecting groups, then connecting N-tert-butoxycarbonyl ethylenediamine through condensation reaction, removing the protecting groups to obtain 11d, and finally connecting N-formyl-L-leucine through condensation reaction to obtain a compound 11, wherein the reaction route is as follows:

Or 6-hydroxyquinoline is used as a raw material, firstly, ethylene carbonate reacts with ethylene carbonate to be connected with an ethylene glycol connecting bridge to obtain 12a, and then N-formyl-L-leucine is connected with the ethylene glycol connecting bridge through condensation reaction to obtain a compound 12; the reaction route is as follows:

Further, the quinoline-5-amino acid conjugate and the derivative thereof have the following structural general formula III:

wherein the connecting bridge is amino or carbonyl, and the amino acid is 1-4 amino acids and derivatives thereof.

The preparation method of the quinoline-5-amino acid conjugate comprises the following reaction steps: the reaction steps are the same as claim 2 with 5-aminoquinoline as raw material, and the reaction route is as follows:

Further, the structural formula of the quinoline-3-amino acid conjugate is one of the following:

the structural formula of the quinoline-6-amino acid conjugate is one of the following:

the structural formula of the quinoline-5-amino acid conjugate is one of the following:

The application of the quinoline amino acid conjugate in preparing the medicine for reducing weight and/or reducing blood fat and/or relieving fatty liver.

The invention has the advantages and positive effects that:

1. the invention synthesizes and discovers that the quinoline amino acid conjugate compound has good activities of losing weight, reducing blood fat and relieving fatty liver. Can inhibit pancreatic lipase activity in vitro and reduce the lipid content of cells induced by high fat; in addition, in vivo level, the composition can reduce the weight of obese hyperlipidemia mice, improve various fat contents and body fat rates in vivo, reduce hyperlipidemia symptoms of serum and liver, improve liver and spleen indexes and the like. Therefore, the quinoline amino acid conjugate synthesized by the invention has wide prospect in the aspects of preparing medicines for losing weight, reducing blood fat and relieving fatty liver and application.

2. The reaction of the method does not need anhydrous and anaerobic operation, is simple and convenient to operate, has cheap and easily obtained raw materials and reagents, and is suitable for large-scale production and development.

3. The lipid-lowering drugs commonly used in clinic at present have a certain side effect on the liver, and the compound has a certain protection effect on the liver.

4. At present, no special medicine for relieving fatty liver is available clinically, and the compound has the effects of reducing fat and relieving fatty liver activity, so that the compound has good market application prospect.

Drawings

FIG. 1 is a nuclear magnetic resonance hydrogen spectrum of compound 1 in deuterated chloroform;

FIG. 2 is a nuclear magnetic resonance hydrogen spectrum of compound 2 of the present invention in deuterated methanol;

FIG. 3 is a nuclear magnetic resonance hydrogen spectrum of compound 3 of the present invention in deuterated methanol;

FIG. 4 is a nuclear magnetic resonance hydrogen spectrum of compound 4 of the present invention in deuterated methanol;

FIG. 5 is a nuclear magnetic resonance hydrogen spectrum of compound 5 of the present invention in deuterated methanol;

FIG. 6 is a nuclear magnetic resonance spectrum of compound 6 of the present invention in deuterated chloroform;

FIG. 7 is a nuclear magnetic resonance spectrum of compound 7 of the present invention in deuterated chloroform;

FIG. 8 is a nuclear magnetic resonance hydrogen spectrum of compound 8 of the present invention in deuterated methanol;

FIG. 9 is a nuclear magnetic resonance hydrogen spectrum of compound 9 of the present invention in deuterated methanol;

FIG. 10 is a nuclear magnetic resonance hydrogen spectrum of compound 10 of the present invention in deuterated methanol;

FIG. 11 is a nuclear magnetic resonance hydrogen spectrum of compound 11 in deuterated chloroform according to the present invention;

FIG. 12 is a nuclear magnetic resonance hydrogen spectrum of compound 12 of the present invention in deuterated chloroform;

FIG. 13 is a nuclear magnetic resonance hydrogen spectrum of compound 13 of the present invention in deuterated methanol;

FIG. 14 is a nuclear magnetic resonance hydrogen spectrum of compound 8c in deuterated methanol according to the present invention;

FIG. 15 is a graph showing the effect of Compound 8c of the present invention on body weight of obese hyperlipidemic mice;

FIG. 16 is a graph showing the effect of Compound 8c of the present invention on adipose tissue morphology in obese hyperlipidemic mice; and (3) injection: (16A) perirenal white fat; (16B) epididymal white fat.

Detailed Description

The invention will now be further illustrated by reference to the following examples, which are intended to be illustrative, not limiting, and are not intended to limit the scope of the invention.

The various experimental operations involved in the specific embodiments are conventional in the art, and are not specifically noted herein, and may be implemented by those skilled in the art with reference to various general specifications, technical literature or related specifications, manuals, etc. before the filing date of the present invention.

Specifically, the related preparation and detection are as follows:

the synthetic route for compounds 1 to 13 is as follows:

scheme 1, synthetic scheme for Compound 1

Scheme 2, synthetic scheme for Compounds 2 and 3

Scheme 3, synthetic scheme for compounds 4,5,8,9

Scheme 4, synthetic scheme for Compound 6

Scheme 5, synthetic scheme for Compounds 7 and 11

Scheme 6, synthetic scheme for Compound 10

Scheme 7, synthetic scheme for Compound 12

Scheme 8, synthetic scheme for Compound 13

Example 1 Synthesis of (R) -2-carboxamide-4-methyl-N- (3-quinolinyl) pentanamide (Compound 1)

The direct condensation of 3-aminoquinoline with N-formyl-L-leucine gives compound 1, as shown in scheme 1. The method comprises the following specific steps:

(1) Synthesis of N-formyl-L-leucine: l-leucine (10 g,76.2 mmol) was dissolved in formic acid (50 mL), acetic anhydride (32 mL,304.8 mmol) was added dropwise at 0deg.C, and the reaction was carried out at room temperature for about 10h. After the completion of the reaction, which was monitored by Thin Layer Chromatography (TLC), the reaction solution was concentrated under reduced pressure, 30mL of water was added, and after precipitation of crystals by standing, filtration and freeze-drying, 10.32g of white needle-like crystalline N-formyl-L-leucine was obtained in the yield of 86％.¹H NMR(400MHz,DMSO-d₆)δ8.34(d,J＝8.0Hz,1H),8.03(s,1H),4.26-4.31(m,1H),1.57-1.65(m,1H),1.49-1.54(m,2H),0.84-0.90(m,6H).

(2) Synthesis of Compound 1: 3-aminoquinoline (100 mg,0.32 mmol) was dissolved in N, N-dimethylformamide (DMF, 1 mL), N-formyl-L-leucine (101 mg,0.64 mmol), 1H-benzotriazol-1-yloxytripyrrolidinyl hexafluorophosphate (PyBoP, 541mg,1.04 mmol), N-diisopropylethylamine (DIEA, 0.91mL,5.52 mmol) was added slowly in sequence while stirring, and the reaction was monitored to completion by thin layer chromatography. The reaction was quenched with a small amount of ice water, the reaction was extracted with EA (30 mL), washed with saturated NaCl solution, dried over anhydrous Na ₂SO₄, and the organic phase was concentrated under reduced pressure and purified by silica gel column chromatography (DCM: meoh=150:1-50:1, v/v) to give the desired product 1 as a white solid in the yield 87％.¹H NMR(400MHz,CDCl₃)δ9.07(s,1H),8.81(s,1H),8.69(s,1H),8.31(s,1H),8.03(d,J＝8.4Hz,1H),7.77(d,J＝8.0Hz,1H),7.59-7.65(m,1H),7.52(t,J＝7.2Hz,1H),6.25(d,J＝7.6Hz,1H),4.82-4.88(m,1H),1.85-1.90(m,1H),1.65-1.78(m,2H),0.96-1.00(m,6H).¹³C NMR(100MHz,CD3OD)δ173.5,163.8,145.6,145.5,133.7,129.8,129.6,128.9,128.8,128.6,126.0,52.5,42.2,26.0,23.5,21.9.HRMS(ESI-TOF)m/z calcd.for C₁₆H₂₀N₃O₂[M+H]⁺:286.1556,found286.1557. as shown in fig. 1.

Example 2 Synthesis of (S) -2-carboxamide-4-methyl-N- ((S) -1-oxo-1- (quinolin-3-ylamino) propan-2-yl) pentanamide (2) and (S) -2-amino-N- (quinolin-3-yl) propanamide (2 b)

As shown in scheme 2, the specific steps are as follows:

(1) Synthesis of compound 2 a: 3-aminoquinoline (1.0 mmol) and N-t-butoxycarbonyl-L-alanine (1.2 mmol) were dissolved in 2mL of anhydrous Dichloromethane (DCM), N' -diisopropylcarbodiimide (DIC, 1.5 mmol) and 4-dimethylaminopyridine (DMAP, 0.3 mmol) were added dropwise with stirring in ice-bath, and after completion of the reaction by thin layer chromatography, 50mL of water was added, followed by three extractions with 50mL of dichloromethane, the organic phases were combined, dried over anhydrous Na ₂SO₄, the drying agent was removed by filtration, the solvent was evaporated, and the crude product was isolated and purified by silica gel column to give compound 2a as a white solid in 85% yield.

(2) Synthesis of compound 2 b: the obtained intermediate 2a (1.0 mmol) was dissolved in 2mL of anhydrous dichloromethane, 0.5mL of DCM solution containing 25% (volume ratio) trifluoroacetic acid (TFA) was added dropwise under ice bath, after the reaction was monitored to be complete by thin layer chromatography, the reaction solution was dried by spin-drying under vacuum, 1mL of water was added, triethylamine was added dropwise to adjust to ph=8, extraction was performed with ethyl acetate, the solvent was evaporated, and the crude product was separated and purified by silica gel column to obtain compound 2b. Yield rate 96％.¹H NMR(400MHz,MeOD)δ9.92(s,1H),8.81(d,J＝2.4Hz,1H),8.33(d,J＝2.0Hz,1H),8.13(s,1H),7.97(d,J＝8.8Hz,1H),7.88(d,J＝8.0Hz,1H),7.67-7.71(m,1H),7.58-7.62(m,1H),3.67(m,2H),1.29(m,3H).

