Mangiferin, derivatives thereof, preparation method and medical application of mangiferin and derivatives thereof

Abstract

The invention discloses a mangiferin derivative, a preparation method and application of the mangiferin derivative in preparation of weight-reducing drugs. The mangiferin derivative is simple to prepare, has a very good inhibition effect on liposynthase, has an inhibition effect on 3T3-L1 fat cell proliferation, and has a prospect of preparing obesity treatment drugs.

Description

Technical Field

[0001] The present invention relates to the field of medicinal chemistry, and particularly to mangiferin and mangiferin derivatives, their preparation methods, pharmaceutical compositions containing these compounds, and their medical uses, especially their use as fatty acid synthase inhibitors for weight loss. Background Art

[0002] Fatty acid synthase (FASN) is closely related to lipid metabolism in organisms. In the presence of NADPH, it catalyzes the synthesis of long-chain fatty acids from acetyl coenzyme A and malonyl coenzyme A, and plays a key role in de novo lipogenesis. As a key enzyme controlling lipid metabolism, FASN has become a dual target for obesity treatment intervention [Oncol Lett, 2012, 4, 878 - 882; Science (Washington, D C), 2000, 288, 2379 - 2381; Expert Opin Drug Discov., 2016, 11, 1187 - 1199]. It is worth noting that so far, relatively few FASN inhibitors have been reported, and there are the following problems in the application and preparation of these inhibitors: the compound synthesis is difficult, its own stability is poor, the inhibitory activity is not high enough, the bioavailability is poor, and there are serious toxic and side effects, which limit its clinical application as a drug [Recent Patents on Anti-Cancer Drug Discovery, 2012, 7, 185 - 197]. Therefore, the discovery and development of new FASN inhibitors with high efficiency and low toxicity for the treatment of obesity have broad application prospects and practical application values.

[0003] Mangiferin is a bisbenzopyrone compound and belongs to special flavonoid C-glycosides. The distribution of mangiferin is very wide and the resources are very rich. Mangiferin exists in large quantities in the fruits, leaves and barks of mango trees, and also exists in the leaves, fruits and barks of almond trees, Gentiana manshurica Kitag. and Swertia mussotii Franch. of Gentianaceae, Pyrrosia calvata (Bak.) Ching of Polypodiaceae, Anemarrhena asphodeloides Bunge of Liliaceae, Belamcanda chinensis (L.) DC. of Iridaceae, etc. At the same time, mangiferin can also be synthesized efficiently and in large quantities artificially.

[0004] Mangiferin compounds have a wide range of pharmacological activities, such as antitussive, expectorant, antiasthmatic, central inhibition, antioxidant, anti-inflammatory, antibacterial, antiviral, lipid-lowering, antitumor, cholagogic and immunomodulatory effects, etc., but the use of mangiferin and its derivatives as FASN inhibitors for the treatment of obesity has not been reported. Summary of the Invention

[0005] The present invention uses mangiferin as a lead compound to develop highly efficient and low-toxic mangiferin fatty acid synthase (FASN) inhibitors and provides compounds for the treatment of obesity.

[0006] The general formula Ⅰ of the compounds of the present invention is as follows:

[0007] where n = 4 - 5; R is:

[0008]

[0009]

[0010] The preparation reaction formula of the mangiferin derivative is:

[0011]

[0012] where a represents the reaction conditions: the solvent is dichloromethane, 1,2 - dichloroethane, acetonitrile, N,N - dimethylformamide, N,N - dimethylacetamide, dimethyl sulfoxide; the acid - binding agent is triethylamine, ethylenediamine, N,N - diisopropylethylamine, pyridine, sodium acetate, sodium carbonate, potassium carbonate; the reaction temperature is 50 - 100 °C; the reaction time is 10 - 72 h;

[0013] The preparation reaction formula of is: where b represents the reaction conditions: the solvent is dichloromethane, 1,2 - dichloroethane, acetonitrile, N,N - dimethylformamide, N,N - dimethylacetamide, dimethyl sulfoxide. The acid - binding agent is triethylamine, ethylenediamine, N,N - diisopropylethylamine, pyridine, sodium acetate, sodium carbonate, potassium carbonate; the reaction temperature is - 10 - 40 °C; the reaction time is 1 - 24 h.

[0014] where a represents the reaction conditions: the solvent is dichloromethane, 1,2 - dichloroethane, acetonitrile, N,N - dimethylformamide, N,N - dimethylacetamide, dimethyl sulfoxide; the acid - binding agent is triethylamine, ethylenediamine, N,N - diisopropylethylamine, pyridine, sodium acetate, sodium carbonate, potassium carbonate; the reaction temperature is 50 - 100 °C; the reaction time is 10 - 72 h;

[0015] Br - R 9 R 10 The preparation reaction formula of is: where b represents the reaction conditions: the solvent is dichloromethane, 1,2 - dichloroethane, acetonitrile, N,N - dimethylformamide, N,N - dimethylacetamide, dimethyl sulfoxide. The acid - binding agent is triethylamine, ethylenediamine, N,N - diisopropylethylamine, pyridine, sodium acetate, sodium carbonate, potassium carbonate; the reaction temperature is - 10 - 40 °C; the reaction time is 1 - 24 h.

[0016] A composition comprising the mangiferin derivative or its salt described above.

[0017] Use of the mangiferin derivative or its salt in the preparation of a medicament for treating obesity.

[0018] Application of mangiferin derivatives in preparing lipogenic enzyme inhibitors.

[0019] Application of mangiferin derivatives in preparing inhibitors for 3T3-L1 adipocyte proliferation.

[0020] Advantages of the present invention:

[0021] Before the present invention, there were still few reported fatty acid synthase (FASN) inhibitors in the industry, and the following problems existed in the application and preparation of these inhibitors: difficult compound synthesis, poor stability of themselves, not high enough inhibitory activity, poor bioavailability, and serious toxic and side effects, which limited their clinical application as drugs. Based on this, the present invention first found that the natural product mango has good FASN inhibitory activity, and at the same time, mangiferin was used as a lead compound for derivatization to obtain a class of mangiferin derivatives, with a view to developing a new type of highly effective and low-toxic FASN inhibitor for the treatment of obesity. Description of the drawings

[0022] Figure 1 It is the general structural formula of the mangiferin derivatives described in the present invention;

[0023] Figure 2 It is the synthesis route of mangiferin derivative I;

[0024] Figure 3 It is the effect diagram of compounds I-12 and I-13 inhibiting the proliferation of 3T3-L1 adipocytes. Detailed implementation manners

[0025] The present invention will be further described below, but it is not limited to the present invention in any way. Any transformation based on the present invention belongs to the protection scope of the present invention.

[0026] The general formula I of the compounds of the present invention is shown in Figure 1 , as follows:

[0027]

[0028] wherein R 1 , R 2 , R 3 , R 4 represent: hydrogen, C1-C4 alkyl, allyl, cyclopropyl, cyclobutyl or cyclopentyl, formyl, acetyl, propionyl, methanesulfonyl or ethanesulfonyl. That is, R 1 , R 2 , R 3 and R 4 can represent the same or different groups as described above.

[0029] R5 , R 6 , R 7 , R 8 represent: hydrogen, fluorine, chlorine, bromine, trifluoromethyl, C1-C4 alkyl, allyl, cyclopropyl, cyclobutyl, cyclopentyl, formyl, acetyl, propionyl, mesyl, ethylsulfonyl, -R 9 R 10 .

[0030] R 9 represent:

[0031]

[0032] n = 0 to 13; x = 0 - 4; y = 1 - 5.

[0033] R 10 represent:

[0034] glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine and histidine, methyl glycinate, methyl alaninate, methyl valinate, methyl leucinate, methyl isoleucinate, methyl methioninate, methyl prolinate, methyl tryptophanate, methyl serine, methyl tyrosine, methyl cysteine, methyl phenylalaninate, methyl asparagine, methyl glutamine, methyl threoninate, methyl aspartate, methyl glutamate, methyl lysinate, methyl arginine and methyl histidine, ethyl glycinate, ethyl alaninate, ethyl valinate, ethyl leucinate, ethyl isoleucinate, ethyl methioninate, ethyl prolinate, ethyl tryptophanate, ethyl serine, ethyl tyrosine, ethyl cysteine, ethyl phenylalaninate, ethyl asparagine, ethyl glutamine, ethyl threoninate, ethyl aspartate, ethyl glutamate, ethyl lysinate, ethyl arginine and ethyl histidine, propyl glycinate, propyl alaninate, propyl valinate, propyl leucinate, propyl isoleucinate, propyl methioninate, propyl prolinate, propyl tryptophanate, propyl serine, propyl tyrosine, propyl cysteine, propyl phenylalaninate, propyl asparagine, propyl glutamine, propyl threoninate, propyl aspartate, propyl glutamate, propyl lysinate, propyl arginine and propyl histidine,

[0035] other benzene ring derivatives, other heterocyclic derivatives.

