Symmetrical and asymmetric indole [2, 3-a] carbazole synthesized by using 2-indolone as raw material

Abstract

In the presence of an acidic reagent and an oxidizing agent, 2-indolone and indole are used as raw materials for one-step reaction to prepare the symmetric and asymmetric indole [2, 3-a] carbazole derivatives, the used raw materials, the acidic reagent and the oxidizing agent are cheap and easy to obtain, the reaction system is simple, the operation is simple, and the reaction steps are short (one-step reaction); the method has the advantages of wide substrate applicability, good functional group compatibility, mild reaction conditions, fast reaction speed, good chemical selectivity, realization of industrial production, and substantial economic and social benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of drug synthesis and chemical product synthesis, and particularly relates to a method for synthesizing symmetrical and asymmetrical indole [2,3-a] carbazole derivatives by direct reaction under acidic oxidation conditions using indole and 2-indole ketone as raw materials. Background Art

[0002] Indole[2,3-a]carbazole is a key skeleton of many natural products and drugs, and its derivatives often have biological activities such as anticancer, antibacterial, and antihypertensive. In addition, the indolecarbazole skeleton has been widely used as a component of organic light-emitting diodes, organic field-effect transistors, and various sensors due to its advantages such as good planarity, wide bandgap, excellent luminescence efficiency, and strong hydrogen bonding activity. In view of the wide range of uses of indole[2,3-a]carbazole derivatives, the study of their synthesis methods is of great significance. There are four main traditional methods for the preparation of indole[2,3-a]carbazole: the double Fischer indole synthesis method, the Cadogan cyclization method, the cycloaromatization method, and the oxidative coupling method. The common disadvantages of these methods are cumbersome synthesis steps, low overall yield, narrow substrate range, limited product types, and the need for precious metal catalysts in most cases. Summary of the invention

