Indolmaleimide derivatives and their use

Abstract

The present application relates to a kind of indole maleimide derivatives and its application, belong to heterocyclic compound synthesis technical field, solve the problem that the kind of drug for treating cancer is not enough rich at present.The indole maleimide derivative of the present application has the structure as shown in structure formula 4: And / or, with the structure as shown in structure formula 3.The indole maleimide derivative of the present application has obvious inhibitory effect on the proliferation of human leukemia cells (K562) and prostate cancer cells (PC-3).

Description

Technical Field

[0001] This invention relates to the field of heterocyclic compound synthesis technology, to nitrogen-containing heterocyclic compounds, their preparation methods and applications, and particularly to an indolemaleimide derivative and its applications. Background Technology

[0002] Nitrogen-containing heterocyclic compounds have wide applications in organic synthesis, medicine, pesticides, and materials science. Therefore, developing novel and practical methods to construct various nitrogen-containing heterocyclic skeletons has become a research goal for many organic synthetic chemists.

[0003] Maleimide and indole, as dominant structural frameworks, have wide applications in drug development, agrochemical research, and advanced materials design.

[0004] Cancer is one of the leading causes of death worldwide; it is a large class of diseases characterized by the uncontrolled growth of abnormal cells. However, the variety of drugs currently available for treating cancer is insufficient. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide an indolemaleimide derivative and its application to solve the problem of insufficient variety of existing drugs for treating cancer.

[0006] The objective of this invention is mainly achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides an indolemaleimide derivative having a structure as shown in structural formula 4:

[0008]

[0009] In the formula, R1 is selected from electron-donating functional groups or electron-withdrawing functional groups; R is selected from electron-donating functional groups or electron-withdrawing functional groups.

[0010] And / or, it has a structure as shown in structural formula 3:

[0011]

[0012] In the formula, R1 is selected from electron-donating or electron-withdrawing functional groups; R2 is selected from any one of hydrogen, methyl, ethyl, and n-propyl.

[0013] Optionally, in R1, the electron-donating functional group is selected from hydrogen; the electron-withdrawing functional group is selected from any one of fluorine, chlorine, and bromine.

[0014] Optionally, in R, the electron-donating functional group is selected from hydrogen, methyl, or methoxy; the electron-withdrawing functional group is selected from fluorine, chlorine, bromine, iodine, phenyl, trifluoromethyl, nitro, and cyano.

[0015] Optionally, structural formula 4 includes the following structure:

[0016]

[0017] Optionally, structural formula 3 includes the following structure:

[0018]

[0019] Optionally, the IC50 of the indolemaleimide derivative having structural formula 4 against human leukemia cells is 21.6-33.0 μmol·L⁻¹. -1 The IC50 for prostate cancer cells was 15.1-29.1 μmol·L⁻¹. -1 .

[0020] Optionally, the IC50 of indolemaleimide derivatives having structural formula 3 against human leukemia cells is 11.2-26.1 μmol·L⁻¹. -1 The IC50 for prostate cancer cells was 16.1-26.2 μmol·L⁻¹. -1 .

[0021] Optionally, the human leukemia cells are K562, and the prostate cancer cells are PC-3.

[0022] Secondly, the present invention provides a method for preparing an indolemaleimide derivative, which includes adding indoleacetamide and a nucleophile to a mixed solution and reacting to obtain the indolemaleimide derivative.

[0023] Thirdly, the present invention provides the application of the above-mentioned indolemaleimide derivative in the preparation of anticancer drugs.

[0024] Compared with the prior art, the indolemaleimide derivative of the present invention enriches the variety of existing anticancer drugs, and has a significant inhibitory effect on the proliferation of human leukemia cells (K562) and prostate cancer cells (PC-3).

[0025] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages will become apparent from the description or may be learned by practicing the invention. Attached Figure Description

[0026] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0027] Unless otherwise specified, the methods in this invention are conventional methods. Unless otherwise specified, the raw materials are all commercially available.

