阅读说明：本技术 一种1,2-取代苯并咪唑类化合物的制备方法 (Preparation method of 1, 2-substituted benzimidazole compound ) 是由 唐伯孝 张振兴 黄翔 沈玉君 邹红 宋宝星 于 2019-12-06 设计创作，主要内容包括：本发明公开了一种以1-丁基-3-甲基咪唑六氟磷酸盐([BMIm][PF<Sub>6</Sub>])为反应介质,无金属和酸条件下邻苯二胺和芳香醛通过缩合偶联反应合成一系列1,2-取代苯并咪唑类化合物的方法。本发明的合成工艺简单,使用[BMIm][PF<Sub>6</Sub>]作为反应催化剂,具有较高的催化产率；不需要使用任何酸或金属催化剂,降低了合成工艺的成本,避免了药物合成中的重金属残留的问题,与传统有机溶剂相比,减少了对环境的污染,同时[BMIm][PF<Sub>6</Sub>]反应体系无需活化就可以重复使用6次,仍然具有较好的反应活性实现了1,2-取代苯并咪唑化合物的绿色合成。(The invention discloses a method for preparing 1-butyl-3-methylimidazolium hexafluorophosphate ([ BMIm)][PF 6 ]) A method for synthesizing a series of 1, 2-substituted benzimidazole compounds by condensation coupling reaction of o-phenylenediamine and aromatic aldehyde under the condition of no metal and acid as reaction media. The synthesis process is simple and uses the BMIm][PF 6 ]As a reaction catalyst, the catalyst has higher catalytic yield; no need of any acid or metal catalyst, low cost, no heavy metal residue, less environmental pollution and BMIm consumption][PF 6 ]The reaction system can be repeatedly used for 6 times without activation, still has better reaction activity, and realizes green synthesis of the 1, 2-substituted benzimidazole compound.)

1. A process for preparing a derivative of 1, 2-substituted benzimidazole from a 1, 2-phenylenediamine derivative and an aromatic aldehyde without any acid or metal catalyst, characterized in that: the method is carried out on 1-butyl-3-methylimidazolium hexafluorophosphate ([ BMIm)][PF₆]) As a reaction medium and a catalyst,

wherein R is₁Represents an electron donating group or an electron withdrawing group, preferably hydrogen, C₁-C₆Alkyl radical, C₁-C₆Alkoxy, halo C₁-C₆Alkyl radical, C₃-C₆Cycloalkyl, hydroxy, cyano, C₁-C₆Alkylamino radical, di (C)₁-C₆Alkyl) NH, tri (C)₁-C₆Alkyl) N, halogen, sulfonic acid group, nitro group, (C)₁-C₆Alkyl radical C (O) -, (C)₁-C₆Alkyl) C (O) O-;

wherein m represents a positive number of 0, 1,2, 3;

wherein Ar represents a group selected from 0, 1,2, 3R₂Substituted phenyl, pyridyl or furyl; wherein R is₂Represents an electron donating group or an electron withdrawing group, preferably hydrogen, C₁-C₆Alkyl radical, C₁-C₆Alkoxy, halo C₁-C₆Alkyl, hydroxy, cyano, C₁-C₆Alkylamino radical, di (C)₁-C₆Alkyl) NH, tri (C)₁-C₆Alkyl) N, halogen, sulfonic acid group, nitro group, (C)₁-C₆Alkyl radical C (O) -, (C)₁-C₆Alkyl) C (O) O-.

2. The method of claim 1Process wherein R¹Hydrogen is preferred.

3. The process of claim 1 wherein Ar represents phenyl.

4. The process as claimed in claim 1, wherein the reaction temperature is preferably 100 ℃ and 130 ℃, more preferably 120 ℃.

5. The process as claimed in any one of claims 1 to 4, wherein the molar ratio of the reactants 1, 2-phenylenediamine derivative to aromatic aldehyde compound is about 1: 2.

6. The process of any one of claims 1 to 4 wherein the reactants 1, 2-phenylenediamine derivative and [ BMIm][PF₆]The molar ratio of the catalyst used is 1: 3.