[0003] The object of the present invention is to provide a method for preparing symmetrical and asymmetrical indole [2,3-a] carbazole derivatives by using indole and 2-indolone as raw materials in a one-step reaction under acidic oxidation conditions. The purpose of the present invention can be achieved by the following technical solutions: A method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles using 2-indoleone as a raw material, characterized in that: in the presence of an acidic reagent and an oxidant, 2-indoleone represented by general formula (I) and indole represented by general formula (II) are used as raw materials for a one-step reaction to prepare an indole[2,3-a]carbazole derivative represented by general formula (III), wherein the chemical reaction formula (A) is as follows: Among them, R 1 is hydrogen or C 1 -C 4 Alkyl; R 2 C 1 -C 4 Alkyl, R 3 C 1 -C 4 Alkyl; or R 2 With R 3 Together they form (CH 2) 4 Chain; R 4 Selected from hydrogen, C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy, halogen or benzyloxy; R 5 Selected from hydrogen, C 1 -C 4 Alkyl or benzyl; the reaction is carried out in a solvent; the reaction temperature is 0-100°C. Preferably, R 1 is hydrogen, methyl or ethyl; R 2 is methyl, R 3 is methyl; or R 2 With R 3 Together they form (CH 2 ) 4 chain; R 4 is selected from hydrogen, methyl, ethyl, methoxy, ethoxy, halogen or benzyloxy; R 5 is selected from hydrogen, methyl or benzyl. The acidic reagent is selected from hydrogen chloride or acetic acid; the oxidant is selected from DDQ, ferric chloride or copper sulfate; the solvent is methanol or ethanol, and the reaction temperature is 0-80°C; the molar ratio of 2-indolone represented by general formula (I), indole represented by general formula (II) and the oxidant is 1:(0.8-1.2):(0.8-1.2), more preferably, the molar ratio of 2-indolone represented by general formula (I), indole represented by general formula (II) and the oxidant is 1:(0.9-1.1):(0.9-1.1). In the above method for synthesizing indole[2,3-a]carbazole, the acidic reagent, solvent and oxidant conditions are selected from: condition (A): ethanol solution saturated with hydrogen chloride gas and copper sulfate; condition (B): CH 3 COOH, ethanol, and ferric chloride; Condition (C): ethanol solution saturated with hydrogen chloride gas and DDQ. In the above-mentioned method for synthesizing indole [2,3-a] carbazole, the operation steps are: adding an acidic reagent, a solvent, an oxidant, 2-indolone represented by general formula (I) and indole represented by general formula (II) into a reactor in a certain order, reacting the obtained mixed solution at room temperature or under heating under stirring, and after the reaction is completed, separating and purifying to obtain the indole [2,3-a] carbazole derivative represented by general formula (III). More preferably, the operation steps are selected from: Step (A): adding 2-indolone represented by the general formula (I) and an ethanol solution saturated with hydrogen chloride gas to a reactor, stirring at room temperature for a certain period of time, then adding indole represented by the general formula (II) and copper sulfate, and continuing to react at room temperature or under heating and stirring; Step (B): adding 2-indolone represented by the general formula (I), acetic acid, ethanol, ferric chloride and indole represented by the general formula (II) to a reactor, and reacting the reaction mixture at room temperature or under heating and stirring; Or step (C): add an ethanol solution saturated with hydrogen chloride gas, the indole of the general formula (II), the 2-indolone of the general formula (I), and DDQ into a reactor, and react the reaction mixture at room temperature or under heating and stirring. In the above method for synthesizing indole[2,3-a]carbazole, preferably, the stirring time of the mixed solution of 2-indolone and ethanol solution saturated with hydrogen chloride gas in step (A) is 0.5 h. In the above-mentioned method for synthesizing indole[2,3-a]carbazole, in its operating steps, the reaction process is monitored by TLC, after the reaction is completed, the solvent is removed by vacuum rotary evaporation, a saturated sodium bicarbonate aqueous solution is added, and the mixture is extracted with ethyl acetate and dichloromethane in turn, the extracts are mixed, dried over anhydrous sodium sulfate, filtered, concentrated, and finally separated and purified by column chromatography to obtain the indole[2,3-a]carbazole derivatives represented by general formula (III). In summary, the technical solution of the present invention has the following beneficial effects: The above-mentioned method for synthesizing symmetrical and asymmetrical indole [2,3-a] carbazoles has the advantages that the raw materials, acidic reagents and oxidants used are cheap and easily available, the reaction system is simple, the operation is simple, and the reaction steps are short (one-step reaction); the substrates have wide applicability and good functional group compatibility, the reaction conditions are mild (most of them can be reacted at room temperature or 50° C.), the reaction speed is fast, the chemical selectivity is good, and the industrial production of symmetrical and asymmetrical indole [2,3-a] carbazole derivatives can be realized, which has significant economic and social benefits. DETAILED DESCRIPTION The present invention is described in detail by the following examples, but the present invention is not limited to the examples. Example 1: Synthesis of 