[0028] Figure 1 The hydrogen spectrum of the product 1-methyl-3-(1-methylindol-3-yl)pyrrole-2,5-dione (3a) in the example;

[0029] Figure 2 Carbon spectrum of the product 1-methyl-3-(1-methylindol-3-yl)pyrrole-2,5-dione (3a) in the examples;

[0030] Figure 3 The 1H NMR spectrum of the product 5-hydroxy-5-phenyl-1-methyl-3-(1-methylindol-3-yl)pyrrole-2-one (4a) in the examples;

[0031] Figure 4 Carbon spectrum (4a) of the product 5-hydroxy-5-phenyl-1-methyl-3-(1-methylindol-3-yl)pyrrole-2-one in the examples;

[0032] Figure 5 3b 1H NMR spectrum of the product;

[0033] Figure 6 3b carbon spectrum of the product;

[0034] Figure 7 3C 1H NMR spectrum of the product;

[0035] Figure 8 3C carbon spectrum of the product;

[0036] Figure 9 3d proton NMR spectrum of the product;

[0037] Figure 10 3D carbon spectrum of the product;

[0038] Figure 11 3e proton spectrum of the product;

[0039] Figure 12 3e carbon spectrum of the product;

[0040] Figure 13 3f proton NMR spectrum of the product;

[0041] Figure 14 3F carbon spectrum of the product;

[0042] Figure 15 3f NMR fluorine spectrum of the product;

[0043] Figure 16 3g of product hydrogen spectrum;

[0044] Figure 17 Carbon spectrum of 3g of product;

[0045] Figure 18 3-hour proton NMR spectrum of the product;

[0046] Figure 19 3-hour carbon spectrum of the product;

[0047] Figure 20 4b 1H NMR spectrum of the product;

[0048] Figure 21 4b carbon spectrum of the product;

[0049] Figure 22 4b NMR fluorine spectrum of the product;

[0050] Figure 23 4c 1H NMR spectrum of the product;

[0051] Figure 24 4c carbon spectrum of the product;

[0052] Figure 25 4d proton NMR spectrum of the product;

[0053] Figure 26 4D carbon spectrum of the product;

[0054] Figure 27 4e proton spectrum of the product;

[0055] Figure 28 4e carbon spectrum of the product;

[0056] Figure 29 4f proton NMR spectrum of the product;

[0057] Figure 30 4F carbon spectrum of the product;

[0058] Figure 31 4g of product hydrogen spectrum;

[0059] Figure 32 Carbon spectrum of 4g product;

[0060] Figure 33 4g of the product's NMR fluorine spectrum;

[0061] Figure 34 4-hour proton NMR spectrum of the product;

[0062] Figure 35 4-hour carbon spectrum of the product;

[0063] Figure 36 4i proton NMR spectrum of the product;

[0064] Figure 37 4i carbon spectrum of the product;

[0065] Figure 38 Product 4j 1H NMR spectrum;

[0066] Figure 394J carbon spectrum of the product;

[0067] Figure 40 4K proton spectrum of the product;

[0068] Figure 41 4K carbon spectrum of the product;

[0069] Figure 42 4L 1H NMR spectrum of the product;

[0070] Figure 43 Carbon 41 spectrum of the product. Detailed Implementation

[0071] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0072] In a first aspect, the present invention provides an indolemaleimide derivative having a structure as shown in structural formula 4:

[0073]

[0074] In the formula, R1 is selected from an electron-donating or electron-withdrawing functional group, where the electron-donating functional group is selected from hydrogen; the electron-withdrawing functional group is selected from any one of fluorine, chlorine, and bromine; R is selected from an electron-donating or electron-withdrawing functional group, where the electron-donating functional group is selected from any one of hydrogen, methyl, or methoxy; the electron-withdrawing functional group is selected from any one of fluorine, chlorine, bromine, iodine, phenyl, trifluoromethyl, nitro, and cyano. The specific structural formula is as follows:

[0075]

[0076] It should be noted that the percentage following the product number is the separation yield.

[0077] Alternatively, indolemaleimide derivatives may have a structure as shown in structural formula 3:

[0078]

[0079] In the formula, R1 is selected from an electron-donating functional group or an electron-withdrawing functional group; the electron-donating functional group is selected from hydrogen; the electron-withdrawing functional group is selected from fluorine, chlorine, and bromine; R2 is selected from hydrogen, methyl, ethyl, and n-propyl. The specific structural formula is as follows:

[0080]

[0081] It should be noted that the percentage following the product number is the separation yield.

[0082] In this invention, the indolemaleimide derivative having structural formula 4 exhibits inhibitory effects on the proliferation of two types of tumor cells: human leukemia cells (K562) and prostate cancer cells (PC-3). Specifically, the IC50 against human leukemia cells (K562) is 21.6-33.0 μmol·L⁻¹. -1 The IC50 against prostate cancer cells (PC-3) was 15.1-29.1 μmol·L⁻¹. -1 .