(4) Synthesis of Compound 2: 2b (1.0 mmol) obtained above was dissolved in 2mL of anhydrous dichloromethane, N-formyl-L-leucine (1.2 mmol) was added, DIC (1.5 mmol) and DMAP (0.3 mmol) were added dropwise under ice bath, the reaction was turned to room temperature, after completion of the reaction monitored by thin layer chromatography, 50mL of water was added, extraction was performed three times with 50mL of dichloromethane, the organic phases were combined, the organic phases were washed with saturated ammonium chloride, dried over anhydrous Na ₂SO₄, the drying agent was removed by filtration, the solvent was evaporated, and the crude product was separated and purified by silica gel column to obtain product 2. The white solid was obtained in a yield 70％.¹H NMR(400MHz,MeOD)δ8.95(d,J＝2.4Hz,1H),8.73(d,J＝2.0Hz,1H),8.13(s,1H),7.97(d,J＝8.8Hz,1H),7.88(d,J＝8.0Hz,1H),7.67-7.71(m,1H),7.58-7.62(m,1H),4.50-4.57(m,2H),1.60-1.78(m,3H),1.50(d,J＝6.8Hz,3H),0.97(dd,J₁＝6.4Hz,J₂＝11.2Hz,6H).¹³C NMR(100MHz,MeOD)δ174.4,173.8,163.9,145.6,145.4,133.9,129.8,129.7,128.9,128.8,128.6,125.7,51.9,51.2,42.0,25.9,23.4,21.9,17.8. as shown in FIG. 2.

Example 3 Synthesis of (R) -2-carboxamide-4-methyl-N- (3-oxo-3- (quinolin-3-ylamino) propyl) pentanamide (3) and 3-amino-N- (quinolin-3-yl) propionamide (3 b)

As shown in scheme 2, the specific procedure is the same as in example 2.

Compound 3a as a white solid, yield 97％.¹H NMR(400MHz,CD₃OD)δ8.89(d,J＝2.4Hz,1H),8.72(s,1H),7.97(d,J＝8.4Hz,1H),7.87(d,J＝8.0Hz,1H),7.65-7.69(m,1H),7.59(t,J＝7.2Hz,1H),3.45(t,J＝6.4Hz,2H),2.65(t,J＝6.8Hz,2H).

Compound 3b was a pale yellow solid, yield 99％.¹H NMR(400MHz,CD₃OD)δ8.93(d,J＝2.4Hz,1H),8.72(d,J＝2.4Hz,1H),7.98(d,J＝8.4Hz,1H),7.87(d,J＝8.0Hz,1H),7.67-7.71(m,1H),7.58-7.62(m,1H),3.33(t,J＝6.3Hz,2H),2.92(t,J＝6.4Hz,2H).

Compound 3 was a white solid in yield 71％.¹H NMR(400MHz,CD₃OD)δ8.91(d,J＝2.4Hz,1H),8.72(d,J＝2.0Hz,1H),8.07(s,1H),7.97(d,J＝8.4Hz,1H),7.88(d,J＝7.6Hz,1H),7.66-7.70(m,1H),7.60(t,J＝7.6Hz,1H),4.40-4.44(m,1H),3.53-3.63(m,2H),2.68-2.71(m,1H),1.59-1.67(m,1H),1.49-1.57(m,2H),0.89(t,J＝6.4Hz,6H).¹³C NMR(100MHz,CD3OD)δ174.6,172.6,163.6,145.4,134.0,129.8,129.7,128.9,128.8,128.6,125.6,52.0,42.3,37.3,36.9,25.9,23.3,22.0.HRMS(ESI-TOF)m/z calcd.for C₁₉H₂₄N₄O₃[M+H]⁺:357.1927,found 357.1923. as shown in figure 3.

Example 4 Synthesis of (S) -3- ((S) -2-carboxamido-4-methylpentanamido) -4-oxo-4- (quinolin-3-ylamino) butanoic acid (4), (S) -3-amino-4-oxo-4- (quinolin-3-ylamino) butanoic acid (4 b) and (S) -3- ((S) -2-carboxamido-4-methylpentanamido) -4-oxo-4- (quinolin-3-ylamino) butanoic acid tert-butyl ester (4 c)

The synthesis of compounds 4, 4b and 4c is shown in scheme 3 and is performed as follows:

(1) Synthesis of compound 4 a: 3-aminoquinoline (1.0 mmol) and N- (9-fluorenylmethoxycarbonyl) -L-aspartic acid-4-tert-butyl ester (1.2 mmol) were dissolved in 2mL of anhydrous dichloromethane, DIC (1.5 mmol) and DMAP (0.3 mmol) were added dropwise under ice bath, the mixture was allowed to react at room temperature, 50mL of water was added after completion of the reaction monitored by thin layer chromatography, three times with 50mL of dichloromethane were added, the organic phases were combined, dried over anhydrous Na ₂SO₄, the drying agent was removed by filtration, the solvent was evaporated, and the crude product was separated and purified by silica gel column to give compound 4a as a white solid in the yield of 72％.¹H NMR(400MHz,CDCl₃)δ8.93(s,1H),8.74(s,1H),8.05(d,J＝8.4Hz,1H),7.78(t,J＝9.0Hz,3H),7.58-7.66(m,3H),7.53(t,J＝7.4Hz,1H),7.39(t,J＝7.2Hz,2H),7.28(t,J＝7.2Hz,2H).6.13(s,1H),4.74(s,1H),4.52(d,J＝4.4Hz,2H),4.24(t,J＝6.6Hz,1H),3.01(d,J＝16.8Hz,1H),2.71-2.75(m,1H),1.47(s,9H).

(2) Synthesis of Compound 4 b: 4a was dissolved in 2mL of dry DMF, 0.5mL of 25% (volume ratio) morpholine in DMF was added with stirring in an ice bath, and the reaction was allowed to proceed to room temperature for about 1h. After the completion of the reaction was monitored by thin layer chromatography, 30mL of water was added, followed by extraction with 50mL of ethyl acetate three times, the organic phases were combined, dried over anhydrous Na ₂SO₄, filtered to remove the drying agent, the solvent was evaporated, and the crude product was purified by silica gel column to give intermediate 4b as a yellow oil with a yield of 81％.¹H NMR(400MHz,CDCl₃)δ8.81(s,2H),8.04(d,J＝8.4Hz,2H),7.79(d,J＝7.2Hz,1H),7.62(t,J＝7.4Hz,1H),7.51(t,J＝6.8Hz,1H),3.90(s,1H),2.94(d,J＝14.8Hz,1H),2.83(dd,J₁＝6.4Hz,J₂＝16.4Hz,1H),1.45(s,9H).¹³C NMR(100MHz,CDCl₃)δ172.2,171.0,145.2,144.1,131.4,129.0,128.3,127.9,127.3,123.4,81.9,52.5,39.9,28.2.

(3) Synthesis of Compound 4 c: intermediate 4b (1.0 mmol) was dissolved in 2mL of anhydrous dichloromethane, N-formyl-L-leucine (1.2 mmol) was added, DIC (1.5 mmol) and DMAP (0.3 mmol) were added dropwise under ice-bath, and the reaction was allowed to proceed to room temperature for about 2h. After the completion of the reaction, 50mL of water was added, followed by three extractions with 50mL of methylene chloride, the organic phases were combined, washed with saturated ammonium chloride, dried over anhydrous Na ₂SO₄, filtered to remove the drying agent, the solvent was evaporated, and the crude product was purified by silica gel column to give intermediate 4c as a white solid in yield 76％.¹H NMR(400MHz,CDCl₃)δ9.43(s,1H),8.95(s,1H),8.72(s,1H),8.28(s,1H),8.00(d,J＝7.6Hz,1H),7.91(d,J＝7.6Hz,1H),7.72(d,J＝8.0Hz,1H),7.58(t,J＝7.2Hz,1H),7.45-7.48(m,1H),7.07(d,J＝5.2Hz,1H),5.01-5.10(m,1H),4.58(s,1H),2.95(dd,J₁＝5.2Hz,J₂＝16.8Hz,1H),2.82(dd,J₁＝6.4Hz,J₂＝16.4Hz,1H),1.68(s,2H),1.39(s,9H)0.89(t,J＝6.4Hz,6H).

(4) Synthesis of Compound 4: intermediate 4c (1.0 mmol) obtained above was dissolved in 2mL of anhydrous dichloromethane, and 0.5mL of DCM containing 25% (volume ratio) trifluoroacetic acid was added dropwise under ice. After the completion of the reaction was monitored by thin layer chromatography, the reaction mixture was dried in vacuo, ice water 1mL was added, the ph=8 of the system was adjusted with saturated sodium bicarbonate, extracted three times with 50mL of dichloromethane, the organic phases were combined, dried over anhydrous Na ₂SO₄, the drying agent was removed by filtration, the solvent was evaporated, and the crude product was recrystallized from methanol to give the final product 4. White solid powder in yield 97％.¹HNMR(400MHz,MeOD)δ9.12(s,1H),8.81(d,J＝2.0Hz,1H),8.17(s,1H),7.99(d,J＝8.8Hz,1H),7.93(d,J＝8.0Hz,1H),7.75(t,J＝7.2Hz,1H),7.64(t,J＝7.6Hz,1H),4.90(s,1H),4.42-4.46(m,1H),3.05(dd,J₁＝6.0Hz,J₂＝16.8Hz,1H),2.88(dd,J₁＝7.6Hz,J₂＝16.8Hz,1H),1.60-1.76(m,3H),0.96(dd,J₁＝6.4Hz,J₂＝12.4Hz,6H).¹³CNMR(100MHz,MeOD)δ174.6,173.9,171.8,164.3,144.4,143.6,134.0,130.9,129.8,129.3,129.2,127.9,127.2,55.6,55.3,41.7,36.3,25.8,23.3,22.0. as shown in fig. 4.