13-methyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIa In 10mL reaction tube, add 2-indole ketone Ia (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution, stir at room temperature for 0.5 hour.Then add indole IIa (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC in the reaction process. After the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIa as a light red solid with a productive rate of 71%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.46(s,1H),8.22(d,J=7.9Hz,2H),7.70(t,J=8.4Hz,2H),7.52–7.38( m,2H),7.29–7.15(m,2H),4.35(s,3H),3.40(d,J=5.4Hz,4H),2.03(s,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ140.75,140.47,126.07,124.34,124.29,124.05,123.97,123.94,123.20,122.55,122.48,12 0.08,119.23,119.13,118.68,111.86,109.43,32.15,28.43,28.41,23.24; HRMS(ESI)m / z:[M+H] + Calculate for C 23 H 21 N 2 :325.1699;Found:325.1703. Example 2: Synthesis of 1-methyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIb In 10mL reaction tube, add 2-indolone Ia (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution, stir at room temperature for 0.5 hour.Then add indole IIb (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC in the reaction process. When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIa as a light yellow solid with a productive rate of 69%. 1 H NMR (600 MHz, DMSO-d 6 )δ10.90(s,1H),10.83(s,1H),8.17(d,J=7.9Hz,1H),8.02(d,J=7.9Hz,1H),7.71(d,J=8.0Hz,1H),7.37(t, J=7.5Hz,1H),7.19(t,J=7.6Hz,2H),7.11(t,J=7.5Hz,1H),3.39(d,J=5.7Hz,4H),2.64(s,3H),2.03(s,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ139.36,138.82,124.79,124.56,124.24,124.14,122.89,122.39,120.15,11 9.34,119.19,118.64,111.77,28.31,28.22,23.27,17.41; HRMS(ESI)m / z:[M+H] + Calculate for C 23 H 21 N 2 :325.1699;Found:325.1705. Example 3: Synthesis of 2-methyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIc In 10mL reaction tube, add 2-indolone Ia (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution, stir at room temperature for 0.5 hour.Then add indole IIc (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC during the reaction. When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIc as a white solid with a productive rate of 68%. 1 H NMR (600 MHz, DMSO-d 6)δ10.96(s,1H),10.84(s,1H),8.17(d,J=7.9Hz,1H),8.04(d,J=8.1Hz,1H),7.67(d,J=8.0Hz,1H),7.48(s,1H ),7.36(t,J=7.5Hz,1H),7.18(t,J=7.2Hz,1H),7.02(d,J=7.9Hz,1H),3.36(s,4H),2.51(s,3H),2.03(s,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ140.08,139.56,133.59,124.61,124.40,124.09,122.71,122.58,122.40,122.34,122.11 ,120.76,119.12,119.02,118.58,111.74,111.68,28.29,23.30,22.01; HRMS(ESI)m / z:[M+H] + Calculate for C 23 H 21 N 2 :325.1699;Found:325.1694. Example 4: Synthesis of 3-methyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIId In 10mL reaction tube, add 2-indolone Ia (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution, stir at room temperature for 0.5 hour.Then add indole IId (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC in the reaction process.When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate.Finally, separate and purify by column chromatography to obtain IIId as a white solid with a productive rate of 71%. 1 H NMR (600 MHz, DMSO-d 6 )δ10.96(s,1H),10.83(s,1H),8.16(d,J=7.9Hz,1H),7.98(s,1H),7.67(d,J=8.0Hz,1H),7. 57(d,J=8.1Hz,1H),7.36(s,1H),7.20–7.18(m,2H),3.39(s,4H),2.51(s,3H),2.03(s,4H);13 C NMR (151 MHz, DMSO-d 6 )δ139.57,137.90,127.59,125.51,124.80,124.64,124.61,124.40,124.10,122.89,122.58,122.3 8,122.33,119.12,118.75,111.73,111.45,28.38,28.32,23.30,23.28,21.91; HRMS(ESI)m / z:[M+H] + Calculate for C 23 H 21 N 2 :325.1699;Found:325.1701. Example 5: Synthesis of 2-methoxy-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIe In a 10mL reaction tube, add 2-indolone Ia (0.3mmol) and 2mL of ethanol solution saturated with hydrogen chloride gas, and stir at room temperature for 0.5 hour. Then add indole IIe (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and continuously monitor the reaction with TLC during the reaction. When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL of saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIe as a white solid with a yield of 61%. 1 H NMR (600 MHz, DMSO-d 6 )δ10.97(s,1H),10.82(s,1H),8.15(d,J=7.9Hz,1H),8.02(d,J=8.7Hz,1H),7.66(d,J=8.0Hz,1H),7.35(t,J=7.6Hz, 1H),7.23(d,J=2.3Hz,1H),7.18(t,J=7.5Hz,1H),6.82(dd,J=8.6,2.3Hz,1H),3.88(s,3H),3.38(s,4H),2.03(s,4H); 13 C NMR (151 MHz, DMSO-d 6)δ157.70,140.97,139.55,124.64,124.36,123.98,123.85,123.00,122.27,119.0 8,118.60,111.60,108.29,95.54,55.75,28.29,28.21,23.28; HRMS(ESI)m / z:[M+H] + Calculate for C 23 H 21 N 2 O:341.1648;Found:341.1642. Example 6: Synthesis of 3-methoxy-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIf In 10mL reaction tube, add 2-indolone Ia (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution, stir at room temperature for 0.5 hour.Then add indole IIf (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC during the reaction. When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIf as a white solid with a productive rate of 65%. 1 H NMR (600 MHz, DMSO-d 6 )δ10.99(s,1H),10.78(s,1H),8.16(d,J=7.9Hz,1H),7.73–7.64(m,2H),7.59(d,J=8.7Hz,1H),7.43–7. 