| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2015: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2014: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Outline of Final Research Achievements |
We focused N-glycosylation reactions to investigate the potential of acidic azolium salts as catalysts. First, various acidic azolium salts were prepared by mixing azoles and acids. We selected nonhygroscopic salts and used them as catalysts. Using suitably protected β-D-ribofuranoses as glycosyl donors, we found that an acidic oxazolium perchlorate was the most active catalyst. On the basis of this result, we prepared a solid-supported acidic oxazolium perchlorate. This salt was found to be an easy-handling catalyst for the synthesis of modified pyrimidine nucleosides via Vorbrueggen-type N-glycosylation. Because the polymer residue derived from the catalyst could be removed from the reaction mixture, the purification procedure was simple. The recovered polymer lost the catalytic activity; however, treatment with perchloric acid activated the polymer residue so that it could be used as a catalyst. We broadened the scope and convenience of the salts.
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