[0083] Among them, products 4b and 4g showed inhibitory activity against K562 comparable to cisplatin, while the inhibitory activity of the remaining products was slightly weaker than that of cisplatin.

[0084] Products 4b, 4c, 4d, 4e, and 4g exhibited superior inhibitory activity against PC-3 compared to cisplatin, while the inhibitory activities of the remaining products were comparable to cisplatin. Product 4g showed the strongest inhibitory activity against PC-3 (IC50 = 15.1 μmol·L⁻¹). -1 It is 1.71 times that of cisplatin.

[0085] In this invention, the indolemaleimide derivative having structural formula 3 exhibits inhibitory effects on the proliferation of two types of tumor cells: human leukemia cells (K562) and prostate cancer cells (PC-3). Specifically, the IC50 against human leukemia cells (K562) is 11.2-26.1 μmol·L⁻¹. -1 The IC50 against prostate cancer cells (PC-3) was 16.1-26.2 μmol·L⁻¹. -1 .

[0086] Among them, products 3b, 3c, 3d, 3f, 3g, and 3h showed significantly better inhibitory activity against K562 than cisplatin, while the inhibitory activity of the remaining products was comparable to that of cisplatin. Product 3f exhibited the strongest inhibitory activity against K562 (IC50 = 11.2 μmol·L⁻¹), which was 2.11 times that of cisplatin.

[0087] Products 3a, 3g, 3h, and 3f showed superior inhibitory activity against PC-3 compared to cisplatin, while the inhibitory activity of the other products was comparable to that of cisplatin. Product 3g exhibited the strongest inhibitory activity against PC-3 (IC50 = 16.1 μmol·L⁻¹), which was 1.60 times that of cisplatin.

[0088] In summary, the products synthesized in this invention, 3: 1-methyl-3-(1-methylindol-3-yl)pyrrole-2,5-dione and 4: 5-hydroxy-5-phenyl-1-methyl-3-(1-methylindol-3-yl)pyrrole-2-one, are both compounds with anticancer activity.

[0089] Secondly, the present invention provides a method for preparing a nitrogen-containing heterocyclic compound, specifically, a method for preparing an indolemaleimide derivative, comprising the following steps:

[0090] Step 1: Add indoleacetamide and a nucleophile to the mixed solution and allow the reaction to proceed;

[0091] Step 2: Post-processing to obtain indolemaleimide derivatives.

[0092] Specifically, indoleacetamide has a structure as shown in structural formula 1a:

[0093]

[0094] In the formula, R1 is selected from electron-donating functional groups or electron-withdrawing functional groups. Electron-donating functional groups are selected from hydrogen, and electron-withdrawing functional groups are selected from any one of fluorine, chlorine, and bromine.

[0095] The nucleophile is a phosphorus ylidene reagent, including one of α-ester phosphorus ylidene reagent and α-acetylphenyl phosphorus ylidene reagent.

[0096] When the nucleophile is an α-ester phosphorus ylidene reagent, it has the structure shown in structural formula 2a:

[0097]

[0098] In the formula, R2 is selected from hydrogen, methyl, ethyl and n-propyl.

[0099] The reaction equation for indoleacetamide with α-esterified phosphorus ylide reagent is as follows:

[0100]

[0101] The indolemaleimide derivative obtained from the reaction has the structure shown in structural formula 3:

[0102]

[0103] In the formula, R1 is selected from an electron-donating functional group or an electron-withdrawing functional group; the electron-donating functional group is selected from hydrogen; the electron-withdrawing functional group is selected from fluorine, chlorine, and bromine; R2 is selected from hydrogen, methyl, ethyl, and n-propyl. The specific structural formula is as follows:

[0104]

[0105] It should be noted that the percentage following the product number is the separation yield.

[0106] When the nucleophile is an α-acetylphenylphosphine ylide reagent, it has the structure shown in structural formula 2b:

[0107]

[0108] In the formula, R is selected from electron-donating functional groups or electron-withdrawing functional groups. Electron-donating functional groups are selected from any one of hydrogen, methoxy, and methyl. Electron-withdrawing functional groups are selected from any one of fluorine, chlorine, bromine, iodine, phenyl, trifluoromethyl, nitro, and cyano.