31(m,1H),7.23–7.11(m,1H),7.03(dd,J=8.7,2.4Hz,1H),3.87(s,3H),3.47–3.35(m,4H),2.03(s,4H); 13 CNMR (151MHz, DMSO-d 6 )δ153.41,139.56,134.63,125.28,124.93,124.60,124.42,124.10,122.82,122.44,122.38,119.14,11 8.93,118.79,113.07,112.25,111.75,105.70,56.13,28.32,28.12,23.31,23.27; HRMS(ESI)m / z:[M+H] +Calculate for C 23 H 21 N 2 O:341.1648;Found:341.1653. Example 7: Synthesis of 3-iodo-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIg In 10mL reaction tube, add 2-indolone Ia (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution, stir at room temperature for 0.5 hour.Then add indole IIg (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC in the reaction process. When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIg as a yellow solid, with a productive rate of 30%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.19(s,1H),11.06(s,1H),8.44(d,J=1.3Hz,1H),8.18(d,J=8.0Hz,1H),7.69(d,J=8.0Hz,1H),7.64(dd,J=8.4,1.6 Hz,1H),7.58(d,J=8.4Hz,1H),7.38(dd,J=8.0,1.0Hz,1H),7.20(d,J=7.1Hz,1H),3.45-3.32(m,4H),2.09-1.92(m,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ139.68,138.68,132.09,130.35,127.16,124.62,124.49,124.35,124.06,123.48,122.99,122.88,12 2.53,119.46,119.34,117.68,114.27,111.84,82.25,28.26,28.19,23.14,23.10; HRMS(ESI)m / z:[M+H] + Calculate for C 22 H 18 IN 2 :437.0509;Found:437.0504. Example 8: Synthesis of 3-benzyloxy-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIh In 10mL reaction tube, add 2-indolone Ia (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution, stir at room temperature for 0.5 hour.Then add indole IIh (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC in the reaction process. When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIh as a white solid with a productive rate of 65%. 1 H NMR (600 MHz, DMSO-d 6 )δ10.99(s,1H),10.79(s,1H),8.16(d,J=7.9Hz,1H),7.75(d,J=2.4Hz,1H ),7.67(d,J=8.0Hz,1H),7.59(d,J=8.7Hz,1H),7.54(dd,J=7.9,0.8Hz,2H ),7.42(dd,J=10.7,4.4Hz,2H),7.39–7.31(m,2H),7.21–7.15(m,1H),7.1 1(dd,J=8.7,2.4Hz,1H),5.22(s,2H),3.36(d,J=15.2Hz,4H),2.02(s,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ152.38,139.53,138.33,134.75,128.84,128.22,128.13,124.86,124.56,124.38,124.11,122.78,122.45,12 2.38,119.14,118.87,118.80,113.84,112.19,111.74,107.36,70.71,28.30,28.12,23.27; HRMS(ESI)m / z:[M+H] + Calculate for C 29 H 25 N 2 O:417.1961;Found:417.1965. Example 9: Synthesis of 13-benzyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIi In a 10mL reaction tube, add 2-indolone Ia (0.3mmol) and 2mL of ethanol solution saturated with hydrogen chloride gas, and stir at room temperature for 0.5 hour. Then add indole IIi (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and continuously monitor the reaction with TLC during the reaction. When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL of saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIi as a white solid with a yield of 64%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.39(s,1H),8.23(dd,J=14.6,8.0Hz,2H),7.63(dd,J=16.2,8.1Hz,2H),7.37( dd,J=11.4,4.1Hz,2H),7.29–7.01(m,7H),6.13(s,2H),3.42(s,4H),2.05(s,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ140.40,139.03,128.98,127.56,127.01,125.58,124.52,123.88,123.70,123.42,122.76,122 .54,120.45,119.62,119.36,119.19,111.82,110.23,47.62,28.47,23.22; HRMS(ESI)m / z:[M+H] + Calculate for C 29 H 25 N 2 :401.2012;Found:401.2016. Example 10: Synthesis of 1,13-dimethyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIj In a 10mL reaction tube, add 2-indolone Ib (0.3mmol) and 2mL of ethanol solution saturated with hydrogen chloride gas, and stir at room temperature for 0.5 hour. Then add indole IIb (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC during the reaction. When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL of saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIj as a light yellow solid with a yield of 71%. 1 H NMR (600 MHz, DMSO-d 6 )δ10.47(s,1H),8.21(d,J=7.9Hz,1H),8.06(d,J=7.9Hz,1H),7.69(d,J=8.2Hz,1H),7.52–7.38( m,1H),7.29–7.19(m,2H),7.18–7.07(m,1H),4.38(s,3H),3.39(s,4H),2.72(s,3H),2.03(s,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ141.03,139.97,126.57,125.43,124.59,124.40,124.34,124.01,123.76,123.18,122.56,121.35,121.2 4,120.14,119.85,119.22,118.87,109.58,32.37,28.47,28.40,23.23,23.18,17.99; HRMS(ESI)m / z:[M+H] + Calculate for C 24 H 23 N 2 :339.1856;Found:339.1859. Example 11: Synthesis of 3,13-dimethyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIk 2-Indole ketone Ib (0.3mmol) and 2mL ethanol solution saturated with hydrogen chloride gas were added to a 10mL reaction tube and stirred at room temperature for 0.5 hour. Then indole IId (0.3mmol) and copper sulfate (0.3mmol) were added, stirring at room temperature was continued, and the reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL saturated sodium bicarbonate aqueous solution was added, and ethyl acetate and dichloromethane were successively extracted. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIk was separated and purified by column chromatography to obtain a light yellow solid with a yield of 70%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.30(s,1H),8.20(d,J=7.9Hz,1H),8.01(s,1H),7.68(d,J=8.2Hz,1H),7.57(d,J=8.1Hz,1H),7.51–7.36( m,1H),7.22(ddd,J=8.8,5.3,0.9Hz,2H),4.33(s,3H),3.39(dd,J=6.0,3.1Hz,4H),2.51(s,3H),2.03(s,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ140.73,138.78,127.66,126.12,125.72,124.36,124.21,123.97,123.24,122.94,122.51,122.37,1 19.94,119.10,118.53,111.55,109.41,32.12,28.49,28.42,23.25,23.24,21.95; HRMS(ESI)m / z:[M+H] + Calculate for C 24 H 23 N 2 :339.1856;Found:339.1860. Example 12: Synthesis of 3-iodo-13-methyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIl Add 2-indolone Ib (0.3mmol) and 2mL ethanol solution saturated with hydrogen chloride gas into 10mL reaction tube, stir at room temperature for 0.5 hour. Then add indole IIg (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC during the reaction. When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain III1 as a white solid