Example 5 Synthesis of (S) -4- ((S) -2-carboxamide-4-methylpentanamido) -5-oxo-5- (quinolin-3-ylamino) pentanoic acid (5), (S) -4-amino-5-oxo-5- (quinolin-3-ylamino) pentanoic acid (5 b) and (S) -4- ((S) -2-carboxamide-4-methylpentanamido) -5-oxo-5- (quinolin-3-ylamino) pentanoic acid tert-butyl ester (5 c)

The synthesis of compounds 5, 5b and 5c is shown in scheme 3 and the specific procedure is the same as example 4.

(1) Synthesis of compound 5 a: the raw materials are 3-aminoquinoline and N- (9-fluorenylmethoxycarbonyl) -L-glutamic acid-5-tertiary butyl ester, the reaction conditions and the post-treatment method are the same as those of 4a, and the product 5a is obtained as a white solid with the yield of 50％.¹H NMR(400MHz,CDCl₃)δ9.22(s,1H),8.79(s,1H),8.72(d,J＝2.0Hz,1H),8.04(d,J＝8.4Hz,1H),7.75-7.79(m,3H),7.58-7.65(m,3H),7.53(t,J＝7.6Hz,2H),7.26-7.30(m,2H),5.98(d,J＝6.0Hz,1H).4.46(s,3H),4.22(t,J＝6.8Hz,1H),2.61(s,1H),2.41-2.45(m,1H),2.22(s,1H),2.02-2.08(m,1H),1.48(s,9H).

(2) Synthesis of compound 5 b: the raw material is 5a, the reaction condition and the post-treatment method are the same as 4b, and the product 5b is obtained as yellow oil with the yield of 85％.¹H NMR(400MHz,CDCl₃)δ9.96(s,1H),8.81(d,J＝4.8Hz,2H),8.02(d,J＝8.4Hz,1H),7.77(d,J＝7.6Hz,1H),7.61(t,J＝7.2Hz,1H),7.51(t,J＝7.6Hz,1H),3.73(d,J＝7.2Hz,1H),2.46-2.50(m,2H),2.27-2.34(m,1H),1.97-2.04(m,1H),1.45(s,9H).

(3) Synthesis of compound 5 c: raw material 5b, reaction condition and post-treatment method 4c are the same, and the product 5c is obtained as white solid with yield of 80％.¹H NMR(400MHz,CDCl₃)δ9.42(s,1H),8.95(d,J＝2.4Hz,1H),8.77(d,J＝4.0Hz,1H),8.30(s,1H),8.03(d,J＝8.4Hz,1H),7.76-7.81(m,2H),7.59-7.63(m,1H),7.51(t,J＝7.2Hz,1H),6.38(d,J＝6.0Hz,1H),4.52-4.67(m,2H),2.56-2.64(m,1H),2.40-2.48(m,1H),2.12-2.21(m,2H),1.71-1.74(m,2H),1.48-1.66(m,1H),1.45(s,9H),0.95(t,J＝2.8Hz,6H).

(4) Synthesis of Compound 5: the raw material is 5c, and the reaction condition and the post-treatment method are the same as 4, so that the product 5 is obtained. White solid, yield 96％.¹H NMR(400MHz,MeOD)δ9.29(d,J＝2.4Hz,1H),8.97(d,J＝2.4Hz,1H),8.15(s,1H),8.07(d,J＝8.4Hz,2H),7.86-7.90(m,1H),7.67(t,J＝7.6Hz,1H),4.55-4.60(m,1H),4.47-4.51(m,1H),2.44-2.58(m,2H),2.24-2.33(m,1H),2.04-2.15(m,1H),1.59-1.77(m,3H),0.97(dd,J₁＝6.4Hz,J₂＝13.2Hz,6H).¹³C NMR(100MHz,MeOD)δ176.4,174.9,172.8,164.2,142.0,140.2,134.4,132.5,130.7,130.2,130.1,129.4,124.6,55.0,52.3,41.8,31.1,27.8,25.9,21.9. as shown in fig. 5.

Example 6 Synthesis of (R) -N- (2- (2-carboxamide-4-methylpentacarboxamide) ethyl) quinoline-3-carboxamide (6) and N- (2-aminoethyl) quinoline-3-carboxamide (6 b)

The synthesis of compounds 6 and 6b is shown in scheme 4, and comprises the following steps:

(1) Synthesis of compound 6 a: quinoline-3-carboxylic acid and N-t-butoxycarbonyl-ethylenediamine are used as raw materials, a synthesis method and a post-treatment method are the same as those of the compound 4a, and the obtained target product 6a is a white solid with a yield of 91%.

(2) Synthesis of compound 6 b: the compound 6a is used as a raw material, the specific synthesis steps are the same as those of the assimilation compound 4b, the obtained target product 6b is white solid, and the yield is 94％.¹H NMR(400MHz,CD₃OD)δ9.29(d,J＝2.0Hz,1H),8.85(d,J＝1.6Hz,1H),8.10(dd,J＝8.4Hz,13.2Hz,2H),7.89-7.94(m,1H),7.73(t,J＝7.2Hz,1H),3.76(t,J＝6.0Hz,2H),3.23(t,J＝6.0Hz,2H).¹³C NMR(100MHz,CD3OD)δ168.8,149.8,137.8,133.1,130.3,129.2,129.0,128.4,127.9,40.9,38.8.

(3) Synthesis of Compound 6: the specific procedure for the synthesis of the same as that of the assimilation compound 4c was carried out using the compound 6b as a raw material, and the obtained target product 6 was a white solid with a yield of 89％.¹H NMR(400MHz,CDCl₃)δ9.33(s,1H),8.55(s,1H),8.15(s,1H),8.09(d,J＝8.4Hz,1H),7.77-7.85(m,2H),7.59(t,J＝7.2Hz,1H),7.47(s,1H),6.56(d,J＝7.6Hz,1H),4.48-4.53(m,1H),3.64-3.72(m,3H),3.51(t,J＝5.6Hz,1H),1.51-1.72(m,3H),0.84(dd,J＝6.0Hz,13.2Hz,6H).¹³C NMR(100MHz,CDCl₃)δ173.6,166.0,161.9,148.8,148.4,136.6,131.5,129.0,128.9,127.5,127.0,126.8,51.1,41.4,40.2,39.3,24.8,22.8,22.0.HRMS(ESI-TOF)m/z calcd.for C₁₉H₂₅N₄O₃[M+H]⁺:357.1927,found 357.1923. as shown in fig. 6.

EXAMPLE 7 Synthesis of (R) -2-carboxamide-4-methyl-N- (2- (2-methyl-2- (quinolin-3-yloxy) propanamido) ethyl) pentanamide (7)

The synthesis of compound 7 is shown in scheme 5 and comprises the following steps:

(1) Synthesis of compound 7 a: tert-butyl α -bromoisobutyrate (2 mmol) was dissolved in 2mL of dry DMF, 3-hydroxyquinoline (1.0 mmol) was added with stirring, cesium carbonate (3 mmol) was added and reacted at 80℃for 4-5 h. After the completion of the reaction, 50mL of water was added, followed by three extractions with 50mL of ethyl acetate, the organic phases were combined, dried over anhydrous Na ₂SO₄, filtered to remove the drying agent, the solvent was evaporated, and the crude product was purified by silica gel column to give compound 7a as a white solid with a yield of 83％.¹H NMR(400MHz,CDCl₃)δ8.65(d,J＝2.8Hz,1H),8.04(d,J＝4.4Hz,1H),7.65(d,J＝8.0Hz,1H),7.57(m,1H),7.49(t,J＝7.0Hz,1H),7.34(d,J＝2.8Hz,1H),1.67(s,6H),1.43(s,9H).

(2) Synthesis of Compound 7 c: 7a (1.0 mmol) obtained above was dissolved in 2mL of anhydrous dichloromethane, and 0.5mL of DCM containing 25% (volume ratio) trifluoroacetic acid was added dropwise under ice. After the reaction was monitored by thin layer chromatography, the reaction solution was dried by spin-drying, and the system was adjusted to ph=8 with triethylamine in ice bath to obtain compound 7b, which was directly taken to the next step without purification. 7b (1.0 mmol) obtained above was dissolved in 2mL of anhydrous dichloromethane, N-t-butoxycarbonyl ethylenediamine (1.2 mmol) was added, DIC (1.5 mmol) and DMAP (0.3 mmol) were added dropwise under ice bath, and the reaction was allowed to proceed to room temperature for 1-2 hours. After the completion of the reaction, 50mL of water was added, followed by three extractions with 50mL of methylene chloride, the organic phases were combined, washed with saturated ammonium chloride, dried over anhydrous Na ₂SO₄, filtered to remove the drying agent, the solvent was evaporated, and the crude product was purified by silica gel column to give intermediate 7c as a white solid in yield 31％.¹H NMR(400MHz,CDCl₃)δ8.67(s,1H),8.06(d,J＝8.4Hz,1H),7.73(d,J＝8.4Hz,1H),7.63(t,J＝7.6Hz,1H),7.53(t,J＝7.6Hz,2H),7.28(s,1H),4.82(s,1H),3.44(t,J＝5.6Hz,2H),3.30(d,J＝5.2Hz,2H),1.61(s,6H),1.37(s,9H).

