Synthesis Of N-heterocyclic Compounds And Aldehydes Catalyzed By Copper Complexes Immobilized Onto Mesoporous MCM-41 Or SBA-15

In this dissertation,we have studied the preparation of mesoporous SBA-15 or MCM-41-supported copper(Ⅰ)complex catalysts and their application in the synthesis of N-heterocyclic compounds and aldehydes.The main research work is divided into three parts as follows:1.The new mesoporous material MCM-41-immobilized copper(Ⅰ)complex[L-Proline-Cu I-MCM-41] was synthesized from easily available starting materials and characterized by different physico-chemical techniques.The application of this heterogenized copper complex in the tandem cyclization between o-haloanilides and primary amines was investigated.The results show that in the presence of 10 mol%L-Proline-Cu I-MCM-41 and K2CO3,the cyclization reaction of various o-haloanilides with different primary amines can proceed smoothly in DMSO at 25-50 ℃,furnishing a broad range of 1,2-disubstituted benzimidazoles with mostly good to high yields.The heterogenized L-Proline-copper(Ⅰ)iodide complex displays a similar catalytic efficiency to the homogeneous analogue(L-Proline/Cu I)and is facile to recover by a simple centrifugation,and can be reused more than 7 times without any remarkable loss of its catalytic efficiency.Therefore,this work provides an efficient and practical green method for the synthesis of 1,2-disubstituted benzimidazoles.2.The MCM-41-immobilized bidentate nitrogen copper(Ⅰ)complex catalyst[MCM-41-2N-Cu Br] was prepared according to our previously reported procedure and the application of MCM-41-2N-Cu Br in three-component tandem cyclization of ketoxime acetates,aldehydes,and activated methylene compounds was studied.The results show that in the presence of 10 mol% MCM-41-2N-Cu Br and Li2CO3,various ketoxime acetates can react effectively with aldehydes and active methylene compounds in DMSO at 120 ℃,delivering diverse functionalized pyridines with good to excellent yield.The heterogenized copper(Ⅰ)catalyst exhibits high activity and can be readily obtained via a simple preparative procedure from commercially available and inexpensive reagents,and reused more than seven times without any apparent drop in its catalytic efficiency.Therefore,this work offers a simple and efficient green approach for the synthesis of diverse functionalized pyridines.3.The addition of di(pyridin-2-yl)amine to triethoxy(3-isocyanatopropyl)silane gave 1,1-di(pyridin-2-yl)-3-(3-(triethoxysilyl)propyl)urea [(Et O)3Si-Dpu].The latter was then condensed with mesoporous SBA-15 followed by reacting with Cu I to afford the 1,1-di(pyridin-2-yl)urea-functionalized SBA-15-anchored copper(Ⅰ)iodide complex [Dpu-SBA-15-Cu I].The structure of the heterogeneous copper catalyst was characterized by small-angle X-ray diffraction(XRD),X-ray energy dispersive spectroscopy(EDS),nitrogen adsorption/desorption(BET)and Fourier transform infrared spectroscopy(FT-IR).We investigated its catalytic behavior in aerobic oxidation of primary aliphatic,allylic,propargylic and benzylic alcohols to aldehydes.The results show that in the presence of 3 mol% Dpu-SBA-15-Cu I and 4 mol% of TEMPO,diverse primary alcohols can be oxidized to corresponding aliphatic,α,β-unsaturated and aromatic aldehydes in good to excellent yields at room temperature under base-free conditions.The new supported copper catalyst has excellent catalytic performance and can be separated from the product by a simple filtration operation.The recovered copper(Ⅰ)catalyst can be recycled at least ten times without any significant loss of activity.The use of reusable copper catalyst and air as the oxidant,as well as mild and base-free conditions make this protocol attractive for environmentally sustainable processes.