with a yield of 26%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.62(s,1H),8.48(d,J=1.4Hz,1H),8.22(d,J=7.9Hz,1H),7.70(d,J=8.2Hz,1H),7.66(dd,J=8.4,1.6Hz,1 H),7.55(d,J=8.4Hz,1H),7.49–7.43(m,1H),7.26–7.19(m,1H),4.33(s,3H),3.42–3.32(m,5H),2.03(s,5H); 13 C NMR (151 MHz, DMSO-d 6 )δ140.75,139.46,132.23,130.42,126.57,125.76,124.51,124.28,123.73,123.16,122.65,119.2 3,119.17,118.77,114.27,109.50,82.37,32.11,28.35,28.29,23.11,23.07; HRMS(ESI)m / z:[M+H] + Calculate for C 23 H 20 IN 2 :451.0666;Found:451.0671. Example 13: Synthesis of 3-methoxy-13-methyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIm In 10mL reaction tube, add 2-indolone Ib (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution, stir at room temperature for 0.5 hour.Then add indole IIf (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC during the reaction.When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate.Finally, separate and purify by column chromatography to obtain IIIm as a light yellow solid with a productive rate of 63%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.24(s,1H),8.20(d,J=7.9Hz,1H),7.69(dd,J=10.5,5.3Hz,2H),7.58(d,J=8.7Hz,1H),7.47–7.39(m,1H), 7.25–7.18(m,1H),7.06(dd,J=8.7,2.4Hz,1H),4.32(s,3H),3.88(s,3H),3.39(d,J=18.5Hz,4H),2.03(s,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ153.41,140.67,135.45,126.10,124.95,124.30,124.22,123.93,123.16,122.79,122.51,120.09,119.1 2,118.54,113.38,112.35,109.42,105.59,56.09,32.10,28.41,28.21,23.26,23.21; HRMS(ESI)m / z:[M+H] + Calculate for C 24 H 23 N 2 O:355.1805;Found:355.1811. Example 14: Synthesis of 3-benzyloxy-13-methyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIn Add 2-indolone Ib (0.3mmol) and 2mL ethanol solution saturated with hydrogen chloride gas to a 10mL reaction tube and stir at room temperature for 0.5 hour. Then add indole IIh (0.3mmol) and copper sulfate (0.3mmol), continue stirring at room temperature, and continuously monitor the reaction with TLC during the reaction. When the reaction is complete, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIn as a white solid with a yield of 60%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.27(s,1H),8.20(d,J=7.9Hz,1H),7.79(d,J=2.3Hz,1H),7.68(d,J=8.2Hz,1H),7.60(d,J=8.7Hz,1H),7.55(dd,J=7.9,0.8Hz,2H),7.43(dd, J=12.0,4.5Hz,3H),7.36(d,J=7.4Hz,1H),7.22(s,1H),7.15(dd,J=8.7, 2.4Hz,1H),5.23(s,2H),4.32(s,3H),3.37(d,J=4.0Hz,3H),2.03(s,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ152.44,140.68,138.32,135.61,128.85,128.24,128.15,126.09,124.96,124.26,124.22,123.94,123.13,122.82,122.5 1,120.06,119.11,118.58,114.12,112.29,109.41,107.28,70.70,32.10,28.40,28.23,23.24,23.22; HRMS(ESI)m / z:[M+H] + calcdfor C 30 H 27 N 2 O:431.2118;Found:431.2122. Example 15: Synthesis of 13-ethyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIo 2-Indole ketone Ic (0.3mmol) and 2mL ethanol solution saturated with hydrogen chloride gas were added to a 10mL reaction tube and stirred at room temperature for 0.5 hour. Then indole IIj (0.3mmol) and copper sulfate (0.3mmol) were added, stirring at room temperature was continued, and the reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL saturated sodium bicarbonate aqueous solution was added, and ethyl acetate and dichloromethane were successively extracted. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIo was separated and purified by column chromatography to obtain a light yellow solid with a yield of 62%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.35(s,1H),8.23(dd,J=7.8,5.0Hz,2H),7.71(d,J=8.1Hz,2H),7.43(d,J=23.9Hz,2H),7.2 8–7.16(m,2H),4.90(d,J=7.1Hz,2H),3.41(d,J=5.2Hz,4H),2.04(s,4H),1.36(t,J=7.1Hz,3H); 13 C NMR (151 MHz, DMSO-d 6 )δ140.48,139.78,124.86,124.35,124.30,123.93,123.68,123.31,123.28,122.74,122.49 ,120.06,119.27,119.22,119.10,111.89,109.41,28.46,23.24,15.93; HRMS(ESI)m / z:[M+H] + calcdfor C 24 H 23 N 2 :339.1856;Found:339.1850. Example 16: Synthesis of 2-methyl-13-ethyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIp 2-Indole ketone Ic (0.3mmol) and 2mL of ethanol solution saturated with hydrogen chloride gas were added to a 10mL reaction tube and stirred at room temperature for 0.5 hours. Then indole IIc (0.3mmol) and copper sulfate (0.3mmol) were added, stirring at room temperature was continued, and the reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL of saturated sodium bicarbonate aqueous solution was added, and the mixture was extracted with ethyl acetate and dichloromethane. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIp was separated and purified by column chromatography to obtain a white solid with a yield of 66%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.20(s,1H),8.21(d,J=7.9Hz,1H),8.07(d,J=8.1Hz,1H),7.69(d,J=8.2Hz,1H),7.50(s,1H),7.46–7.36(m,1H),7.29–7 .12(m,1H),7.03(dd,J=8.1,0.9Hz,1H),4.87(d,J=7.1Hz,2H),3.38(s,4H),2.52(s,3H),2.02(s,4H),1.35(t,J=7.2Hz,3H); 13 C NMR (151 MHz, DMSO-d 6 )δ141.02,139.79,133.65,125.00,124.42,124.19,123.50,123.18,123.01,122.63,122.16,121.85,120.8 6,120.25,119.14,118.82,111.87,109.30,39.14,28.45,23.28,23.24,22.08,15.83; HRMS(ESI)m / z:[M+H] + Calculate for C 25 H 25 N 2 :353.2012;Found:353.2003. Example 17: Synthesis of 3-methoxy-13-ethyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIq 2-Indole ketone Ic (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution were added to 10mL reaction tubes and stirred at room temperature for 0.5 hour. Then indole IIf (0.3mmol) and copper sulfate (0.3mmol) were added, stirring at room temperature was continued, and the reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL saturated sodium bicarbonate aqueous solution was added, and ethyl acetate and dichloromethane were successively extracted. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIq was separated and purified by column chromatography to obtain a light yellow solid with a yield of 61%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.14(s,1H),8.21(d,J=7.9Hz,1H),7.69(d,J=7.5Hz,2H),7.60(d,J=8.7Hz,1H),7.43(s,1H),7.22(d,J=7.6Hz,1H),7 .07(dd,J=8.7,2.3Hz,1H),4.86(d,J=7.1Hz,2H),3.88(s,3H),3.40(d,J=19.6Hz,4H),2.03(s,4H),1.35(t,J=7.1Hz,3H); 13 C NMR (151 MHz, DMSO-d 6 )δ153.42,139.70,135.45,124.90,124.55,124.27,123.23,122.88,122.69,120.07,119.20,118.9 7,113.38,112.39,109.38,105.60,56.11,28.46,28.24,23.26,23.22,15.96; HRMS(ESI)m / z:[M+H] + Calculate for C 25 H 25 N 2 O:369.1961;Found:369.1969. Example 18: Synthesis of 5,6,11-trimethyl-11,12-dihydroindole[2,3-a]carbazole IIIr 2-Indole ketone Id (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution were added to a 10mL reaction tube and stirred at room temperature for 0.5 hour. Then indole IIj (0.3mmol) and copper sulfate (0.3mmol) were added and heated with stirring. The reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL saturated sodium bicarbonate aqueous solution was added, and ethyl acetate and dichloromethane were successively extracted. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIr was separated and purified by column chromatography to obtain a white solid with a yield of 60%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.44(s,1H),8.31(dd,J=7.9,4.0Hz,2H),7.77–7.64(m,2H),7.47(ddd,J=8.1,7.1,1.1Hz,1 H),7.41(ddd,J=8.1,7.1,1.0Hz,1H),7.33–7.07(m,2H),4.35(s,3H),2.92(s,3H),2.91(s,3H); 13 C NMR (151 MHz, DMSO-d 6 )δ140.86,140.58,126.09,124.42,124.39,124.11,122.45,122.39,121.61,120.78 ,119.38,119.23,119.14,111.90,109.46,32.15,16.57,16.56; HRMS(ESI)m / z:[M+H] + Calculate for C 21 H 19 N 2 :299.1543;Found:299.1548. Example 19: Synthesis of 1,5,6,11-tetramethyl-11,12-dihydroindole[2,3-a]carbazole IIIs 2-Indole ketone Id (0.3mmol) and 2mL of ethanol solution saturated with hydrogen chloride gas were added to a 10mL reaction tube and stirred at room temperature for 0.5 hour. Then indole IIb (0.3mmol) and copper sulfate (0.3mmol) were added and heated with stirring. The reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL of saturated sodium bicarbonate aqueous solution was added, and the mixture was extracted with ethyl acetate and dichloromethane. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIs was separated and purified by column chromatography to obtain a white solid with a yield of 59%. 1 H NMR (600 MHz, DMSO-d 6 )δ10.44(s,1H),8.31(d,J=7.9Hz,1H),8.15(d,J=7.9Hz,1H),7.70(d,J=8.2Hz,1H),7.47(s,1H),7.2 4(dd,J=16.9,7.4Hz,2H),7.17(d,J=7.8Hz,1H),4.38(s,3H),2.91(s,3H),2.91(s,3H),2.72(s,3H); 13 C NMR (151 MHz, DMSO-d 6 )δ141.14,140.09,126.58,125.50,124.68,124.59,124.45,124.18,122.46,122.21,121.96,121.60 ,121.40,120.04,119.88,119.58,119.23,109.59,32.33,17.95,16.59,16.51; HRMS(ESI)m / z:[M+H] + Calculate for C 22 H 21 N 2 :313.1699;Found:313.1692. Example 20: Synthesis of 3,5,6,11-tetramethyl-11,12-dihydroindole[2,3-a]carbazole IIIt 2-Indole ketone Id (0.3mmol) and 2mL of ethanol solution saturated with hydrogen chloride gas were added to a 10mL reaction tube and stirred at room temperature for 0.5 hour. Then indole IId (0.3mmol) and copper sulfate (0.3mmol) were added and heated with stirring. The reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL of saturated sodium bicarbonate aqueous solution was added, and the mixture was extracted with ethyl acetate and dichloromethane. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIt was separated and purified by column chromatography to obtain a white solid with a yield of 56%. 1 H NMR (600 MHz, DMSO-d 6)δ11.30(s,1H),8.29(d,J=7.9Hz,1H),8.10(s,1H),7.68(d,J=8.2Hz,1H),7.59(d,J=8.1Hz,1 H),7.51–7.38(m,1H),7.30–7.15(m,2H),4.32(s,3H),2.91(s,3H),2.89(s,3H),2.53(s,3H); 13 C NMR (151 MHz, DMSO-d 6 )δ140.82,138.88,127.65,126.13,125.79,124.40,124.34,124.32,124.12,122.41,122.25,121.63 ,121.34,120.64,119.23,119.10,111.61,109.41,32.09,21.99,16.60,16.54; HRMS(ESI)m / z:[M+H] + Calculate for C 22 H 21 N 2 :313.1699;Found:313.1706. Example 21: Synthesis of 3-methoxy-5,6,11-trimethyl-11,12-dihydroindole[2,3-a]carbazole IIIu 2-Indole ketone Id (0.3mmol) and 2mL of ethanol solution saturated with hydrogen chloride gas were added to a 10mL reaction tube and stirred at room temperature for 0.5 hour. Then indole IIf (0.3mmol) and copper sulfate (0.3mmol) were added and heated with stirring. The reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL of saturated sodium bicarbonate aqueous solution was added, and the mixture was extracted with ethyl acetate and dichloromethane. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIu was separated and purified by column chromatography to obtain a white solid with a yield of 61%. 1 H NMR (600 MHz, DMSO-d 6)δ11.22(s,1H),8.29(d,J=7.9Hz,1H),7.77(d,J=2.4Hz,1H),7.68(d,J=8.2Hz,1H),7.59(d,J=8.7Hz,1H),7.48– 7.41(m,1H),7.26–7.19(m,1H),7.08(dd,J=8.7,2.4Hz,1H),4.32(s,4H),3.89(s,4H),2.91(s,3H),2.89(s,3H); 13 C NMR (151 MHz, DMSO-d 6 )δ153.44,140.83,126.17,124.33,122.44,121.18,119.28,119.14,113.35 ,112.39,109.46,105.73,56.13,32.11,16.55,16.45; HRMS(ESI)m / z:[M+H] + Calculate for C 22 H 21 N 2 O:329.1648;Found:329.1657. Example 22: Synthesis of 2-methoxy-5,6,11-trimethyl-11,12-dihydroindole[2,3-a]carbazole IIIv 2-Indole ketone Id (0.3mmol) and 2mL of ethanol solution saturated with hydrogen chloride gas were added to a 10mL reaction tube and stirred at room temperature for 0.5 hours. Then indole IIe (0.3mmol) and copper sulfate (0.3mmol) were added and heated with stirring. The reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL of saturated sodium bicarbonate aqueous solution was added, and the mixture was extracted with ethyl acetate and dichloromethane. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIv was separated and purified by column chromatography to obtain a white solid with a yield of 63%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.29(s,1H),8.30(d,J=7.9Hz,1H),8.10(s,1H),7.69(d,J=8.2Hz,1H),7.58(d,J=8.1Hz,1H),7.45(dd d,J=8.2,7.1,1.0Hz,1H),7.23(td,J=7.5,0.8Hz,2H),4.33(s,3H),2.91(s,3H),2.90(s,3H),2.53(s,3H);13 C NMR (151 MHz, DMSO-d 6 )δ140.83,138.88,127.64,125.79,124.41,124.34,124.13,122.42,122.26,121.63,12 1.34,120.64,119.10,111.61,109.43,32.12,22.00,16.61,16.56; HRMS(ESI)m / z:[M+H] + Calculate for C 22 H 21 N 2 O:329.1648;Found:329.1652. Example 23: Synthesis of 2-benzyloxy-5,6,11-trimethyl-11,12-dihydroindole[2,3-a]carbazole IIIw 2-Indole ketone Id (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution were added to a 10mL reaction tube and stirred at room temperature for 0.5 hour. Then indole IIh (0.3mmol) and copper sulfate (0.3mmol) were added and heated with stirring, and the reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL saturated sodium bicarbonate aqueous solution was added, and ethyl acetate and dichloromethane were successively extracted. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIw was separated and purified by column chromatography to obtain a white solid with a yield of 65%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.26(s,1H),8.30(d,J=8.0Hz,1H),7.86(d,J=2.4Hz,1H),7.68(d,J=8.2Hz,1H),7.60(d,J=8.7Hz,1H),7.55(dd,J=7.9,0.9Hz, 2H),7.48–7.40(m,3H),7.35(s,1H),7.23(s,1H),7.16(dd,J=8.7,2.4Hz,1H),5.24(s,2H),4.32(s,3H),2.89(s,3H),2.87(s,3H); 13 C NMR (151 MHz, DMSO-d 6)δ152.45,140.87,138.34,135.82,128.84,128.18,128.12,126.19,125.10,124.49,124.33,124.16,122.42,121.55 ,121.24,120.83,119.35,119.13,114.22,112.34,109.43,107.44,70.82,32.10,16.50,16.39; HRMS(ESI)m / z:[M+H] + Calculate for C 28 H 25 N 2 O:405.1961;Found:405.1967. Example 24: Synthesis of 5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIx 2-Indole ketone Ia (0.3mmol), acetic acid (1.0mmol), ethanol (2mL), ferric chloride (0.3mmol) and indole IIj (0.3mmol) were added to a 10mL two-necked flask connected to a reflux condenser. The reaction mixture was stirred at 50°C, and the reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10mL of saturated sodium bicarbonate aqueous solution was added, and the mixture was extracted with ethyl acetate and dichloromethane. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIx was separated and purified by column chromatography to obtain a white solid with a yield of 72%. 1 H NMR (600 MHz, DMSO-d 6 )δ11.00(s,2H),8.18(d,J=7.9Hz,2H),7.69(d,J=8.0Hz,2H),7.37(t,J=7.5Hz,2H),7.19(t,J=7.5Hz,2H),3.39(s,4H),2.04(s,4H); 13 CNMR (151MHz, DMSO-d 6 )δ139.60,124.57,124.35,124.18,122.85,122.42,119.17,118.90,111.78,28.32,23.28.MS(ESI)m / z:[M+H]+calcd for C22H19N2:311.1; Found:311.2. Example 25: Synthesis of 13,14-dimethyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIy To a 10 mL two-necked flask connected to a reflux condenser, add 2 mL of ethanol solution saturated with hydrogen chloride gas, indole IIa (0.3 mmol), 2-indolone Ib (0.4 mmol), and DDQ (0.3 mmol). The reaction mixture was stirred at 50 ° C, and the reaction was continuously monitored by TLC during the reaction. When the reaction was completed, the solvent was removed by vacuum rotary evaporation, 10 mL of saturated sodium bicarbonate aqueous solution was added, and extracted with ethyl acetate and dichloromethane. The mixed extracts were dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, IIIy was separated and purified by column chromatography to obtain a white solid with a yield of 50%. 1 H NMR (600 MHz, DMSO-d 6 )δ8.30(d,J=7.9Hz,2H),7.52(dd,J=11.8,7.2Hz,4H),7.31(t,J=7.3Hz,2H),4.14(s,6H),3.49(s,4H),2.11(s,4H); 13 C NMR (151 MHz, DMSO-d 6 )δ144.55,128.40,125.70,124.76,124.55,122.83,121.88,119.79,110.06,36.54,28.53,23.11; HRMS(ESI)m / z:[M+H]+calcd for C24H23N2:339.1856; Found:339.1849. Example 26: Synthesis of 13-methyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIa In 10mL reaction tube, add 2-indolone Ia (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution, stir at room temperature for 0.5 hour.Then add indole IIa (0.36mmol) and copper sulfate (0.36mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC in the reaction process. After the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate. Finally, separate and purify by column chromatography to obtain IIIa as a light red solid with a productive rate of 69%. Example 27: Synthesis of 1-methyl-5,6,7,8,13,14-hexahydrobenz[c]indole[2,3-a]carbazole IIIb In 10mL reaction tube, add 2-indolone Ia (0.3mmol) and 2mL hydrogen chloride gas saturated ethanol solution, stir at room temperature for 0.5 hour.Then add indole IIb (0.24mmol) and copper sulfate (0.24mmol), continue stirring at room temperature, and constantly monitor the reaction with TLC in the reaction process.When the reaction is completed, remove the solvent by vacuum rotary evaporation, add 10mL saturated sodium bicarbonate aqueous solution, and extract with ethyl acetate and dichloromethane successively. Mix the extracts, dry over anhydrous sodium sulfate, filter, and concentrate.Finally, by column chromatography separation and purification, obtain IIIa as a light yellow solid, with a productive rate of 65%.