[0109] The reaction equation for indoleacetamide with α-acetylphenylphosphine ylide reagent is as follows:

[0110]

[0111] The indolemaleimide derivative obtained from the reaction has the structure shown in structural formula 4:

[0112]

[0113] In the formula, R is selected from electron-donating or electron-withdrawing functional groups. Electron-donating functional groups are selected from hydrogen, methyl, or methoxy; electron-withdrawing functional groups are selected from fluorine, chlorine, bromine, iodine, phenyl, trifluoromethyl, nitro, and cyano. The specific structural formula is as follows:

[0114]

[0115] It should be noted that the percentage following the product number is the separation yield.

[0116] Specifically, in step 1, the reaction temperature is 70-120℃, for example, 70℃, 75℃, 80℃, 85℃, 90℃, 100℃, 110℃, 120℃. The reaction time is 3-14h, for example, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h.

[0117] The mixed solution includes alkali, additives, and organic solvents.

[0118] The base includes one of triethylamine (Et3N), N,N-diisopropylethylamine (DIPEA), pyridine, and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), preferably triethylamine.

[0119] The additives include one of the following: dipotassium hydrogen phosphate (K2HPO4), potassium dihydrogen phosphate (KH2PO4), glacial acetic acid, 4-dimethylaminopyridine (DMAP), sodium carbonate, and zinc chloride (ZnCl2).

[0120] Organic solvents include one of tetrahydrofuran (THF), acetonitrile (MeCN), 1,4-dioxane, and chloroform.

[0121] More specifically, when the nucleophile is an α-esterified phosphorus ylide reagent, the reaction temperature is 70-120℃, for example, 70℃, 75℃, 80℃, 85℃, 90℃, 100℃, 110℃, 120℃. The reaction time is 3-5h, for example, 3h, 3.5h, 4h, 4.5h, 5h.

[0122] The molar ratio of indoleacetamide to α-esterified phosphorus ylide reagent is (0.5-2):1, for example, 1:2, 1:1, 2:1.

[0123] The mixed solution comprises triethylamine, potassium dihydrogen phosphate, and an organic solvent. The molar ratio of indoleacetamide to triethylamine is 1:(2-4), for example, 1:2, 1:3, or 1:4. The molar ratio of indoleacetamide to potassium dihydrogen phosphate is 1:(4-6), for example, 1:4, 1:5, or 1:6. The organic solvent includes one of tetrahydrofuran (THF), acetonitrile (MeCN), 1,4-dioxane, or chloroform. The molar-volume ratio of indoleacetamide to the organic solvent is (0.1-0.2):1, where moles are in mmol and volumes are in mL.

[0124] When the nucleophile is α-acetylphenylphosphine ylide reagent, the reaction temperature is 70-90℃, for example, 70℃, 75℃, 80℃, 85℃, 90℃. The reaction time is 8-15h, for example, 8h, 9h, 10h, 12h, 14h, 15h.

[0125] The molar ratio of indoleacetamide to α-acetylphenylphosphine ylide reagent is (3-1):2, for example, 3:2, 1:1, 1:2.

[0126] The mixed solution includes triethylamine, zinc chloride, and organic solvents.

[0127] The molar ratio of α-acetylphenylphosphine ylide reagent to triethylamine is 1:(2-4), for example, 1:2, 1:3, or 1:4. The molar ratio of α-acetylphenylphosphine ylide reagent to zinc chloride is 1:(1-3), for example, 1:1, 1:2, or 1:3. The organic solvent includes one of tetrahydrofuran (THF), acetonitrile (MeCN), 1,4-dioxane, and chloroform. Tetrahydrofuran (THF) is preferred. The molar-volume ratio of α-acetylphenylphosphine ylide reagent to the organic solvent is (0.1-0.2):1, where moles are in mmol and volumes are in mL.

[0128] In step 2, the post-processing includes concentration and purification. Specifically, it includes: concentrating the reaction mixture from step 1 under vacuum to obtain a residue; purifying the residue by rapid silica gel column chromatography, eluting to obtain the product, indolemaleimide derivative. The eluent is a mixture of petroleum ether and ethyl acetate, with a volume ratio of petroleum ether:ethyl acetate of 10:1 to 2:1, for example, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, or 2:1.