(3) Synthesis of Compound 7: 7c (1.0 mmol) obtained above was dissolved in 2mL of anhydrous dichloromethane, and 0.5mL of DCM containing 25% (volume ratio) trifluoroacetic acid was added dropwise under ice. After the reaction was monitored by thin layer chromatography, the reaction solution was dried by spin-drying, and the system was adjusted to ph=8 with triethylamine in ice bath to obtain compound 7d, which was directly taken to the next step without purification. 7d (1.0 mmol) obtained above was dissolved in 2mL of anhydrous DCM, N-formyl-L-leucine (1.2 mmol) was added, DIC (1.5 mmol) and DMAP (0.3 mmol) were added dropwise in ice bath, and the reaction was allowed to proceed to room temperature for 1-2 h. After the completion of the reaction, 50mL of water was added, followed by extraction three times with 50mL of ethyl acetate, the organic phases were combined, washed with saturated ammonium chloride, dried over anhydrous Na ₂SO₄, filtered to remove the drying agent, the solvent was evaporated, and the crude product was purified by silica gel column separation to give the final product 7 as a white solid with a yield of 88％.¹H NMR(400MHz,CDCl₃)δ8.67(d,J＝2.4Hz,1H),8.05(d,J＝8.4Hz,1H),7.96(s,1H),7.74(d,J＝7.6Hz,1H),7.62-7.65(m,1H),7.53-7.57(m,1H),7.49(d,J＝2.4Hz,1H),7.38(s,1H),6.58(s,1H),5.82(s,1H),4.26-4.29(m,1H),3.45-3.52(m,3H),3.28-3.34(m,1H),1.59-1.63(m,6H),1.53-1.57(m,2H),1.34(t,J＝8.4Hz,1H),0.85(d,J＝5.6Hz,6H).¹³C NMR(100MHz,CDCl₃)δ174.6,172.9,161.4,147.8,147.0,144.1,128.7,128.1,127.9,127.2,127.1,127.1,82.1,50.3,41.2,39.4,39.2,24.9,24.8,24.5,22.7.21.8. as shown in fig. 7.

Example 8 Synthesis of (S) -3- ((S) -2-carboxamide-4-methylpentanamido) -4-oxo-4- (quinolin-6-amino) butanoic acid (8), (S) -3-amino-4-oxo-4- (quinolin-6-amino) butanoic acid (8 b) and (S) -3- ((S) -2-carboxamide-4-methylpentanamido) -4-oxo-4- (quinolin-6-amino) butanoic acid tert-butyl ester (8 c)

The synthesis of compounds 8, 8b and 8c is shown in scheme 3, and the synthesis is performed in the same manner as in example 4, and the specific procedure is as follows:

(1) Synthesis of compound 8 a: the raw materials are 6-aminoquinoline and N- (9-fluorenylmethoxycarbonyl) -L-aspartic acid-4-tert-butyl ester, the reaction conditions and the post-treatment method are the same as those of 4a, and the product 8a is obtained as a white solid with the yield of 69％.¹H NMR(400MHz,CDCl₃)δ8.83(d,J＝1.2Hz,2H),8.30(d,J＝2.4Hz,1H),8.12(d,J＝8.0Hz,1H),8.05(d,J＝8.0Hz,1H),7.77(d,J＝7.6Hz,2H),7.55-7.61(m,3H),7.38-7.42(m,3H),7.26-7.32(m,2H),4.71(s,1H),4.51(d,J＝6.4Hz,2H),4.25(t,J＝6.8Hz,1H),3.02(d,J＝14.0Hz,1H),2.70-2.76(m,1H),1.48(s,9H).

(2) Synthesis of compound 8 b: raw material is 8a, the reaction condition and the post-treatment method are the same as 4b, and the product 8b is obtained as white solid with the yield of 78％.¹H NMR(400MHz,CDCl₃)δ8.77(dd,J₁＝1.6Hz,J₂＝4.4Hz,1H),8.40(d,J＝2.0Hz,1H),8.30(d,J＝8.0Hz,1H),8.00(d,J＝8.8Hz,1H),7.85(dd,J₁＝2.4Hz,J₂＝9.2Hz,1H),7.53(dd,J₁＝4.4Hz,J₂＝8.4Hz,1H),4.03-4.06(m,1H),2.92(dd,J₁＝5.2Hz,J₂＝16.8Hz,1H),2.79(dd,J₁＝7.2Hz,J₂＝16.8Hz,1H),1.46(s,9H).

(3) Synthesis of Compound 8 c: raw material is 8b, the reaction condition and the post-treatment method are the same as 4c, and the product 8c is obtained as white solid with the yield of 87％.¹H NMR(400MHz,CDCl₃)δ8.76(t,J＝2.0Hz,1H),8.40(d,J＝2.4Hz,1H),8.30(d,J＝8.4Hz,1H),8.15(s,1H),7.97(d,J＝7.6Hz,1H),7.91(d,J＝7.6Hz,1H),7.72(d,J＝8.0Hz,1H),7.58(t,J＝9.2Hz,1H),7.89-7.92(m,1H),7.51-7.54(dd,J₁＝4.4Hz,J₂＝8.4Hz,1H),4.87-4.91(m,1H),4.45-4.49(m,1H),3.30-3.32(m,1H),2.93-2.99(m,1H),1.60-1.76(m,3H),1.46(s,9H),0.95(dd,J₁＝6.4Hz,J₂＝12.0Hz,6H).

(4) Synthesis of Compound 8: raw material 8c, reaction condition and post-treatment method are the same as 4, so that a product 8 is obtained as white solid, and the yield is 89％.¹H NMR(400MHz,MeOD)δ8.88(d,J＝4.0Hz,1H),8.20(d,J＝7.6Hz,1H),8.54(d,J＝1.6Hz,1H),8.15(d,J＝6.0Hz,1H),8.03-8.09(m,2H),7.73(dd,J₁＝3.2Hz,J₂＝8.4Hz,1H),4.43-4.46(m,1H),3.04(dd,J₁＝6.4Hz,J₂＝16.8Hz,1H),2.86(dd,J₁＝7.6Hz,J₂＝16.8Hz,1H),1.59-1.75(m,3H),0.95(dd,J₁＝6.4Hz,J₂＝12.8Hz,6H).¹³C NMR(100MHz,MeOD)δ174.6,173.9,171.5,147.1,142.7,140.9,139.4,130.7,127.7,125.9,123.1,117.4,52.6,52.4,41.7,36.4,25.8,23.3,22.0. as shown in figure 8.

Example 9 Synthesis of (S) -4- ((S) -2-carboxamide-4-methylpentanamido) -5-oxo-5- (quinolin-6-amino) pentanoic acid (9), (S) -4-amino-5-oxo-5- (quinolin-6-amino) pentanoic acid (9 b) and (S) -4- ((S) -2-carboxamide-4-methylpentanamido) -5-oxo-5- (quinolin-6-amino) pentanoic acid tert-butyl ester (9 c)

The synthesis of compounds 9, 9b and 9c is shown in scheme 3 and proceeds as follows in example 4:

(1) Synthesis of compound 9 a: the raw materials are 6-aminoquinoline and N- (9-fluorenylmethoxycarbonyl) -L-glutamic acid-5-tertiary butyl ester, the reaction conditions and the post-treatment method are the same as those of 4a, and the product 9a is obtained as a white solid with the yield of 80％.¹H NMR(400MHz,CDCl₃)δ9.01(s,1H),8.83(dd,J₁＝1.6Hz,J₂＝4.4Hz,1H),8.34(d,J＝2.4Hz,1H),8.10(d,J＝8.0Hz,1H),8.04(d,J＝8.0Hz,1H),8.04(d,J＝9.2Hz,1H),7.76(d,J＝7.2Hz,2H),7.59(dd,J₁＝2.4Hz,J₂＝8.4Hz,3H),7.37-7.41(m,3H),7.30(d,J＝6.4Hz,2H),5.95(d,J＝5.2Hz,1H),4.45(d,J＝7.2Hz,2H),4.41(s,1H),4.23(t,J＝7.2Hz,1H),2.60(s,1H),2.40-2.45(m,1H),2.22(d,J＝5.2Hz,1H),2.05(dd,J₁＝6.8Hz,J₂＝13.6Hz,1H),1.49(s,9H).

(2) Synthesis of compound 9 b: the raw material is 9a, the reaction condition and the post-treatment method are the same as 4b, and the product 9b is obtained as yellow oil with the yield of 87％.¹H NMR(400MHz,CDCl₃)δ9.80(s,1H),8.81(d,J＝6.8Hz,,1H),8.44(d,J＝1.6Hz,1H),8.11(d,J＝4.0Hz,1H),8.04(d,J＝9.2Hz,1H),7.63(dd,J₁＝2.0Hz,J₂＝8.8Hz,1H),7.35(dd,J₁＝4.4Hz,J₂＝8.4Hz,1H),3.27(s,1H),2.44-2.48(m,2H),2.22-2.31(m,1H),1.96(dd,J₁＝6.8Hz,J₂＝14.0Hz,1H),1.45(s,9H).

(3) Synthesis of compound 9 c: raw material 9b, reaction condition and post-treatment method are the same as 4c, and the product 9c is obtained as white solid with yield of 89％.¹H NMR(400MHz,MeOD)δ8.74-8.75(m,1H),8.39(d,J＝2.0Hz,1H),8.28(d,J＝8.4Hz,1H),8.14(s,1H),7.85(dd,J₁＝2.4Hz,J₂＝9.2Hz,2H),7.50(dd,J₁＝4.4Hz,J₂＝8.4Hz,1H),4.50-4.57(m,2H),2.35-2.50(m,2H),2.17-2.26(m,1H),1.99-2.08(m,1H),1.60-1.74(m,3H),1.44(s,9H),0.95(dd,J₁＝2.8Hz,J₂＝5.6Hz,6H).

(4) Synthesis of compound 9: raw material 9c, reaction condition and post-treatment method are the same as 4, and product 9 is obtained as white solid with yield 98％.¹H NMR(400MHz,MeOD)δ8.79(d,J＝2.8Hz,1H),8.44(d,J＝2.0Hz,1H),8.39(d,J＝8.0Hz,1H),8.14(s,1H),8.00(d,J＝9.2Hz,1H),7.90(dd,J₁＝2.4Hz,J₂＝9.2Hz,1H),7.58(dd,J₁＝4.4Hz,J₂＝8.0Hz,1H),4.50-4.59(m,2H),2.42-2.56(m,2H),2.20-2.30(m,1H),2.03-2.12(m,1H),1.57-1.76(m,3H),0.96(dd,J₁＝4.4Hz,J₂＝8.0Hz,6H).¹³C NMR(100MHz,MeOD)δ176.4,174.7,172.3,164.0,149.2,144.5,139.5,138.5,130.5,128.6,126.0,123.0,117.6,54.9,52.1,41.9,31.2,28.2,25.9,24.0,22.0. shown in figure 9.