[0036] Among them, the preferred compounds of general formula I:

[0037] R1 -R 4 Preferably represents hydrogen. R 5 -R 8 Preferably represents -R 9 R 10 . R 9 Preferably represents R 10 Preferably represents methyl ester compounds of twenty amino acids that make up human proteins, including methyl glycinate, methyl alaninate, methyl valinate, methyl leucinate, methyl isoleucinate, methyl methionine (methyl 2-amino-4-methylsulfanylbutanoate), methyl prolinate, methyl tryptophanate, methyl serine, methyl tyrosine, methyl cysteine, methyl phenylalaninate, methyl asparagine, methyl glutamine, methyl threonine, methyl aspartate, methyl glutamate, methyl lysinate, methyl arginine, and methyl histidine.

[0038] The pharmaceutically acceptable salts of the present invention include acid addition salts formed by the compound of general formula I and the following acids: hydrochloric acid, hydrobromic acid, sulfuric acid, carbonic acid, citric acid, tartaric acid, phosphoric acid, lactic acid, pyruvic acid, acetic acid, maleic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, or arginine.

[0039] The pharmaceutically acceptable salts of the present invention include base addition salts formed by the compound of general formula I and the following bases: sodium hydroxide, sodium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, sodium carbonate, calcium hydroxide, calcium carbonate, calcium bicarbonate, ammonia, aqueous ammonia, methylamine, ethylamine, ethylenediamine, triethylamine.

[0040] The compounds of the present invention are:

[0041] 3,6,7-(6-Hexanoyl methionine methyl ester) trisubstituted mangiferin (I-1)

[0042] 3,6,7-(6-Hexanoyl alanine methyl ester) trisubstituted mangiferin (I-2)

[0043] 3,6,7-(6-Hexanoyl tryptophan methyl ester) trisubstituted mangiferin (I-3)

[0044] 3,6,7-(6-Hexanoyl phenylalanine methyl ester) trisubstituted mangiferin (I-4)

[0045] 3,6,7-(6-Hexanoyl proline methyl ester) trisubstituted mangiferin (I-5)

[0046] 3,6,7-(6-Hexanoyl leucine methyl ester) trisubstituted mangiferin (I-6)

[0047] 3,6,7-(6-Hexanoyl isoleucine methyl ester) trisubstituted mangiferin (I-7)

[0048] 3,6,7-(6-Hexanoylvaline methyl ester) trisubstituted mangiferin (Ⅰ-8)

[0049] 3,6,7-(6-Hexanoylglycine methyl ester) trisubstituted mangiferin (Ⅰ-9)

[0050] 3,6,7-(5-Valerylmethionine methyl ester) trisubstituted mangiferin (Ⅰ-10)

[0051] 3,6,7-(5-Valerylalanine methyl ester) trisubstituted mangiferin (Ⅰ-11)

[0052] 3,6,7-(5-Valeryltryptophan methyl ester) trisubstituted mangiferin (Ⅰ-12)

[0053] 3,6,7-(5-Valerylphenylalanine methyl ester) trisubstituted mangiferin (Ⅰ-13)

[0054] 3,6,7-(5-Valerylproline methyl ester) trisubstituted mangiferin (Ⅰ-14)

[0055] 3,6,7-(5-Valerylleucine methyl ester) trisubstituted mangiferin (Ⅰ-15)

[0056] 3,6,7-(5-Valeryl isoleucine methyl ester) trisubstituted mangiferin (Ⅰ-16)

[0057] 3,6,7-(5-Valerylvaline methyl ester) trisubstituted mangiferin (Ⅰ-17)

[0058] 3,6,7-(5-Valerylglycine methyl ester) trisubstituted mangiferin (Ⅰ-18)

[0059] The preparation method of the preferred compound of general formula Ⅰ in the present invention is as follows, see Figure 2 :

[0060]

[0061] Among them, a represents the reaction conditions: the solvent is dichloromethane, 1,2-dichloroethane, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide. The acid-binding agent is triethylamine, ethylenediamine, N,N-diisopropylethylamine, pyridine, sodium acetate, sodium carbonate, potassium carbonate. The reaction temperature is 50-100 °C. The reaction time is 10-72 h.

[0062] The preparation reaction formula of

[0063]

[0064] Among them, b represents the reaction conditions: the solvent is dichloromethane, 1,2-dichloroethane, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide. The acid-binding agent is triethylamine, ethylenediamine, N,N-diisopropylethylamine, pyridine, sodium acetate, sodium carbonate, potassium carbonate. The reaction temperature is -10 - 40 °C. The reaction time is 1 - 24 h.

[0065] For other compounds, the corresponding raw materials are used to prepare by referring to the above method.

[0066] Example 1

[0067] Preparation of 3,6,7-(6-hexanoyl methionine methyl ester) trisubstituted mangiferin (Ⅰ-1):

[0068]

[0069] 1.1 Synthesis of 6-bromohexanoyl methionine methyl ester

[0070] Weigh 1.0 g of L-methionine methyl ester hydrochloride and 2.09 mL of triethylamine, dissolve them in 20 mL of dichloromethane in a 100 mL round-bottom flask. Place the round-bottom flask in a magnetic stirrer, and slowly add 0.77 mL of 6-bromohexanoyl chloride dropwise under ice-water bath conditions while stirring. After the addition is completed, remove the ice bag and let it warm up to room temperature naturally. React for 3 h. After detecting by TLC (developing agent: petroleum ether: ethyl acetate = 2:1) and iodine fuming, it is found that the raw material spot disappears and a new spot is generated (the Rf value of the new spot is greater than that of the raw material spot). Then, separate it by column chromatography to obtain 1.31 g of intermediate 1, with a yield of 76.8%. 1 H NMR (600 MHz, DMSO-d6), δ8.27 (1H, d, J = 7.6 Hz, N H ), 4.39 (1H, quin, C H ), 3.66 (3H, s, OC H 3 ), 3.55 (2H, t, J = 6.8 Hz, Br-C H 2 ), 2.54 (2H, t, J = 2.3 Hz, S-C H 2 ), 2.16 (2H, quin, J = 7.2 Hz, C H 2 ), 2.07 (3H, s, S-C H 3 ), 1.93 (2H, m, CO-C H 2 ), 1.83 (2H, m, C H 2 ), 1.55 (2H, m, C H2 ), 1.39 (2H, m, C H 2 ). 13 C NMR (150 MHz, DMSO-d6), δ 172.4 ( C =O), 172.3 ( C =O), 51.9 (O- C H 3 ), 50.8 (NH- C H), 35.0 (CO- C H 2 ), 34.7 (Br- C H 2 ), 32.0 ( C H 2 ), 30.5 ( C H 2 ), 29.6 ( C H 2 ), 27.1 ( C H 2 ), 24.3 ( C H 2 ), 14.5 (S- C H 3 )

[0071] 1.2 Preparation of 3,6,7-(6-Hexanoyl Methionine Methyl Ester) Trisubstituted Mangiferin (I-1) Weigh 0.3 g of mangiferin, 0.49 g of potassium carbonate, 6 mL of DMF and 1.21 g of 6-Bromohexanoyl Methionine Methyl Ester into a 50 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 12 h. After checking by TLC (developing solvent: petroleum ether: ethyl acetate = 2:1), a new spot was found under ultraviolet light irradiation (the Rf value of the new spot is greater than that of the raw material spot). After the reaction is completed, evaporate the DMF to dryness. After natural cooling to room temperature, add anhydrous methanol to dissolve it, filter off a little insoluble matter, and finally separate the product by column chromatography to obtain 0.29 g of the target compound 1, with a yield of 34.1%. 1 H NMR (600 MHz, DMSO-d6), δ 13.57 (1H, s), 8.24 (6H, d, J = 7.3 Hz, NH), 7.49 (1H, s), 7.17 (1H, s), 6.61 (1H, s), 3.34 - 4.86 (O H , NC H , OC H 3 and OC H 2 ), 1.69 - 2.50 (SC H 3 , SCH 2 and C H 2 ).

