Studies On C-O And C-N Bonds Formation Reactions Catalyzed By MCM-41-immobilized Bidentate Nitrogen Copper(Ⅱ) Acetate Complex

1.The mesoporous material MCM-41 was condensed with 3-(2-aminoethylamino)-propyltrimethoxysilane in toluene to afford the bidentate nitrogen-functionalized MCM-41 material(MCM-41-2N),the latter was reacted with Cu(OAc)2 in DMF at room temperature to give the bidentate nitrogen-functionalized MCM-41-immobilized copper(II)acetate complex [MCM-41-2N-Cu(OAc)2].This heterogenous copper catalyst was characterized by element analysis,small angler XRD,N2 adsorptiondesorption and ICP-AES.2.We studied the catalytic properties of bidentate nitrogen-functionalized MCM-41-immobilized copper(II)acetate complex [MCM-41-2N-Cu(OAc)2] in the O-arylation of nitroarenes with phenols.The results showed that in the presence of catalytic amount of MCM-41-2N-Cu(OAc)2,the C–O coupling reaction proceeded smoothly in DMF with Cs2CO3 as base at 110 oC to give the corresponding diaryl ethers in good to excellent yields.This heterogeneous copper catalyst could be recovered by a simple filtration of the reaction solution,and recycled for several times without significant loss of activity,providing a novel,practical and green route to substituted diaryl ethers.3.We investigated the catalytic properties of bidentate nitrogen-functionalized MCM-41-immobilized copper(II)acetate complex [MCM-41-2N-Cu(OAc)2] in the tandem oxidative cyclization of various benzylamines with different 1,3-dicarbonyl compounds.The results showed that this heterogeneous copper-catalyzed tandem oxidative cyclization of various benzylamines with different 1,3-dicarbonyl compounds could proceed smoothly to afford a variety of polysubstituted oxazoles in good to excellent yields.This heterogeneous copper catalyst could be easily separated from the product,and recycled for several times without significant loss of activity,providing a novel,practical and green route to polysubstituted oxazoles.4.We investigated the catalytic properties of bidentate nitrogen-functionalized MCM-41-immobilized copper(II)acetate complex [MCM-41-2N-Cu(OAc)2] in the cascade annulation of amidines with methylarenes.The results showed that in the presence of catalytic amount of MCM-41-2N-Cu(OAc)2,the cascade annulation of amidines with methylarenes proceeded smoothly to give a variety of 3,5-disubstituted 1,2,4-oxadiazoles in good to high yields.This heterogeneous copper catalyst could be recycled for several times without significant loss of activity,providing a novel,practical and green route to 3,5-disubstituted 1,2,4-oxadiazoles.