Synthesis method of polysubstituted [1,2,3,4,5]pentathio[6,7-b]indole and its derivatives

Abstract

The present invention relates to a method for synthesizing polysubstituted [1,2,3,4,5]pentathio[6,7-b]indole and derivatives. The present invention adopts, for the first time, a technical solution for converting indole compounds and elemental sulfur into polysubstituted [1,2,3,4,5]pentathio[6,7-b]indole and derivatives in an air atmosphere by activating elemental sulfur with an organic base under the catalysis of an iodine compound and using a sulfoxide compound as a co-oxidant. The technical solution has the following advantages: (1) the required reagents are stable, do not require pretreatment, are cheap and readily available; (2) a one-pot synthesis method has a significant step economy advantage, saving time and labor; (3) no transition metal catalysis is required, thus fundamentally eliminating the problem of metal residue; (4) the use of inexpensive iodine compounds as catalysis reduces environmental pollution and saves reaction costs; (5) the entire reaction system is simple, has excellent selectivity, requires less reaction equipment, and is simple to operate; and (6) is particularly suitable for preparing bioactive molecules and drug molecules.

Description

Technical Field

[0001] The present invention relates to a method for synthesizing polysubstituted [1,2,3,4,5]pentathio[6,7-b]indole and derivatives thereof, belonging to the technical field of organic compound synthesis. Background Art

[0002] Polysubstituted [1,2,3,4,5]pentathio[6,7-b]indoles and their derivatives are an important subclass of indole compounds, and many bioactive molecules contain this polysulfidoindole structure. These molecules contain a "-S5-" bond and a seven-membered ring structure composed of "S5C2." This unique non-planar five-sulfur seven-membered ring structure gives [1,2,3,4,5]pentathio[6,7-b]indole compounds unique properties, as shown in Examples 1, 19, 25, and 26, demonstrating potential applications in medicine and lithium battery materials. (a)CRMAsquith,T.Laitinen,LSKonstantinova,G.Tizzard,A.Poso,OARakitin,STHilton,ChemMedChem,2019,14(4):454-461.DOI:10.1002 / cmdc.201800718;b) LSKonstantinova,OARakitin,CWRees,Chem.Commun.,2002,(11):1204-1205.DOI:10.1039 / b203349f and H.Tsutsumi,H.Higashiyama,K.Onimura,T.Oishi,Journal ofPower Sources 2005,146(2005):345–348.DOI:10.1016 / j.jpowsour.2005.03.015)

[0003] To date, the synthetic methods for polysubstituted [1,2,3,4,5]pentathia[6,7-b]indoles have the following disadvantages: (1) the use of chemically equivalent metallic lithium reagents to promote sulfurization, which requires multiple steps; (2) the difficulty in controlling the regioselectivity of the reaction; and (3) the use of highly toxic and malodorous sulfur chloride as a sulfur source. (Based on a)Gordon W Rewcastle,Tomasz Janosik,JanBergman.Tetrahedron 2001,57(33):7185-7189.DOI:10.1016 / S0040-4020(01)00660-3;b)S.Behnisch-Cornwell,SSMBandaru,M.Napierkowski,L.Wolff,M.Zubair,C.Urbains ky,PJBednarski.ChemMedChem,2020,15(16):1515-1518.DOI:10.1002 / cmdc.202000160 and LSKonstantinova,OARakitin,CWRees,SAAmelichev,Mendeleev Commun., 2004, 14(3): 91-92. DOI: 10.1070 / MC2004v014n03ABEH001912.) Therefore, it is very necessary to develop a one-pot regioselective synthesis of polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole compounds using simple and inexpensive starting materials under transition metal-free conditions. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for synthesizing polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole and its derivatives.

