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[摘要]:The key precursor, N-2-(N,N-dimethylaminomethylene)-6-hydroxymethy1-8-methyl-3[2-(4-nitroph enypethyl]-7-xanthopterin (9) was efficiently prepared from 2,5-diamino-6-methylam1no-3H-pyrimidin-4-one (3) and ethyl 3-(tert-butyldimethylsilyloxy)-2-oxopropionate (11). The first synthesis of asperopterin-A (2b) was achieved by treatment of 9 with 1-O-acetyl-2,3,5-tri-O-benzoy1-beta-D-ribofuranose (15) in the presence of tin(IV) chloride, followed by removal of the protecting groups. |
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