THE FORMATION OF 2-FURALDEHYDE AND FORMIC-ACID FROM PENTOSES IN SLIGHTLY ACIDIC DEUTERIUM-OXIDE STUDIED BY H-1-NMR SPECTROSCOPY
THE FORMATION OF 2-FURALDEHYDE AND FORMIC-ACID FROM PENTOSES IN SLIGHTLY ACIDIC DEUTERIUM-OXIDE STUDIED BY H-1-NMR SPECTROSCOPY
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DOI：
10.1016/0008-6215(95)00176-t
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发表时间：
1995-10-23
影响因子：
3.1
通讯作者：
THEANDER, O
中科院分区：
文献类型：
--
作者：
AHMAD, T;KENNE, L;THEANDER, O
在96 ° C和pD 1.5、3.0或4.5下的标题反应之后进行1H-1 NMR光谱。戊糖降解速率的顺序为：阿拉伯糖接近木糖<核糖< 2-戊酮糖。在pD1.5时，2-糠醛的形成速率在相同的cader中增加。增加pD强烈加速了醛糖的降解，但略微延缓了酮糖的降解。增加pD也延缓了2-糠醛的形成，特别是由酮糖形成，并增加了其在H-α（从8-25原子%至50-83原子%）和H-3（从79-100原子%至100原子%）处的氘含量。这可以通过假设2-糠醛主要通过无环中间体形成来解释，其中可逆地形成3-脱氧戊糖。甲酸的形成是缓慢的，并且不通过2-糠醛进行。从用1-或5-C-13-取代的戊醛糖的实验中可以明显看出，甲酸完全来自末端戊糖碳，C-1比C-5更重要。
The title reaction at 96 degrees C and pD 1.5, 3.0, or 4.5 was followed by H-1 NMR spectroscopy. The rate of pentose degradation increased in the order: arabinose approximate to xylose < ribose < 2-pentuloses. At pD 1.5, the rate of 2-furaldehyde formation increased in the same cader. Increasing pD strongly accelerated the degradation of the aldoses but slightly retarded that of the ketoses. Increasing pD also retarded the formation of 2-furaldehyde, particularly from the ketoses, and increased its deuterium content at H-alpha (from 8-25 to 50-83 atom %) and H-3 (from 79-100 to 100 atom %). This is explained by assuming that 2-furaldehyde had formed mainly via acyclic intermediates, with reversible formation of a 3-deoxypentosulose. The formation of:Formic acid was slow and did not proceed via 2-furaldehyde. As evident from experiments with 1- or 5-C-13-substituted aldopentoses, the formic acid was derived exclusively from the terminal pentose carbons, C-1 being somewhat more important than C-5.