Claims

1. A method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles using 2-indolone as a raw material, characterized in that: In the presence of an acidic reagent and an oxidant, the indole [2,3-a] carbazole derivatives represented by the general formula (III) are prepared by a one-step reaction using 2-indolone represented by the general formula (I) and indole represented by the general formula (II) as raw materials, and the chemical reaction formula (A) is as follows: Among them, R 1 is hydrogen or C1-C4 alkyl; R 2 is C1-C4 alkyl, R 3 is C1-C4 alkyl; or R 2 With R 3 Together they form a (CH2)4 chain; R 4 is selected from hydrogen, C1-C4 alkyl, C1-C4 alkoxy, halogen or benzyloxy; R 5 is selected from hydrogen, C1-C4 alkyl or benzyl; the reaction is carried out in a solvent; the reaction temperature is 0-100°C.

2. The method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles according to claim 1, characterized in that: R 1 For hydrogen, Methyl or ethyl; R 2 Methyl, R 3 is methyl; or R 2 With R 3 Together they form a (CH2)4 chain; R 4 is selected from hydrogen, methyl, ethyl, methoxy, ethoxy, iodine or benzyloxy; R 5 is selected from hydrogen, methyl or benzyl.

3. The method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles according to claim 1, characterized in that: The acidic reagent is selected from hydrogen chloride or acetic acid; the oxidant is selected from DDQ, ferric chloride or copper sulfate; the solvent is methanol or ethanol, and the reaction temperature is 0-80°C.

4. The method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles according to claim 1, characterized in that: The molar ratio of 2-indolone represented by general formula (I), indole represented by general formula (II) and the oxidant is 1:(0.8-1.2):(0.8-1.2).

5. The method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles according to claim 4, characterized in that: The molar ratio of 2-indolone represented by general formula (I), indole represented by general formula (II) and the oxidant is 1:(0.9-1.1):(0.9-1.1).

6. The method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles according to claim 1, characterized in that: The acidic reagent, solvent and oxidant conditions are selected from: condition (A): ethanol solution saturated with hydrogen chloride gas and copper sulfate; condition (B): CH3COOH, ethanol and ferric chloride; condition (C): ethanol solution saturated with hydrogen chloride gas and DDQ.

7. The method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles according to claim 1, characterized in that: The operation steps are as follows: adding the acidic reagent, solvent, oxidant, 2-indolone represented by general formula (I) and indole represented by general formula (II) into a reactor in a certain order, reacting the obtained mixed solution at room temperature or under heating under stirring, and after the reaction is completed, separating and purifying to obtain the indole [2,3-a] carbazole derivative represented by general formula (III).

8. The method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles according to claim 7, characterized in that: The operation steps are selected from: Step (A): adding 2-indolone represented by the general formula (I) and an ethanol solution saturated with hydrogen chloride gas to a reactor, stirring at room temperature for a certain period of time, then adding indole represented by the general formula (II) and copper sulfate, and continuing to react at room temperature or under heating and stirring; Step (B): adding 2-indolone represented by the general formula (I), acetic acid, ethanol, ferric chloride and indole represented by the general formula (II) to a reactor, and reacting the reaction mixture at room temperature or under heating and stirring; Or step (C): add an ethanol solution saturated with hydrogen chloride gas, the indole of the general formula (II), the 2-indolone of the general formula (I), and DDQ into a reactor, and react the reaction mixture at room temperature or under heating and stirring.

9. The method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles according to claim 8, characterized in that: The stirring time of the mixed solution of 2-indolone and ethanol solution saturated with hydrogen chloride gas in step (A) is 0.5 h.

10. The method for synthesizing symmetrical and asymmetrical indole[2,3-a]carbazoles according to claim 8, characterized in that: In the operation steps, the reaction process is monitored by TLC. After the reaction is completed, the solvent is removed by rotary evaporation under reduced pressure, a saturated sodium bicarbonate aqueous solution is added, and the mixture is extracted with ethyl acetate and dichloromethane in turn. The mixed extracts are dried over anhydrous sodium sulfate, filtered, and concentrated. Finally, the mixture is separated and purified by column chromatography to obtain an indole [2,3-a] carbazole derivative represented by the general formula (III).

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