Example 10 Synthesis of Compound 10 of (R) -6-amino-2- ((S) -2-carboxamide-4-methylpentanamide) -N- (quinolin-6-yl) hexanamide (10) As shown in scheme 5, the steps are followed:

(1) Synthesis of Compound 10 a: N-Boc-N- (9-fluorenylmethoxycarbonyl) - α -D-lysine (1.2 mmol) was dissolved in 2mL of anhydrous dichloromethane, 6-aminoquinoline (1.0 mmol) was added under stirring, DIC (1.5 mmol) and DMAP (0.3 mmol) were added dropwise to the solution in ice, and the reaction was carried out at room temperature for 1 to 2 hours. After the completion of the reaction was monitored by thin layer chromatography, 50mL of water was added, followed by three extractions with 50mL of dichloromethane, the organic phases were combined, dried over anhydrous Na ₂SO₄, the drying agent was removed by filtration, the solvent was evaporated, and the crude product was purified by separation on a silica gel column. The product was a white solid 10a in yield of 78％.¹H NMR(400MHz,CDCl₃)δ8.91(s,1H),8.82(d,J＝2.8Hz,1H),8.33(s,1H),8.03(dd,J₁＝8.4Hz,J₂＝21.6Hz,2H),7.75(d,J＝7.2Hz,2H),7.57-7,63(m,3H),7.34-7,40(m,3H),7.27(s,2H),5.69(s,1H),4.70(s,1H),4.45(s,2H),4.36(s,1H),4.22(t,J＝6.8Hz,1H),3.07-3.20(m,2H),2.03(s,1H),1.43-1,54(m,14H).

(2) Synthesis of Compound 10 b: 10a obtained above was dissolved in 2mL of dry DMF, and 0.5mL of DMF containing 25% (v/v) morpholine was added under ice bath stirring to react at room temperature for 0.5-1 h. After the completion of the reaction was monitored by thin layer chromatography, 30mL of water was added, followed by extraction with 50mL of ethyl acetate three times, the organic phases were combined, dried over anhydrous Na ₂SO₄, filtered to remove the drying agent, the solvent was evaporated, and the crude product was purified by silica gel column separation to give a white solid 10b in the yield of 98％.¹H NMR(400MHz,CDCl₃)δ9.85(s,1H),8.78(s,1H),8.40(s,1H),8.07(d,J＝7.6Hz,1H),7.01(d,J＝8.8Hz,1H),7.62(d,J＝8.8Hz,1H),7.33-7,35(m,1H),4.70(s,1H),3.53(s,1H),3.12(s,2H),2.18(s,3H),1.96(s,1H),1.48(s,4H),1.40(s,9H).

(3) Synthesis of Compound 10 c: the intermediate 10b (1.0 mmol) obtained above was dissolved in 2mL of anhydrous dichloromethane, N-formyl-L-leucine (1.2 mmol) was added, DIC (1.5 mmol) and DMAP (0.3 mmol) were added dropwise under ice bath, and the reaction was allowed to proceed to room temperature for 1-2 h. After the reaction is monitored to be complete by thin layer chromatography, 50mL of water is added, the mixture is extracted three times by 50mL of dichloromethane, the organic phases are combined, the saturated ammonium chloride is used for washing the organic phases, anhydrous Na ₂SO₄ is used for drying, the drying agent is removed by filtration, the solvent is evaporated, the crude product is separated and purified by a silica gel column, and the white solid 10c is obtained with the yield of 90％.¹H NMR(400MHz,CDCl₃)δ9.30(s,1H),8.76-8.77(m,1H),8.27-8.29(m,2H),7.93-7.98(m,2H),7.60(d,J＝8.8Hz,1H),7.30(dd,J₁＝4.4Hz,J₂＝8.4Hz,1H),7.20(d,J＝6.4Hz,1H),6.92(s,1H),4.80(s,1H),4.61-4.69(m,2H),3.09(d,J＝5.2Hz,2H),2.02(d,J＝8.0Hz,1H),1.60-1.65(m,2H),1.40-1.42(m,15H),0.92-0.94(m,6H).

(4) Synthesis of Compound 10: intermediate 10c (1.0 mmol) obtained above was dissolved in 2mL of anhydrous dichloromethane, and 0.5mL of DCM containing 25% (volume ratio) trifluoroacetic acid was added dropwise under ice. After the reaction was monitored by thin layer chromatography, the reaction solution was dried by spin-drying, adjusting the pH of the system to 10 with 5mol/L potassium hydroxide in ice bath, extracting three times with 50mL of methylene chloride, mixing the organic phases, drying with anhydrous Na ₂SO₄, filtering to remove the drying agent, evaporating the solvent, and recrystallizing the crude product with methanol diethyl ether to obtain the final product 10 as a white solid with the yield of 87％.¹H NMR(400MHz,MeOD)δ8.74-8.75(m,1H),8.37(d,J＝6.4Hz,1H),8.28(d,J＝8.8Hz,1H),8.13(s,1H),7.96(d,J＝9.2Hz,1H),7.84(dd,J₁＝2.4Hz,J₂＝9.2Hz,1H),7.50(dd,J₁＝4.4Hz,J₂＝8.4Hz,1H),4.53(dd,J₁＝5.2Hz,J₂＝8.8Hz,2H),2.68(t,J＝5.6Hz,2H),1.51-1.95(m,12H),0.92-0.94(m,6H).¹³C NMR(100MHz,MeOD)δ174.6,173.0,163.8,150.0,145.7,138.0,137.8,130.1,129.6,125.1,122.9,117.3,55.6,51.8,42.0,42.0,32.8,25.8,24.2,23.4,22.0. shown in FIG. 10.

EXAMPLE 11 Synthesis of (R) -2-carboxamide-4-methyl-N- (2- (2-methyl-2- (quinolin-6-yloxy) propionamido) ethyl) pentanamide (11)

The synthesis of compound 11 is shown in scheme 6, and is performed as follows:

(1) Synthesis of Compound 11 a: tert-butyl α -bromoisobutyrate (2 mmol) was dissolved in 2mL of dry DMF, 6-hydroxyquinoline (1.0 mmol) was added with stirring, cesium carbonate (3 mmol) was added and reacted at 80℃for 4-5 h. After the completion of the reaction, 50mL of water was added, followed by three extractions with 50mL of ethyl acetate, the organic phases were combined, dried over anhydrous Na ₂SO₄, filtered to remove the drying agent, the solvent was evaporated, and the crude product was purified by silica gel column to give compound 11a as yellow oil with a yield of 50％.¹HNMR(400MHz,CDCl₃)δ8.78(d,J＝3.2Hz,1H),7.96-8.00(m,2H),7.32-7.36(m,2H),7.02(d,J＝2.4Hz,1H),1.67(s,6H),1.41(s,9H).

(2) Synthesis of Compound 11 c: 11a (1.0 mmol) obtained above was dissolved in 2mL of anhydrous dichloromethane, and 0.5mL of DCM containing 25% (volume ratio) trifluoroacetic acid was added dropwise under ice. After the reaction was monitored by thin layer chromatography, the reaction solution was dried by spin-drying, and the system was adjusted to ph=8 with triethylamine in ice bath to obtain compound 11b, which was directly taken to the next step without purification. 11b (1.0 mmol) obtained above was dissolved in 2mL of anhydrous dichloromethane, N-t-butoxycarbonyl ethylenediamine (1.2 mmol) was added, DIC (1.5 mmol) and DMAP (0.3 mmol) were added dropwise under ice bath, and the reaction was allowed to proceed to room temperature for 1-2 hours. After the completion of the reaction, 50mL of water was added, followed by three extractions with 50mL of methylene chloride, the organic phases were combined, washed with saturated ammonium chloride, dried over anhydrous Na ₂SO₄, filtered to remove the drying agent, the solvent was evaporated, and the crude product was purified by silica gel column to give intermediate 11c as a white solid in yield 65％.¹H NMR(400MHz,CDCl₃)δ8.82(d,J＝2.4Hz,1H),8.01-8.06(m,2H),7.36-7.40(m,2H),7.19(d,J＝2.8Hz,2H),4.76(s,1H),3.41-3.46(m,2H),3.29(d,J＝5.6Hz,2H),1.61(s,6H),1.37(s,9H).

(3) Synthesis of Compound 11: 11c (1.0 mmol) obtained above was dissolved in 2mL of anhydrous dichloromethane, and 0.5mL of DCM containing 25% (volume ratio) trifluoroacetic acid was added dropwise under ice. After the reaction was monitored by thin layer chromatography, the reaction solution was dried by spin-drying, and the system was adjusted to ph=8 with triethylamine in ice bath to obtain compound 11d, which was directly taken to the next step without purification. 11d (1.0 mmol) obtained above was dissolved in 2mL of anhydrous DCM, N-formyl-L-leucine (1.2 mmol) was added, DIC (1.5 mmol) and DMAP (0.3 mmol) were added dropwise in ice bath, and the reaction was allowed to proceed to room temperature for 1-2 h. After the completion of the reaction was monitored by thin layer chromatography, 50mL of water was added, followed by three extractions with 50mL of ethyl acetate, the organic phases were combined, the organic phases were washed with saturated ammonium chloride, dried over anhydrous Na ₂SO₄, the drying agent was removed by filtration, the solvent was evaporated, and the crude product was purified by silica gel column separation to give the final product 11 as a white solid with a yield of 82％.¹H NMR(400MHz,CDCl₃)δ8.82-8.83(m,1H),8.01-8.08(m,3H),7.36-7.40(m,2H),7.31(s,1H),7.17(d,J＝2.4Hz,1H),6.75(s,1H),5.94(s,1H),4.34(dd,J₁＝8.0Hz,J₂＝13.2Hz,1H),3.29-3.46(m,4H),1.52-1.61(m,8H),1.40-1.44(m,1H),0.86(d,J＝6.0Hz,6H).¹³C NMR(100MHz,CDCl₃)δ175.6,172.7,161.3,152.5,149.2,145.0,135.4,130.8,128.8,125.7,121.7,115.2,81.9,50.6,41.3,39.9,39.5,25.3,25.1,24.8,22.9.22.0. as shown in fig. 11.