[0129] The possible reaction mechanism in this invention is as follows:

[0130]

[0131] First, substrate 1a undergoes a concerted deprotonation and elimination reaction in the presence of triethylamine to yield the α-lactam intermediate Int-1, which is isomerizes to Int-2. Subsequently, phosphorus ylide reagent 2 reacts with Int-2 to generate the zwitterionic intermediate Int-3, whose nitrogen anion attacks the carbonyl group to undergo a 5-exo cyclization reaction to generate Int-4. When R3 is a benzene ring, Int-4 undergoes proton transfer and elimination of triphenylphosphine to obtain the hydroxylated product 4; when R3 is an ethoxy group, the hydroxylated product is further deprotonated, thereby eliminating one molecule of ethoxy anion to obtain the maleimide derivative 3.

[0132] In summary, this invention utilizes indoleacetamide and a phosphorus ylide reagent containing an α-carbonyl group to achieve a cascade olefination / cyclization reaction under the action of triethylamine. Specifically, the nucleophilic phosphine reagent containing an α-ester group yields the indolemaleimide derivative: 1-methyl-3-(1-methylindole-3-yl)pyrrole-2,5-dione (product 3); while the phosphorus ylide reagent containing an α-acetylphenyl group isolates the hydroxylated unsaturated alcohol: 5-hydroxy-5-phenyl-1-methyl-3-(1-methylindole-3-yl)pyrrole-2-one (product 4). This reaction is simple to operate, requires no expensive transition metals, and has broad substrate applicability. This invention will contribute to expanding the application of nucleophilic phosphine reagents in the synthesis of nitrogen heterocycles, providing an effective new method for the synthesis of heterocyclic compounds.

[0133] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0134] (1) This invention compresses the traditional multi-step reaction into a single-step one-pot method by jointly adjusting the reaction raw materials and the reaction system, thereby improving the reaction efficiency and reducing energy consumption.

[0135] (2) The present invention optimizes the reaction system into a mixed solution including alkali, additives and organic solvents, and optimizes the types of alkali, additives and organic solvents so that the reaction can be carried out without the addition of expensive transition metal catalysts, thereby reducing production costs and leaving no metal residue in the product.

[0136] (3) The reaction conditions of the present invention are mild and can be carried out in an atmospheric pressure and air environment. It does not require a deoxygenated and low-temperature reaction environment, thus reducing production costs.

[0137] (4) The same system of the present invention is compatible with electron-withdrawing groups (fluorine, chlorine, bromine, iodine, phenyl, trifluoromethyl, nitro, cyano and naphthyl), electron-donating groups (hydrogen, methoxy, methyl) and α-position sterically hindered groups (such as naphthalene ring), realizing the compatibility of dynamic functional groups in the same system, solving the problem of insufficient functional group compatibility of existing methods, and realizing broad-spectrum substrate applicability.

[0138] Example 1

[0139] In this invention, indoleacetamide (structure 1) and α-esterified phosphorus ylide reagent (structure 2a) are added in a single step to a THF solution containing triethylamine and K₂HPO₄. After the reaction is complete, the reaction mixture is concentrated under vacuum. A small amount of product 3a was successfully detected (Table 1, item 1). When DMAP was used instead of K₂HPO₄, the product yield decreased significantly (item 3). When Na₂CO₃ and KH₂PO₄ were added to the reaction system, the yields of product 3 were 37% and 42%, respectively (items 2 and 4). Screening of organic solvents revealed that chloroform yielded the best product yield, reaching 63% (item 7). Without the addition of K₂HPO₄, the NMR yield of product 3a was only 44% (item 8). Furthermore, the reaction was not effective after adding acidic additives HCl and glacial acetic acid (items 9-10). When the reactant ratio was adjusted to 2:1 or 1:1, the yield decreased slightly (items 11-12). Even with extended reaction time at 40°C, the reaction did not proceed effectively (item 13).

[0140] Table 1 Optimization of reaction conditions a

[0141]

[0142] Unless otherwise stated, all reactions were carried out at 80°C for 4 hours. The reaction system contained 1a (0.1 mmol), 2a (0.2 mmol), Et3N (0.3 mmol), additive (0.5 mmol) and solvent (1.0 mL).

[0143] b 1 The yield was determined by ¹H NMR using 4-methylbenzophenone as an internal standard.

[0144] c 1a:2a=2:1.

[0145] d 1a:2a=1:1.

[0146] react at 40℃ for 24 hours.

[0147] f. Separation yield.

[0148] It should be noted that in reaction number 7 in Table 1, the volume ratio of petroleum ether to ethyl acetate as eluent was 10:1 when determining the separation yield.

[0149] In addition, unless otherwise specified, the processes used in this invention are all existing processes. For example, vacuum concentration, rapid silica gel column chromatography, elution, etc., all employ existing processes.

[0150] The reaction equation for this embodiment is as follows:

[0151]

[0152] Example 2

[0153] This embodiment is basically the same as embodiment number 7 in Embodiment 1, except that the reaction temperature is 70°C, the reaction time is 5 hours, and the product 3a is... 1 The H NMR yield was 57%.

[0154] Example 3

[0155] This embodiment is basically the same as embodiment number 7 in Embodiment 1, except that the reaction temperature is 120°C, the reaction time is 3 hours, and the product 3a is... 1 The H NMR yield was 55%.

[0156] Comparative Example 1

[0157] This comparative example is basically the same as example number 7 in Example 1, except that the reaction temperature is 65°C, the reaction time is 5 hours, and the product 3a... 1 The H NMR yield was 26%.

[0158] Example 3-1

[0159] This embodiment is basically the same as embodiment number 7 in Embodiment 1, except that the base used is N,N-diisopropylethylamine (DIPEA), and the product 3a... 1 The H NMR yield was 43%.

[0160] Example 4

[0161] In this embodiment, the molar ratio of 1a to 2a was 1:2, and the amount of 1a was 0.2 mmol, the amount of 2a was 0.4 mmol (2 equivalents), the organic solvent used was chloroform (1.0 mL), the amount of KH₂PO₄ was 1 mmol (5 equivalents), the amount of Et₃N was 0.6 mmol (3 equivalents), the reaction temperature was 80 °C, and the reaction time was 4 hours. After the reaction was completed, the reaction mixture was concentrated under vacuum. The yield was the separation yield. When determining the separation yield, the volume ratio of petroleum ether to ethyl acetate was 10:1.

[0162] In addition, unless otherwise specified, the processes used in this invention are all existing processes. For example, vacuum concentration, rapid silica gel column chromatography, elution, etc., all employ existing processes.

[0163] The reaction equation for this embodiment is as follows:

[0164]

[0165] This example expands the substrate scope of α-ester phosphorus ylide reagents (Table 2). Some long-chain α-ester phosphorus ylide reagents can yield indolemaleimide derivatives in good yields, product 3: 1-methyl-3-(1-methylindole-3-yl)pyrrole-2,5-dione (3b-3d). Notably, when using α-cyclic lactone phosphorus ylide reagents as nucleophiles, the CO bond breaks, and the ring-opening product (3e) is obtained in 43% yield. The structural formula 2c of the α-cyclic lactone phosphorus ylide reagent is as follows:

[0166]

[0167] Table 2. Reaction of different indoleacetamides with different α-esterified phosphorus ylide reagents

[0168]

[0169] Note: The phosphorus ylidene reagent of the synthesized product 3e is not an α-ester phosphorus ylidene reagent, but an α-cyclic lactone phosphorus ylidene reagent with the structural formula 2c. The yields in the table refer to the separation yields.

[0170] Example 5

[0171] In this embodiment, indoleacetamide with structural formula 1 (i.e., the structure when R1 is hydrogen in structural formula 1a) and α-acetylphenylphosphine ylide reagent with structural formula 2b are used. The molar ratio of 1 to 2b is 3:2 (numbers 1-5, 10-12) or 1:2 (numbers 6-9), and in numbers 1-5 and 10-12, the amount of 1 is 0.3 mmol (1.5 equivalents) and the amount of 2b is 0.2 mmol (1 equivalent); in numbers 6-9, the amount of 1 is 0.1 mmol (1.5 equivalents) and the amount of 2b is 0.2 mmol (1 equivalent). The organic solvent used was tetrahydrofuran (2.0 mL), the additive was ZnCl2 (0.4 mmol, 2 equivalents), and the additive was Et3N (0.6 mmol, 3 equivalents). The reaction temperature was 80 °C, and the reaction time was 10 hours (the reaction time for item 5 in Table 3 was 14 hours). After the reaction was complete, the reaction mixture was concentrated under vacuum. The yield was the separation yield. The eluent for determining the separation yield was petroleum ether:ethyl acetate at a volume ratio of 10:1.

[0172] In addition, unless otherwise specified, the processes used in this invention are all existing processes. For example, vacuum concentration, rapid silica gel column chromatography, elution, etc., all employ existing processes.

