Design And Synthesis Of Basic Ionic Liquids And Their Catalytic Preparation Of Quinazolinones From CO₂

As a major greenhouse gas,CO₂ is also an abundant,readily available and renewable natural C1 resource.Achieving efficient resource utilization of CO₂ is of great significance to both environmental protection and sustainable development,and is in line with the international strategic goals of "carbon peaking" and "carbon neutrality".In this paper,a series of basic ionic liquid-based catalytic systems were designed and synthesized to achieve efficient conversion of CO₂ under normal pressure and mild conditions,and quinazolinones with different substituents were synthesized in high yields.The specific research contents and results are as follows:1.A series of binary catalytic systems were synthesized via organic base-coupled ionic liquids in which 1,8-diazabicyclo[5.4.0]undec-7-ene（DBU）was coupled to 1-butyl-3-methyl The DBU/[Bmim][OAc]catalyst system synthesized from imidazole acetate（[Bmim][OAc]）has the best activity.Under the conditions of normal pressure,60℃,and no other solvent addition,CO₂ and 2-aminobenzonitrile were realized,and a series of quinazolinones with different substituents were efficiently synthesized with a yield of up to 98%.The catalytic system exhibited good substrate universality and could catalyze the conversion of various 2aminobenzonitrile derivatives.In addition,the ionic liquid[Bmim][OAc]has good stability and recyclability,and its quinazolinone yield remains basically unchanged after five cycles.The mechanistic studies showed that DBU could react with CO₂ to form a carbamate intermediate,which realized the activation and conversion of CO₂.At the same time,the[OAc-]anion of[Bmim][OAc]ionic liquid could activate the substrate 2-aminobenzonitrile through hydrogen bonding.Thereby,the two synergistically promote the reaction to generate the target product.2.A series of protic basic ionic liquids were designed and synthesized,among which 1,8diazabicyclo[5.4.0]undec-7-ene-2-hydroxypyridine（[HDBU][2-Py]）could catalyze the conversion of CO₂ and 2-aminobenzonitrile to synthesize the corresponding quinazolinones with a yield of 92%under the conditions of normal pressure,60℃,and no other solvent addition.Furthermore,[HDBU][2-Py]could catalyze the conversion of 2-aminobenzonitrile with different substituents to synthesize the target product in high yield.In addition,the product of the catalytic system was easy to separate,and the ionic liquid is recycled for 5 times,and its catalytic activity did not change significantly.Mechanistic studies showed that the anion and cation of[HDBU][2-Py]respectively form hydrogen bonds with 2-aminobenzonitrile to achieve effective molecular activation.At the same time,the ionic liquid could activate atmospheric CO₂ to convert into carbamate,so that the activated substrate and CO₂ intermediate could further react to generate quinazolinone product.3.A series of aprotic alkaline ionic liquids were designed and synthesized,in which choline triazole（[Ch][Triz]）can catalyze the reaction between CO₂ and 2-aminobenzonitrile to synthesize the corresponding quinazolinones and their derivatives at normal pressure,50℃,and without any solvent,and the yield was up to 96%.The basic ionic liquid[Ch][Triz]exhibited excellent universality to 2-aminobenzonitrile and its derivatives,and could catalyze the efficient conversion of various substrates.In addition,the ionic liquid has excellent stability,and the yield of quinazolinone almost always tends to be stable after being recycled for 5 times.The mechanistic exploration showed that[Ch][Triz]could activate the amino and cyano groups in atmospheric CO₂ and 2-aminobenzonitrile,respectively,and effectively promote the reaction to synthesize the target product.The excellent catalytic performance of this ionic liquid can be attributed to its triple activation of three different reaction centers for the two reactants.