Example 122 Synthesis of (quinoline-6-yloxy) formyl-L-leucine ethyl ester (12)

The synthesis of the compound 12 is shown in a synthesis route 7, and the specific reaction steps are as follows:

in an argon-protected round-bottomed flask, 6-hydroxyquinoline (0.38 mmol) was dissolved in DMF (1 mL) a and ethylene carbonate (41 mg,0.46 mmol), potassium carbonate (79 mg,0.57 mmol) was added slowly with stirring and reacted at 150℃under reflux for 1h. Adding a small amount of ice water to quench the reaction in the reaction system, adding a small amount of NaOH aqueous solution, extracting the reaction solution with DCM (30 mL), washing with saturated NaCl, drying with anhydrous Na ₂SO₄, filtering to remove the desiccant, concentrating under reduced pressure and vacuum to obtain a crude product, and purifying by silica gel column chromatography (DCM: meOH=100:1-30:1, v/v) to obtain a pale yellow solid product 12a with the yield of 92％.¹H NMR(400MHz,CDCl₃)δ8.74-8.75(m,1H),7.97-8.02(m,2H),7.32-7.35(m,2H),7.05(d,J＝2.8Hz,1H),4.20(t,J＝4.0Hz,2H),4.05(t,J＝4.8Hz,2H).

12A (0.32 mmol) was dissolved in anhydrous DCM (2 mL) under argon and N-formyl-L-leucine (101 mg,0.64 mmol), DMAP (39 mg,0.32 mmol) and DIC (0.10 mL,0.64 mmol) were added slowly in sequence with stirring and stirring at room temperature until TLC detection was complete. The reaction was quenched with a small amount of ice water, quenched with NaHCO ₃ (2.5 mL), extracted 3 times with DCM (20 mL), the combined organic phases were washed with saturated NaCl solution, dried over anhydrous Na ₂SO₄, concentrated under reduced pressure and then purified by silica gel column chromatography (petroleum ether: acetone=5:1 to 1:1, v/v) to give the desired product 12 as a white solid with a yield of 90％.¹HNMR(400MHz,CDCl₃)δ8.79(dd,J＝1.6Hz,4.0Hz,1H),8.21(s,1H),8.01-8.07(m,2H),7.36-7.39(m,2H),7.08(d,J＝2.8Hz,1H),5.99(d,J＝6.8Hz,1H),4.75-4.81(m,1H),4.58-4.65(m,1H),4.51-4.56(m,1H),4.32-4.36(m,2H),1.64-1.72(m,2H),1.55-1.61(m,1H),0.91-0.93(m,6H).¹³C NMR(100MHz,CDCl₃)δ172.7,160.9,156.5,148.3,144.6,135.0,131.1,129.3,122.4,121.6,106.3,65.9,63.6,49.5,41.6,24.9,22.8,22.0.HRMS(ESI-TOF)m/z calcd.for C₁₈H₂₃N₂O₄[M+H]⁺:331.1658,found 331.1658. as shown in FIG. 12.

Example 13 Synthesis of (S) -4- ((S) -2-carboxamide-4-methylpentanamido) -5-oxo-5- (quinolin-5-ylamino) pentanoic acid (13), (S) -4-amino-5-oxo-5- (quinolin-5-ylamino) pentanoic acid tert-butyl ester (13 b) and (S) -4- ((S) -2-carboxamide-4-methylpentanamido) -5-oxo-5- (quinolin-5-ylamino) pentanoic acid tert-butyl ester (13 c)

The synthesis of compounds 13, 13b and 13c is shown in scheme 8 and is carried out in the same manner as in example 4, with the following steps:

(1) Synthesis of compound 13 a: the raw materials are 5-aminoquinoline and N- (9-fluorenylmethoxycarbonyl) -L-glutamic acid-5-tertiary butyl ester, the reaction conditions and the post-treatment method are the same as those of 4a, and the product 13a is obtained as a red solid with the yield of 98％.¹HNMR(400MHz,CDCl₃)δ8.91-8.95(m,2H),8.25(d,J＝8.4Hz,1H),7.97(d,J＝8.4Hz,1H),7.68-7.75(m,3H),7.59(d,J＝7.6Hz,2H),7.33-7.39(m,3H),7.28(s,1H),7.24(d,J＝7.6Hz,1H),6.24(d,J＝7.2Hz,1H),4.80(s,1H),4.53(d,J＝5.2Hz,2H),4.24(t,J＝6.8Hz,1H),3.03(dd,J₁＝4.0Hz,J₂＝17.2Hz,1H),2.77(dd,J₁＝6.8Hz,J₂＝16.4Hz,1H),1.49(s,9H).

(2) Synthesis of compound 13 b: the raw material is 13a, the reaction condition and the post-treatment method are the same as 4b, and the product 13b is obtained as yellow oil with the yield of 97％.¹H NMR(400MHz,CDCl₃)δ10.24(s,1H),8.92(d,J＝3.2Hz,,1H),8.30(d,J＝8.4Hz,1H),8.13(d,J＝7.6Hz,1H),7.70(t,J＝8.0Hz,,1H),7.43(dd,J₁＝4.0Hz,J₂＝8.4Hz,1H),4.00(s,1H),2.96(dd,J₁＝3.6Hz,J₂＝16.8Hz,1H),2.86(dd,J₁＝7.2Hz,J₂＝16.8Hz,1H),1.94(s,2H),1.46(s,9H).

(3) Synthesis of Compound 13 c: the raw material is 13b, the reaction condition and the post-treatment method are the same as 4c, and the product 13c is obtained as white solid with the yield of 83％.¹H NMR(400MHz,CDCl₃)δ8.90(d,J＝3.6Hz,1H),8.8(d,J＝3.2Hz,1H),8.20-8.34(m,2H),7.81-8.00(m,3H),7.61-7.70(m,1H),7.36-7.44(m,1H),6.52(d,J＝7.2Hz,1H),5.01-5.08(m,1H),4.60-4.65(m,1H),2.95-3.06(m,1H),2.74-2.83(m,1H),1.59-1.76(m,3H),1.46(s,9H),0.89-0.6(m,6H).

(4) Synthesis of Compound 13: the starting material was 13c and the reaction conditions and work-up procedure were the same as 4 to give the product 13 as a yellow oil in the yield 96％.¹H NMR(400MHz,MeOD)δ8.92(d,J＝5.2Hz,1H),8.56(s,1H),8.20(d,J＝9.2Hz,1H),8.08(d,J＝10.0Hz,2H),7.75(d,J＝5.2Hz,1H),7.58-7.62(m,2H),7.26-7.30(m,2H),4.79(t,J＝7.2Hz,1H),4.36(d,J＝7.2Hz,1H),2.94-2.99(dd,J₁＝6.0Hz,J₂＝16.8Hz,1H),2.77-2.83(dd,J₁＝7.6Hz,J₂＝16.0Hz,1H),1.54-1.70(m,3H),0.87-0.91(m,6H).¹³C NMR(100MHz,MeOD)δ174.6,173.8,171.7,166.5,164.2,164.0,156.5,144.5,140.6,133.2,133.1,133.0,129.0,128.5,124.2,123.5,117.3,117.1,115.5,52.6,52.5,41.7,36.2,25.8,23.4,22.0. shown in FIG. 13.

EXAMPLE 14 evaluation of pancreatic lipase inhibition Activity by Compounds 1 to 13

(1) Preparation of Tris-HCl buffer: an appropriate amount of tris (hydroxymethyl) aminomethane powder was weighed by a precision balance, distilled water was added until complete dissolution, and the pH was adjusted to 8.0 to give a final concentration of 13mM buffer.

(2) Preparing a sodium citrate reaction stop solution: weighing a proper amount of citric acid and sodium citrate powder, preparing a solution of 0.1mol/L by distilled water respectively, slowly dripping the citric acid solution into the sodium citrate solution, and regulating the pH value to 4.2 to obtain a reaction stopping solution.

(3) Preparation of pancreatic lipase solution: a proper amount of pancrelipase powder is weighed and prepared into an enzyme reaction solution with the concentration of 1mg/mL by using Tris-HCl buffer solution.

(4) Preparation of the reaction substrate: the substrate 4-methylumbelliferone propyl oleate was dissolved in dimethyl sulfoxide (DMSO) to a stock solution of 5mM and then diluted to a concentration of 0.1mM with Tris-HCl buffer for use.

(5) Preparation of test compound solutions: compounds 1 to 13 and positive control orlistat were dissolved in DMSO to test concentrations.

(6) Test system: blank background group (A1): tris-HCl buffer (50. Mu.L) +substrate (50. Mu.L) +sodium citrate stop solution (100. Mu.L); blank (A2): tris-HCl buffer (25. Mu.L) +substrate (50. Mu.L) +pancreatic lipase reaction solution (25. Mu.L) +sodium citrate stop solution (100. Mu.L); compound background group (A3): tris-HCl buffer (40. Mu.L) +substrate (50. Mu.L) +compound (10. Mu.L) +sodium citrate stop solution (100. Mu.L); compound test group (A4): tris-HCl buffer (15. Mu.L) +substrate (50. Mu.L) +compound (10. Mu.L) +pancreatic lipase reaction solution (25. Mu.L) +sodium citrate stop solution (100. Mu.L).