7. A process according to any one of claims 1 to 6 wherein the reaction medium and catalyst [ BMIm][PF₆]Can be recycled.

Technical Field

The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of a 1, 2-substituted benzimidazole compound.

Background

The benzimidazole derivative is a benzo heterocyclic compound containing two nitrogen atoms and is a structural unit of various medicaments. Benzimidazole derivatives have diverse biological activities and are widely used in clinical medicine: such as antiulcer, antihypertensive, antiviral, antifungal, and anticancer drugs. Meanwhile, the benzimidazole derivative has better optical performance. The benzimidazole derivative has good practical application value, and the synthetic method of the benzimidazole derivative is one of the focuses of organic synthetic research. The traditional synthesis method of the 1, 2-substituted benzimidazole derivative is mainly realized by coupling 1, 2-phenylenediamine and aldehyde. The condensation coupling reaction generally can achieve the synthesis goal under the condition of acid, metal or other auxiliary agents (reaction formula I).

For example, the Salehi research group reported that the condensation coupling reaction of o-phenylenediamine with aromatic aldehydes under acidic conditions exhibited high selectivity. In 2016, a Manesh research group realizes the condensation coupling of 1, 2-phenylenediamine and aromatic aldehyde by using an iron compound as a catalyst under the condition of no solvent. Although these methods provide an effective way to synthesize 1, 2-substituted benzimidazole compounds and achieve good catalytic efficiency, there are some disadvantages such as the use of acid and metal catalysts, and the failure of the reaction system to recycle, which affect the practical application value of the condensation coupling reaction in industrial processes. Therefore, finding some simple, green, recyclable synthetic methods remains a good strategy in this field of research.

Disclosure of Invention

The invention aims to provide a compound which is 1-butyl-3-methylimidazolium hexafluorophosphate ([ BMIm)][PF₆]) In the method, the 1, 2-substituted benzimidazole derivative is synthesized from the 1, 2-phenylenediamine derivative and aromatic aldehyde without any acid or metal catalyst, and high yield (reaction formula I) can be obtained.

Wherein R is₁Represents an electron donating group or an electron withdrawing group, preferably hydrogen, C₁-C₆Alkyl radical, C₁-C₆Alkoxy, halo C₁-C₆Alkyl radical, C₃-C₆Cycloalkyl, hydroxy, cyano, C₁-C₆Alkylamino radical, di (C)₁-C₆Alkyl) NH, tri (C)₁-C₆Alkyl) N, halogen, sulfonic acid group, nitro group, (C)₁-C₆Alkyl radical C (O) -, (C)₁-C₆Alkyl) C (O) O-;

wherein m represents a positive number of 0, 1,2, 3;

wherein Ar represents a group selected from 0, 1,2, 3R₂Substituted phenyl, pyridyl or furanyl; wherein R is₂Represents an electron donating group or an electron withdrawing group, preferably hydrogen, C₁-C₆Alkyl radical, C₁-C₆Alkoxy, halo C₁-C₆Alkyl, hydroxy, cyano, C₁-C₆Alkylamino radical, di (C)₁- C₆Alkyl) NH, tri (C)₁-C₆Alkyl) N, halogen, sulfonic acid group, nitro group, (C)₁-C₆Alkyl radical C (O) -, (C)₁-C₆Alkyl) C (O) O-.

In a preferred embodiment of the present invention, wherein R is¹Preferably hydrogen;

in a preferred embodiment of the present invention, wherein Ar is preferably phenyl;

in the preferred technical scheme of the invention, the reaction temperature is preferably 100-130 ℃, and more preferably 120 ℃;

in a preferred embodiment of the present invention, the molar ratio of the 1, 2-phenylenediamine derivative to the aromatic aldehyde compound is about 1: 2;

in a preferred embodiment of the present invention, the reactants 1, 2-phenylenediamine derivative and [ B MIm][PF₆]The molar ratio of the catalyst is 1: 3;

in addition, the catalyst of the invention [ BMIm][PF₆]Can be repeatedly recycled, and still maintain higher catalytic activity after the recycling.