[0072] 13 C NMR(150 MHz, DMSO-d6), δ 179.1 (C-9), 172.6 (C=O × 6), 165.0 (C-3), 160.4 (C-1), 156.9 (C-4a), 154.2 (C-6), 150.3 (C-10a), 146.2 (C-7), 112.2 (C-8a), 109.0 (C-8), 100.8 (C-9a), 91.0 (C-4), 81.9 (C-1’), 79.2 (C-5’), 72.5 (C-2’), 71.0 (C-3’), 70.4 (C-4’), 69.0 (O C H 2 ), 68.8 (O C H 2 ), 68.7 (O C H 2 ), 62.0 (C-6’), 51.9 (N C H×3), 50.9 (OCH 3 ×3), 35.0 (CO- C H 2 ), 34.9 (CO- C H 2 ), 34.9 (CO- C H 2 ), 30.5 ( C H 2 ×3), 29.6 ( C H 2 ×3), 28.4 ( C H 2 ×3), 25.3 ( C H 2 ), 25.2 ( C H 2 ), 25.1 ( C H 2 ), 14.6 ( C H 3 ), 14.6 ( C H 3 ), 14.4 ( C H 3 ).

[0073] Example 2

[0074] Preparation of 3,6,7-(6-Hexanoylalanine methyl ester) trisubstituted mangiferin (Ⅰ-2):

[0075]

[0076] 2.1 Synthesis of Methyl 6-bromohexanoylalaninate

[0077] Weigh 1.0 g of L-alanine methyl ester hydrochloride and 2.99 mL of triethylamine, and dissolve them in 20 mL of dichloromethane in a 100 mL round-bottom flask. Place the round-bottom flask in a magnetic stirrer, and slowly add 1.10 mL of 6-bromohexanoyl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and allow the temperature to rise to room temperature naturally. React for 3 h. After identification by TLC (developing agent: petroleum ether: ethyl acetate = 2:1), iodine fuming shows that the raw material spot disappears and a new spot is formed (the Rf value of the new spot is greater than that of the raw material spot). Then, separate by column chromatography to obtain 1.57 g of intermediate 3, with a yield of 78.11%. 1 H NMR(600MHz,DMSO-d6),δ8.22(1H,d,J=6.9Hz,N H ),4.24(1H,quin,J=7.3Hz,C H ),3.61(3H,s,C H 3 ),3.51(2H,t,J=6.7Hz,C H 2 ),2.10(2H,t,J=7.4Hz,C H 2 ),1.79(2H,m,C H 2 ),1.50(3H,m,C H 2 ),1.36(2H,m,C H 2 ),1.25(3H,d,J=7.3Hz,C H 3 ). 13 C NMR(150MHz,DMSO-d6),δ173.3( C =O),172.0( C =O),51.8(O- C H 3 ),47.4(NH- C H),35.0(CO- C H 2 ),34.7(Br- C H 2 ),32.0( C H 2 ),27.1( C H 2 ),24.3(C H 2 ),17.0( C H 3 ).

[0078] Preparation of 2.2 3,6,7-(6-Hexanoylalanine methyl ester) trisubstituted mangiferin (Ⅰ-2)

[0079] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF and 1.30 g of 6-bromohexanoylalanine methyl ester into a 50 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 14 h. After checking by TLC (developing solvent: dichloromethane: methanol = 4:1), a new spot was found under ultraviolet light irradiation (the Rf value of the new spot is greater than that of the raw material spot). After the reaction is completed, evaporate the DMF to dryness. After natural cooling to room temperature, add anhydrous methanol to dissolve, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.45 g of the target compound 3, with a yield of 46.6%. 1 H NMR(600MHz,DMSO-d6),δ13.56(1H,s,OH-1),8.23(3H,d,J=7.2Hz,N H ×3),7.47(1H,s,H-8),7.16(1H,s,H-5),6.61(1H,s,H-4),3.61(9H,s,OC H 3 ×3),2.14(6H,t,J=6.7Hz,C H 2 ×3),1.77(6H,m,C H 2 ×3),1.58(6H,m,C H 2 ×3),1.44(6H,m,C H 2 ×3),1.25(9H,m,C H 3 ×3). 13 C NMR(150MHz,DMSO-d6),δ179.1(C-9),173.4( C =O×3),172.1( C= O×3, )165.0(C - 3), 160.4(C - 1), 156.8(C - 4a), 155.5(C - 6), 151.8(C - 10a), 146.2(C - 7), 112.2(C - 8a), 109.0(C - 8), 105.5(C - 2), 101.9(C - 5), 100.8(C - 9a), 91.0(C - 4), 81.7(C - 1’), 79.3(C - 5’), 72.5(C - 2’), 71.0(C - 3’), 70.4(C - 4’), 69.0(O C H 2 ), 68.7(O C H 2 ), 68.3(O C H 2 ), 62.0(C - 6’), 51.8(O C H 3 ×3), 47.5(NH - C H×3), 35.0(CO - C H 2 ), 34.9(CO - C H 2 ), 34.8(CO - C H 2 ), 28.3( C H 2 ), 28.3( C H 2 ), 28.1( C H 2 ), 25.3( C H 2 ), 25.3( C H 2 ), 25.2( C H 2 ), 24.9( C H 2 ), 24.8( C H 2 ), 24.8( C H 2 ), 17.0( C H 3 ×3).

[0080] Example 3

[0081] Preparation of 3,6,7 - (6 - hexanoyltryptophan methyl ester) trisubstituted mangiferin (Ⅰ - 3):

[0082]

[0083] 3.1 Synthesis of 6 - bromohexanoyltryptophan methyl ester

[0084] Weigh 1.7 g of L-tryptophan methyl ester hydrochloride and 2.78 mL of triethylamine, and dissolve them in 34 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer and slowly add 1.02 mL of 6-bromohexanoyl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and allow the temperature to rise to room temperature naturally. React for 4 h. After identification by TLC (developing solvent: petroleum ether: ethyl acetate = 2:1), iodine fuming, the raw material spot disappears and a new spot appears (the Rf value of the new spot is greater than that of the raw material spot). Then, separate by column chromatography to obtain 2.46 g of intermediate 5 with a yield of 93.2%. 1 H NMR(600MHz,DMSO-d6),δ10.86(1H,d,J=2.6Hz,NH),8.24(1H,d,J=7.7Hz,NH),The hydrogen signals of the benzene ring[δ7.50(1H,d,J=7.8Hz),7.34(1H,d,J=8.1Hz),7.07(1H,d,J=2.4Hz),6.99(1H,t,J=7.4Hz)],7.14(1H,m,NH-C H ),4.53(1H,td,J=8.1,5.5Hz,CO-C H ),3.59(3H,s,OC H 3 ),3.45(2H,t,J=6.7Hz,Br-C H 2 ),3.09(2H,m,C H 2 ),2.09(2H,m,CO-C H 2 ),1.74(2H,m,C H 2 ,),1.44(2H,m,C H 2 ),1.27(2H,m,J=9.5,6.4Hz,CH 2 ). 13 C NMR(150MHz,DMSO-d6),δ172.6(C=O),172.1(C=O),The carbon signals of the benzene ring[136.1,127.1,120.9,118.4,118.0,111.4],123.6(C= C H),109.6( C =CH),53.0(O C H 3), 51.8 (NH- C H), 34.9 (Br- C H2), 34.8 (CO- C H 2 ), 32.0 ( C H 2 ), 27.1 ( C H 2 ), 27.0 ( C H 2 ), 24.2 ( C H 2 ).

[0085] 3.2 Preparation of 3,6,7-(6-Hexanoyltryptophan methyl ester) trisubstituted mangiferin (Ⅰ-3)

[0086] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF and 1.87 g of 6-bromohexanoyltryptophan methyl ester into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 12 h 30 min. After checking by TLC (developing solvent: dichloromethane: methanol = 4:1), a new spot was found under ultraviolet light irradiation (the Rf value of the new spot is greater than that of the starting material spot). After the reaction is completed, evaporate the DMF to dryness. After natural cooling to room temperature, add anhydrous methanol to dissolve, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.36 g of the target compound 5, with a yield of 27.9%. 1 1H NMR (600 MHz, DMSO-d6), δ 13.60 (1H, s, OH-1), 10.86 (3H, s, N H ), 8.26 (3H, d, J = 4.4 Hz, N H ), The hydrogen signals of the benzene ring [7.50 (3H, d), 7.34 (3H, d, J = 4.5 Hz), 7.15 (4H, d, J = 8.5 Hz), 7.05 (3H, q, J = 8.5 Hz), 6.98 (3H, q), 6.60 (1H, s)], 4.66 (1H, d, J = 10.0 Hz, H-1’), 3.08 - 4.53 (O H , OC H 3 , OC H 2 , C H 2 ), 2.13 (6H, t, CO-C H 2 ), 1.72 (6H, m, C H 2 ), 1.51 (6H, m, CH 2 ), 1.34 (6H, m, C H 2 ). 13 C NMR (150 MHz, DMSO-d6), δ 179.4 (C-9), 172.6 (NH- C O), 172.3 (CH- C O), 165.0 (C-3), 160.4 (C-1), 156.9 (C-4a), 155.5 (C-6), 151.8 ((C-4a), 146.2 (C-7), The carbon signals of the benzene ring [136.1, 127.1, 121.0, 118.4, 118.0, 111.4], 123.7 (C= C H×3), 112.2 (C-8a), 109.6 ( C =CH), 109.0 (C-8), 105.5 (C-2), 102.0 (C-5), 100.7 (C-9a), 91.0 (C-4), 81.7 (C-1’), 79.0 (C-5’), 72.5 (C-2’), 71.0 (C-3’), 70.4 (C-4’), 69.0 (O C H 2 ), 68.6 (O C H 2 ), 68.3 (O C H 2 ), 62.0 (C-6’), 53.0 (NH- C H×3), 51.8 (O C H 3 ×3), 35.0 (CO- C H2), 34.9 (CO- C H2), 34.9 (CO- C H2), 28.3 ( C H 2 ×3), 28.0 (CH 2 ×3), 25.2 ( C H 2 ), 25.0 ( C H 2 ), 25.0 ( C H 2 ), 24.9 ( C H 2 ), 24.8 ( C H 2 ), 24.8 ( C H 2 ).

[0087] Example 4

[0088] Preparation of 3,6,7-(6-hexanoyl phenylalanine methyl ester) trisubstituted mangiferin (I-4):

[0089]

[0090] 4.1 Synthesis of 6-bromohexanoyl phenylalanine methyl ester

[0091] Weigh 1.5 g of L-phenylalanine methyl ester hydrochloride and 2.9 mL of triethylamine, and dissolve them in 30 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer, and slowly add 1.07 mL of 6-bromohexanoyl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and let the temperature rise to room temperature naturally. React for 4 h. Check by TLC (developing agent: petroleum ether: ethyl acetate = 2:1), and after iodine fuming, the raw material spot disappears and a new spot appears (the Rf value of the new spot is greater than that of the raw material spot). Then separate by column chromatography to obtain 2.19 g of intermediate 7, with a yield of 88.4%.

[0092] 4.2 Preparation of 3,6,7-(6-hexanoyl phenylalanine methyl ester) trisubstituted mangiferin (I-4)

[0093] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF, and 1.69 g of 6-bromohexanoyl phenylalanine methyl ester into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 13 h. Check by TLC (developing agent: dichloromethane: methanol = 4:1), and under ultraviolet light irradiation, a new spot appears (the Rf value of the new spot is greater than that of the raw material spot). After the reaction is completed, evaporate the DMF to dryness. After naturally cooling to room temperature, add anhydrous methanol to dissolve, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.33 g of the target compound 7, with a yield of 27.9%. 1313C NMR (151 MHz, DMSO) δ 179.24 (C-9), 172.29 (C=O), 172.24 (C=O), 164.96 (C-3), 160.42 (C-1), 156.88 (C-4a), 155.50 (C-6), 151.84 (C-4b), 146.17 (C-7), 137.33 (C-1”), 129.07 (C-3”), 128.22 (C-2”), 126.50 (C-4”), 112.21 (C-8a), 108.98 (C-8), 105.43 (C-2), 102.48 (C-5), 101.94 (C-9a), 90.95 (C-4), 81.83 (C-1’), 79.14 (C-5’), 72.52 (C-2’), 71.01 (C-3’), 70.43 (C-4’), 68.96 (-OCH 2 -), 68.61 (-OCH 2 -), 68.25 (-OCH 2 -), 62.06 (C-6’), 53.45 (-NCH-), 53.41 (-NCH-), 53.38 (-NCH-), 51.82 (-O-CH 3 *3), 36.71 (-CH2-ph*3), 34.93 (-OC-CH 2 -), 34.90 (-OC-CH 2 -), 34.87 (-OC-CH 2 -), 28.23 (-CH 2 -×3), 27.97 (-CH 2 -×3), 24.83 (-CH 2 -×3).

[0094] Example 5

[0095] Preparation of 3,6,7-(6-Hexanoylprolinemethyl ester) trisubstituted mangiferin (I-5):

[0096]

[0097] 5.1 Synthesis of 6-Bromohexanoylprolinemethyl ester

[0098] Weigh 1.2 g of L-proline methyl ester hydrochloride and 3 mL of triethylamine, and dissolve them in 24 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer, and slowly add 1.1 mL of 6-bromohexanoyl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and allow the temperature to rise to room temperature naturally. React for 4 h. After checking by TLC (developing agent: petroleum ether: ethyl acetate = 2:1), iodine fuming shows that the starting material spot disappears and new spots are formed (the Rf value of the new spots is greater than that of the starting material spot). Then, separate by column chromatography to obtain 1.51 g of intermediate 17 with a yield of 68%.

[0099] 5.2 Preparation of 3,6,7-(6-hexanoylproline methyl ester) trisubstituted mangiferin (Ⅰ-5)

[0100] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF, and 1.45 g of 6-bromohexanoylproline methyl ester in a 100 mL round-bottom flask. Stir and dissolve at room temperature, then stir in an 80 °C oil bath for 14 h. After checking by TLC (developing agent: dichloromethane: methanol = 4:1), under ultraviolet light irradiation, new spots are found to be formed (the Rf value of the new spots is greater than that of the starting material spot) and there is no mangiferin spot in the reaction solution. After the reaction is completed, evaporate the DMF to dryness. After naturally cooling to room temperature, add anhydrous methanol to dissolve, filter off a small amount of insoluble substances, and finally separate the product by column chromatography to obtain 0.38 g of the target compound 17 with a yield of 38%.

[0101] Example 6

[0102] Preparation of 3,6,7-(6-hexanoylleucine methyl ester) trisubstituted mangiferin (Ⅰ-6):

[0103]

[0104] 6.1 Synthesis of 6-bromohexanoylleucine methyl ester

[0105] Weigh 1.43 g of L-leucine methyl ester hydrochloride and 3.28 mL of triethylamine, and dissolve them in 27 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer, and slowly add 1.205 mL of 6-bromohexanoyl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and allow the temperature to rise to room temperature naturally. React for 4 h. After checking by TLC (developing agent: petroleum ether: ethyl acetate = 2:1), iodine fuming shows that the starting material spot disappears and new spots are formed (the Rf value of the new spots is greater than that of the starting material spot). Then, separate by column chromatography to obtain 2.29 g of intermediate 13 with a yield of 90.1%.

[0106] 6.2 Preparation of 3,6,7-(6-hexanoylleucine methyl ester) trisubstituted mangiferin (Ⅰ-6)

[0107] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF and 1.53 g of methyl 6-bromohexanoyl leucinate into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 14 h. After checking by TLC (developer: dichloromethane:methanol = 4:1), under ultraviolet light irradiation, new spots are found to be generated (the Rf value of the new spots is greater than that of the raw material spots) and there is no mangiferin spot in the reaction solution. After the reaction is completed, evaporate the DMF to dryness. After naturally cooling to room temperature, add anhydrous methanol to dissolve, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.4 g of the target compound 13 with a yield of 36.8%.

[0108] Example 7

[0109] Preparation of 3,6,7-(6-hexanoyl isoleucine methyl ester) trisubstituted mangiferin (Ⅰ-7):

[0110]

[0111] 7.1 Synthesis of methyl 6-bromohexanoyl isoleucinate

[0112] Weigh 1.43 g of L-isoleucine methyl ester hydrochloride and 3.28 mL of triethylamine, dissolve them in 28 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer, slowly add 1.205 mL of 6-bromohexanoyl chloride dropwise under ice-water bath conditions while stirring. After the addition is completed, remove the ice bag and let it warm up to room temperature naturally. React for 4 h. After checking by TLC (developer: petroleum ether:ethyl acetate = 2:1), iodine fuming, the raw material spots disappear and new spots are generated (the Rf value of the new spots is greater than that of the raw material spots). Then separate by column chromatography to obtain 2.18 g of intermediate 9 with a yield of 85.8%.