The various solutions are sequentially added into a 96-well plate, the 96-well plate is incubated at 25 ℃ before enzyme solution is added, so that liquids are uniformly mixed, the mixture is reacted for 30min at 25 ℃ after enzyme solution is added, 100 mu L of sodium citrate reaction stopping solution is added into each well to stop the reaction, OD value is measured at excitation wavelength of 360+/-20 nm and emission wavelength of 460+/-20 nm, and the calculation formula of the inhibition rate of the compound to pancreatic lipase is as follows:

Pancreatic lipase inhibition% = ((A2-A1) - (A4-A3))/(A2-A1) 100

The results of pancreatic lipase inhibition activity of compounds 1 to 13 are shown in Table 1.

TABLE 1 pancreatic lipase inhibitory Activity of Compounds 1 to 13

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Note that: ^a Pancreatic lipase inhibition rate is the average value of three parallel experiments, and two compound holes are arranged in each experiment; ^b Na=inactive (no active); ^c Orlistat was used as a positive control and the test concentration was 0.08 μm.

The results in Table 1 show that compounds 1-13 all exhibited varying degrees of inhibitory activity at the 10. Mu.M test concentration, with compounds 1,2, 7, 8, 10, 11, 13 and 13c being better active.

EXAMPLE 15 Effect of Compounds 1-13 on cellular lipid content

(1) Preparation of long chain fatty acid inducers (FFAs): appropriate amounts of sodium oleate and sodium palmitate powder were weighed, dissolved in 0.1M sodium hydroxide solution at 95℃and prepared as 200mM solutions, respectively. 1% Bovine Serum Albumin (BSA) powder was added to a DMEM low-sugar medium containing 1g/L glucose, and the mixture was dissolved by heating in a water bath at 65 ℃. Uniformly mixing the prepared DMEM low-sugar culture, sodium oleate solution and sodium palmitate solution according to the volume ratio of 400:2:1, and filtering and sterilizing by using a filter membrane with the volume ratio of 0.45 mu m to obtain the FFAs inducer. A tube of DMEM low-sugar medium containing only 1% BSA was also used as a blank.

(2) Preparation of oil red O working solution: oil red O powder was weighed and dissolved with isopropanol to a stock solution of 10 mg/mL. Mixing the stock solution of oil red O with water in a ratio of 3:2, and filtering with a 0.45 μm filter membrane to obtain the working solution of oil red O.

(3) Preparation of 4% paraformaldehyde: paraformaldehyde powder was added to 1×pbs heated to 65 ℃ to be sufficiently dissolved, to obtain a 4% paraformaldehyde solution.

(4) Determination of lipid content: hepG2 cells were seeded at a density of 1X 10 ⁵ in 6-well plates, 2mL per well, incubated for 24h, washed three times with 1X PBS, changed to DMEM serum-free high-sugar medium containing 4.5g/L glucose, and placed in a cell incubator at 37℃with 5% CO ₂ for further incubation for 24h. After washing for three times with 1 XPBS, the cells were stimulated with FFAs inducer, the blank group was added with DMEM low sugar medium of 1% BSA, and the compound solution of different concentrations was added according to the system volume and compound solution volume of 200:1, and the negative control group was added with an equal volume of solvent. After 24h, the original liquid was pipetted off, washed three times with 1 XPBS and cells were fixed for 30min with 2mL of 4% paraformaldehyde solution per well. The cells were fixed by washing three times with 1 XPBS and adding 2mL of isopropanol solution to each well for 5 min. Isopropanol was removed by pipetting, and each well was stained with 2mL of oil red O working solution for 1h in the dark. The cells were washed 4 times with distilled water to exclude the interference of extracellular lipids stained with oil red O, the water was sucked off, 1mL of isopropanol solution was added to each well, washed out by shaking at 37℃for 10min, and the change in intracellular lipid content was reflected by detecting the magnitude of absorbance at a wavelength of 492 nm. The intracellular lipid content was calculated as follows:

Lipid content% = (a _{Group of compounds}-A_{Blank control group})/(A_{negative control group}-A_{Blank control group}) ×100

The effect of compounds 1-13 on fatty acid-induced lipid content of HepG2 cells is shown in table 2.

TABLE 2 Effect of Compounds 1 to 13 on lipid content of HepG2 cells

Note that: ^a The cell lipid content is the average value of three parallel experiments + -SD, and two compound holes are arranged in each experiment; ^b Pitavastatin was used as a positive control at a test concentration of 10 μm.

The results in Table 2 show that compounds 1-13 each reduced fatty acid-induced lipid levels in HepG2 cells to varying degrees, wherein the lipid lowering activity of the remaining compounds, except compounds 7 and 12, was superior or comparable to that of pitavastatin at the same concentrations. The lipid lowering activity of the compounds at 3, 8c, 13c was higher than that of pitavastatin at 10. Mu.M at 2. Mu.M.

Example 12 Effect of Compound 8c on obese hyperlipemic mice

Pancreatic lipase activity and cell level lipid-lowering activity were comprehensively analyzed, and a representative compound 8c (nuclear magnetic resonance spectrum see fig. 14) was selected for evaluation of in vivo activity in mice.

(1) Experimental animal modeling

About 48 male C57BL/6J mice weighing 20g were purchased. After one week of adaptive feeding, 8 mice were randomly selected as normal groups, fed with normal feed, and the remaining 40 mice were fed with high-fat feed for 8 weeks before and after dosing as model groups, and the weight and blood lipid index showed significant differences, which was considered as successful modeling.

(2) Grouping and administration

The high fat housed mice were randomly divided into 5 groups of 8 animals each, including: high fat diet group (60% high fat feed), positive control group (60% high fat feed+1 mg/kg pitavastatin calcium), compound 8c low dose high fat diet group (60% high fat feed+1 mg/kg compound), compound 8c medium dose high fat diet group (60% high fat feed+5 mg/kg compound), compound 8c high dose high fat diet group (60% high fat feed+25 mg/kg compound). Wherein, the positive control pitavastatin calcium is dissolved by normal saline, and the compound 8c is dissolved by normal saline with 5% Tween 80. Oral administration by gastric lavage. Dosing was started once daily for 4 weeks (model mice were perfused with 5% tween 80 in normal saline by equal volume) at week eight.

(3) Influence of Compound 8c on body weight of obese hyperlipemic mice

During the course of the experiment, the body weight of the mice was recorded weekly and analyzed. The effect of compound 8c on mouse body weight is shown in figure 15. As can be seen from the figure, after four weeks of administration, the model group had 22.48% weight gain (P < 0.001) over the normal group, and compared with the model group, the positive control drug pitavastatin had 18.05% weight loss at 1mg/kg, compound 8c had 8.17% weight loss at 1mg/kg, 15.41% weight loss at 5mg/kg, and 19.89% weight loss at 25mg/kg, indicating that compound 8c significantly reduced the weight of high-fat diet mice.

(4) Influence of Compound 8c on blood lipid of obese hyperlipemic mice

Four weeks after dosing, mice were sacrificed from dislocation. Femoral artery blood is taken and then stored in a 1.5mL EP tube containing 1% heparin sodium, and the mixture is gently mixed upside down to make the blood fully contact with the anticoagulant in the tube, and the mixture is placed on ice for standing for 2 hours to separate serum from plasma. Centrifuge at 4℃at 3500rpm for 10min, transfer the upper serum into a new EP tube and store at-80 ℃. According to the kit method, the effect of 8C on the levels of mouse serum total Triglycerides (TG), total Cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) was examined.

As shown in Table 3, the various indexes of the blood lipid in the model group show significant changes compared with the normal group, the content of TG, TC, LDL-C in serum is significantly increased, and the HDL-C level is significantly reduced, which indicates that the lipid level in the mouse body is abnormal or disordered in metabolism so as to cause disorder of blood lipid metabolism. After administration of different doses of compound 8c, the high dose of 8c significantly improved all 4 criteria, especially for very significant total cholesterol reduction levels, even better than the equivalent dose of pitavastatin.

TABLE 3 influence of Compound 7C on mouse serum TG, TC, LDL-C, HDL-C

	TG(mmol/L)	TC(mmol/L)	LDL-C(mmol/L)	HDL-C(mmol/L)
					Normal group	0.59±0.03	3.88±0.40	1.83±0.31	4.94±0.10
Model group	0.92±0.20^##	5.87±0.06^###	4.19±0.41^###	3.18±0.54^###
					Pitavastatin (1 mg/kg)	0.66±0.18^*	5.10±0.27	4.06±0.22	4.38±0.36^**
8 C-Low (1 mg/kg)	0.92±0.07	4.98±0.52^*	4.12±1.06	3.57±0.70
					8 C-middle (5 mg/kg)	0.87±0.02	4.20±0.38^***	3.69±0.19	4.11±0.12^*
8 C-Gao (25 mg/kg)	0.71±0.17^*	3.74±0.70^***	2.42±0.70^***	4.31±0.06^*

Note that: the test results are the average value of three experiments + -SD. Normal group vs model group ^###P<0.001;^## P <0.01; dose group vs model group ^***P<0.001;^**P<0.01;^* P <0.05.

(5) Effect of Compound 8c on liver lipid of obese hyperlipemic mice

After mice were sacrificed, liver was homogenized by grinding the liver with absolute ethanol as a homogenization medium at a ratio of liver (g) to absolute ethanol (mL) of 1:9, centrifuging at 2500rpm for 15min, sucking the supernatant, and detecting the levels of TG, TC, LDL-C and HDL-C in the mouse liver according to the kit method, and the results are shown in table 4.