[0005] The technical solution adopted by the present invention to solve the technical problem is: the polysubstituted [1,2,3,4,5]pentathio[6,7-b]indole and its derivatives of the present invention have the general formula I:

[0006]

[0007] in

[0008] R 1 Selected from:

[0009] Hydrogen atom; C1-C10 straight-chain alkyl, branched-chain alkyl, cyclic alkyl; substituted or unsubstituted C6-C20 aryl; substituted or unsubstituted heterocyclic group containing nitrogen, oxygen, or sulfur atoms; halogen, methoxy, or benzyloxy;

[0010] R2 Selected from:

[0011] Hydrogen atom; C1-C10 straight-chain alkyl, oxygen-containing alkane, branched alkyl, cyclic alkyl; substituted or unsubstituted C6-C20 aryl;

[0012] A method for synthesizing polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole and its derivatives, using an iodine-containing compound as a catalyst, an organic base as an elemental sulfur activating reagent, and a sulfoxide compound as a co-oxidant, comprises the following synthetic steps:

[0013] Adding an indole compound, elemental sulfur, a catalyst, an organic base, a sulfoxide compound and an organic solvent into a reaction container;

[0014] The reactants were mixed thoroughly and then heated for reaction;

[0015] Purification afforded the product.

[0016] Preferably, in the synthesis method of the present invention, the indole compound is selected from C7-C30 aromatic indoles, and its general formula is Formula II:

[0017]

[0018] in

[0019] R 1 Selected from:

[0020] Hydrogen atom; C1-C10 straight-chain alkyl, branched-chain alkyl, cyclic alkyl; substituted or unsubstituted C6-C20 aryl; substituted or unsubstituted heterocyclic group containing nitrogen, oxygen, or sulfur atoms; halogen, methoxy, or benzyloxy;

[0021] R 2 Selected from:

[0022] Hydrogen atom; C1-C10 straight-chain alkyl, oxygen-containing alkyl, branched alkyl, cyclic alkyl; substituted or unsubstituted C6-C20 aryl; substituted or unsubstituted heterocyclic group containing nitrogen, oxygen, or sulfur atoms;

[0023] Preferably, in the synthesis method of the present invention, the indole compound is selected from the group consisting of: 1-methylindole, 1,4-dimethylindole, 1-methyl-4-fluoroindole, 1,5-dimethylindole, 1-methyl-5-methoxyindole, 1-methyl-5-benzyloxyindole, 1-methyl-5-fluoroindole, 1-methyl-5-chloroindole, 1-methyl-5-bromoindole, 1,6-dimethylindole, 1-methyl-6-methoxyindole, 1-methyl-6-fluoroindole, 1,7-dimethylindole, 1-methyl-7-methoxyindole, indole, 1-ethylindole, 1-propylindole, 1-(2-methoxyethyl)indole, 1-methyl-7-azaindole, 3-methylpyrrole, and 2-methylpyrrole.

[0024] Preferably, in the synthesis method of the present invention, the organic base compound has the general formula III:

[0025]

[0026] in

[0027] R 3 Selected from:

[0028] Hydrogen atom; C1-C10 straight-chain alkyl, branched-chain alkyl, cyclic alkyl; substituted or unsubstituted C6-C20 aryl; substituted or unsubstituted heterocyclic group containing nitrogen, oxygen, or sulfur atoms;

[0029] R 4 Selected from:

[0030] Hydrogen atom; C1-C10 straight-chain alkyl, branched-chain alkyl, cyclic alkyl; substituted or unsubstituted C6-C20 aryl; substituted or unsubstituted heterocyclic group containing nitrogen, oxygen, or sulfur atoms;

[0031] R 5 Selected from:

[0032] Hydrogen atom; C1-C10 straight-chain alkyl, branched-chain alkyl, cyclic alkyl; substituted or unsubstituted C6-C20 aryl; substituted or unsubstituted heterocyclic group containing nitrogen, oxygen, or sulfur atoms;

[0033] Ar is selected from: aromatic five-membered ring, aromatic six-membered ring, aromatic benzo-fused ring

[0034] Preferably, in the synthesis method of the present invention, the organic base compound is selected from the group consisting of: diethylamine, triethylamine, triethylenetetramine, 1,8-diazabicycloundec-7-ene, triethylenediamine, tetrahydropyrrole, piperidine, morpholine, pyrrole, 1-methylpyrrole, 2-methylpyrrole, pyridine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, quinoline, and one or more isoquinoline.

[0035] Preferably, in the synthesis method of the present invention, the iodine-containing compound is selected from the group consisting of: elemental iodine, hydroiodic acid, potassium iodide, sodium iodide, ammonium iodide, iodine chloride, iodine bromide, iodine trichloride, N-iodosuccinimide, tetramethylammonium iodide, tetrabutylammonium iodide, [bis(trifluoroacetoxy)iodo]benzene, iodobenzenediacetic acid, and one or more trimethylsulfoxide iodide.

[0036] Preferably, in the synthesis method of the present invention, the sulfoxide compound is selected from one or more of dimethyl sulfoxide, dibutyl sulfoxide, methyl phenyl sulfoxide, dibenzyl sulfoxide, diphenyl sulfoxide, and tetramethylene sulfoxide.

[0037] Preferably, in the synthesis method of the present invention, the reaction atmosphere is: air atmosphere; the molar ratio of the indole compound, the organic base compound, the sulfoxide compound, the elemental sulfur and the iodine-containing compound is 1.0-5.0:5.0-25:4.0-25:10-50:0.2-5.0; at the same time, the reaction temperature is 125°C-135°C; the reaction time is 4h-24h; the organic solvent is: one or more of mesitylene, chlorobenzene, o-dichlorobenzene, 1,4-dioxane and ethylbenzene.

[0038] The beneficial effects of the present invention compared to the prior art are as follows:

[0039] (I) The present invention is the first to adopt a technical solution in which indole compounds and elemental sulfur are converted into a novel polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole in an air atmosphere using an iodine-containing compound as a catalyst, an organic base to activate elemental sulfur, and a sulfoxide compound as a co-oxidant, thereby producing a polythioindole product with stable structure and excellent chemical properties and its by-products;

[0040] (II) Under the catalysis of an iodine-containing compound, an organic base activates elemental sulfur, and a sulfoxide compound acts as a co-oxidant. In an air atmosphere, an indole compound and elemental sulfur are converted into a polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole. The reaction raw materials are inexpensive and readily available, and no pretreatment is required, resulting in a high atom economy.

[0041] (III) Under the catalysis of an iodine-containing compound, an organic base is used to activate elemental sulfur, and a sulfoxide compound is used as a co-oxidant. In an air atmosphere, an indole compound and elemental sulfur are converted into a polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole. The reaction does not require the use of a metal catalyst or an equivalent amount of a metal oxidant, but only uses inexpensive iodine-containing compounds and sulfoxide compounds, thereby reducing environmental pollution, saving raw materials, and lowering reaction costs.

[0042] (IV) Under the catalysis of iodine-containing compounds, organic bases are used to activate elemental sulfur, and sulfoxide compounds are used as co-oxidants. In the air atmosphere, indole compounds and elemental sulfur are converted into a polysubstituted [1,2,3,4,5] pentathio[6,7-b]indole. This technical solution uses a one-pot direct and selective synthesis of the target product, overcoming the huge waste of manpower, financial resources, and materials caused by existing multi-step synthesis methods, saving a considerable amount of research and development time and production cycle;

[0043] (V) Under the catalysis of an iodine-containing compound, an organic base activates elemental sulfur, and a sulfoxide compound is used as a co-oxidant. In an air atmosphere, an indole compound and elemental sulfur are converted into a polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole. This technical solution overcomes the difficulties of existing elemental sulfur as a sulfur source, the low introduction rate of sulfur atoms, and the difficulty in controlling the number of introduced sulfur atoms. This greatly advances the practical application of the product and creates the basic conditions for early industrial production.

[0044] (VI) A technical solution for converting indole compounds and elemental sulfur into a polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole in an air atmosphere using an organic base to activate elemental sulfur under the catalysis of an iodine-containing compound and a sulfoxide compound as a co-oxidant. This solution is scientific and reasonable, easy to operate, has few reaction steps, and requires minimal equipment.

[0045] (VII) A technical solution for converting indole compounds and elemental sulfur into a polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole in an air atmosphere using an organic base to activate elemental sulfur under the catalysis of an iodine-containing compound and a sulfoxide compound as a co-oxidant. This solution has the advantages of a wide range of raw materials, low input, high output, and is easy to further mass-produce and popularize;

[0046] (VIII) Under the catalysis of iodine-containing compounds, organic bases activate elemental sulfur, and sulfoxide compounds serve as co-oxidants. In an air atmosphere, indole compounds and elemental sulfur are converted into a polysubstituted [1,2,3,4,5] pentathio[6,7-b]indole. This technical solution has the characteristics of a simple reaction system, mild reaction conditions, elemental sulfur selectively providing an "S5" source to generate a double C-S bond, simple and safe experimental operation, excellent reaction selectivity, a wide range of material sources, high product utilization value, and predictable market commercialization prospects.

[0047] The polysubstituted [1,2,3,4,5]pentathio[6,7-b]indole and derivatives of the present invention and their synthesis methods can be widely used in multiple fields such as medicine and lithium-sulfur batteries. They are particularly suitable for the research and development of polysubstituted [1,2,3,4,5]pentathio[6,7-b]indole compounds with high efficiency and selectivity using a metal-free, multi-component, one-pot process. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to prove the products of the present invention, the present invention provides H-NMR spectra and C-NMR spectra of some examples.

[0049] Figure 1a and 1b This is the NMR spectrum of the product of Example 1;

[0050] Figure 2a and 2b This is the NMR spectrum of the product of Example 2;

[0051] Figure 3a and 3b This is the NMR spectrum of the product of Example 3;

[0052] Figure 4a and 4b This is the NMR spectrum of the product of Example 4;

[0053] Figure 5a and 5b This is the NMR spectrum of the product of Example 6;

[0054] Figure 6a and 6b This is the NMR spectrum of the product of Example 7;

[0055] Figure 7a and 7b This is the NMR spectrum of the product of Example 8;

[0056] Figure 8a and 8b This is the NMR spectrum of the product of Example 9;

[0057] Figure 9a and 9b This is the NMR spectrum of the product of Example 10;

[0058] Figure 10a and 10b This is the NMR spectrum of the product of Example 11;

[0059] Figure 11a and 11b This is the NMR spectrum of the product of Example 13;

[0060] Figure 12a and 12b This is the NMR spectrum of the product of Example 15;

[0061] Figure 13a and 13b This is the NMR spectrum of the product of Example 19;

[0062] Figure 14a and 14b This is the NMR spectrum of the product of Example 20;

[0063] Figure 15a and 15b This is the NMR spectrum of the product of Example 22;

[0064] Figure 16a and 16b This is the NMR spectrum of the product of Example 23;

[0065] Figure 17a and 17b This is the NMR spectrum of the product of Example 24;

[0066] Figure 18a and 18b This is the NMR spectrum of the product of Example 26;

[0067] Where a is the hydrogen spectrum and b is the carbon spectrum. DETAILED DESCRIPTION

[0068] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0069] The reaction equation is: PhCl is chlorobenzene (organic solvent), and air is air (but the gas atmosphere is not limited, and nitrogen or argon atmospheres are also acceptable).

[0070]

[0071] Examples 1-26

[0072] Examples 1-26 are respectively methods for synthesizing polysubstituted [1,2,3,4,5]pentathio[6,7-b]indole and derivatives, comprising the following steps:

[0073] Step 1: Add an indole compound (specific substances are shown in Table 1), an organic base (specific substances are shown in Table 1), a sulfoxide compound (specific substances are shown in Table 1), and elemental sulfur into a reaction vessel, and separately add an iodine-containing compound (specific substances are shown in Table 1) and an organic solvent (specific substances are shown in Table 1) into the reaction vessel. Alternatively, a mixture of the iodine-containing compound (specific substances are shown in Table 1) and the organic solvent (specific substances are shown in Table 1) may be added separately into the vessel;

[0074] Step 2: uniformly heating and stirring the reaction vessel (e.g., heating in an oil bath) to the temperature specified in Table 1, reacting the indole compound and elemental sulfur in the solvent for the time specified in Table 1;

[0075] Step 3: Purify to obtain the product. The specific product is shown in Table 2.

[0076] Table 1: Molar ratio of indole compound, organic base compound, iodine-containing compound, sulfoxide compound, organic solvent (indole compound, organic base compound, sulfoxide compound, elemental sulfur and iodine-containing compound), reaction temperature and reaction time in Examples 1-26.

[0077]

[0078]

[0079]

[0080] * is the molar ratio of indole compound, organic base compound, sulfoxide compound, elemental sulfur and iodine-containing compound

[0081] In the reaction described in the preceding examples, elemental sulfur undergoes selective ring opening under activation with an organic base, breaking the bond to produce the "S5" fragment. This fragment then undergoes a [5+2] cyclization reaction with the C2 and C3 sites of the indole compound under the action of iodide and sulfoxide compounds to construct a [1,2,3,4,5]pentathio[6,7-b]indole skeleton, selectively forming a double C-S bond to produce the target compound.

[0082] The substance in the reaction container after step 3 was tested for conversion rate and subjected to nuclear magnetic resonance. The results of some examples are as follows:

[0083] The NMR data of the product of Example 1 are as follows:

[0084] 1 H NMR (500MHz, CDCl3, ppm) δ7.68 (dd, J=8.0, 1.3Hz, 1H), 7.35–7.30 (m, 1H), 7.30–7.24 (m, 4h), 3.89 (s, 3H); 13 C NMR (126MHz, CDCl3) δ141.3,136.6,128.9,124.7,122.2,130.6,119.1,110.5,31.5.

[0085] The NMR data of the product of Example 2 are as follows:

[0086] 1 H NMR (500MHz, CDCl3, ppm) δ7.23–7.16(m,1H),7.11(d,J=8.4Hz,1H),6.93(d,J=7.1Hz,1H),3.86(s,3H),2.76(s,3H); 13C NMR (126MHz, CDCl3) δ142.1,136.9,132.1,126.8,125.0,123.9,119.6,108.6,31.7,20.7.

[0087] The NMR data of the product of Example 3 are as follows:

[0088] 1 H NMR (500MHz, CDCl3, ppm) δ7.25–7.21(m,1H),7.07(d,J=8.3Hz,1H),6.92–6.83(m,1H),3.90(s,3H); 13 C NMR (126MHz, CDCl3) δ156.13 (d, J=252.5Hz), 142.39, 138.92 (d, J=9.2Hz), 125.50 (d, J= 7.7Hz), 117.63 (d, J = 17.8Hz), 116.80, 107.46 (d, J = 18.8Hz), 106.78 (d, J = 4.2Hz), 32.2.

[0089] The NMR data of the product of Example 4 are as follows:

[0090] 1 H NMR (500MHz, Chloroform-d) δ7.44 (d, J = 1.1Hz, 1H), 7.16–7.13 (m, 4h), 3.84 (s, 3H), 2.46 (s, 3H); 13 C NMR (126MHz, CDCl3) δ141.0,135.0,131.8,129.2,126.5,119.9,118.4,110.2,31.5,21.5.

[0091] The NMR data of the product of Example 6 are as follows:

[0092] 1 H NMR(500MHz,Chloroform-d)δ7.18(d,J=9.0Hz,1H),7.07(d,J=2.5Hz,1H),6.97(dd,J=9.0,2.5Hz,1H),3.88(s,3H),3.87(s,3H); 13 C NMR (126MHz, CDCl3) δ155.9,141.1,131.8,129.7,118.4,116.1,111.6,100.6,55.7,31.7.

[0093] The NMR data of the product of Example 7 are as follows:

[0094] 1 H NMR (500MHz, CDCl3, ppm) δ7.53–7.45(m,4h),7.44–7.37(m,3H),7.38–7.32(m, 1H),7.20–7.15(m,1H),7.06(dd,J=9.0,2.5Hz,1H),5.13(s,4h),3.88(s,3H); 13 C NMR (126MHz, CDCl3) δ155.1,141.3,136.9,132.0,130.0,128.6,128.0,127.7,118.4,116.6,111.7,102.2,31.7.

[0095] The NMR data of the product of Example 8 are as follows:

[0096] 1 H NMR (500MHz, CDCl3, ppm) δ7 7.33 (dd, J=8.9, 2.5Hz, 1H), 7.23 (dd, J=9.0, 4.1Hz, 1H), 7.08 (td, J=9.0, 2.5Hz, 1H), 3.90 (s, 3H). 13 C NMR(126MHz,ppm)δ159.1(d,J=239.8Hz),142.8,133.2,129.5(d,J=10.4Hz),118.8 (d,J=3.6Hz),113.7(d,J=26.8Hz),111.7(d,J=9.3Hz),105.4(d,J=24.5Hz),31.8.

[0097] The NMR data of the product of Example 9 are as follows:

[0098] 1 H NMR (500MHz, Chloroform-d) δ7.69–7.64(m,1H),7.28(dd,J=8.8,2.0Hz,1H),7.22(d,J=8.8Hz,1H),3.90(s,3H); 13 C NMR (126MHz, ppm) δ142.7,135.0,129.9,128.2,125.3,130.0,118.6,111.8,31.8.

[0099] The NMR data of the product of Example 10 are as follows:

[0100] 1H NMR(500MHz,Chloroform-d)δ7.57(d,J=8.5Hz,1H),7.28(d,J=1.7Hz,1H),7.21(dd,J=8.5,1.8Hz,1H),3.85(s,3H); 13 C NMR (126MHz, ppm) δ142.0,136.8,130.9,127.4,123.0,121.7,119.5,110.5,31.7.

[0101] The NMR data of the product of Example 11 are as follows:

[0102] 1 H NMR (500MHz, Chloroform-d) δ7.54 (d, J = 8.1Hz, 1H), 7.15–6.88 (m, 4h), 3.84 (s, 3H), 2.49 (s, 3H); 13 C NMR (126MHz, CDCl3) δ140.5,136.9,135.0,127.0,124.1,130.2,119.2,110.2,31.4,22.0.

[0103] The NMR data of the product of Example 13 are as follows:

[0104] 1 H NMR(500MHz,Chloroform-d)δ7.66–7.50(m,1H),7.02(td,J=9.0,2.2Hz,1H),6.95(dd,J=9.3,2.2Hz,1H),3.84(s,3H); 13 C NMR (126MHz, CDCl3) δ161.2 (d, J = 243.4Hz), 141.6 (d, J = 3.6Hz), 136.6 (d, J = 12.0Hz) ,125.4,122.0(d,J=10.3Hz),119.6,111.4(d,J=25.0Hz),96.8(d,J=26.7Hz),31.7.

[0105] The NMR data of the product of Example 15 are as follows:

[0106] 1 H NMR(500MHz,Chloroform-d)δ7.54–7.48(m,1H),7.10(t,J=7.6Hz,1H),7.03–6.99(m,1H),4.16(s,3H),2.74(s,3H); 13C NMR (126MHz, CDCl3) δ142.0,135.7,129.8,127.4,122.1,122.1,119.4,118.7,34.9,20.2.

[0107] The NMR data of the product of Example 19 are as follows:

[0108] 1 H NMR (500MHz, DMSO-d6) δ12.70(s,1H),7.58(d,J=7.9Hz,1H),7.43(d,J=8.1Hz,1H),7.30(t,J=7.5Hz,1H),7.23(t,J=7.5Hz,1H); 13 C NMR (126MHz, DMSO) δ138.7,135.3,129.2,124.5,121.96,119.5,117.1,112.6.

[0109] The NMR data of the product of Example 20 are as follows:

[0110] 1 H NMR(500MHz,Chloroform-d)δ7.70(d,J=7.9Hz,1H),7.35–7.31(m,4h),7.28–7.21(m,1H),4.55–4.23(m,4h),1.40(t,J=7.2Hz,3H); 13 C NMR (126MHz, CDCl3) δ140.6,135.5,129.2,124.6,122.1,130.8,119.1,110.4,40.1,16.2.