[0173] The reaction equation for this embodiment is as follows:

[0174]

[0175] Table 3. Reaction patterns of different α-acetylphenylphosphine ylide reagents

[0176]

[0177] Note: The phosphorus ylide reagent for synthesized product 4j is obtained by replacing the phenyl group in structural formula 2b with a naphthyl group. Yields in the table refer to separation yields.

[0178] Experimental results show that when the phenyl group in general formula 2b is replaced with a naphthyl group (i.e., a phosphorus ylide reagent containing a naphthyl ring), the preparation method of this invention can also successfully react to obtain the corresponding indolemaleimide derivative, the structural formula of which is shown in 4j (yield 68%). Therefore, various halogens (fluorine (4b), chlorine (4c), bromine (4d), iodine (4e)) and various electron-withdrawing groups (phenyl (4f), trifluoromethyl (4g), nitro (4h), cyano (4i), and naphthyl (4j)) are well compatible in the reaction system and successfully generate the corresponding cycloaddition products. When an electron-donating group (methoxy and methyl) is introduced at the para position of the benzene ring, its reactivity is better than that of the introduction of an electron-withdrawing group (4k-4l).

[0179] Depend on Figures 1-2It can be confirmed that the preparation method of the present invention yields the expected product 1-methyl-3-(1-methylindol-3-yl)pyrrole-2,5-dione (3a).

[0180] Depend on Figures 3-4 It can be confirmed that the product obtained by the preparation method of the present invention is the expected product 5-hydroxy-5-phenyl-1-methyl-3-(1-methylindol-3-yl)pyrrole-2-one (4a).

[0181] Specifically, 4a was a white solid (42 mg, 66% yield) with Rf = 0.44 (PE:EA = 2:1).

[0182] Figure 3 middle, 1 H NMR(500MHz, CDCl3)δ8.15(s,1H),7.62(d,J=7.9Hz,1H),7.47–7.45(m,2H),7.38–7.35(m,2H),7.34–7 .32(m,1H),7.19–7.14(m,2H),7.12–7.09(m,1H),7.00(s,1H),3.77(s,1H),3.57(s,3H),2.78(s,3H).

[0183] Figure 4 middle, 13 C NMR (126MHz, CDCl3) δ170.9,137.6,136.9,135.2,131.5,129.5,128.8,128.5,126.4,126.1,122.2,120.4,119.9,109.8,105.3,91.0,32.9,24.2.

[0184] in addition, Figures 5-43 The proton, carbon, and nuclear magnetic resonance fluorine spectra of other products synthesized in this invention confirm that the obtained products are the expected products.

[0185] Application Example 1

[0186] This application example tested the in vitro anticancer activity of some of the products synthesized in the embodiments.

[0187] Using cisplatin as a positive control, the in vitro anticancer activities of products 3 and 4 synthesized in this invention against human leukemia cells (K562) and prostate cancer cells (PC-3) were evaluated using the MTT assay (tetrazole salt reduction method). The inhibitory activity against tumor cell growth was expressed as IC50 (half-inhibitory concentration). The specific experimental results are shown in Tables 4 and 5, respectively.

[0188] The MTT assay is performed as follows: The target product is dissolved in a small amount of DMSO to prepare a solution of 10 mmol·L⁻¹. -1 The stock solution was diluted to the required concentration using RPMI 1640 culture medium (GIBICO, Invitrogen) containing 10% bovine fetal serum, to 50 μmol·L⁻¹. -1 10 μmol·L -1 1 μmol·L -1 0.1 μmol·L -1 10 nmol·L -1 0.1 nmol·L -1 The final DMSO concentration was kept below 0.1%. Human leukemia cells (K562) and prostate cancer cells (PC-3) were cultured in RPMI 1640 medium containing 10% bovine fetal serum at 37°C in an incubator with 5% CO2. Cell proliferation and growth inhibition were detected by the MTT assay. The number of experimental cells was adjusted to obtain an absorbance of 1.3–2.2 at 570 nm. The target product test solutions at the above 6 concentrations were used to treat cells for 72 h, with at least 3 parallel and 3 replicate experiments for each concentration. The IC50 value was determined by statistical analysis using GraphPadPrism 5.0 software.

[0189] Table 4. Anticancer activity of product 3 synthesized in this invention.

[0190]

[0191] Note: IC50 (half-inhibitory concentration) refers to the drug concentration required to inhibit 50% of cell growth. The lower the IC50 value, the stronger the drug activity.

