An efficient and recyclable chitosan supported copper(II) heterogeneous catalyst for C–N cross coupling between aryl halides and aliphatic diaminesTetrahedron Letters

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Authors
Chandan Bodhak, Ashis Kundu, Animesh Pramanik
Year
2015
DOI
10.1016/j.tetlet.2014.11.120
Subject
Organic Chemistry / Biochemistry / Drug Discovery

Text

Accepted Manuscript

An efficient and recyclable chitosan supported copper(II) heterogeneous catalyst for C-N cross coupling between aryl halides and aliphatic diamines

Chandan Bodhak, Ashis Kundu, Animesh Pramanik

PII: S0040-4039(14)02034-6

DOI: http://dx.doi.org/10.1016/j.tetlet.2014.11.120

Reference: TETL 45504

To appear in: Tetrahedron Letters

Received Date: 8 September 2014

Revised Date: 25 November 2014

Accepted Date: 26 November 2014

Please cite this article as: Bodhak, C., Kundu, A., Pramanik, A., An efficient and recyclable chitosan supported copper(II) heterogeneous catalyst for C-N cross coupling between aryl halides and aliphatic diamines, Tetrahedron

Letters (2014), doi: http://dx.doi.org/10.1016/j.tetlet.2014.11.120

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An efficient and recyclable chitosan supported copper(II) heterogeneous catalyst for C-N cross coupling between aryl halides and aliphatic diamines

Chandan Bodhak, Ashis Kundu and Animesh Pramanik*

Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata-700 009, India;

Fax: +91-33-2351-9755; Tel: +91-33-2484-1647.

E-mail: animesh_in2001@yahoo.co.in

Abstract: A useful and convenient methodology has been developed for synthesis of mono

N-arylated aliphatic 1,2- and 1,3-diamines and amino alcohols. A highly efficient and renewable heterogeneous chitosan supported copper(II) catalyst has been employed for the C-N cross coupling between aryl halides and aliphatic diamines/amino alcohols. The main advantages of this reaction are the high yield of the products, reduced reaction time, convenient work up procedure, renewability of the catalyst and less metal contamination of the products. All these factors make the present C-N cross coupling reaction economical, green and sustainable.

Keywords: Aryl halides, 1,2- and 1,3- diamines/amino alcohols, chitosan@copper catalyst, chelation pathway.

Nitrogen-containing compounds are ubiquitous among biologically active molecules.1 The development of efficient methodologies for generating C–N bonds are of great importance due to their wide applicability in pharmaceutical as well as agrochemical research.2 The C-N bond forming 2 reactions also produce N-arylated amino moieties which are essential components of many bioactive compounds, such as oxcarbazepine and imatinib.3 Moreover many polyamines are used in coordination and biological chemistry, cellular growth, and ribonucleic acid transcription activity as well as in protein synthesis and regulation of immune responses.4,5

Many C-N coupling reactions such as Ullmann reaction,6 Chan-Lam coupling reaction,7 and Buchwald-Hartwig amination reactions8 are reported in the literature. In all these reactions various metal catalysts such as palladium, nickel9,10 and copper11,12 are employed along with different coordinating ligands such as bisamines,13 amino acids,14 DPPF,15 phosphoramidites,16 and oxime-phosphine oxides.17 Although these catalysts and ligands are used in low loadings they are very expensive and the toxicity caused by the presence of metals in the products is a serious disadvantage of these reactions.18 Previously Han et al.19 reported N-arylation of amines/amino alcohols with aryl halides using free CuCl as catalyst which causes high metal contamination of the final products and also the reaction takes longer time (~ 8 h). Aguiar et al.20 reported the use of

Cu2O and CuO nanoparticles (NPs) as catalysts in N-arylation reactions which demand N2 atmosphere and prolonged reaction times (~12-48 h). Therefore development of new methodologies taking into consideration of reduction of reaction time, minimum metal contamination of products, simple reaction conditions, easy isolation of products and catalysts, and renewability of catalyst is highly desirable. In this regards applications of environment-friendly polymer supported metal catalysts are very promising due to low cost and less toxicity.21 Chitin is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (acetylated unit),22 which is the principal component of protective cuticles of crustaceans such as crabs, shrimps, prawns, lobsters and cell walls of some fungi such as aspergillus and mucor.23 Generally chitosan which possesses both free amino and alcoholic groups is prepared by alkaline deacetylation of chitin. In the present 3 paper we wish to report a new strategy for C-N cross coupling between aryl halides and aliphatic diamines/amino alcohols using an efficient and ecofriendly chitosan scaffold based copper(II) catalyst (chitosan@copper). The chitosan@copper catalyst was prepared following a simple procedure where the copper sulfate was immobilized over the chitosan scaffold (Scheme 1). 24,25

Scheme 1. Schematic representation of preparation of chitosan embedded copper catalyst

In order to find out the appropriate reaction conditions for the C-N coupling, initially we have carried out an optimization study for N-arylation reaction employing iodobenzene 1a and ethylenediamine 2a in a ratio of 1:2 equiv using different catalysts, reactions time and solvent systems (Table 1). When the reaction was carried out in different solvents such as THF, CH3CN and EtOH without using any catalyst, the reaction did not proceed at all even after prolonged refluxing (Table 1, entries 1-3). Then the reaction was performed with 5 mol% CuI as catalyst in

O

OH

HO NH2

O O

HO NH2

OH

O

O

HO NH2

OH

O O

HO NH2

OH

O

O

HO

OHH2N

O

O

OHH2N

HO

O

O

OHH2N

HO

OO

OHH2N

HO

O

CuSO4Stirring, 3 hr

H2O

O

OH

HO NH2

O

O

HO NH2

OH

O

O

HO NH2

OH

O