With 2 - Methyl-benzimidazolyl Isoflavone Derivatives Synthesis And Antioxidant Activity

A method for the synthesis of 2-methyl-benzimidazolyl isoflavone derivatives have been reported.Deoxybenzoin(3) was prepareded by using the resorcinol and substituted phenylacetic as starting meterials in microwave-mediated.Then the compound(3) was reacted with acetic anhydride to produce(4).The compound(4) was hydrolyzed to convert compound(5) in the acid-mediated. The compound(5) was reacted with the 1,2-dibromo-ethane and 1,3-dibromo-propane in refluxed condition with acetone as solvent to give(6) or(7),respectively.Lastly,the title compounds were synthesized by refluxing(6) or(7) with 2-methyl-benzimidazole and potassium carbonate in acetone solution.In this method,thirty-five compounds including ten kinds of 2-methyl-benzimidazolyl isoflavone derivatives were synthesized via five steps.All the structures of target compounds were confirmed by IR,¹H NMR,¹³C NMR,elemental analysis and so on.The target compounds have not been reported in documents so far by way of searching sciFinder Scholar.During synthesis of all target compounds,we not only have optimized the reaction condition of C-O bond and C-N bond but also have introduced successfully the microwave promoting method to our protocol which shortened the reaction time greatly.The antioxidative ability of ten target compounds have been investigated, all of them possess good scavenging capacity to free radical.The results of experiment on radical scavenging effect suggest that the ability of scavenging radical not only releted to the numbers of hydroxyl and the length of allyl-chain which join with 7-hydroxy but also possibly releted to the structure of the group which join with 7-hydroxy.The other actives of ten target compounds will be further undergoes in future.This thesis is consisted of three parts as follows:Chapter one,the researching progress in the derivatives of isoflavone was described.There are mainly involving two aspects:The section one is researching progress in synthetic methods.For example,deoxybenzoin method,oxidation rearrangement,Pd-catalyzed cross-coupling method, one-pot method and microwave-mediated synthesis et al.Currently,deoxybenzoin method is applied extensively because of facile materials and mild reaction condition.The section two is researching progress in the pharmacological effects of isoquinolinones such as disinfection,anticancer, antifungal,antiosteporosis and therapy vascular diseases.Chapter two,ten target compounds were designed and synthesized by our protocol. 4'-chloro-2-methyl-7-(2-(1H-(2-methyl-benzimidazole)-1-yl)ethoxy) isoflavone(1a),2,4'-dimethyl -7-(2-(1H-(2-methyl-benzimidazole)-1-yl)ethoxy) isoflavone(1b),2-methyl-7-(2-(1H-(2-methyl-benzimidazole) -1-yl)ethoxy) isoflavone(1c),4'-methoxy-2-methyl-7-(2-(1H-(2-methyl-benzimidazole) -1-yl)ethoxy) isoflavone(1d),4'-hydroxy-2-methyl-7-(2-(1H-(2-methyl-benzimidazole) -1-yl)ethoxy) isoflavone(1e),4'-chloro-2-methyl-7-(3-(1H-(2-methyl-benzimidazole) -1-yl)propoxy) isoflavone(2a),2,4'-dimethyl-7-(3-(1H-(2-methyl-benzimidazole) -1-yl)propoxy) isoflavone(2b),2-methyl-7-(3-(1H-(2-methyl-benzimidazole)-1-yl)propoxy) isoflavone(2c),4'-methoxy-2-methyl-7-(3-(1H-(2-methyl-benzimidazole)-1-yl)propoxy) isoflavone (2d),4'-hydroxy-2-methyl-7-(3-(1H-(2-methyl-benzimidazole)-1-yl)propoxy) isoflavone(2e).All of these target compounds were never reported so far,and their structure were confirmed by IR,¹H NMR,¹³C NMR,elemental analysis.Chapter three,a pilot evaluation on their antioxidative activity of the title compounds was investigated by safranine T-Mn²⁺-H₂O₂ system.The results indicated that the antioxidative activity has been enhanced by the introducing of 2-methyl-benzimidazolyl.All of the target compounds possess good scavenging capacity to free radical.The other activity of the compounds will be further investigated.