TABLE 4 influence of Compound 8C on mouse liver TG, TC, LDL-C, HDL-C

	TG(mmol/L)	TC(mmol/L)	LDL-C(mmol/L)	HDL-C(mmol/L)
					Normal group	14.56±2.28	7.64±0.52	3.85±0.09	0.56±0.07
Model group	21.46±0.77^##	11.72±0.26^###	4.65±0.22^##	0.17±0.02^##
					Pitavastatin (1 mg/kg)	17.42±0.30^*	8.29±0.82^***	4.09±0.63^*	0.41±0.01^*
8 C-Low (1 mg/kg)	18.37±0.74	10.24±1.31	4.26±0.15	0.22±0.02
					8 C-middle (5 mg/kg)	18.14±3.14	9.12±0.26^**	4.17±0.15	0.33±0.11
8 C-Gao (25 mg/kg)	15.93±2.24^*	8.66±0.90^***	3.98±0.06^*	0.42±0.04^*

As can be seen from Table 4, the levels of TG, TC, LDL-C in the livers of the mice in the model group were significantly increased and HDL-C levels were significantly reduced. After administration, the positive control pitavastatin had 11.56% lower TG content than the model group. Compound 8c was 21.47% lower in the high dose group with significant differences. TC levels, pitavastatin group was reduced by 29.25%, compound 8c dose group was reduced by 22.13% and high dose group was reduced by 26.09%. For LDL-C, the positive control pitavastatin group was reduced by 12.07% and the compound 8C high dose group was reduced by 14.55%. Compared with the model group, the HDL-C content of the liver of the pitavastatin group is increased by 143.97%, and the high-dose group of the compound 8C is increased by 147.41%, so that the method has statistical significance.

The results show that the compound 8C can reduce the content of the liver TG, TC, LDL-C of the mice with hyperlipidemia, increase the content of HDL-C, inhibit lipid generation, promote lipid metabolism and show good lipid-lowering activity.

(6) Influence of Compound 8c on mouse adipose tissue and morphology

After the four weeks of administration, the body fat of the mice is taken out for cleaning and weighing, including perirenal white fat, epididymal white fat, intestinal mucosa white fat and scapular brown fat, and the body fat rate of each group of mice is calculated. Body fat% = white fat weight (mg)/body weight (g) 100%

The effect of compound 8c on the adipose tissue and body fat rate of mice is shown in table 5.

TABLE 5 influence of Compound 8c on the adipose tissue and body fat Rate of mice

	Perirenal fat	Epididymal fat	Intestinal mucosa fat	Scapular brown fat	Body fat percentage (white fat)%
						Normal group	0.02±0.01	0.40±0.22	0.12±0.07	0.12±0.01	2.04±0.05
Model group	0.62±0.14^###	1.74±0.36^###	0.31±0.09^###	0.05±0.01^##	7.95±0.12^###
						Pitavastatin (1 mg/kg)	0.21±0.09^***	0.89±0.24^***	0.19±0.05^*	0.09±0.02^*	4.54±0.12^***
8 C-Low (1 mg/kg)	0.35±0.07^***	1.60±0.49	0.26±0.11	0.08±0.04	6.84±0.07^***
						8 C-middle (5 mg/kg)	0.20±0.06^***	1.16±0.15^*	0.21±0.06^*	0.08±0.03	5,34±0.14^***
8 C-Gao (25 mg/kg)	0.08±0.02^***	0.84±0.30^***	0.11±0.06^***	0.10±0.03^*	3.80±0.10^***

Note that: the test results are the mean ± SD of the three experiments (n=5). Normal group vs model group ^###P<0.001;^## P <0.01; dose group vs model group ^***P<0.001;^* P <0.05.

Excessive fat content in human body can cause injury of various viscera, thereby causing obesity related diseases such as hyperlipidemia, hypertension, diabetes, etc. White adipose tissue is a white tissue mass in appearance, is widely distributed around subcutaneous tissue and viscera in the body, and is a main storage form of fat in the body. As shown in figure 16A, the model group showed a significant increase in white fat around the kidneys of the mice as compared to the normal group. The pitavastatin group was significantly improved, the effect of compound 8c on perirenal fat was also dose dependent, and medium and high dose groups significantly reduced perirenal white fat production compared to the model group.

In epididymal white fat, as shown in fig. 16B, epididymal fat of mice in the model group was greatly increased compared with that in the normal group, and generation of epididymal fat was significantly inhibited after administration of the positive control pitavastatin group. The compound 8c reduces the production of epididymal white fat in a dose-dependent manner, and the medium dose and the high dose are obvious, which indicates that the compound 8c can effectively inhibit the production of white fat in the body of the mice with hyperlipidemia.

In combination with table 4, the perirenal white fat of the model mice was significantly increased over that of the normal mice, and the positive control pitavastatin group was reduced by 65.80% after dosing, and the low, medium and high doses of compound 8c were reduced by 44.23%, 68.36% and 87.07%, respectively. Compared with the normal group, the epididymal white fat of the mice in the model group is increased by 63.15%, the pitavastatin group is reduced by 48.66% after administration, and the dose and the high dose of the compound 8c are respectively reduced by 33.65% and 51.64%. In the intestinal mucosa white fat, the model group increased by 33.71% compared with the normal group, the pitavastatin group decreased by 38.46%, the dose group in compound 8c decreased by 33.93%, and the high dose group decreased by 65.80%.

Brown fat is an important thermogenic site that maintains body temperature, resists severe cold. The biggest characteristic of brown fat cells is that fat drops are few, mitochondrial content is quite rich, under the condition that the organism is stimulated correspondingly, fat in brown fat tissues is oxidized in a large amount, and the scapula area has larger brown fat tissues. The brown fat of the shoulder blade of the model group is reduced by 54.53%, the positive control pitavastatin group is increased by 64.87% compared with the model group, and the high-dose group of the compound 8c is increased by 88.30%.

As can be seen from table 5, the body fat rate of the model group was significantly increased compared to the normal group mice. Compared with the model group, the pitavastatin group is reduced by 42.86%, and the low dose, the medium dose and the high dose of the compound 8c are respectively reduced by 13.93%, 32.78% and 52.18%.

In sum, compound 8c inhibits white fat production in a dose-dependent manner, reduces body fat rate, increases the amount of brown fat in the shoulder blade, has a remarkable effect, and can be used for treating diseases related to overweight and hyperlipidemia.

(7) Effect of Compound 8c on mouse organ index and morphology

The organs of each group of mice were washed and weighed, and the organ indexes were calculated as shown in Table 6.

TABLE 6 influence of Compound 8c on the organ index of mice (organ g/body weight g)

	Heart and method for producing the same	Liver	Spleen	Lung (lung)	Sausage (sausage)
						Normal group	0.61±0.02	3.77±0.25	0.21±0.02	0.62±0.05	1.28±0.05
Model group	0.53±0.07	4.28±0.36^#	0.35±0.09^###	0.58±0.03	1.28±0.06
						Pitavastatin (1 mg/kg)	0.56±0.11	3.90±0.16	0.25±0.03^***	0.61±0.06	1.27±0.08
8 C-Low (1 mg/kg)	0.51±0.04	3.93±0.17	0.25±0.03^**	0.57±0.04	1.31±0.07
						8 C-middle (5 mg/kg)	0.57±0.07	3.87±0.25	0.24±0.01^**	0.62±0.02	1.28±0.06
8 C-Gao (25 mg/kg)	0.60±0.06	3.74±0.33^**	0.23±0.05^***	0.60±0.10	1.35±0.09

Note that: the test results are the mean ± SD of the three experiments (n=5). Normal group vs model group ^###P<0.001;^# P <0.05; dose group vs model group ^***P<0.001;^** P <0.01.

As shown in table 6, only liver and spleen were significantly increased in the organ indexes of the model group, and compound 8c was able to significantly improve liver index at 25mg/kg dose, while alleviating the problem of splenomegaly at all three doses. Thus, in combination with lipid content data in the liver, compound 8c was able to reduce liver lipid content and alleviate liver index and morphology, indicating that this compound can alleviate fatty liver.

In conclusion, a series of quinoline amino acid conjugates are synthesized for the first time, the synthesis process exploration is completed, and in-vitro activity test is carried out on the compounds. The invention has simple synthesis process and does not need anhydrous and anaerobic conditions. The activity research shows that the compounds can inhibit the activity of pancreatic lipase and reduce the lipid level at the cellular level. In vivo experiments, the compound can obviously reduce the weight of mice, reduce TG, TC, LDL-C levels in serum and liver and increase HDL-C levels. Meanwhile, the compound can reduce the generation of white fat in vivo, promote the generation of brown fat in shoulder blades and obviously reduce the body fat rate of mice. In addition, the compounds can improve organ indexes of livers and spleens, which shows that the compounds have a certain effect on fatty livers. Therefore, the compound has good application prospect in the aspects of losing weight, reducing blood fat and relieving fatty liver.

Although embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the disclosure of the embodiments.

Claims

1. A quinoline amino acid conjugate, characterized in that: the quinoline-amino acid conjugate is quinoline-3-amino acid conjugate and derivatives thereof, quinoline-6-amino acid conjugate and derivatives thereof, or quinoline-5-amino acid conjugate and derivatives thereof.

2. The quinoline amino acid conjugate according to claim 1, wherein: the quinoline-3-amino acid conjugate and the derivative thereof have the following structural general formula I:

4. The quinoline amino acid conjugate according to claim 1, wherein: the quinoline-6-amino acid conjugate and the derivative thereof have the following structural general formula II:

5. The method for preparing the quinoline-6-amino acid conjugate according to claim 4, wherein: taking 6-aminoquinoline as a raw material, connecting N- (9-fluorenylmethoxycarbonyl) -L-aspartic acid-4-tert-butyl ester through condensation reaction to obtain 8a or connecting N-formyl-L-leucine through condensation reaction after removing protective groups to obtain a compound 8c or 9c, and removing tert-butyl ester protective groups to obtain 8 or 9; the reaction route is as follows:

6. the quinoline amino acid conjugate according to claim 1, wherein: the quinoline-5-amino acid conjugate and the derivative thereof have the following structural general formula III:

7. The method for preparing a quinoline-5-amino acid conjugate according to claim 6, wherein: the reaction steps are as follows: the reaction steps are the same as claim 2 with 5-aminoquinoline as raw material, and the reaction route is as follows:

8. The quinoline amino acid conjugate according to claim 1, wherein: the structural formula of the quinoline-3-amino acid conjugate is one of the following:

9. Use of a quinoline amino acid conjugate according to any one of claims 1 to 8 for the preparation of a medicament for reducing weight and/or reducing blood lipid and/or alleviating fatty liver.