New Heterogeneous Catalysts Derived from Chitosan for Clean Technology Applications

Macquarrie, Duncan J.; Hardy, Jeffrey; Hubert, Sandrine; Deveaux, Alexa J.; Bandini, Marco; Alvarez, R; Chabrel, Marie

doi:10.1021/bk-2006-0921.ch013

Cited by 4 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Chitosans, fully or partially deacetylated chitin derivatives, and their modifications [3] possess antiviral and antimicrobial properties [4], and know a number of applications, being useful in enzyme inhibition and immobilization [5], in grafts copolymerization [6], as carriers for drugs [7] and genes [8], and for biomedical purposes such as wound healing and immunostimulation [9]. Further applications include their use as food supplements or preservatives [10], as adsorbents of metals [11], for treatment of waste waters [12], as support for heterogeneous catalysis [13], and as packaging material [14]. The NH 2 group at C(2) of chitosan was modified in many ways, mostly by N-alkylation [15], N-acylation [16], N-phosphorylation [17], Nsulfation [18], and by condensation with thiolated reagents [19].…”

mentioning

confidence: 99%

2‐Azido‐2‐deoxycellulose: Synthesis and 1,3‐Dipolar Cycloaddition

Zhang

Bernet

Bonnet

et al. 2008

Helvetica Chimica Acta

View full text Add to dashboard Cite

Chitosan (1) was prepared by basic hydrolysis of chitin of an average molecular weight of 70000 Da, 1 H-NMR spectra indicating almost complete deacetylation. N-Phthaloylation of 1 yielded the known Nphthaloylchitosan (2), which was tritylated to provide 3a and methoxytritylated to 3b. Dephthaloylation of 3a with NH 2 NH 2 · H 2 O gave the 6-O-tritylated chitosan 4a. Similarly, 3b gave the 6-O-methoxytritylated 4b. CuSO 4 -Catalyzed diazo transfer to 4a yielded 95% of the azide 5a, and uncatalyzed diazo transfer to 4b gave 82% of azide 5b. Further treatment of 5a with CuSO 4 produced 2-azido-2-deoxycellulose (7). Demethoxytritylation of 5b in HCOOH gave 2-azido-2-deoxy-3,6-di-O-formylcellulose (6), which was deformylated to 7. The 1,3-dipolar cycloaddition of 7 to a range of phenyl-, (phenyl)alkyl-, and alkylmonosubstituted alkynes in DMSO in the presence of CuI gave the 1,2,3-triazoles 8 -15 in high yields. 2-Azido-2-deoxycellulose should be available from chitosan by diazo transfer. 1,3-Cycloadditions of 2-azido-2-deoxycellulose to alkynes should introduce 1,2,3-triazolyl side chains into chitosan and formally into cellulose, similarly as it is known for 6-azido-6-deoxypolysaccharides [20] [21] 1 ). In the following, we describe the synthesis of 2-azido-2-deoxycellulose and its reactivity in the 1,3-dipolar cycloaddition to alkynes, leading to new chitin/cellulose derivatives.

show abstract

mentioning

confidence: 99%

2‐Azido‐2‐deoxycellulose: Synthesis and 1,3‐Dipolar Cycloaddition

Zhang

Bernet

Bonnet

et al. 2008

Helvetica Chimica Acta

View full text Add to dashboard Cite

show abstract

“…[24][25][26] We have shown that chitosan forms stable (leachingresistant) complexes with palladium and nickel by borrowing surface complexation developed for silica. 27 The resulting chitosan-metal complexes show comparable activity to the original silica materials in Heck and Suzuki coupling reactions (Pd catalysts) and in Baeyer-Villiger oxidations (Ni catalysts) (Fig.…”

Section: Chitosanmentioning

confidence: 99%

Green Chemistry and the Biorefinery: A Partnership for a Sustainable Future

Clark

2007

ChemInform

View full text Add to dashboard Cite

show abstract

“…To date chitosan derived from the shells of crustaceans has been proven to be a suitable support for palladium. [10][11][12][13][14][15] We have recently developed expanded starch as a novel catalyst support 16 and as a chromatographic medium. 17,18 Various surface modifications have been made to the starch, including attachment of amino-moieties.…”

Section: Introductionmentioning

confidence: 99%