In the definition of the invention C₁-C₆Alkyl represents straight or branched chain alkyl groups having 1,2, 3, 4, 5, 6 carbon atoms, including but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, and the like.

The invention has the following advantages:

1. simple synthesis process and use of [ BMIm][PF₆]As a reaction catalyst, the catalyst has higher catalytic yield;

2. no acid or metal catalyst is needed, so that the cost of the synthesis process is reduced, and the problem of heavy metal residue in the drug synthesis is avoided;

3、[BMIm][PF₆]compared with the traditional organic solvent, the difficult volatility reduces the pollution to the environment and realizes the green synthesis of the 1, 2-substituted benzimidazole compound.

4. The general method for realizing the recycling of the catalyst is to fix the catalyst on an inert carrier, thereby improving the utilization efficiency of the catalyst. The preparation of the supported catalyst is a multi-step and tedious process, and new impurities are easily introduced in the preparation process, so that the practical application value of the supported catalyst is limited. In the method, under the condition of no load, p-methyl benzaldehyde and 1, 2-phenylenediamine are taken as research objects, and [ BMIm][PF₆]The experimental result shows that when the [ BMIm ] is used circularly][PF₆]After being recycled for 6 times, [ BMI m ]][PF₆]Still has good reactivity.

Detailed Description

1 experimental part

1.1 instruments and reagents

Melting point apparatus: WRS-1B; nuclear magnetic resonance apparatus: bruker AVANCE III HD 400.

The drugs and reagents used were either commercially available, analytically pure or chemically pure, and were not further processed. The column chromatography uses 300-400 mesh silica gel.

Synthesis of 1.21, 2-substituted benzimidazoles

(1) Synthesis of 1-benzyl-2-phenylbenzimidazole (3a)

1, 2-phenylenediamine (1mmol), benzaldehyde (2.05mmol) and [ B MIm ] were added to a reaction tube][PF₆](1.0 g), the reaction was carried out in a 120 ℃ oil bath, followed by TLC, and after completion of the reaction, the reaction mixture was cooled to room temperature, 15mL of a saturated saline solution was added thereto, extracted with ethyl acetate (10 mL. times.3), separated, and the organic phase was separated with anhydrous MgSO₄Drying, filtering, distilling under reduced pressure to remove ethyl acetate to obtain crude product, and separating by column chromatography to obtain target product 3 a.

(2) Synthesis of 1- (4-methylbenzyl) -2- (4-methylphenyl) benzimidazole (3b)

1, 2-phenylenediamine (1mmol), p-tolualdehyde (2.05 mm. sup. ol) and [ BMim ] were added to a reaction tube][PF₆](1.0 g) was reacted in a 120 ℃ oil bath and followed by TLC. After completion of the reaction, the reaction mixture was cooled to room temperature, and 15mL of saturated brine was added, followed by extraction with ethyl acetate (10 mL. times.3), liquid separation, and extraction with anhydrous MgSO₄Drying, filtering, evaporating the organic solvent under reduced pressure to obtain a crude product, and separating by column chromatography to obtain a target product 3 b.

2. Results and discussion

2.1 Effect of different catalyst types on the condensation coupling reaction

The effect of the type of ionic liquid (3mmol) on the condensation coupling reaction was investigated under reaction conditions of 120 ℃ in the absence of metal or acid using 1, 2-phenylenediamine (1a) (1mmol) and benzaldehyde (2a) (2.05mmol) as the template for the condensation coupling reaction (as shown in Table 1). Wherein 1-butyl-3-methylimidazolium hexafluorophosphate [ BMIm][PF₆]The best reactivity was shown (comparative 7). When tetrabutylammonium bromide, 1-butyl-3-methylimidazolium tetrafluoroborate, bromo-1-ethyl-3-methylimidazole, 1-ethyl-3-methylimidazolium nonafluorobutanesulfonate and 1-ethyl-3-methylimidazolium bistrifluoromethylphosphoryl imide salt were used as reaction media, the condensation coupling reaction could achieve a yield of about moderate (comparative examples 2-5,8), and when 1-sulfonic acid butyl-3-methylimidazolium inner salt and 1-butyl-3-methylimidazolium iron tetrafluoride salt were used as reaction media, the condensation coupling reaction could hardly obtain the target product (comparative examples 1, 6).

TABLE 1 Effect of different catalyst types on the condensation coupling reaction

Comparative example	Ionic liquids	Yield of
			1	1-sulfonic acid butyl-3-methylimidazole inner salt	No products
2	Tetrabutylammonium bromide	51％
			3	1-butyl-3-methylimidazolium tetrafluoroborate	65％
4	Bromo-1-ethyl-3-methylimidazole	48％
			5	1-ethyl-3-methylimidazolium nonafluorobutanesulfonate	58％
6	1-butyl-3-methylimidazolium iron tetrafluoride salt	No products
			7	1-butyl-3-methylimidazolium hexafluorophosphate	80％
8	1-ethyl-3-methylimidazolium bis (trifluoromethyl) phosphoryl imide salts	48％

2.2 Effect of different reaction temperatures on the condensation coupling reaction

1, 2-phenylenediamine (1a) (1mmol) and benzaldehyde (2a) (2.05mmol) are used as condensation coupling reaction templates, and the reaction temperature is studied under the condition of no metal or acid for 1-butyl-3-methylimidazolium hexafluorophosphate [ BMIm][PF₆](3mmol) on the catalytic condensation coupling reaction (the reaction results are shown in Table 2), the condensation coupling yields were 62% and 49% respectively at 100 ℃ and 130 ℃.

TABLE 2 Effect of the reaction on the condensation coupling reaction

Comparative example	Reaction temperature	Yield of
			7	120℃	80％
8	100℃	62％
			9	130℃	49％

And (4) conclusion: as can be seen by comparative experiments, 1, 2-phenylenediamine (1a) (1mmol) and benzaldehyde (2a) (2.05mmol) are used as condensation coupling reaction templates, and the yield of condensation coupling is best when 1-butyl-3-methylimidazolium hexafluorophosphate is used as a catalyst under the reaction condition of 120 ℃ under the condition of no metal or acid.

Condensation coupling of 2.31-butyl-3-methylimidazolium hexafluorophosphate as catalyst for catalyzing different reaction substrates

1, 2-phenylenediamine (1mmol) and different aromatic aldehydes (2.05mmol) are taken as reaction substrates, and 1-butyl-3-methylimidazolium hexafluorophosphate [ BMIm ] is taken as a substrate][PF₆](3mmol) as a catalyst, the effect on the catalytic condensation coupling reaction at a reaction temperature of 120 ℃ (the reaction results are shown in Table 3)

TABLE 3 condensation coupling of different reaction substrates

Comparative example	Aromatic aldehyde type	Yield of
			10	Para-methyl benzaldehyde	65％
11	4-isopropylbenzaldehyde3c	73％
			12	4-methoxybenzaldehyde3d	78％
13	2-methoxybenzaldehyde3e	58％
			14	4-chlorobenzaldehyde3f	60％
15	2-chlorobenzaldehyde3g	52％
			16	4-fluorobenzaldehyde3h	62％
17	4-nitrobenzaldehydes3i	50％
			18	2-nitrobenzaldehydes3j	36％
19	Furanal aldehyde3k	58％
			20	Pyridine-2-carbaldehyde3l	55％

In an optimal reaction medium [ BMIm][PF₆]In the method, a series of aldehydes and 1, 2-phenylenediamine are selected to carry out condensation coupling reaction, and the experimental results are shown in table 3. In [ BMIm][PF₆]The aldehyde having an electron-withdrawing group is less reactive than the aldehyde having an electron-donating group (comparative example 10 to comparative example 18). For example, the condensation coupling yield can reach 78% when isopropyl group is present (comparative example 11), whereas the yield drops to 50% when nitro group is present (comparative example 17-comparative example 18). When the substituents are in the ortho position, the yield decreases due to steric effects when the aldehyde, whether electron-withdrawing or electron-donating, is subjected to a condensation coupling reaction. Furthermore, the aldehyde containing a hetero atom in the aromatic ring can be condensation-coupled with 1, 2-phenylenediamine, and the yield can be more than moderate (comparative examples 19 to 20).

2.4[BMIm][PF₆]Recycled in condensation coupling reaction

1, 2-phenylenediamine (1mmol), benzaldehyde (2.05mmol) and [ BMIm ] were added to the reaction tube][PF₆](2.0 g), reacted in a 120 ℃ oil bath, followed by TLC, after completion of the reaction, cooled to room temperature, extracted with petroleum ether/ethyl acetate (5: 1,10 mL. times.6), and the organic phase petroleum ether/ethyl acetate was extracted with anhydrous MgSO₄Drying, filtering, decompressing and evaporating the solvent to obtain a crude product, and separating by column chromatography to obtain the target product 1-benzyl-2-phenylbenzimidazole. Heating the extracted reaction system to remove residual petroleum ether/ethyl acetate, cooling to room temperature, and continuously adding 1, 2-phenylenediamine (1mmol) and benzaldehyde (2.05mmol) into the reaction tube to perform the next condensation coupling reaction. As shown in Table 4, it can be seen from Table 4 that after 6 cycles of use, [ BMIm ]][PF₆]The catalyst can keep higher catalytic activity in the reaction of catalyzing 1, 2-phenylenediamine and p-methylbenzaldehyde to prepare 1-benzyl-2-phenylbenzimidazole.

Table 4 exploration[BMIm][PF₆]In the case of recycling in condensation coupling reactions

Comparative example

1a

2b

3b

4b

5b

6b

Yield of

78％

77％

75％

75％

74％

72％

3. Product structural characterization

1-benzyl-2-phenylbenzimidazole (3 a): white solid, yield 80%, m.p.130-131 ℃;¹H NMR(400MHz,CDCl₃)δ:7.89(d,J＝8.0Hz,1H),7.7 0～7.67(m,2H),7.47～7.42(m,3H),7.34～7.28(m,4H),7.25～7. 19(m,2H),7.11～7.08(m,2H),5.44(s,2H)；¹³C NMR(100MH z,CDCl₃)δ:154.1,143.0,136.3,136.0,130.0,129.9,129.2,129.0, 128.7,127.7,125.9,123.0,122.7,119.9,110.5,48.3。

1- (4-methylbenzyl) -2- (4-methylphenyl) benzimidazole (3 b): white solid, yield 65%, m.p.124-125 ℃;¹H NMR(400MHz,CDCl₃)δ:7.77(d,J＝ 8.0Hz,1H),7.50(d,J＝8.0Hz,2H),7.22～7.09(m,5H),7.03(d, J＝8.0Hz,2H),6.90(d,J＝8.0Hz,2H),5.30(s,2H),2.31(s,3H),2.23(s,3H)；¹³C NMR(100MHz,CDCl₃)δ:154.2,143.1,134.0, 137.4,136.0,133.4,129.6,129.4,129.1,127.1,125.8,122.8,122.5, 119.7,110.4,48.1,21.4,21.0。

1- (4-isopropylbenzyl) -2- (4-isopropylphenyl) benzimidazole (3 c): white solid, yield 73%, m.p.175-176 ℃;¹H NMR(400MHz,DMSO)δ:7.72～7. 66(m,3H),7.42～7.38(m,3H),7.25～7.18(m,2H),7.15(d,J＝8. 0Hz,2H),6.92(d,J＝8.0Hz,2H),5.53(s,2H),2.99～2.92(m,1H),2.84～2.78(m,1H),1.23(d,J＝6.8Hz,6H),1.13(d,J＝6.8H z,6H)；¹³C NMR(100MHz,DMSO)δ:153.3,150.2,147.6,142.7, 135.9,134.3,129.0,127.7,126.8,126.7,126.0,122.5,122.1,119. 1,111.1,47.2,33.3,33.0,23.7,23.6。

1- (4-methoxybenzyl) -2- (4-methoxyphenyl) -benzimidazole (3 d): white solid, yield 78%, m.p.128-130 ℃;¹H NMR(400MHz,DMSO)δ:7.69～7. 67(m,3H),7.45～7.42(m,1H),7.24～7.18(m,2H),7.09(d,J＝8.6 Hz,2H),6.94(d,J＝8.6Hz,2H),6.84(d,J＝8.6Hz,2H),5.49(s,2H),3.82(s,3H),3.68(s,3H)；¹³C NMR(100MHz,DMSO) δ:160.4,158.5,153.2,142.7,135.8,130.5,128.8,127.4,122.4,12 2.3,122.0,119.0,114.2,114.2,111.0,55.3,55.0,46.9。

1- (2-methoxybenzyl) -2- (2-methoxyphenyl) benzimidazole (3 e): white solid, yield 58%, m.p.152-153 ℃;¹H NMR(400MHz,DMSO)δ:7.69～7. 67(m,1H),7.53～7.49(m,1H),7.44～7.42(m,1H),7.37～7.35 (m,1H),7.22～7.15(m,4H),7.07(t,J＝7.4Hz,1H),6.91(d,J＝8. 2Hz,1H),6.75(t,J＝7.4Hz,1H),6.59(d,J＝6.8Hz,1H),5.22(s, 2H),3.67(s,3H),3.66(s,3H)；¹³C NMR(100MHz,DMSO)δ: 157.1,156.4,151.9,142.9,135.2,131.9,131.6,128.7,127.5,124.2, 122.2,121.6,120.5,120.1,119.5,119.1,111.5,110.9,110.7,55.3, 55.3,42.8。

1- (4-chlorobenzyl)Yl) -2- (4-chlorophenyl) benzimidazole (3 f): white solid with yield of 60%, m, p.136-138 ℃;¹H NMR(400MHz,DMSO)δ:7.75～7.72(m,3 H),7.59(d,J＝8.4Hz,2H),7.49～7.47(m,1H),7.35(d,J＝8.4 Hz,2H),7.29～7.23(m,2H),7.02(d,J＝8.4Hz,2H),5.59(s,2H)；¹³CNMR(100MHz,DMSO)δ:152.0,142.6,135.9,135.8,134.8, 132.1,130.7,128.9,128.8,128.7,128.0,123.0,122.4,119.4,111. 0,46.8。

1- (2-chlorobenzyl) -2- (2-chlorophenyl) benzimidazole (3 g): white solid, yield 52%, m.p. 155-156 deg.C;¹H NMR(400MHz,DMSO)δ:7.79～7.70(m, 1H),7.61(dd,J＝8.0,0.8Hz,1H),7.56～7.52(m,1H),7.51～7.47 (m,2H),7.44～7.36(m,2H),7.31～7.22(m,3H),7.17～7.13(m, 1H),6.65(dd,J＝7.8,1.2Hz,1H),5.42(s,2H)；¹³C NMR(100M Hz,DMSO)δ:150.9,142.5,135.0,133.4,133.2,132.3,131.9,131. 7,129.8,129.5,129.4,128.3,127.5,127.4,123.2,122.4,119.7,11 1.0,45.2。

1- (4-fluorobenzyl) -2- (4-fluorophenyl) benzimidazole (3 h): white solid, yield 62%, m.p.110-111 ℃;¹H NMR(400MHz,DMSO)δ:7.78～7.20(m, 3H),7.50～7.47(m,1H),7.36(t,J＝8.8Hz,2H),7.28～7.22(m,2 H),7.13～7.08(m,2H),7.05～7.01(m,2H),5.56(s,2H)；13C N MR(100MHz,DMSO)δ:163.4(d,J＝156.2Hz),161.0(d,J＝152. 2Hz),152.3,142.6,135.8,133.0(d,J＝3.0Hz),131.4(d,J＝8.4 Hz),128.2(d,J＝8.4Hz),126.6(d,J＝3.0Hz),122.8,122.3,119.3, 115.9(d,J＝21.6Hz),115.6(d,J＝21.6Hz),111.1,46.8。

