2001 Fiscal Year Final Research Report Summary
Synthesis of functional Amino Polysaccharides by Branching of Linear Polysaccharides
| Project/Area Number |
12650872
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
高分子合成
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| Research Institution | Seikei University |
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Principal Investigator |
KURITA Keisuke Seikei University, Dept.Of Applied Chemistry, Professor, 工学部, 教授 (30102180)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMOJOH Manabu Toyo Suisan Kaisha, Div, of research, Researcher, 研究員
HARATA Manabu Seikei University, Dept.Of Applied Chemistry, Reserch Associate, 工学部, 嘱託助手
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| Project Period (FY) |
2000 – 2001
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| Keywords | Chitin / Chemical modification / Branched polysaccharide / Functional Polysaccharide / Phthaloylation / Silylation / Glycosylation / Antimicrobial activity |
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| Research Abstract |
Chitin is important as an unutilized biomass resource in view of its high potential in various fields. Our interest has been focused on the synthesis of chitin derivatives with advanced functions, particularly those having branches, because of the distinctive biological activities as well as unique physicochemical properties of this amino polysaccharide.
Although chemical modifications of chitin are generally difficult, a series of regioselective and quantitative modification reactions became possible using N-phthaloyl-chitosan. Based on this precursor, branched chitin and chitosan were prepared. The resulting products were water-soluble and exhibited various interesting properties such as biodegradability and antimicrobial activity. Phthaloylated chitosan has thus proved to be an indispensable precursor for efficient modifications, but phthaloylation usually results in partial O-phthaloylation besides N-phthaloylation. In dimethylformamide containing some water, however, chemoselectively N-phthaloylated chitosan could be prepared in one-step.
Trimethylsilylation of chitin was also examined in detail to give a fully substituted product. It was readily soluble in common solvents and showed high reactivity in some reactions. For instance, glycosylation of silylated chitin gave branched chitin, and this process is much simpler than that based on N-phthaloyl-chitosan.
Mercapto-chitin easily generated free radicals on mild heating due to the presence of labile mercapto groups. Graft copolymerization of methyl methacrylate thus proceeded efficiently to give chitin-graft-poly(methyl methacrylate). The methyl methacrylate units in the introduced side chains could be hydrolyzed under appropriate conditions to form sodium methacrylate units, which were in turn transformed into methacrylic acid units by treatment with acid. These modifications of the side chains enabled fine control of properties including solubility, hygroscopicity, and biodegradability.
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