[0113] 7.2 Preparation of 3,6,7-(6-hexanoyl isoleucine methyl ester) trisubstituted mangiferin (Ⅰ-7)

[0114] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF and 1.53 g of methyl 6-bromohexanoyl isoleucinate into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 14 h. After checking by TLC (developer: dichloromethane:methanol = 4:1), under ultraviolet light irradiation, new spots are found to be generated (the Rf value of the new spots is greater than that of the raw material spots) and the mangiferin reaction is complete. After the reaction is completed, evaporate the DMF to dryness. After naturally cooling to room temperature, add anhydrous methanol to dissolve, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.35 g of the target compound 9 with a yield of 32%.

[0115] Example 8

[0116] Preparation of 3,6,7-(6-hexanoylvaline methyl ester) trisubstituted mangiferin (Ⅰ-8):

[0117]

[0118] 8.1 Synthesis of methyl 6-bromohexanoylvalinate

[0119] Weigh 1.15 g of L-valine methyl ester hydrochloride and 2.86 mL of triethylamine, and dissolve them in 23 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer and slowly add 1.05 mL of 6-bromohexanoyl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and allow the temperature to rise to room temperature naturally. React for 4 h. After identification by TLC (developing agent: petroleum ether: ethyl acetate = 2:1), iodine fuming shows that the starting material spot disappears and a new spot is formed (the Rf value of the new spot is greater than that of the starting material spot). Then, separate by column chromatography to obtain 1.71 g of intermediate 11 with a yield of 80.9%.

[0120] 8.2 Preparation of 3,6,7-(6-hexanoylvaline methyl ester) trisubstituted mangiferin (Ⅰ-8)

[0121] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF, and 1.46 g of methyl 6-bromohexanoylvalinate into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 14 h. After identification by TLC (developing agent: dichloromethane: methanol = 4:1), irradiation under ultraviolet light shows that a new spot is formed (the Rf value of the new spot is greater than that of the starting material spot) and there is no mangiferin spot in the reaction solution. After the reaction is completed, evaporate the DMF to dryness. After naturally cooling to room temperature, add anhydrous methanol to dissolve, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.34 g of the target compound 11 with a yield of 32.4%.

[0122] Example 9

[0123] Preparation of 3,6,7-(6-hexanoylglycine methyl ester) trisubstituted mangiferin (Ⅰ-9):

[0124]

[0125] 9.1 Synthesis of methyl 6-bromohexanoylglycinate

[0126] Weigh 1.2 g of L-glycine methyl ester hydrochloride and 3.28 mL of triethylamine, and dissolve them in 24 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer, and slowly add 1.46 mL of 6-bromohexanoyl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and let the temperature rise to room temperature naturally. React for 4 h. After checking by TLC (developing agent: petroleum ether: ethyl acetate = 2:1), iodine fuming shows that the raw material spot disappears and a new spot is formed (the Rf value of the new spot is greater than that of the raw material spot). Then, separate by column chromatography to obtain 1.83 g of intermediate 15 with a yield of 72%.

[0127] 9.2 Preparation of 3,6,7-(6-hexanoylglycine methyl ester) trisubstituted mangiferin (Ⅰ-9)

[0128] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF, and 1.26 g of 6-bromohexanoylglycine methyl ester into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 14 h. After checking by TLC (developing agent: dichloromethane: methanol = 4:1), irradiation under ultraviolet light shows that a new spot is formed (the Rf value of the new spot is greater than that of the raw material spot) and there is no mangiferin spot in the reaction solution. After the reaction is completed, evaporate the DMF to dryness. After naturally cooling to room temperature, add anhydrous methanol to dissolve, filter off a little insoluble matter, and finally separate the product by column chromatography to obtain 0.315 g of the target compound 15 with a yield of 34%.

[0129] Example 10

[0130] Preparation of 3,6,7-(5-pentanoylmethionine methyl ester) trisubstituted mangiferin (Ⅰ-10):

[0131]

[0132] 10.1 Synthesis of 5-bromopentanoylmethionine methyl ester

[0133] Weigh 1.0 g of L-methionine methyl ester hydrochloride and 2.09 mL of triethylamine, and dissolve them in 20 mL of dichloromethane in a 100 mL round-bottom flask. Place the round-bottom flask in a magnetic stirrer, and slowly add 0.67 mL of 5-bromopentanoyl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and let the temperature rise to room temperature naturally. React for 3 h. After checking by TLC (developing agent: petroleum ether: ethyl acetate = 2:1), iodine fuming shows that the raw material spot disappears and a new spot is formed (the Rf value of the new spot is greater than that of the raw material spot). Then, separate by column chromatography to obtain 1.24 g of intermediate 2 with a yield of 76%. 1 H NMR(600MHz,DMSO-d6),δ8.25(1H,d,J=7.6Hz,N H ),4.35(1H,quin,C H), 3.61 (3H, s, OC H 3 ), 3.52 (2H, t, J=6.7 Hz, Br - C H 2 ), 2.46 (2H, m, S - C H 2 ), 2.15 (2H, quin, J=7.3 Hz, C H 2 ), 2.03 (3H, s, S - C H 3 ), 1.88 (2H, m, CO - C H 2 ), 1.78 (2H, m, C H 2 ), 1.60 (2H, m, C H 2 ). 13 C NMR (150 MHz, DMSO - d6), δ 172.4 ( C =O), 172.2 ( C =O), 51.9 (O - C H 3 ), 50.8 (NH - C H), 34.7 (CO - C H 2 ), 33.9 (Br - C H 2 ), 31.6 ( C H 2 ), 30.4 ( C H 2 ), 29.6 ( C H 2 ), 23.8 ( C H 2 ), 14.6 (S - C H 3 ).

[0134] 10.2 Preparation of 3,6,7 - (5 - Valerylmethionine methyl ester) trisubstituted mangiferin (Ⅰ - 10)

[0135] Weigh 0.3 g of mangiferin, 0.49 g of potassium carbonate, 6 mL of DMF and 1.19 g of methyl 5-bromovaleryl-L-methionine into a 50 mL round-bottom flask, stir and dissolve at room temperature, then stir in an oil bath at 80 °C for 12 h. After checking by TLC (developer: dichloromethane:methanol = 4:1), a new spot was found under ultraviolet light irradiation (the Rf value of the new spot is greater than that of the raw material spot). After the reaction is completed, evaporate the DMF to dryness. After natural cooling to room temperature, dissolve it with anhydrous methanol, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.20 g of the target compound 2, with a yield of 24.4%. 1 H NMR(600MHz,DMSO-d6),δ13.55(1H,s,O H -1),8.27(6H,d,N H ),7.48(1H,s,H-8),7.16(1H,s,H-5),6.60(1H,s,H-4),3.34-4.86(O H ,NC H ,OC H 3 and OC H 2 ),1.69-2.50(SC H 3 ,SC H 2 and C H 2 ). 13 C NMR(150MHz,DMSO-d6),δ179.1(C-9),172.5( C =O×6),164.9(C-3),160.4(C-1),156.9(C-4a),155.5(C-6),151.8(C-4b),146.2(C-7),112.2(C-8a),109.0(C-8),105.5(C-2),102.0(C-5),100.8(C-8b),91.0(C-4),81.8(C-1’),79.0(C-5’),72.5(C-2’),71.0(C-3’),70.4(C-4’),68.7(O C H 2 ),68.3(O C H 2 ),68.0(O C H 2 ),62.0(C-6’),51.9(N C H),51.9(N C H),51.9(N C H),50.9(O-C H 3 ),50.9(O- C H 3 ),50.9(O- C H 3 ),34.5(CO- C H 2 ),34.5(CO- C H 2 ),34.4(CO- C H 2 ),30.5( C H 2 ),30.5( C H 2 ),30.5( C H 2 ),29.6( C H 2 ),29.6( C H 2 ),29.6( C H 2 ),27.9( C H 2 ),27.9( C H 2 ),27.7( C H 2 ),21.7( C H 2 ),21.7( C H 2 ),21.7( C H 2 ),14.6( C H 3 ),14.6( C H 3 ),14.6( C H 3 ).

