Chinese Journal of Magnetic Resonance

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Structural Changes of 2-Keto-L-Gulonic Acid Studied by NMR Spectroscopy

AN Zhi-min,MA Er-qian,YANG Qiu-qing*   

  1. College of Chemistry and Material Science, Analysis and Testing Center, Hebei Normal University, Shijiazhuang 050024, China
  • Received:2013-10-11 Revised:2014-07-20 Online:2014-09-05 Published:2014-09-05
  • About author:*Corresponding author:YANG Qiu-qing, Tel: 0311-80786318,E-mail: qiuqingyang@sina.com.
  • Supported by:

    河北师范大学自然科学基金资助项目(L2011Y09).

Abstract:

2-keto-L-gulonic acid (2-KLG) changes its molecular structure in many solvents at room temperature. A five-membered intramolecular ring structure can easily be formed by the 2,5-hemiacetal reaction after the opening of the carbonyl group in 2-KLG (-C=O) to form a O-C-O interlinkage. In this study, we showed that the 13C chemical shift of the carbonyl changed from δ 200 towards high field to about δ 96 after forming the intramolecular ring. Two-dimensional HMBC experiments revealed that 2-keto-L-gulonic acid formed five-membered ring 2,5-hemiacetal derivates in seven solvents, instead of
six-membered 2,6-hemiacetal derivates.

Key words: liquid NMR, structure changes, 2D NMR, 2-keto-L-gulonic acid

CLC Number: