A method for synthesizing axially chiral N-arylbenzimidazole analogs and their application

Abstract

The present invention discloses a method for synthesizing axially chiral N-arylbenzimidazole analogs catalyzed by chiral phosphoric acid and its application, belonging to the field of organic chemistry. N-(aryl)benzene-1,2-diamine and aromatic aldehyde are used as raw materials and reacted in the presence of a chiral phosphoric acid catalyst to obtain axially chiral N-arylbenzimidazole analogs with biological activity. The present invention uses environmentally friendly chiral phosphoric acid as a catalyst, does not require transition metals or stoichiometric oxidants, has readily available reaction raw materials, simple synthesis steps, and mild reaction conditions. The axially chiral N-arylbenzimidazole analogs have strong physiological activity against the replication of HBV DNA and can be further used in potential antiviral drugs.

Description

Technical Field

[0001] The invention belongs to the field of organic chemistry, and particularly relates to a method for synthesizing axially chiral N-arylbenzimidazole analogs by catalysis of chiral phosphoric acid and application thereof. Background Art

[0002] Imidazole benzo derivatives are called benzimidazoles, also known as 1H-benzimidazole and 1,3-benzodiazole. They are composed of a benzene ring fused with a five-membered imidazole ring and are an important heterocyclic pharmacophore.

[0003] Benzimidazoles are also important building blocks of many bioactive heterocyclic compounds, which have attracted widespread attention due to their diverse biological and clinical applications. Furthermore, benzimidazole derivatives are structural isomers of naturally occurring nucleotides, which allows them to readily interact with biopolymers in living systems, sparking the interest of researchers. Various benzimidazole derivatives have been synthesized and screened for various bioactivities, namely anticancer, antibacterial, antiviral, anti-inflammatory, analgesic, anti-ulcer, and antioxidant.

[0004] Among the many axial chiral compounds, benzimidazoles have very broad biological activities due to their special structure. They exist in many bioactive molecules. They can be used as intermediates for certain drugs and are widely used in the research of medicines and pesticides.

[0005] The introduction of aromatic functional groups at the 1- and 2-positions of a parent molecule significantly influences its chemical, physical, and biological properties. Many molecules containing aromatic rings are known to possess important therapeutic applications. Many pharmaceutical molecules contain aromatic groups. Traditional benzimidazole synthesis involves the cyclization of o-phenylenediamine and formic acid, without incorporating the concept of chirality.

[0006] In view of the above shortcomings of the prior art, the present invention introduces the concept of chirality into the synthesis of benzimidazoles, and also realizes for the first time the introduction of aromatic rings into benzimidazoles, ultimately generating N-arylbenzimidazole analogs with axial chirality containing aromatic rings at the 2-position. Summary of the Invention

[0007] In order to overcome the above-mentioned technical defects, the purpose of the present invention is to provide an axially chiral N-arylbenzimidazole analogue, and to study its synthesis method and compound application. By reacting N-(aryl)benzene-1,2-diamine with aromatic aldehyde, axially chiral benzimidazole is selectively constructed with chiral phosphoric acid to obtain an axially chiral N-arylbenzimidazole analogue containing biological activity. The method of the present invention does not require transition metals or stoichiometric oxidants, the reaction raw materials are easily available, the synthesis steps are simple, and the reaction conditions are mild. These axially chiral N-arylbenzimidazole analogues show strong physiological activity against HepG2 / 2.2.15 cells that can continuously and stably express HBV virus, and can be further used in potential antiviral substances.

[0008] The axially chiral N-arylbenzimidazole analogs of the present invention, including racemates and enantiomerically pure compounds, have the following general structural formula:

[0009]

[0010] Wherein: R is selected from phenyl, substituted phenyl, furyl; wherein the substituent in the substituted phenyl is C1-C4 alkyl, halogen, trifluoromethyl; R 1 ,R 2 Each is independently selected from C1-C4 alkyl, halogen, and trifluoromethyl.

[0011] The present invention also provides a method for synthesizing the aforementioned axially chiral N-arylbenzimidazole analogs, comprising the following steps: using N-(aryl)benzene-1,2-diamine 1 and aromatic aldehyde 2 as raw materials, reacting in an organic solvent in the presence of a chiral phosphoric acid catalyst CPA to obtain an axially chiral N-arylbenzimidazole analog 3. The reaction equation is as follows:

[0012]

[0013] Wherein: R is selected from phenyl, substituted phenyl, furyl; wherein the substituent in the substituted phenyl is C1-C4 alkyl, halogen, trifluoromethyl; R 1 ,R 2 Each is independently selected from C1-C4 alkyl, halogen, and trifluoromethyl.

[0014] Furthermore, in the above technical solution, the molar ratio of the N-(aryl)benzene-1,2-diamine 1, aromatic aldehyde 2 and chiral phosphoric acid CPA is 1:1-2:0.05-0.10.

[0015] Furthermore, in the above technical solution, the reaction is carried out in ethyl acetate solvent in the presence of sodium sulfate.

[0016] Furthermore, in the above technical solution, the reaction is carried out under the protection of an inert gas.

[0017] Furthermore, in the above technical solution, the organic solvent is selected from ethyl acetate; and the reaction temperature is selected from 0-30°C.

[0018] Furthermore, in this technical solution, by changing the substituents of substrates 1 and 2, axially chiral N-arylbenzimidazoles containing different substituents can be obtained; the representative structures are as follows:

[0019]

[0020] The present invention also provides the use of the aforementioned axially chiral N-arylbenzimidazole analogues in the preparation of antiviral drugs.

[0021] Furthermore, in the above technical solution, the antiviral agent is selected from HepG2 / 2.2.15 cells that can sustainably and stably express HBV virus.

[0022] Advantageous Effects of the Invention

[0023] 1. The present invention uses N-(naphthalene-1-yl)benzene-1,2-diamine and aromatic aldehyde as raw materials and chiral phosphoric acid as a catalyst to selectively construct axially chiral benzimidazole analogs, introducing the concept of chirality into the synthesis of benzimidazole. It is also the first time that an aromatic ring has been introduced into benzimidazole, ultimately generating an N-arylbenzimidazole analog with axial chirality containing an aromatic ring at the 2-position.

[0024] 2. The N-arylbenzimidazole analogs of the present invention exhibit strong cell activity against HepG2 / 2.2.15 cells that can stably and continuously express HBV virus. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The experimental steps for the biological activity test of axially chiral N-arylbenzimidazole analogs in the examples;

[0026] Figure 2 The relative expression of HBV DNA in HepG2 / 2.2.15 cells by axially chiral N-arylbenzimidazole analogs in the examples;

[0027] Figure 3 The expression level of HBsAg in HepG2 / 2.2.15 cells by axial chiral N-arylbenzimidazole analogs in the examples;

[0028] Figure 4 The expression level of HBeAg in HepG2 / 2.2.15 cells by the axially chiral N-arylbenzimidazole analogs in the examples. Specific embodiments

[0029] The present invention will be further described below by way of specific examples. These embodiments should be understood to be merely illustrative of the present invention and not intended to limit the scope of protection of the present invention. After reading the contents described herein, those skilled in the art may make various changes or modifications to the present invention, and these equivalent variations and modifications also fall within the scope defined by the claims of the present invention.

[0030] This reaction, using N-(aryl)benzene-1,2-diamine 1a and benzaldehyde 2a as template substrates, was optimized for the chiral phosphoric acid catalyst configuration, solvent, water absorbent, temperature, and the molar ratio of the two substrates. Ultimately, the optimal reaction conditions were achieved. Under these optimal conditions, the substrate range of aromatic aldehyde 2 was expanded, ultimately yielding six highly active axially chiral N-arylbenzimidazole analogs.

[0031] Example 1

[0032] General experimental procedure: Under argon, add 100 mg of sodium sulfate to a 10 mL Schlenk tube equipped with a stir bar and flame-dry under high vacuum. After cooling the reaction tube and sodium sulfate to room temperature, ventilate the tube and place it in a glove box. Dissolve N-(aryl)benzene-1,2-diamine 1 (0.10 mmol) and chiral phosphoric acid CPA (0.01 mmol, 10 mol%) in 1 mL of ultra-dry ethyl acetate and stir at 5°C for 10 minutes. Finally, add aromatic aldehyde 2 (0.20 mmol). After monitoring by TLC (thin-layer chromatography), the reaction mixture is directly purified by flash column chromatography to yield the axially chiral N-arylbenzimidazole analog 3.