[0192] As shown in Table 4, the IC50 of product 3 of the present invention against human leukemia cells (K562) is 11.2-26.1 μmol·L⁻¹. -1 The IC50 against prostate cancer cells (PC-3) was 16.1-26.2 μmol·L⁻¹. -1 This indicates that product 3 of the present invention has an inhibitory effect on the proliferation of both types of tumor cells. Among them, products 3b, 3c, 3d, 3f, 3g, and 3h have significantly better inhibitory activity against K562 than cisplatin, while the inhibitory activity of the remaining products is comparable to that of cisplatin. Product 3f has the strongest inhibitory activity against K562 (IC50 = 11.2 μmol·L⁻¹), which is 2.11 times that of cisplatin.

[0193] Table 4 also shows that products 3a, 3g, 3h, and 3f exhibited better inhibitory activity against PC-3 than cisplatin, while the inhibitory activity of the remaining products was comparable to that of cisplatin. Product 3g showed the strongest inhibitory activity against PC-3 (IC50 = 16.1 μmol·L⁻¹), which was 1.60 times that of cisplatin.

[0194] Table 5. Anticancer activity of product 4 synthesized in this invention.

[0195]

[0196]

[0197] Note: IC50 (half-inhibitory concentration) refers to the drug concentration required to inhibit 50% of cell growth. The lower the IC50 value, the stronger the drug activity.

[0198] As shown in Table 5, the IC50 of product 4 of this invention against human leukemia cells (K562) is 21.6-33.0 μmol·L⁻¹. -1 The IC50 against prostate cancer cells (PC-3) was 15.1-29.1 μmol·L⁻¹. -1 This indicates that product 4 of the present invention has an inhibitory effect on the proliferation of both types of tumor cells. The inhibitory activity of products 4b and 4g against K562 is comparable to that of cisplatin, while the inhibitory activity of the other products is slightly weaker than that of cisplatin.

[0199] Table 5 also shows that products 4b, 4c, 4d, 4e, and 4g exhibited superior inhibitory activity against PC-3 compared to cisplatin, while the inhibitory activities of the remaining products were comparable to cisplatin. Product 4g showed the strongest inhibitory activity against PC-3 (IC50 = 15.1 μmol·L⁻¹). -1 It is 1.71 times that of cisplatin.

[0200] In summary, the products synthesized in this invention, 3: 1-methyl-3-(1-methylindol-3-yl)pyrrole-2,5-dione and 4: 5-hydroxy-5-phenyl-1-methyl-3-(1-methylindol-3-yl)pyrrole-2-one, are both compounds with anticancer activity.

[0201] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An indolemaleimide derivative, characterized in that, It has the following structure: ； ； 。 2. A method for preparing an indolmaleimide derivative, characterized by, The derivative of claim 1 is prepared by adding indole acetamide and nucleophile into a mixed solution, reacting to obtain indole maleimide derivative; The indole acetamide has the structure shown in formula 1a: 1a In the formula, R1 is selected from an electron-donating functional group or an electron-withdrawing functional group, the electron-donating functional group is selected from hydrogen, and the electron-withdrawing functional group is selected from any one of fluorine, chlorine, and bromine; The nucleophile is a phosphorus ylide reagent, including one of an α-ester phosphorus ylide reagent and an α-acetylphenyl phosphorus ylide reagent; When the nucleophile is the α-ester phosphorus ylide reagent, it has the structure shown in formula 2a: 2a In the formula, R2 is selected from any one of hydrogen, methyl, ethyl, and n-propyl; When the nucleophile is the α-acetylphenyl phosphorus ylide reagent, it has the structure shown in formula 2b: 2b In the formula, R is selected from an electron-donating functional group or an electron-withdrawing functional group, the electron-donating functional group is selected from any one of hydrogen, methoxy, and methyl, and the electron-withdrawing functional group is selected from any one of fluorine, chlorine, bromine, iodine, phenyl, trifluoromethyl, nitro, and cyano; The mixed solution includes a base, an additive, and an organic solvent; The additive is selected from one of dipotassium hydrogen phosphate (K2HPO4), potassium dihydrogen phosphate (KH2PO4), glacial acetic acid, 4-dimethylaminopyridine (DMAP), sodium carbonate, and zinc chloride (ZnCl2); The organic solvent is selected from one of tetrahydrofuran (THF), acetonitrile (MeCN), 1,4-dioxane, and chloroform.

3. Use of the indole maleimide derivative of claim 1 in the preparation of a drug for resisting human leukemia cell K562 and prostate cancer cell PC-3.

Images