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【答案】应助回帖
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爱与雨下(金币+2): 2011-12-12 08:35:18
hmily601(金币+80, 翻译EPI+1): xiexie谢谢你了啊！ 2011-12-12 22:11:06
Upon a review of the literature, combined with the hydrogen spectrum ends six sugar proton chemical shifts and coupling constants J, these two signals of the chemical shifts δH 5.31 (1H, d, J = 7.7 Hz) and δH 5.17 (1H, d, J = 5.5 Hz) was initially identified, which indicated that it was directly connected to the ends proto of two galactose-based segments within a parent structure of kaempferol C-3 and C-7. According to its known coupling constants [18], both of the galactose exists in a form of β-type glycosidic bond. Besides, chemical shift δH 4.90 (1H, d, J = 5.3 Hz) and δH 4.40 (1H, d, J = 7.8 Hz) of the proton is the first hydrogen which in the middle of the galactose sugar chains. From its coupling constant, both of the galactose exists also in a form of β-type glycosidic bond. In addition, chemical shift for two hydrogen signals δH 4.57 (1H, d, J = 4.5 Hz) and δH 4.53 (1H, d, J = 4.2 Hz) are corresponding to the rhamnose proton signal of branched-chain sugars ends. According to the coupling constants, they exist in a form ofα-type rhamnose glycosidic bond.
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