[0033]

[0034] 2-(3-bromophenyl)-1-(naphthalen-1-yl)-1H-benzo[d]imidazole (29.1 mg); yield 53%; 1 H NMR (600MHz, CDCl3) δ8.05(d,J=8.4Hz,1H),8.01(d,J=8.4Hz,1H),7.96(d,J=8.4Hz,1H),7.92(t,J=1.8Hz,1H),7.59 -7.55(m,2H),7.45-7.40(m,2H),7.39-7.34(m,3H),7.23-7.19(m,2H),6.95(t,J=7.8Hz,1H),6.89(d,J=7.8Hz,1H); 1313C NMR (150 MHz, CDCl3) δ 151.7, 142.9, 138.4, 134.6, 133.3, 132.6, 132.1, 132.0, 130.3, 130.1, 129.8, 128.8, 128.0, 127.3, 127.0, 126.7, 125.8, 123.9, 123.4, 122.7, 122.6, 120.2, 111.2; HRMS (ESI) m / z: [M+H] + Calcd for C23H16N2Br 399.0491; Found 399.0491.

[0035]

[0036] 1-(naphthalen-1-yl)-2-(4-(trifluoromethyl)phenyl)-1H-benzo[d]imidazole (31.8 mg); Yield 62%; 1 1H NMR (400 MHz, CDCl3) δ 8.07 - 7.96 (m, 3H), 7.67 - 7.54 (m, 4H), 7.44 - 7.38 (m, 6H), 7.24 - 7.19 (m, 1H), 6.89 (d, J = 8.0 Hz, 1H); 13 13C NMR (100 MHz, CDCl3) δ 151.7, 143.0, 138.5, 134.7, 133.5, 133.3, 131.4, 131.1, 130.3, 130.2, 129.1, 128.8, 128.1, 127.4, 126.7, 125.9, 125.4 (q, J = 4.0 Hz), 125.3, 124.1, 123.5, 122.7, 122.6, 120.3, 111.3; 19 19F NMR (564 MHz, CDCl3) δ –63.0; HRMS (ESI) m / z: [M+H] + Calcd for C24H16N2F3 389.1260; Found 389.1252.

[0037] 1-(naphthalene-1-yl)-2-phenyl-1H-benzo[d]imidazole (25.6 mg); Yield 60%; 11H NMR (400 MHz, CDCl3) δ 8.02 - 7.94 (m, 3H), 7.58 - 7.50 (m, 4H), 7.41 (d, J = 3.6 Hz, 2H), 7.39 - 7.34 (m, 2H), 7.26 - 7.22 (m, 1H), 7.20 - 7.14 (m, 3H), 6.86 (d, J = 8.1 Hz, 1H); 13 13C NMR (100 MHz, CDCl3) δ 153.5, 143.0, 138.3, 134.6, 133.7, 130.4, 130.0, 129.8, 129.6, 128.9, 128.7, 128.4, 127.8, 127.2, 126.7, 125.8, 123.5, 123.2, 123.0, 120.0, 111.1; HRMS (ESI) m / z: [M + H] + Calcd for C23H17N2 321.1386; Found 321.1385.

[0038]

[0039] 2-(2-chlorophenyl)-1-(naphthalen-1-yl)-1H-benzo[d]imidazole (22.0 mg); Yield 42%; 1 1H NMR (400 MHz, CDCl3) δ 8.00 (d, J = 8.1 Hz, 1H), 7.91 (d, J = 8.8 Hz, 2H), 7.54 - 7.49 (m, 1H), 7.47 - 7.28 (m, 7H), 7.24 - 7.17 (m, 2H), 7.09 - 7.04 (m, 1H), 6.95 (d, J = 8.1 Hz, 1H); 13 13C NMR (100 MHz, CDCl3) δ 151.6, 142.8, 137.1, 134.6, 134.5, 134.4, 132.1, 130.9, 130.1, 130.06, 129.9, 129.7,  128.5, 127.4, 126.9, 126.4, 126.36, 125.4, 123.8, 123.3, 123.1, 120.4, 111.3; HRMS (ESI) m / z: [M + H] + Calcd for C23H16N2Cl 355.0997; Found 355.0993.