[0136] Example 11

[0137] Preparation of 3,6,7-(5-valerylalanine methyl ester) trisubstituted mangiferin (Ⅰ-11):

[0138]

[0139] 11.1 Synthesis of methyl 5-bromovalerylalanine

[0140] Weigh 1.0 g of L-alanine methyl ester hydrochloride and 2.99 mL of triethylamine, and dissolve them in 20 mL of dichloromethane in a 100 mL round-bottom flask. Place the round-bottom flask in a magnetic stirrer, and slowly add 0.96 mL of 5-bromovaleryl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and allow the temperature to rise to room temperature naturally. React for 2 h 30 min. After identification by TLC (developing agent: petroleum ether: ethyl acetate = 2:1) and iodine fuming, the starting material spot disappears and a new spot appears (the Rf value of the new spot is greater than that of the starting material). Then, separate it by column chromatography to obtain 1.49 g of intermediate Ⅳ, with a yield of 74.5%. 1 H NMR (600 MHz, DMSO-d6), δ8.27(1H, d, J=7.0 Hz, N H ), 4.24(1H, quin, C H ), 3.60(3H, s, C H 3 ), 3.52(2H, t, J=6.8 Hz, C H 2 ), 2.13(2H, t, J=1.9 Hz, C H 2 ), 1.78(2H, m, C H 2 ), 1.60(2H, m, C H 2 ), 1.25(3H, d, J=7.3 Hz, C H 3 ). 13 C NMR (150 MHz, DMSO-d6), δ173.2( C =O), 171.8( C =O), 51.8(O- C H 3 ), 47.5(NH- C H), 34.8(Br- C H 2 ), 33.8(CO- C H 2 ), 31.6( C H 2 ), 23.8( C H 2 ), 16.9( C H 3 ).

[0141] 11.2 Preparation of 3,6,7-(5-valerylalanine methyl ester) trisubstituted mangiferin (Ⅰ-11)

[0142] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF and 1.27 g of methyl 5-bromovalerylalaninate into a 50 mL round-bottom flask, stir and dissolve at room temperature, then stir in an oil bath at 80 °C for 11 h. After checking by TLC (developer: dichloromethane: methanol = 4:1), a new spot was found under ultraviolet light irradiation (the Rf value of the new spot is greater than that of the raw material spot). After the reaction is completed, evaporate the DMF to dryness. After natural cooling to room temperature, dissolve it with anhydrous methanol, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.31 g of the target compound 4 with a yield of 32.0%. 1 H NMR(600MHz,DMSO-d6),δ13.56(1H,s,O H -1),8.27(3H,d,J=6.8Hz,N H ×3),7.47(1H,s,H-8),7.16(1H,s,H-5),6.61(1H,s,H-4),3.36-4.86(O H ,OC H 3 ,OC H 2 and C H ),2.21(6H,m,CO-C H 2 ),1.78(6H,m,C H 2 ×3),1.69(6H,m,C H 2 ×3),1.27(9H,m,C H 3 ×3). 13 C NMR(150MHz,DMSO-d6),δ179.1(C-9),173.3(NH- C O),172.1( C O-CH),164.9(C-3),160.4(C-1),155.5(C-6),151.8(C-10a),146.2(C-7),112.2(C-8a),109.0(C-8),105.5(C-2),101.9(C-5),100.8(C-9a),91.0(C-4),81.9(C-1’),79.0(C-5’),72.5(C-2’),71.0(C-3’),70.4(C-4’),68.8(O C H 2 ),68.4(O C H 2 ),68.1(O C H 2),62.0(C-6’),51.8(N C H×3),34.4(CO- C H 2 ),34.4(CO- C H 2 ),34.4(CO- C H 2 ),27.9( C H 2 ),27.8( C H 2 ),27.7( C H 2 ),21.7( C H 2 ×3),16.9( C H 3 ×3).

[0143] Example 12

[0144] Preparation of 3,6,7-(5-valeryltryptophan methyl ester) trisubstituted mangiferin (Ⅰ-12):

[0145]

[0146] 12.1 Synthesis of 5-bromovaleryltryptophan methyl ester

[0147] Weigh 1.06 g of L-tryptophan methyl ester hydrochloride and 2.61 mL of triethylamine, and dissolve them in 32 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer, and slowly add 0.84 mL of 5-bromovaleryl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and let the temperature rise to room temperature naturally. React for 4 h. After TLC identification (developing agent: petroleum ether: ethyl acetate = 2:1), iodine fuming, the raw material spot disappears and a new spot is formed (the Rf value of the new spot is greater than that of the raw material spot). Then, separate it by column chromatography to obtain 1.89 g of intermediate 6, with a yield of 78.8%. 1 H NMR(600MHz,DMSO-d6),δ10.86(1H,d,N H ),8.28(1H,d,J=7.6Hz,N H ),The hydrogen signals of the benzene ring[7.49(1H,d,J=7.8Hz),7.34(1H,d,J=8.1Hz),7.06(1H,t),6.98(1H,t,J=7.4Hz)],7.15(1H,d,J=2.4Hz,NH-C H ),4.51(1H,quin,J=8.3,5.6Hz,NH-CH ), 3.58 (3H, s, OC H 3 ), 3.46 (1H, t, J=6.7Hz, Br - C H 2 ), 3.09 (2H, m, CH - C H 2 ), 2.12 (2H, m, CO - C H 2 ), 1.66 (2H m, C H 2 ), 1.54 (2H, m, C H 2 ). 13 C NMR (150MHz, DMSO - d6), δ172.6 ( C =O), 171.9 ( C =O), The carbon signals of the benzene ring [136.1, 127.1, 121.0, 118.4, 118.0, 111.4], 123.7 (C= C H), 109.6 ( C -CH 2 ), 53.0 (O C H3), 51.8 (NH - C H), 34.8 (Br - C H 2 ), 33.8 (CO - C H 2 ), 31.4 ( C H 2 ), 27.1 ( C H 2 ), 23.7 ( C H 2 ).

[0148] 12.2 Preparation of 3,6,7 - (5 - pentanoyltryptophan methyl ester) trisubstituted mangiferin (Ⅰ - 12)

[0149] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF and 1.8 g of methyl 5-bromovaleryltryptophan into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 13 h. After checking by TLC (developing solvent: dichloromethane:methanol = 4:1), a new spot was found under ultraviolet light irradiation (the Rf value of the new spot is greater than that of the raw material spot). After the reaction is completed, evaporate the DMF to dryness. After naturally cooling to room temperature, dissolve it with anhydrous methanol, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.33 g of the target compound 6, with a yield of 26.4%. 1 H NMR(600MHz,DMSO-d6),δ13.59(1H,s,OH-1),10.86(3H,d,J=5.0Hz,N H ),8.30(3H,d,N H ),The hydrogen signals of thebenzene ring[7.50(3H,d,J=4.2Hz),7.34(3H,d),7.16(4H,d,J=2.9Hz),7.06(3H,dd,J=7.6,2.8Hz),6.99(3H,dd,J=6.6,2.7Hz),6.59(1H,s)],3.37-4.90(O H ,C H 2 ,OC H 2 ,OC H 3 ,C H ),1.66-2.19(C H 2 ). 13 C NMR(150MHz,DMSO-d6),δ179.1(C-9),172.6(C=O),172.2(C=O),164.9(C-3),160.4(C-1),156.9(C-4a),155.4(C-6),151.8(C-10a),146.2(C-7),Thecarbon signals of the benzene ring[136.1,127.1,121.0,118.4,118.0,111.5],123.7(C= C H),112.2(C-8a),109.6( C=CH), 109.0 (C-8), 105.5 (C-2), 102.0 (C-5), 100.7 (C-9a), 91.0 (C-4), 81.8 (C-1’), 79.0 (C-5’), 72.5 (C-2’), 71.0 (C-3’), 70.4 (C-4’), 68.7 (O C H 2 ), 68.3 (O C H 2 ), 67.9 (O C H 2 ), 62.0 (C-6’), 53.0 (NH- C H), 51.8 (O C H 3 ), 34.4 (CO- C H 2 ), 34.4 (CO- C H 2 ), 34.3 (CO- C H 2 ), 27.8 ( C H 2 ), 27.6 ( C H 2 ), 27.5 ( C H 2 ), 27.1 ( C H 2 ×3), 21.7 ( C H 2 ), 21.6 ( C H 2 ), 21.2 ( C H 2 ).

[0150] Example 13

[0151] Preparation of 3,6,7-(5-valeryl phenylalanine methyl ester) trisubstituted mangiferin (Ⅰ-13):

[0152]

[0153] 13.1 Synthesis of methyl 5-bromovaleryl phenylalanine

[0154] Weigh 1.8 g of L-phenylalanine methyl ester hydrochloride and 3.48 mL of triethylamine, and dissolve them in 36 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer and slowly add 1.12 mL of 5-bromovaleryl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice pack and let the temperature rise to room temperature naturally. React for 4 h. After checking by TLC (developing agent: petroleum ether: ethyl acetate = 2:1) and iodine fuming, the raw material spot disappears and a new spot is formed (the Rf value of the new spot is greater than that of the raw material spot). Then, separate by column chromatography to obtain 2.18 g of intermediate 8 with a yield of 76.2%.

