The Application Of Lewis Acid Catalyst Added Montmorillonite In Organic Synthesis Studies

Using the porous structure and large specific surface area of montmorillonite,Lewis acids such as metal chlorides and Iodine are loaded onto montmorillonite to prepare supported Lewis acid catalysts,which are used to catalyze the synthesis of Bis?indole?methane and the Biginelli reaction,Knoevengle reaction,Hantzsch ester synthesis and many other reactions.Montmorillonite is a layered silicate structure with a large specific surface area,and it is rich in natural resources,cheap and easy to obtain,and the Lewis acid can be loaded onto montmorillonite to form a synergistic catalytic effect;The large specific surface area can effectively improve the catalytic efficiency of the catalyst,improve a large amount of Lewis acid,difficulty in recovery,and the like,and can also improve the disadvantages of easy sublimation of iodine.The reaction conditions of several types of reactions under microwave,ultrasound,etc.,were investigated to find that microwave,ultrasonic and other auxiliary technologies provided a special physical and chemical environment for the reaction,which can further shorten the reaction time and reduce energy while ensuring the yield.Consumption.The main conclusions are as follows:1.Synthesis of diterpene methane derivatives:Using hydrazine and aldehyde as raw materials,montmorillonite immobilized Lewis acid as catalyst?a?.Montmorillonite immobilized metal chloride as a catalyst,synthesizing diterpene under ultrasonic conditions Deuterium methane derivatives.The optimal synthesis conditions were obtained as follows:the molar ratio of indole to aldehyde was n?indole?:n?aldehyde?=2.0:1.1,and the montmorillonite-supported cupric chloride was the catalyst?amount of 10mol%aldehyde?.Dichloromethane was used as a solvent,the reaction temperature was 50°C,and the ultrasonication time was 15 min.At this time,the yield was up to 99.3%.b.The montmorillonite-supported metal chloride was used as a catalyst to synthesize the bis-indole methane derivatives by microwave.The optimal synthesis conditions were obtained by screening:MMT/NiCl₂ as the catalyst?amount of 10mol%aldehyde?,dichloromethane as solvent,reaction temperature60°C,time 2 min,the molar ratio of aldehyde to indole is 1.1:2.0.The yield is up to93.4%;c.The montmorillonite-supported iodine?10mol%of aldehyde?as a catalyst,and the optimal conditions for synthesis of the bis-indole methane derivative under magnetic stirring are:the ratio of the amount of aldehyde to indole is 1.1:2.0,acetonitrile as a solvent,stirring at 25°C for 5 min.The highest yield of 96.2%was obtained.2.Biginelli reaction study:Aromatic aldehyde,ethyl acetoacetate and urea as raw materials,montmorillonite immobilized Lewis acid as catalyst,synthesis of3,4-dihydropyrimidin-2?1H?-one derivativesa.The montmorillonite loaded metal chloride was used as a catalyst to synthesize3,4-dihydropyrimidin-2?1H?-one derivatives under ultrasonic conditions.The reaction temperature was 90°C and the ultrasonication time was 15 min.The molar ratio of aromatic aldehyde,ethyl acetoacetate and urea was 1.2:1.0:1.0,the catalyst is montmorillonite-supported copper chloride?with an amount of 20%mol urea?under the optimal conditions,the highest yield of 88.4%;b.Montmorillonite immobilized metalchlorideascatalyst,microwave-assistedsynthesisof3,4-dihydropyrimidin-2?1H?-one derivatives,reaction temperature 90°C,microwave time 10 min.The molar ratio of aromatic aldehyde,ethyl acetoacetate and urea is1.0:1.2:1.2,the catalyst is montmorillonite-supported copper chloride?with an amount of 10%mol aldehyde?under the optimal conditions,the highest yield up to 95.7%;c.MontmorilloniteloadedI2wasusedascatalysttosynthesize3,4-dihydropyrimidin-2?1H?-one derivatives under solvent-free magnetic stirring.The reaction was completed in 15 min.The reaction temperature was 90°C.Aromatic aldehyde,ethyl acetoacetate and urea were used.The molar ratio is 1.0:1.0:1.0 and the amount of catalyst was 10 mol%of aldehyde.Yield up to 94.7%;d.montmorillonite-supported I₂ was used as a catalyst to synthesize3,4-dihydropyrimidin-2?1H?-one derivatives under ultrasonic conditions.The optimum conditions were as follows:reaction temperature 80°C,ultrasonic time 5min,ethanol as solvent,molar ratio of aromatic aldehyde,ethyl acetoacetate and urea is 1:1:1,and catalyst amount of 10 mol%aldehyde.Yield up to 86.9%.3.Hantzsch ester synthesis reaction:Witj aromatic acid,acetylacetone/ethyl acetoacetate,and ammonium bicarbonate as starting materials,montmorillonite loaded Lewis acid as catalyst,synthesis of Hantzsch ester.a.The microwave-assisted synthesis of Hantzsch ester,the reaction temperature of80°C,microwave irradiation time 15min,aromatic aldehyde,acetylacetone/ethyl acetoacetate and ammonium bicarbonate molar ratio of 1.0:2.4:1.0,the catalyst is montmorillonite-supported nickel chloride?amount of 10 mol%aldehyde?.The yield of synthesized Hantzsch ester can be up to 98.4%;b.The Hantzsch ester was synthesized under ultrasonic conditions.The reaction temperature was 80°C and the ultrasonication time was 15 min.The molar ratio of aldehyde,acetylacetone/ethyl acetoacetate and ammonium bicarbonate was 1.2:2.0:1.0.The catalyst was montmorillonite-supported aluminum chloride?amount of 10mol%aldehyde?.The yield of synthesized 1,4-dihydropyridine derivatives was up to 93.7%under the optimum conditions.4.Knoevenagel reaction study:catalyzed Knoevenagel reaction using aldehyde and malononitrile as raw materials,montmorillonite loaded with iodine and alkali additives as catalystsa.The Knoevenagel reaction was carried out under magnetic stirring.The reaction conditions were as follows:The amount of montmorillonite loaded iodine was 5mol%of aldehyde,the same stoichiometric amount of?CH3COO?2Zn as a base additive,ethanol was used as solvent,and the molar ratio of aldehyde to malononitrile was 1.0:1.0,reaction temperature 45°C,reaction time 15 min,the highest yield up to93.0%;b.Under ultrasonic conditions,the reaction conditions were as follows:The amount of montmorillonite loaded iodine was 5 mol%of aldehyde,equimolar amount of Na2CO3 as additive,ethanol as solvent,molar ratio of aldehyde to malononitrile was 1.0:1.1,reaction temperature 45°C,the reaction time is 5 min,the highest yield of 95.5%;c.Under microwave irradiation,the reaction conditions were as follows:The amount of montmorillonite loaded iodine was 5 mol%of aldehyde,equimolar amount of CH₃COONa as additive,ethanol as solvent,raw material molar ratio aldehyde to malononitrile 1.0:1.0,under 40°rreaction time 2min,the highest yield of 97.0%.