[0040] 1-(naphthalen-1-yl)-2-(p-tolyl)-1H-benzo[d]imidazole (26.8 mg); Yield 60%; 1 H NMR (600 MHz, CDCl3) δ 7.99 (dd, J = 12.0, 7.8 Hz, 2H), 7.94 (d, J = 7.8 Hz, 1H), 7.56 - 7.50 (m, 2H), 7.42 - 7.39 (m, 4H), 7.38 - 7.35 (m, 1H), 7.35 - 7.31 (m, 1H), 7.17 - 7.13 (m, 1H), 6.96 (d, J = 8.4 Hz, 2H), 6.83 (d, J = 7.8 Hz, 1H), 2.23 (s, 3H); 13 C NMR (150 MHz, CDCl3) δ 153.6, 143.1, 139.7, 138.4, 134.6, 133.8, 130.4, 129.7, 129.1, 128.8, 128.6, 127.8, 127.1, 126.7, 125.8, 123.3, 123.0, 119.8, 111.0, 21.4; HRMS (ESI) m / z: [M + H] + Calcd for C24H19N2 335.1543; Found 335.1539.

[0041]

[0042] 2-(furan-3-yl)-1-(naphthalen-1-yl)-1H-benzo[d]imidazole (25.1 mg); Yield 61%; 1 H NMR (400 MHz, CDCl3) δ 8.11 (d, J = 8.4 Hz, 1H), 8.01 (d, J = 8.0 Hz, 1H), 7.92 (d, J = 8.0 Hz, 1H), 7.65 (t, J = 7.2 Hz, 1H), 7.58 - 7.54 (m, 2H), 7.41 - 7.30 (m, 2H), 7.26 - 7.14 (m, 3H), 6.90 - 6.85 (m, 2H), 6.66 (d, J = 1.2 Hz, 1H); 13 C NMR (100 MHz, CDCl3) δ 147.6, 143.1, 143.06, 142.3, 138.0, 134.7, 132.9, 130.6, 130.5, 128.6, 127.4, 126.8, 125.9, 123.4, 123.0, 122.7, 119.5, 116.9, 110.4, 110.0; HRMS (ESI) m / z: [M + H]+ Calcd for C21H15N2O311.1179; Found 311.1177

[0043] Example 2

[0044] This example demonstrates the testing process and results for the inhibition of HBV viral replication in cells by the compounds described in Example 1. Materials and consumables listed in this example were commercially available unless otherwise specified. Cells and viruses were obtained from the cell and microbial resource libraries of the CTCC or other relevant institutions. The experimental methods used in this example follow standard molecular biology, cell biology, or virology procedures and are readily understood and implemented by researchers in the field.

[0045] The specific steps are as follows:

[0046] 1. Cells:

[0047] HepG2 / 2.2.15 (HBV ayw insertion, D subtype, 3182 bp, stable expression), culture conditions: DMEM+10% FBS+1% (strep++pen+)+380 μg / ml G418+0.2% L-Glutamine+0.2% non-essential amino acids.

[0048] NOTE: HBV DNA is carried by these cells as chromosomally integrated sequences and episomally as relaxed circular, covalently closed, and incomplete copies of the HBV genome. The majority of HBV DNA appears to be present in the form of covalently closed circular (ccc) and nicked recircularized forms, as well as incomplete copies of the genome.