1- (4-nitrobenzyl) -2- (4-nitrophenyl) benzimidazole (3 i): yellow solid, yield 50%, m.p.185-187 ℃;¹H NMR(400MHz,CDCl₃)δ:8.31(d,J＝ 8.8Hz,2H),8.23(d,J＝8.8Hz,2H),7.93(d,J＝8.0Hz,1H),7.84 (d,J＝8.8Hz,2H),7.42～7.36(m,2H),7.34～7.20(m,3H),5.58 (s,2H)；¹³C NMR(100MHz,CDCl₃)δ:151.3,148.7,147.9,143.0, 142.8,135.8,135.6,130.0,126.7,124.6,124.1,123.9,120.7,110. 2,48.0。

1- (2-nitrobenzyl) -2- (2-nitrophenyl) benzimidazole (3 j): yellow solid with the yield of 36 percent, m.p.169-171 ℃;¹H NMR(400MHz,CDCl₃)δ:8.15～8.11 (m,2H),7.84(d,J＝8.0Hz,1H),7.68～7.65(m,2H),7.50～7.45 (m,3H),7.37～7.27(m,2H),7.14(d,J＝8.0Hz,1H),6.94(d,J＝7.6Hz,1H),5.69(s,2H)；¹³C NMR(100MHz,CDCl₃)δ:149.8,1 49.0,147.0,143.1,134.8,134.2,133.2,132.0,131.4,131.3,128.9, 128.3,125.4,125.3,125.1,123.9,123.1,120.5,110.2,45.7。

1- (furan-2-methyl) -2- (furan-2-yl) benzimidazole (3 k): a light yellow solid, yield 58%, m.p.88-89 ℃;¹H NMR(400MHz,DMSO)δ:8.01(d,J＝0.8 Hz,1H),7.73(d,J＝8.0Hz,1H),7.66(d,J＝7.2Hz,1H),7.54(d, J＝0.8Hz,1H),7.31～7.23(m,3H),6.76～6.75(m,1H),6.48(d, J＝2.9Hz,1H),6.38～6.37(m,1H),5.77(s,2H)；¹³C NMR(100 MHz,DMSO)δ:149.8,145.0,144.8,143.4,143.2,142.5,135.3,1 22.9,122.5,119.0,112.9,112.1,110.8,110.6,108.7,40.9。

1- (pyridin-2-methyl) -2- (pyridin-2-yl) benzimidazole (3 l): a light yellow solid with a yield of 55%, m.p.130-131 ℃;¹H NMR(400MHz,CDCl3)δ:8.49～6.46 (m,2H),8.38(d,J＝8.0Hz,1H),7.78～7.71(m,2H),7.38～7.35 (m,1H),7.27(d,J＝8.0Hz,1H),7.22～7.16(m,3H),7.05～7.02 (m,1H),6.80(d,J＝8.0Hz,1H),6.20(s,2H)；¹³C NMR(100MH z,CDCl₃)δ:157.4,150.3,149.8,149.1,148.6,142.6,136.8,136.7 8,136.7,124.5,123.8,123.7,122.9,122.2,120.9,120.0,110.7,51. 0。

the above-mentioned embodiments are merely exemplary embodiments for fully illustrating the present invention, and the scope of the present invention is not limited to the above-mentioned embodiments, but defined by the contents of the claims. All of the disclosure in this specification, and all of the methods and steps disclosed, may be combined in any combination, except combinations where features and/or steps are mutually exclusive. Each feature disclosed in the specification may be replaced by an alternative feature serving the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. Those skilled in the art should also realize that such equivalent substitutions and alterations can be made without departing from the spirit and scope of the present invention. Such modifications are also within the scope of the present invention. Each reference cited in this application is incorporated herein in its entirety.