[0155] 13.2 Preparation of 3,6,7-(5-valeryl phenylalanine methyl ester) trisubstituted mangiferin (Ⅰ-13): Weigh 0.5 g of mangiferin, 0.82 g of potassium carbonate, 10 mL of DMF, and 2.03 g of 5-bromovaleryl phenylalanine methyl ester into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 12 h. After checking by TLC (developing agent: dichloromethane: methanol = 4:1), a new spot is found to be formed under ultraviolet light irradiation (the Rf value of the new spot is greater than that of the raw material spot). After the reaction is completed, evaporate the DMF to dryness. After naturally cooling to room temperature, add anhydrous methanol to dissolve, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.44 g of the target compound 8 with a yield of 30.7%. 13 C NMR(151MHz,DMSO)δ179.07,172.23,172.12,164.91,160.44,156.84,155.43,151.81,146.15,137.31,129.04,128.22,126.50,112.20,108.99,105.43,102.47,101.94,90.99,81.87,79.25,72.53,71.02,70.41,69.75,68.65,68.21,67.85,62.01,53.46,53.42,51.84,36.74,34.37,34.32,34.22,27.71,27.68,27.56,27.45,21.61,21.55,21.51.

[0156] Example 14

[0157] Preparation of 3,6,7-(5-valeryl proline methyl ester) trisubstituted mangiferin (Ⅰ-14):

[0158]

[0159] 14.1 Synthesis of 5-bromovaleryl proline methyl ester

[0160] Weigh 1.35 g of L-proline methyl ester hydrochloride and 3.4 mL of triethylamine, dissolve them in 27 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer, slowly add 1.08 mL of 5-bromovaleryl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and let it warm up to room temperature naturally. React for 4 h. Check by TLC (developing solvent: petroleum ether: ethyl acetate = 2:1), iodine fuming. The starting material spot disappears and a new spot appears (the Rf value of the new spot is greater than that of the starting material). Then separate by column chromatography to obtain 1.32 g of intermediate 18 with a yield of 56%.

[0161] 14.2 Preparation of 3,6,7-(5-valerylproline methyl ester) trisubstituted mangiferin (Ⅰ-14)

[0162] Weigh 0.38 g of mangiferin, 0.63 g of potassium carbonate, 7.6 mL of DMF and 1.32 g of 5-bromovalerylproline methyl ester into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 14 h. Check by TLC (developing solvent: dichloromethane: methanol = 4:1), under ultraviolet light irradiation, a new spot appears (the Rf value of the new spot is greater than that of the starting material) and there is no mangiferin spot in the reaction solution. After the reaction is complete, evaporate the DMF to dryness. After cooling to room temperature naturally, add anhydrous methanol to dissolve, filter off a little insoluble matter, and finally separate the product by column chromatography to obtain 0.34 g of the target compound 18 with a yield of 35%.

[0163] Example 15

[0164] Preparation of 3,6,7-(5-valeryl leucine methyl ester) trisubstituted mangiferin (Ⅰ-15):

[0165]

[0166] 15.1 Synthesis of 5-bromovaleryl leucine methyl ester

[0167] Weigh 1.24 g of L-leucine methyl ester hydrochloride and 2.85 mL of triethylamine, dissolve them in 25 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer, slowly add 0.914 mL of 5-bromovaleryl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and let it warm up to room temperature naturally. React for 4 h. Check by TLC (developing solvent: petroleum ether: ethyl acetate = 2:1), iodine fuming. The starting material spot disappears and a new spot appears (the Rf value of the new spot is greater than that of the starting material). Then separate by column chromatography to obtain 1.81 g of intermediate 14 with a yield of 86.2%.

[0168] 15.2 Preparation of 3,6,7-(5-valeryl leucine methyl ester) trisubstituted mangiferin (Ⅰ-15)

[0169] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF and 1.46 g of methyl 5-bromovaleryl leucinate into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an oil bath at 80 °C for 14 h. After checking by TLC (developing solvent: dichloromethane:methanol = 4:1), under ultraviolet light irradiation, new spots are found to be generated (the Rf value of the new spots is greater than that of the raw material spots) and there is no mangiferin spot in the reaction solution. After the reaction is completed, evaporate DMF to dryness. After natural cooling to room temperature, add anhydrous methanol to dissolve, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.37 g of the target compound 14 with a yield of 35.2%.

[0170] Example 16

[0171] Preparation of 3,6,7-(5-valeryl isoleucine methyl ester) trisubstituted mangiferin (Ⅰ-16):

[0172]

[0173] 16.1 Synthesis of methyl 5-bromovaleryl isoleucinate

[0174] Weigh 1.24 g of L-isoleucine methyl ester hydrochloride and 2.85 mL of triethylamine, dissolve them in 25 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer and slowly add 0.914 mL of 5-bromovaleryl chloride dropwise under ice-water bath conditions while stirring. After the addition is completed, remove the ice bag and let it warm up to room temperature naturally. React for 4 h. After checking by TLC (developing solvent: petroleum ether:ethyl acetate = 2:1), iodine fuming, the raw material spots disappear and new spots are generated (the Rf value of the new spots is greater than that of the raw material spots). Then separate by column chromatography to obtain 1.47 g of intermediate 10 with a yield of 70%.

[0175] 16.2 Preparation of 3,6,7-(5-valeryl isoleucine methyl ester) trisubstituted mangiferin (Ⅰ-16)

[0176] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF and 1.46 g of methyl 5-bromovaleryl isoleucinate into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an oil bath at 80 °C for 14 h. After checking by TLC (developing solvent: dichloromethane:methanol = 4:1), under ultraviolet light irradiation, new spots are found to be generated (the Rf value of the new spots is greater than that of the raw material spots) and there is no mangiferin spot in the reaction solution. After the reaction is completed, evaporate DMF to dryness. After natural cooling to room temperature, add anhydrous methanol to dissolve, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.46 g of the target compound 10 with a yield of 44%.

[0177] Example 17

[0178] Preparation of 3,6,7-(5-valerylvaline methyl ester) trisubstituted mangiferin (Ⅰ-17):

[0179]

[0180] 17.1 Synthesis of methyl 5-bromovalerylvalinate

[0181] Weigh 1.32 g of L-valine methyl ester hydrochloride and 3.284 mL of triethylamine, and dissolve them in 27 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer, and slowly add 1.054 mL of 5-bromovaleryl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and let the temperature rise to room temperature naturally. React for 4 h. Check by TLC (developing agent: petroleum ether: ethyl acetate = 2:1), and after iodine fuming, the starting material spot disappears and a new spot appears (the Rf value of the new spot is greater than that of the starting material spot). Then separate by column chromatography to obtain 1.72 g of intermediate 12 with a yield of 74.1%.

[0182] 17.2 Preparation of 3,6,7-(5-valerylvaline methyl ester) trisubstituted mangiferin (Ⅰ-17)

[0183] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF, and 1.39 g of methyl 5-bromovalerylvalinate into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 14 h. Check by TLC (developing agent: dichloromethane: methanol = 4:1), and under ultraviolet light irradiation, a new spot appears (the Rf value of the new spot is greater than that of the starting material spot) and there is no mangiferin spot in the reaction solution. After the reaction is complete, evaporate the DMF to dryness. After naturally cooling to room temperature, add anhydrous methanol to dissolve, filter off a small amount of insoluble matter, and finally separate the product by column chromatography to obtain 0.484 g of the target compound 12 with a yield of 48.2%.

[0184] Example 18

[0185] Preparation of 3,6,7-(5-valeryl glycine methyl ester) trisubstituted mangiferin (Ⅰ-18):

[0186]

[0187] 18.1 Synthesis of methyl 5-bromovaleryl glycinate

[0188] Weigh 1.2 g of L-glycine methyl ester hydrochloride and 3.99 mL of triethylamine, and dissolve them in 24 mL of dichloromethane in a 250 mL round-bottom flask. Place the flask in a magnetic stirrer and slowly add 1.28 mL of 5-bromovaleryl chloride dropwise under an ice-water bath while stirring. After the addition is complete, remove the ice bag and allow the temperature to rise to room temperature naturally. React for 4 h. After identification by TLC (developing solvent: petroleum ether: ethyl acetate = 2:1), iodine fuming shows that the raw material spot disappears and a new spot is formed (the Rf value of the new spot is greater than that of the raw material spot). Then, separate by column chromatography to obtain 1.81 g of intermediate 16 with a yield of 75%.

