| Budget Amount *help |
¥3,950,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2007: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2006: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
Although microwave has been applied for chemical reactions, especially as an effective heating tool, we have had some hints that microwaves could also bring nonthermal effects through, studying three of carbohydrate-related synthetic studies.
1) Glycosylation using methyl glycoside donor : Methyl glycosides are very stable compounds and easy to be prepared and easy to be handled, but they were not suitable as glycosyl donors because the conditions to activate methoxy group could also cut C-O bond off in sugar ring. Nevertheless this background, methyl glycosides could behave as glycosyl donors under microwave irradiation with Lewis acids. Transglycosylation from methyl to octyl was performed in 88% yield.
2) Microwave irradiation at low temperatures to synthesize Lewis X oligosaccharide : Galactosylation onto 4-OH in a fucosyl glucosamine accepted has not achieved without microwave support, which yielded only side reactions and byproducts, namely cleavage of the fucosyl bond, nucleophili
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c reactions by methylthio group and so on. Nevertheless this background, microwave irradiation at low temperature gave fruitful result.
3) Microwaves accelerated glycopeptide synthesis : In our experiment as coupling of a threonine having acetylated Core2 trisaccharide to an alanine onto Tenta gel resin, warming up to 50℃ by pulsed microwave irradiation pushed up to 98% yield while the reaction in the same temperature by conventional heating gave only 93% yield. Based on these preliminary experiments, we synthesized the MUC1 repeating unit which consisted of twenty of amino acid residues with five of acetylated Core2 trisaccharides. Microwave led fourteen times faster preparation or three times higher yield.
4) Other than above, we have studied for development of immobilized reagents, microwave effects for enzyme reactions and related cyclodextrin effects basical study for gold-nanoparticle supported oligosaccharide syntheses and development of glycopeptide reactor using microwave irradiation effectively. Less
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