A Copper-Based Metal-Organic Framework as an Efficient and Reusable Heterogeneous Catalyst for Ullmann and Goldberg Type C-N Coupling Reactions.

Wei Long,Chongwei Guo,Guizhen Zhang,Hong He,Liyun Song,Wenge Qiu,Chuanqiang Li,Guangmei Bai

doi:10.3390/molecules201219756

Abstract

A highly porous metal-organic framework (Cu-TDPAT), constructed from a paddle-wheel type dinuclear copper cluster and 2,4,6-tris(3,5-dicarboxylphenylamino)-1,3,5-triazine (H6TDPAT), has been tested in Ullmann and Goldberg type C–N coupling reactions of a wide range of primary and secondary amines with halobenzenes, affording the corresponding N-arylation compounds in moderate to excellent yields. The Cu-TDPAT catalyst could be easily separated from the reaction mixtures by simple filtration, and could be reused at least five times without any significant degradation in catalytic activity.

Highlights

The N-aryl heterocycles are very important structural motifs in biological, pharmaceutical and material science products [1,2,3]
The coupling reactions of 4-nitro-N-methylaniline proceeded with difficulty to give the N-arylation product in a low yield (Table 2, entry 7). These results demonstrated that the electronic properties of the substituent(s) on the aryl amine play an important role in determining its reactivity in the C–N coupling reactions
A detailed investigation of N-arylation reaction of 5-methyl-2-(1H)-pyridone with halobenzenes was carried out using Cu-TDPAT, a metal-organic framework with high density of open copper sites within its framework, as an efficient heterogeneous catalyst

Summary

Introduction

The N-aryl heterocycles are very important structural motifs in biological, pharmaceutical and material science products [1,2,3]. 1,3,5-benzenetricarboxylate molecules, exhibited high activity in the C–N coupling reaction showed that both copper(I) salts—CuI and CuCl—produced pirfenidone in high yield, while the copper(II) salts resulted in relative low yields of coupled product. A widely used MOF, namely MCuoleBcTulCes 2[08135], 2(0F,ipgaugree–psaSg6e and S7) that was constructed from paddle-wheel type copper clusters and 1,3,5-benzenetricarboxylate molecules, exhibited high activity in the C–N coupling reaction between iodobenzene and 5-methyl-2-(1HH)-pyridone (Table 1, entry 19), but the poor stability of CuBTC uunnddeerr tthheerreeaacctitoionnccoonndditiitoionnsspprervevenentetdeditsitsrerceyccylcinlign.gS.imSimlarilaprhepnhoemnoemnaenwaerweerreeproerpteodrtbedy GbyarGciaarc[7ia5][7a5n]daKndanKtamnta[8m4][.8I4n].thIne cthaseecoafseCoufBCTuCB, TaCh,igahhyigiehldyi(e8l8d%()88o%f 1) wofa1s wobatsaionbetda,inwehdi,cwh hwicahs mwauschmuhicghhherighthearnthtahnatthoaft tohfethheohmoomgoengenoueosucsactaltyatlyicticprporcoecsessessescacatatalylyzzeeddbbyy CCuu((NNOO33)) oorr both Cu(NO33))22aannddBBTTCC((TTaabbllee11,,eennttrriieess1188aanndd2200).).MMoorereoovveer,r,tthheessaammeerreessuulltt wwaass aallssoo oobbseerved in the compaarriissoonnooffCCuu-T-TDDPPAATTananddCCu(uN(NOO3)23/T)2D/PTADTPA(TTab(Tleab1l,een1t,rieenst4riaensd42a1n).dO2w1i)n. The coupling reactions of 4-nitro-N-methylaniline proceeded with difficulty to give the N-arylation product in a low yield (Table 2, entry 7). DMSO, KOH, 125 ̋C, 24 h H2O, K3PO4, 120 ̋C, 8 h H2O, KOH, 120 ̋C, 12 h Toluene, Cs2CO3, 100 ̋C, 8 h DMSO, K2CO3, 120 ̋C, 8 h

Mechanistic Considerations

General Information

Catalytic Reactions

Reuse of Cu-TDPAT

Findings

Conclusions