[0189] 18.2 Preparation of 3,6,7-(5-valeryl glycine methyl ester) trisubstituted mangiferin (Ⅰ-18)

[0190] Weigh 0.4 g of mangiferin, 0.66 g of potassium carbonate, 8 mL of DMF, and 1.19 g of 5-bromovaleryl glycine methyl ester into a 100 mL round-bottom flask, stir and dissolve at room temperature, then stir in an 80 °C oil bath for 14 h. After identification by TLC (developing solvent: dichloromethane: methanol = 4:1), under ultraviolet light irradiation, a new spot is found to be formed (the Rf value of the new spot is greater than that of the raw material spot) and there is no mangiferin spot in the reaction solution. After the reaction is completed, evaporate the DMF to dryness. After natural cooling to room temperature, add anhydrous methanol to dissolve, filter a little insoluble matter, and finally separate the product by column chromatography to obtain 0.4 g of the target compound 16 with a yield of 44.9%.

[0191] Example 19

[0192] Activity test

[0193] The mangiferin derivatives are from Examples 1 to 18.

[0194] Preparation of sample solution: Take the mangiferin derivatives, mangiferin, and orlistat prepared according to the above examples, and add them to the corresponding volume of dimethyl sulfoxide (DMSO) to dissolve, obtaining a drug stock solution with a concentration of about 20 mM. Oscillate to dissolve and store at -20 °C for later use.

[0195] I. Determination of FASN inhibitory activity

[0196] 1. Experimental operation

[0197] Fatty acid synthase can catalyze the reaction of acetyl-CoA, malonyl-CoA, and NADPH to generate long-chain fatty acids and NADP +, NADPH has a characteristic absorption peak at 340 nm, and the activity of fatty acid synthase can be characterized by the rate of decrease in absorbance value. In this method, the activity of fatty acid synthase was measured using a fatty acid synthase activity detection kit (Beijing BoxbioScience & Technology Co., Ltd) in a 96-well plate. This kit does not contain crude FASN enzyme and needs to be prepared by oneself. The specific experimental operation steps are carried out according to the manufacturer's instructions. Specifically, take the fresh liver of mice fed with high-fat diet, weigh the tissue, and process the sample according to the ratio of tissue mass (g): extraction solution volume (mL) of 1:(5 - 10), homogenize in an ice bath, centrifuge at 12000 g at 4 °C for 40 min, and take the supernatant and place it on ice for further measurement. Preheat the ultraviolet spectrophotometer or microplate reader for more than 30 min, adjust the wavelength to 340 nm, and zero with distilled water. Preheat the reagents at 40 °C for 30 min before the experiment. Add the test drug and each reagent in the kit to the 96-well plate, mix well and start timing immediately, measure the absorbance values at 340 nm at 30 s and 90 s respectively, and record them as A1 and A2; calculate ΔA = A1 - A2. The activity of the test compound is reported as % inhibition. The data was analyzed using Graphpad Prism.

[0198] 2. Results

[0199] The results are shown in Table 1. The inhibition rate of mangiferin at a concentration of 10 μM was 63%. Most mangiferin derivatives had strong FASN activity. For example, I-9 was 93.5%; I-15 was 88.7%.

[0200] Table 1. FASN inhibitory activity of mangiferin derivatives

[0201]

[0202]

[0203] II. In vitro cell activity experiment

[0204] 1. Cell experiment operation

[0205] 1.1 Cell resuscitation

[0206] Preheat ddH 2 O to 37 °C. Wear gloves, masks and hats, take out the cryopreservation tube containing the target cells (with 1 mL of cell mixture) from the liquid nitrogen tank, and immediately put it into 37 °C ddH 2In O, gently shake the cryopreservation tube to dissolve it quickly within 1 minute. After complete dissolution, wipe the outer wall of the cryopreservation tube with 75% alcohol for disinfection and then bring it into the laminar flow hood. In the laminar flow hood, pre-add 10 mL of freshly prepared medium into a 15 mL sterilized centrifuge tube. Open the cryopreservation tube and add all the thawed cell suspension into this centrifuge tube. Centrifuge at 1000 rpm for 3 minutes at room temperature, and aspirate the upper layer of the culture medium. Resuspend the cell pellet with 1 mL of medium, gently pipette to mix evenly and then add it into a T25 cell culture flask, supplement the medium to 5 mL, and place it in an incubator at 37°C and 5% CO 2 culture. Change the medium after 48 hours. Passage can be carried out when the cell confluence is close to 80%.

[0207] 1.2 Cell culture

[0208] The 3T3-L1 cells are cultured in DMEM medium containing 10% fetal bovine serum and 1% double antibiotics in an incubator at 37°C with saturated humidity and containing 5% CO 2 .

[0209] 1.3 Experimental methods

[0210] Take 3T3-L1 cells in the logarithmic growth phase, digest them with 0.25% trypsin, and then perform cell counting. Seed the cells into a 96-well plate at a density of 8000 cells / well and continue the culture. After 24 hours, change the culture medium for the control group, add test substances at different concentrations to the experimental group, and use the MTT method to detect cell viability by colorimetry after 48 hours. At the detection time point for each group of cells, add 1 / 10 volume of MTT solution (5 mg / mL) to each well, and culture in an incubator at 37°C and 5% CO 2 for 4 hours; carefully aspirate the culture supernatant in the wells, avoiding sucking away the purple crystals. Add 150 μL of DMSO to each well and shake for 10 minutes to fully dissolve the crystals. Select a wavelength of 490 nm and measure the optical absorbance value of each well on an enzyme-linked immunosorbent assay monitor, and record the results. Analyze all the data using Graphpad Prism. The final activity is expressed as the IC 50 value. For the determination of IC 50 , all experiments are repeated at least three times. DMSO (0.1%) is used as a negative control.

[0211] 2. Anti-proliferation activity of mangiferin derivatives on 3T3-L1 adipocytes in vitro

[0212] The results of the experimental study on the activity of 3T3-L1 adipocytes show that compared with mangiferin, the mangiferin derivatives have a stronger anti-proliferation effect on adipocytes in vitro. The results of the experimental study on the activity of 3T3-L1 adipocytes show that compared with mangiferin, the mangiferin derivatives have a stronger anti-proliferation effect on adipocytes in vitro. The activity of the representative compounds is shown in Table 2.

[0213] Table 2. In vitro anti-proliferative activities of mangiferin derivatives against 3T3-L1 adipocytes

[0214]

[0215] a The concentration of an inhibitor where the response is reduced by half. All values are the means±SD of four independent experiments。

[0216] 3. Inhibitory effects of compounds I-12 and I-13 on cells

[0217] 3T3-L1 adipocytes were treated with different concentrations of compound I-12 or I-13 for 48 h, and cell viability was detected by the MTT method. The results showed that compounds I-12 and I-13 significantly reduced the viability of 3T3-L1 adipocytes in a dose-dependent manner and were more potent than mangiferin. The results are shown in Figure 3 。

Claims

1. Mangiferin derivatives, characterized in that, It is a compound and its salt as shown in formula (I): wherein n = 4 to 5; R is:

2. The preparation method of the mangiferin derivative according to claim 1, characterized in that, The reaction formula is: wherein a represents reaction conditions: the solvent is dichloromethane, 1,2-dichloroethane, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide; the acid-binding agent is triethylamine, ethylenediamine, N,N-diisopropylethylamine, pyridine, sodium acetate, sodium carbonate, potassium carbonate; the reaction temperature is 50-100 °C; the reaction time is 10-72 h; The preparation reaction formula is as follows: Wherein b represents the reaction conditions: the solvent is dichloromethane, 1,2-dichloroethane, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide; the acid-binding agent is triethylamine, ethylenediamine, N,N-diisopropylethylamine, pyridine, sodium acetate, sodium carbonate, potassium carbonate; the reaction temperature is -10 - 40 °C; the reaction time is 1 - 24 h.

3. A composition comprising the mangiferin derivative according to claim 1 or a salt thereof.

4. Use of the mangiferin derivative according to claim 1 or a salt thereof in the preparation of a drug for treating obesity.

5. Use of the mangiferin derivative according to claim 1 in the preparation of a fatty acid synthase inhibitor.

6. Use of the mangiferin derivative according to claim 1 in the preparation of an inhibitor of 3T3-L1 adipocyte proliferation.

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