[0049] 2. Main reagents:

[0050] DMEM (Gibco, cat:C11995500BT);

[0051] Fetal bovine serum (FBS) (Gibco, cat: 10270-106);

[0052] Double Pen-Strep (10,000U / mL) (M&C gene biotechnology, cat: G2723M3);

[0053] Anti-HBV positive drug: 3TC (lamivudine; gift from Academician Chang Junbiao);

[0054] Tguide Smart Universal Genomic DNA Extraction Kit (TIANGEN, mat: 4995051)

[0055] Hepatitis B virus surface antigen (HBsAg) diagnostic kit (enzyme-linked immunosorbent assay) (KHB) Hepatitis B virus e antigen (HBeAg) detection kit (enzyme-linked immunosorbent assay) (KHB)

[0056] 3. Experimental steps: ( Figure 1 )

[0057] Step 1: Preliminary screening of compounds for HBV inhibition activity:

[0058] The experiment set up two control groups, namely ① positive drug group: add the final concentration of 50

[0059] μM 3TC; ② Virus control group: only DMSO was added without compound.

[0060] Step 2: HepG2 / 2.2.15 cells, 1 x 105 cells / well, 12-well plate, 750 μL / well.

[0061] Step 3: 12-16 h after the cells are completely attached, add 750 μL DMEM and 1.5 μL of the compound to be tested (5 mM) to a final concentration of 5 μM.

[0062] Step 4: On the fourth day of culturing at 37°C, add 250 μL of culture medium containing 5 μM of the test compound.

[0063] Step 5: On the sixth day of culturing at 37°C, add 250 μL of culture medium containing 5 μM of the compound to be tested.

[0064] Step 6: On the 8th day of culturing at 37°C, collect the cells and culture supernatant.

[0065] Step 7: Extract the sample DNA using an automatic nucleic acid extractor, and determine the inhibition rate of the compound on HBV virus using qPCR (real-time fluorescence quantitative polymerase chain reaction).

[0066] Step 8: Detect the expression levels of HBsAg and HBeAg using the ELASA method (enzyme-linked immunosorbent assay) using HBsAg and HBeAg detection kits.

[0067] Supplement: qPCR detection:

[0068] Primer: F Primer: 5'-CCTAGTAGTCAGTTATGTCAAC-3'

[0069] R Primer:5'-TCTATAAGCTGGAGGAGTGCGA-3'

[0070] Amplified gene: C gene

[0071] Amplification conditions: 95°C, 10 min;

[0072] 95℃, 15s; 60℃, 30s; 72℃, 30s×40

[0073] 4. Test results:

[0074] Primary screening of anti-HBV activity at a single concentration (5 μM) Figure 2-4 )

[0075] (Compound concentration: 5 μM)

[0076] (Control drug 3TC concentration: 50 μM)

[0077] in conclusion:

[0078] 1. At a concentration of 5μM, the differences in HBV DNA expression between compounds 3a, 3c, and 3f and the DMSO control group were extremely significant. The relative expression of HBV DNA in 3f reached 9.3%, demonstrating a significant inhibitory effect on DNA replication. Figure 2 )

[0079] 2. At a concentration of 5 μM, the six compounds had no significant inhibitory effect on the expression of HBsAg. Figure 3 )

[0080] 3. At a concentration of 5 μM, the six compounds had no significant inhibitory effect on the expression of HBeAg. Figure 4 )

[0081] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. Axially chiral N-arylbenzimidazole analogs, whose chemical structures are shown below:

2. The method for synthesizing an axially chiral N-arylbenzimidazole analogue according to claim 1, wherein: The method comprises the following steps: using N-(aryl)benzene-1,2-diamine 1 and aromatic aldehyde 2 as raw materials, reacting in an organic solvent in the presence of a chiral phosphoric acid catalyst CPA to obtain axially chiral N-arylbenzimidazole analogs 3a-e; the organic solvent is selected from ethyl acetate; the reaction temperature is selected from 0-30°C; and the reaction is carried out under the protection of an inert gas; Wherein: R is selected from phenyl, 2-chlorophenyl, 3-bromophenyl, 4-trifluoromethylphenyl or 4-methylphenyl.

3. The method for synthesizing the axially chiral N-arylbenzimidazole analogue according to claim 2, characterized in that: The molar ratio of N-(aryl)benzene-1,2-diamine 1, aromatic aldehyde 2 and chiral phosphoric acid CPA is 1:1-2:0.05-0.

10.

4. Use of the axially chiral N-arylbenzimidazole analogue as claimed in claim 1 in the preparation of an antiviral drug, wherein the antiviral corresponding cells are selected from HepG2 / 2.2.15 cells.

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