[0111] The NMR data of the product of Example 22 are as follows:

[0112] 1 H NMR(500MHz,Chloroform-d)δ7.70(d,J=8.0Hz,1H),7.31(d,J=3.5Hz,4h),7.28–7.22(m,1H),4.47–4.08(m,4h),1.93–1.65(m,4h),0.94(t,J=7.4Hz,3H); 13 C NMR (126MHz, CDCl3) δ141.2,135.9,129.1,124.5,122.0,130.7,119.0,110.7,46.7,24.1,11.4.

[0113] The NMR data of the product of Example 23 are as follows:

[0114] 1 H NMR(500MHz,Chloroform-d)δ7.68(d,J=7.9Hz,1H),7.35–7.29(m,4h),7.27–7.18(m,1H),4.50(q,J=5.8Hz,4h),3.62(t,J=5.6Hz,4h),3.25(s,3H); 13 C NMR (126MHz, CDCl3) δ141.8,136.1,129.1,124.6,122.1,130.6,119.1,110.7,71.4,59.1,44.9.

[0115] The NMR data of the product of Example 24 are as follows:

[0116] 1 H NMR (500MHz, CDCl3, ppm) δ8.44 (dd, J=4.6, 1.5Hz, 1H), 7.99 (dd, J=7.9, 1.6Hz, 1H), 7.25–7.17 (m, 1H), 4.01 (s, 3H); 13 C NMR (126 MHz, CDCl3, ppm) δ 146.5, 146.1, 142.3, 128.9, 122.0, 118.2, 117.1, 30.2. The NMR data of the product of Example 26 are as follows:

[0117] 1 H NMR(500MHz,Chloroform-d)δ8.34(s,1H),6.20(s,1H),2.22(s,3H); 13 C NMR (126MHz, CDCl3) δ129.71,129.05,128.14,115.11,13.17.

[0118] Table 2: Conversion rate and product diagram of the reaction of Examples 1-26

[0119]

[0120]

[0121]

[0122] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A method for synthesizing polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole and its derivatives, characterized in that: Polysubstituted [1,2,3,4,5]pentathio[6,7-b]indole and its derivatives are: The method comprises the following steps: Step 1: adding an indole compound, an organic base, a sulfoxide compound, and elemental sulfur to a reaction vessel, and separately adding an iodine-containing compound and an organic solvent to the reaction vessel, or separately adding a mixture of the iodine-containing compound and the organic solvent to the vessel; wherein the indole compound is 1,7-dimethylindole, the organic base is 1-methylpyrrole:pyridine in a ratio of 1:1, the iodine-containing compound is elemental iodine:hydroiodic acid in a ratio of 1:2, the sulfoxide compound is dimethyl sulfoxide, and the organic solvent is o-dichlorobenzene; the molar ratio of the indole compound, the organic base compound, the sulfoxide compound, elemental sulfur, and the iodine-containing compound is 5:25:25:50:3; Step 2: The reaction vessel is uniformly heated and stirred to 135°C, and the indole compound and elemental sulfur react in the solvent for 8 hours; Step 3: Purify to obtain the product.

2. A method for synthesizing polysubstituted [1,2,3,4,5]pentathia[6,7-b]indole and its derivatives, characterized in that: Polysubstituted [1,2,3,4,5]pentathio[6,7-b]indole and its derivatives are: The method comprises the following steps: Step 1: adding an indole compound, an organic base, a sulfoxide compound, and elemental sulfur to a reaction container, and separately adding an iodine-containing compound and an organic solvent to the reaction container, or separately adding a mixture of the iodine-containing compound and the organic solvent to the container; wherein the indole compound is 1-ethylindole, the organic base is 4-methylpyridine:quinoline in a ratio of 1:1, the iodine-containing compound is sodium iodide:hydroiodic acid in a ratio of 1:2, the sulfoxide compound is dimethyl sulfoxide, and the organic solvent is mesitylene:o-dichlorobenzene in a ratio of 1:1; the molar ratio of the indole compound, the organic base compound, the sulfoxide compound, elemental sulfur, and the iodine-containing compound is 1:5:4:10:0.4; Step 2: The reaction vessel is uniformly heated and stirred to 135°C, and the indole compound and elemental sulfur react in the solvent for 6 hours; Step 3: Purify to obtain the product.

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